Merge remote-tracking branch 'spi/for-next'

19 files changed, 1343 insertions, 137 deletions

diff --git a/Documentation/devicetree/bindings/spi/sh-msiof.txt b/Documentation/devicetree/bindings/spi/sh-msiof.txt
index dc975064fa27..64ee489571c4 100644
--- a/Documentation/devicetree/bindings/spi/sh-msiof.txt
+++ b/Documentation/devicetree/bindings/spi/sh-msiof.txt
@@ -38,6 +38,8 @@ Optional properties:
 			 specifiers, one for transmission, and one for
 			 reception.
 - dma-names            : Must contain a list of two DMA names, "tx" and "rx".
+- spi-slave            : Empty property indicating the SPI controller is used
+			 in slave mode.
 - renesas,dtdl         : delay sync signal (setup) in transmit mode.
 			 Must contain one of the following values:
 			 0   (no bit delay)
diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
index 4b1d6e74c744..1f6e86f787ef 100644
--- a/Documentation/devicetree/bindings/spi/spi-bus.txt
+++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
@@ -1,17 +1,23 @@
 SPI (Serial Peripheral Interface) busses
 
-SPI busses can be described with a node for the SPI master device
-and a set of child nodes for each SPI slave on the bus.  For this
-discussion, it is assumed that the system's SPI controller is in
-SPI master mode.  This binding does not describe SPI controllers
-in slave mode.
+SPI busses can be described with a node for the SPI controller device
+and a set of child nodes for each SPI slave on the bus.  The system's SPI
+controller may be described for use in SPI master mode or in SPI slave mode,
+but not for both at the same time.
 
-The SPI master node requires the following properties:
+The SPI controller node requires the following properties:
+- compatible      - Name of SPI bus controller following generic names
+		    recommended practice.
+
+In master mode, the SPI controller node requires the following additional
+properties:
 - #address-cells  - number of cells required to define a chip select
 		address on the SPI bus.
 - #size-cells     - should be zero.
-- compatible      - name of SPI bus controller following generic names
-		recommended practice.
+
+In slave mode, the SPI controller node requires one additional property:
+- spi-slave       - Empty property.
+
 No other properties are required in the SPI bus node.  It is assumed
 that a driver for an SPI bus device will understand that it is an SPI bus.
 However, the binding does not attempt to define the specific method for
@@ -21,7 +27,7 @@ assumption that board specific platform code will be used to manage
 chip selects.  Individual drivers can define additional properties to
 support describing the chip select layout.
 
-Optional properties:
+Optional properties (master mode only):
 - cs-gpios	  - gpios chip select.
 - num-cs	  - total number of chipselects.
 
@@ -41,28 +47,36 @@ cs1 : native
 cs2 : &gpio1 1 0
 cs3 : &gpio1 2 0
 
-SPI slave nodes must be children of the SPI master node and can
-contain the following properties.
-- reg             - (required) chip select address of device.
-- compatible      - (required) name of SPI device following generic names
-		recommended practice.
-- spi-max-frequency - (required) Maximum SPI clocking speed of device in Hz.
-- spi-cpol        - (optional) Empty property indicating device requires
-		inverse clock polarity (CPOL) mode.
-- spi-cpha        - (optional) Empty property indicating device requires
-		shifted clock phase (CPHA) mode.
-- spi-cs-high     - (optional) Empty property indicating device requires
-		chip select active high.
-- spi-3wire       - (optional) Empty property indicating device requires
-		3-wire mode.
-- spi-lsb-first   - (optional) Empty property indicating device requires
-		LSB first mode.
-- spi-tx-bus-width - (optional) The bus width (number of data wires) that is
-                      used for MOSI. Defaults to 1 if not present.
-- spi-rx-bus-width - (optional) The bus width (number of data wires) that is
-                      used for MISO. Defaults to 1 if not present.
-- spi-rx-delay-us  - (optional) Microsecond delay after a read transfer.
-- spi-tx-delay-us  - (optional) Microsecond delay after a write transfer.
+
+SPI slave nodes must be children of the SPI controller node.
+
+In master mode, one or more slave nodes (up to the number of chip selects) can
+be present.  Required properties are:
+- compatible      - Name of SPI device following generic names recommended
+		    practice.
+- reg             - Chip select address of device.
+- spi-max-frequency - Maximum SPI clocking speed of device in Hz.
+
+In slave mode, the (single) slave node is optional.
+If present, it must be called "slave".  Required properties are:
+- compatible      - Name of SPI device following generic names recommended
+		    practice.
+
+All slave nodes can contain the following optional properties:
+- spi-cpol        - Empty property indicating device requires inverse clock
+		    polarity (CPOL) mode.
+- spi-cpha        - Empty property indicating device requires shifted clock
+		    phase (CPHA) mode.
+- spi-cs-high     - Empty property indicating device requires chip select
+		    active high.
+- spi-3wire       - Empty property indicating device requires 3-wire mode.
+- spi-lsb-first   - Empty property indicating device requires LSB first mode.
+- spi-tx-bus-width - The bus width (number of data wires) that is used for MOSI.
+		    Defaults to 1 if not present.
+- spi-rx-bus-width - The bus width (number of data wires) that is used for MISO.
+		    Defaults to 1 if not present.
+- spi-rx-delay-us - Microsecond delay after a read transfer.
+- spi-tx-delay-us - Microsecond delay after a write transfer.
 
 Some SPI controllers and devices support Dual and Quad SPI transfer mode.
 It allows data in the SPI system to be transferred using 2 wires (DUAL) or 4
diff --git a/Documentation/devicetree/bindings/spi/spi-meson.txt b/Documentation/devicetree/bindings/spi/spi-meson.txt
index dc6d0313324a..825c39cae74a 100644
--- a/Documentation/devicetree/bindings/spi/spi-meson.txt
+++ b/Documentation/devicetree/bindings/spi/spi-meson.txt
@@ -20,3 +20,34 @@ Required properties:
 		#address-cells = <1>;
 		#size-cells = <0>;
 	};
+
+* SPICC (SPI Communication Controller)
+
+The Meson SPICC is generic SPI controller for general purpose Full-Duplex
+communications with dedicated 16 words RX/TX PIO FIFOs.
+
+Required properties:
+ - compatible: should be "amlogic,meson-gx-spicc" on Amlogic GX SoCs.
+ - reg: physical base address and length of the controller registers
+ - interrupts: The interrupt specifier
+ - clock-names: Must contain "core"
+ - clocks: phandle of the input clock for the baud rate generator
+ - #address-cells: should be 1
+ - #size-cells: should be 0
+
+Optional properties:
+ - resets: phandle of the internal reset line
+
+See ../spi/spi-bus.txt for more details on SPI bus master and slave devices
+required and optional properties.
+
+Example :
+	spi@c1108d80 {
+		compatible = "amlogic,meson-gx-spicc";
+		reg = <0xc1108d80 0x80>;
+		interrupts = <GIC_SPI 112 IRQ_TYPE_LEVEL_HIGH>;
+		clock-names = "core";
+		clocks = <&clk81>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};
diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary
index d1824b399b2d..1721c1b570c3 100644
--- a/Documentation/spi/spi-summary
+++ b/Documentation/spi/spi-summary
@@ -62,8 +62,8 @@ chips described as using "three wire" signaling: SCK, data, nCSx.
 (That data line is sometimes called MOMI or SISO.)
 
 Microcontrollers often support both master and slave sides of the SPI
-protocol.  This document (and Linux) currently only supports the master
-side of SPI interactions.
+protocol.  This document (and Linux) supports both the master and slave
+sides of SPI interactions.
 
 
 Who uses it?  On what kinds of systems?
@@ -154,9 +154,8 @@ control audio interfaces, present touchscreen sensors as input interfaces,
 or monitor temperature and voltage levels during industrial processing.
 And those might all be sharing the same controller driver.
 
-A "struct spi_device" encapsulates the master-side interface between
-those two types of driver.  At this writing, Linux has no slave side
-programming interface.
+A "struct spi_device" encapsulates the controller-side interface between
+those two types of drivers.
 
 There is a minimal core of SPI programming interfaces, focussing on
 using the driver model to connect controller and protocol drivers using
@@ -177,10 +176,24 @@ shows up in sysfs in several locations:
    /sys/bus/spi/drivers/D ... driver for one or more spi*.* devices
 
    /sys/class/spi_master/spiB ... symlink (or actual device node) to
-	a logical node which could hold class related state for the
-	controller managing bus "B".  All spiB.* devices share one
+	a logical node which could hold class related state for the SPI
+	master controller managing bus "B".  All spiB.* devices share one
 	physical SPI bus segment, with SCLK, MOSI, and MISO.
 
+   /sys/devices/.../CTLR/slave ... virtual file for (un)registering the
+	slave device for an SPI slave controller.
+	Writing the driver name of an SPI slave handler to this file
+	registers the slave device; writing "(null)" unregisters the slave
+	device.
+	Reading from this file shows the name of the slave device ("(null)"
+	if not registered).
+
+   /sys/class/spi_slave/spiB ... symlink (or actual device node) to
+	a logical node which could hold class related state for the SPI
+	slave controller on bus "B".  When registered, a single spiB.*
+	device is present here, possible sharing the physical SPI bus
+	segment with other SPI slave devices.
+
 Note that the actual location of the controller's class state depends
 on whether you enabled CONFIG_SYSFS_DEPRECATED or not.  At this time,
 the only class-specific state is the bus number ("B" in "spiB"), so
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 1761c9004fc1..fd1b4fdb72a4 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -393,6 +393,13 @@ config SPI_FSL_ESPI
 	  From MPC8536, 85xx platform uses the controller, and all P10xx,
 	  P20xx, P30xx,P40xx, P50xx uses this controller.
 
+config SPI_MESON_SPICC
+	tristate "Amlogic Meson SPICC controller"
+	depends on ARCH_MESON || COMPILE_TEST
+	help
+	  This enables master mode support for the SPICC (SPI communication
+	  controller) available in Amlogic Meson SoCs.
+
 config SPI_MESON_SPIFC
 	tristate "Amlogic Meson SPIFC controller"
 	depends on ARCH_MESON || COMPILE_TEST
@@ -457,6 +464,7 @@ config SPI_OMAP24XX
 
 config SPI_TI_QSPI
 	tristate "DRA7xxx QSPI controller support"
+	depends on HAS_DMA
 	depends on ARCH_OMAP2PLUS || COMPILE_TEST
 	help
 	  QSPI master controller for DRA7xxx used for flash devices.
@@ -784,6 +792,30 @@ config SPI_TLE62X0
 
 endif # SPI_MASTER
 
-# (slave support would go here)
+#
+# SLAVE side ... listening to other SPI masters
+#
+
+config SPI_SLAVE
+	bool "SPI slave protocol handlers"
+	help
+	  If your system has a slave-capable SPI controller, you can enable
+	  slave protocol handlers.
+
+if SPI_SLAVE
+
+config SPI_SLAVE_TIME
+	tristate "SPI slave handler reporting boot up time"
+	help
+	  SPI slave handler responding with the time of reception of the last
+	  SPI message.
+
+config SPI_SLAVE_SYSTEM_CONTROL
+	tristate "SPI slave handler controlling system state"
+	help
+	  SPI slave handler to allow remote control of system reboot, power
+	  off, halt, and suspend.
+
+endif # SPI_SLAVE
 
 endif # SPI
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index b375a7a89216..31dccfbb335e 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_SPI_LANTIQ_SSC)		+= spi-lantiq-ssc.o
 obj-$(CONFIG_SPI_JCORE)			+= spi-jcore.o
 obj-$(CONFIG_SPI_LM70_LLP)		+= spi-lm70llp.o
 obj-$(CONFIG_SPI_LP8841_RTC)		+= spi-lp8841-rtc.o
+obj-$(CONFIG_SPI_MESON_SPICC)		+= spi-meson-spicc.o
 obj-$(CONFIG_SPI_MESON_SPIFC)		+= spi-meson-spifc.o
 obj-$(CONFIG_SPI_MPC512x_PSC)		+= spi-mpc512x-psc.o
 obj-$(CONFIG_SPI_MPC52xx_PSC)		+= spi-mpc52xx-psc.o
@@ -105,3 +106,7 @@ obj-$(CONFIG_SPI_XILINX)		+= spi-xilinx.o
 obj-$(CONFIG_SPI_XLP)			+= spi-xlp.o
 obj-$(CONFIG_SPI_XTENSA_XTFPGA)		+= spi-xtensa-xtfpga.o
 obj-$(CONFIG_SPI_ZYNQMP_GQSPI)		+= spi-zynqmp-gqspi.o
+
+# SPI slave protocol handlers
+obj-$(CONFIG_SPI_SLAVE_TIME)		+= spi-slave-time.o
+obj-$(CONFIG_SPI_SLAVE_SYSTEM_CONTROL)	+= spi-slave-system-control.o
diff --git a/drivers/spi/spi-bcm63xx-hsspi.c b/drivers/spi/spi-bcm63xx-hsspi.c
index 5514cd02e93a..4da2d4a524ca 100644
--- a/drivers/spi/spi-bcm63xx-hsspi.c
+++ b/drivers/spi/spi-bcm63xx-hsspi.c
@@ -484,6 +484,7 @@ static const struct of_device_id bcm63xx_hsspi_of_match[] = {
 	{ .compatible = "brcm,bcm6328-hsspi", },
 	{ },
 };
+MODULE_DEVICE_TABLE(of, bcm63xx_hsspi_of_match);
 
 static struct platform_driver bcm63xx_hsspi_driver = {
 	.driver = {
diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 15201645bdc4..d89127f4a46d 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -1032,7 +1032,8 @@ static int dspi_probe(struct platform_device *pdev)
 		goto out_master_put;
 
 	if (dspi->devtype_data->trans_mode == DSPI_DMA_MODE) {
-		if (dspi_request_dma(dspi, res->start)) {
+		ret = dspi_request_dma(dspi, res->start);
+		if (ret < 0) {
 			dev_err(&pdev->dev, "can't get dma channels\n");
 			goto out_clk_put;
 		}
diff --git a/drivers/spi/spi-meson-spicc.c b/drivers/spi/spi-meson-spicc.c
new file mode 100644
index 000000000000..7f8429635502
--- /dev/null
+++ b/drivers/spi/spi-meson-spicc.c
@@ -0,0 +1,619 @@
+/*
+ * Driver for Amlogic Meson SPI communication controller (SPICC)
+ *
+ * Copyright (C) BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/reset.h>
+#include <linux/gpio.h>
+
+/*
+ * The Meson SPICC controller could support DMA based transfers, but is not
+ * implemented by the vendor code, and while having the registers documentation
+ * it has never worked on the GXL Hardware.
+ * The PIO mode is the only mode implemented, and due to badly designed HW :
+ * - all transfers are cutted in 16 words burst because the FIFO hangs on
+ *   TX underflow, and there is no TX "Half-Empty" interrupt, so we go by
+ *   FIFO max size chunk only
+ * - CS management is dumb, and goes UP between every burst, so is really a
+ *   "Data Valid" signal than a Chip Select, GPIO link should be used instead
+ *   to have a CS go down over the full transfer
+ */
+
+#define SPICC_MAX_FREQ	30000000
+#define SPICC_MAX_BURST	128
+
+/* Register Map */
+#define SPICC_RXDATA	0x00
+
+#define SPICC_TXDATA	0x04
+
+#define SPICC_CONREG	0x08
+#define SPICC_ENABLE		BIT(0)
+#define SPICC_MODE_MASTER	BIT(1)
+#define SPICC_XCH		BIT(2)
+#define SPICC_SMC		BIT(3)
+#define SPICC_POL		BIT(4)
+#define SPICC_PHA		BIT(5)
+#define SPICC_SSCTL		BIT(6)
+#define SPICC_SSPOL		BIT(7)
+#define SPICC_DRCTL_MASK	GENMASK(9, 8)
+#define SPICC_DRCTL_IGNORE	0
+#define SPICC_DRCTL_FALLING	1
+#define SPICC_DRCTL_LOWLEVEL	2
+#define SPICC_CS_MASK		GENMASK(13, 12)
+#define SPICC_DATARATE_MASK	GENMASK(18, 16)
+#define SPICC_DATARATE_DIV4	0
+#define SPICC_DATARATE_DIV8	1
+#define SPICC_DATARATE_DIV16	2
+#define SPICC_DATARATE_DIV32	3
+#define SPICC_BITLENGTH_MASK	GENMASK(24, 19)
+#define SPICC_BURSTLENGTH_MASK	GENMASK(31, 25)
+
+#define SPICC_INTREG	0x0c
+#define SPICC_TE_EN	BIT(0) /* TX FIFO Empty Interrupt */
+#define SPICC_TH_EN	BIT(1) /* TX FIFO Half-Full Interrupt */
+#define SPICC_TF_EN	BIT(2) /* TX FIFO Full Interrupt */
+#define SPICC_RR_EN	BIT(3) /* RX FIFO Ready Interrupt */
+#define SPICC_RH_EN	BIT(4) /* RX FIFO Half-Full Interrupt */
+#define SPICC_RF_EN	BIT(5) /* RX FIFO Full Interrupt */
+#define SPICC_RO_EN	BIT(6) /* RX FIFO Overflow Interrupt */
+#define SPICC_TC_EN	BIT(7) /* Transfert Complete Interrupt */
+
+#define SPICC_DMAREG	0x10
+#define SPICC_DMA_ENABLE		BIT(0)
+#define SPICC_TXFIFO_THRESHOLD_MASK	GENMASK(5, 1)
+#define SPICC_RXFIFO_THRESHOLD_MASK	GENMASK(10, 6)
+#define SPICC_READ_BURST_MASK		GENMASK(14, 11)
+#define SPICC_WRITE_BURST_MASK		GENMASK(18, 15)
+#define SPICC_DMA_URGENT		BIT(19)
+#define SPICC_DMA_THREADID_MASK		GENMASK(25, 20)
+#define SPICC_DMA_BURSTNUM_MASK		GENMASK(31, 26)
+
+#define SPICC_STATREG	0x14
+#define SPICC_TE	BIT(0) /* TX FIFO Empty Interrupt */
+#define SPICC_TH	BIT(1) /* TX FIFO Half-Full Interrupt */
+#define SPICC_TF	BIT(2) /* TX FIFO Full Interrupt */
+#define SPICC_RR	BIT(3) /* RX FIFO Ready Interrupt */
+#define SPICC_RH	BIT(4) /* RX FIFO Half-Full Interrupt */
+#define SPICC_RF	BIT(5) /* RX FIFO Full Interrupt */
+#define SPICC_RO	BIT(6) /* RX FIFO Overflow Interrupt */
+#define SPICC_TC	BIT(7) /* Transfert Complete Interrupt */
+
+#define SPICC_PERIODREG	0x18
+#define SPICC_PERIOD	GENMASK(14, 0)	/* Wait cycles */
+
+#define SPICC_TESTREG	0x1c
+#define SPICC_TXCNT_MASK	GENMASK(4, 0)	/* TX FIFO Counter */
+#define SPICC_RXCNT_MASK	GENMASK(9, 5)	/* RX FIFO Counter */
+#define SPICC_SMSTATUS_MASK	GENMASK(12, 10)	/* State Machine Status */
+#define SPICC_LBC_RO		BIT(13)	/* Loop Back Control Read-Only */
+#define SPICC_LBC_W1		BIT(14) /* Loop Back Control Write-Only */
+#define SPICC_SWAP_RO		BIT(14) /* RX FIFO Data Swap Read-Only */
+#define SPICC_SWAP_W1		BIT(15) /* RX FIFO Data Swap Write-Only */
+#define SPICC_DLYCTL_RO_MASK	GENMASK(20, 15) /* Delay Control Read-Only */
+#define SPICC_DLYCTL_W1_MASK	GENMASK(21, 16) /* Delay Control Write-Only */
+#define SPICC_FIFORST_RO_MASK	GENMASK(22, 21) /* FIFO Softreset Read-Only */
+#define SPICC_FIFORST_W1_MASK	GENMASK(23, 22) /* FIFO Softreset Write-Only */
+
+#define SPICC_DRADDR	0x20	/* Read Address of DMA */
+
+#define SPICC_DWADDR	0x24	/* Write Address of DMA */
+
+#define writel_bits_relaxed(mask, val, addr) \
+	writel_relaxed((readl_relaxed(addr) & ~(mask)) | (val), addr)
+
+#define SPICC_BURST_MAX	16
+#define SPICC_FIFO_HALF 10
+
+struct meson_spicc_device {
+	struct spi_master		*master;
+	struct platform_device		*pdev;
+	void __iomem			*base;
+	struct clk			*core;
+	struct spi_message		*message;
+	struct spi_transfer		*xfer;
+	u8				*tx_buf;
+	u8				*rx_buf;
+	unsigned int			bytes_per_word;
+	unsigned long			tx_remain;
+	unsigned long			txb_remain;
+	unsigned long			rx_remain;
+	unsigned long			rxb_remain;
+	unsigned long			xfer_remain;
+	bool				is_burst_end;
+	bool				is_last_burst;
+};
+
+static inline bool meson_spicc_txfull(struct meson_spicc_device *spicc)
+{
+	return !!FIELD_GET(SPICC_TF,
+			   readl_relaxed(spicc->base + SPICC_STATREG));
+}
+
+static inline bool meson_spicc_rxready(struct meson_spicc_device *spicc)
+{
+	return FIELD_GET(SPICC_RH | SPICC_RR | SPICC_RF_EN,
+			 readl_relaxed(spicc->base + SPICC_STATREG));
+}
+
+static inline u32 meson_spicc_pull_data(struct meson_spicc_device *spicc)
+{
+	unsigned int bytes = spicc->bytes_per_word;
+	unsigned int byte_shift = 0;
+	u32 data = 0;
+	u8 byte;
+
+	while (bytes--) {
+		byte = *spicc->tx_buf++;
+		data |= (byte & 0xff) << byte_shift;
+		byte_shift += 8;
+	}
+
+	spicc->tx_remain--;
+	return data;
+}
+
+static inline void meson_spicc_push_data(struct meson_spicc_device *spicc,
+					 u32 data)
+{
+	unsigned int bytes = spicc->bytes_per_word;
+	unsigned int byte_shift = 0;
+	u8 byte;
+
+	while (bytes--) {
+		byte = (data >> byte_shift) & 0xff;
+		*spicc->rx_buf++ = byte;
+		byte_shift += 8;
+	}
+
+	spicc->rx_remain--;
+}
+
+static inline void meson_spicc_rx(struct meson_spicc_device *spicc)
+{
+	/* Empty RX FIFO */
+	while (spicc->rx_remain &&
+	       meson_spicc_rxready(spicc))
+		meson_spicc_push_data(spicc,
+				readl_relaxed(spicc->base + SPICC_RXDATA));
+}
+
+static inline void meson_spicc_tx(struct meson_spicc_device *spicc)
+{
+	/* Fill Up TX FIFO */
+	while (spicc->tx_remain &&
+	       !meson_spicc_txfull(spicc))
+		writel_relaxed(meson_spicc_pull_data(spicc),
+			       spicc->base + SPICC_TXDATA);
+}
+
+static inline u32 meson_spicc_setup_rx_irq(struct meson_spicc_device *spicc,
+					   u32 irq_ctrl)
+{
+	if (spicc->rx_remain > SPICC_FIFO_HALF)
+		irq_ctrl |= SPICC_RH_EN;
+	else
+		irq_ctrl |= SPICC_RR_EN;
+
+	return irq_ctrl;
+}
+
+static inline void meson_spicc_setup_burst(struct meson_spicc_device *spicc,
+					   unsigned int burst_len)
+{
+	/* Setup Xfer variables */
+	spicc->tx_remain = burst_len;
+	spicc->rx_remain = burst_len;
+	spicc->xfer_remain -= burst_len * spicc->bytes_per_word;
+	spicc->is_burst_end = false;
+	if (burst_len < SPICC_BURST_MAX || !spicc->xfer_remain)
+		spicc->is_last_burst = true;
+	else
+		spicc->is_last_burst = false;
+
+	/* Setup burst length */
+	writel_bits_relaxed(SPICC_BURSTLENGTH_MASK,
+			FIELD_PREP(SPICC_BURSTLENGTH_MASK,
+				burst_len),
+			spicc->base + SPICC_CONREG);
+
+	/* Fill TX FIFO */
+	meson_spicc_tx(spicc);
+}
+
+static irqreturn_t meson_spicc_irq(int irq, void *data)
+{
+	struct meson_spicc_device *spicc = (void *) data;
+	u32 ctrl = readl_relaxed(spicc->base + SPICC_INTREG);
+	u32 stat = readl_relaxed(spicc->base + SPICC_STATREG) & ctrl;
+
+	ctrl &= ~(SPICC_RH_EN | SPICC_RR_EN);
+
+	/* Empty RX FIFO */
+	meson_spicc_rx(spicc);
+
+	/* Enable TC interrupt since we transferred everything */
+	if (!spicc->tx_remain && !spicc->rx_remain) {
+		spicc->is_burst_end = true;
+
+		/* Enable TC interrupt */
+		ctrl |= SPICC_TC_EN;
+
+		/* Reload IRQ status */
+		stat = readl_relaxed(spicc->base + SPICC_STATREG) & ctrl;
+	}
+
+	/* Check transfer complete */
+	if ((stat & SPICC_TC) && spicc->is_burst_end) {
+		unsigned int burst_len;
+
+		/* Clear TC bit */
+		writel_relaxed(SPICC_TC, spicc->base + SPICC_STATREG);
+
+		/* Disable TC interrupt */
+		ctrl &= ~SPICC_TC_EN;
+
+		if (spicc->is_last_burst) {
+			/* Disable all IRQs */
+			writel(0, spicc->base + SPICC_INTREG);
+
+			spi_finalize_current_transfer(spicc->master);
+
+			return IRQ_HANDLED;
+		}
+
+		burst_len = min_t(unsigned int,
+				  spicc->xfer_remain / spicc->bytes_per_word,
+				  SPICC_BURST_MAX);
+
+		/* Setup burst */
+		meson_spicc_setup_burst(spicc, burst_len);
+
+		/* Restart burst */
+		writel_bits_relaxed(SPICC_XCH, SPICC_XCH,
+				    spicc->base + SPICC_CONREG);
+	}
+
+	/* Setup RX interrupt trigger */
+	ctrl = meson_spicc_setup_rx_irq(spicc, ctrl);
+
+	/* Reconfigure interrupts */
+	writel(ctrl, spicc->base + SPICC_INTREG);
+
+	return IRQ_HANDLED;
+}
+
+static u32 meson_spicc_setup_speed(struct meson_spicc_device *spicc, u32 conf,
+				   u32 speed)
+{
+	unsigned long parent, value;
+	unsigned int i, div;
+
+	parent = clk_get_rate(spicc->core);
+
+	/* Find closest inferior/equal possible speed */
+	for (i = 0 ; i < 7 ; ++i) {
+		/* 2^(data_rate+2) */
+		value = parent >> (i + 2);
+
+		if (value <= speed)
+			break;
+	}
+
+	/* If provided speed it lower than max divider, use max divider */
+	if (i > 7) {
+		div = 7;
+		dev_warn_once(&spicc->pdev->dev, "unable to get close to speed %u\n",
+			      speed);
+	} else
+		div = i;
+
+	dev_dbg(&spicc->pdev->dev, "parent %lu, speed %u -> %lu (%u)\n",
+		parent, speed, value, div);
+
+	conf &= ~SPICC_DATARATE_MASK;
+	conf |= FIELD_PREP(SPICC_DATARATE_MASK, div);
+
+	return conf;
+}
+
+static void meson_spicc_setup_xfer(struct meson_spicc_device *spicc,
+				   struct spi_transfer *xfer)
+{
+	u32 conf, conf_orig;
+
+	/* Read original configuration */
+	conf = conf_orig = readl_relaxed(spicc->base + SPICC_CONREG);
+
+	/* Select closest divider */
+	conf = meson_spicc_setup_speed(spicc, conf, xfer->speed_hz);
+
+	/* Setup word width */
+	conf &= ~SPICC_BITLENGTH_MASK;
+	conf |= FIELD_PREP(SPICC_BITLENGTH_MASK,
+			   (spicc->bytes_per_word << 3) - 1);
+
+	/* Ignore if unchanged */
+	if (conf != conf_orig)
+		writel_relaxed(conf, spicc->base + SPICC_CONREG);
+}
+
+static int meson_spicc_transfer_one(struct spi_master *master,
+				    struct spi_device *spi,
+				    struct spi_transfer *xfer)
+{
+	struct meson_spicc_device *spicc = spi_master_get_devdata(master);
+	unsigned int burst_len;
+	u32 irq = 0;
+
+	/* Store current transfer */
+	spicc->xfer = xfer;
+
+	/* Setup transfer parameters */
+	spicc->tx_buf = (u8 *)xfer->tx_buf;
+	spicc->rx_buf = (u8 *)xfer->rx_buf;
+	spicc->xfer_remain = xfer->len;
+
+	/* Pre-calculate word size */
+	spicc->bytes_per_word =
+	   DIV_ROUND_UP(spicc->xfer->bits_per_word, 8);
+
+	/* Setup transfer parameters */
+	meson_spicc_setup_xfer(spicc, xfer);
+
+	burst_len = min_t(unsigned int,
+			  spicc->xfer_remain / spicc->bytes_per_word,
+			  SPICC_BURST_MAX);
+
+	meson_spicc_setup_burst(spicc, burst_len);
+
+	irq = meson_spicc_setup_rx_irq(spicc, irq);
+
+	/* Start burst */
+	writel_bits_relaxed(SPICC_XCH, SPICC_XCH, spicc->base + SPICC_CONREG);
+
+	/* Enable interrupts */
+	writel_relaxed(irq, spicc->base + SPICC_INTREG);
+
+	return 1;
+}
+
+static int meson_spicc_prepare_message(struct spi_master *master,
+				       struct spi_message *message)
+{
+	struct meson_spicc_device *spicc = spi_master_get_devdata(master);
+	struct spi_device *spi = message->spi;
+	u32 conf = 0;
+
+	/* Store current message */
+	spicc->message = message;
+
+	/* Enable Master */
+	conf |= SPICC_ENABLE;
+	conf |= SPICC_MODE_MASTER;
+
+	/* SMC = 0 */
+
+	/* Setup transfer mode */
+	if (spi->mode & SPI_CPOL)
+		conf |= SPICC_POL;
+	else
+		conf &= ~SPICC_POL;
+
+	if (spi->mode & SPI_CPHA)
+		conf |= SPICC_PHA;
+	else
+		conf &= ~SPICC_PHA;
+
+	/* SSCTL = 0 */
+
+	if (spi->mode & SPI_CS_HIGH)
+		conf |= SPICC_SSPOL;
+	else
+		conf &= ~SPICC_SSPOL;
+
+	if (spi->mode & SPI_READY)
+		conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_LOWLEVEL);
+	else
+		conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_IGNORE);
+
+	/* Select CS */
+	conf |= FIELD_PREP(SPICC_CS_MASK, spi->chip_select);
+
+	/* Default Clock rate core/4 */
+
+	/* Default 8bit word */
+	conf |= FIELD_PREP(SPICC_BITLENGTH_MASK, 8 - 1);
+
+	writel_relaxed(conf, spicc->base + SPICC_CONREG);
+
+	/* Setup no wait cycles by default */
+	writel_relaxed(0, spicc->base + SPICC_PERIODREG);
+
+	writel_bits_relaxed(BIT(24), BIT(24), spicc->base + SPICC_TESTREG);
+
+	return 0;
+}
+
+static int meson_spicc_unprepare_transfer(struct spi_master *master)
+{
+	struct meson_spicc_device *spicc = spi_master_get_devdata(master);
+
+	/* Disable all IRQs */
+	writel(0, spicc->base + SPICC_INTREG);
+
+	/* Disable controller */
+	writel_bits_relaxed(SPICC_ENABLE, 0, spicc->base + SPICC_CONREG);
+
+	device_reset_optional(&spicc->pdev->dev);
+
+	return 0;
+}
+
+static int meson_spicc_setup(struct spi_device *spi)
+{
+	int ret = 0;
+
+	if (!spi->controller_state)
+		spi->controller_state = spi_master_get_devdata(spi->master);
+	else if (gpio_is_valid(spi->cs_gpio))
+		goto out_gpio;
+	else if (spi->cs_gpio == -ENOENT)
+		return 0;
+
+	if (gpio_is_valid(spi->cs_gpio)) {
+		ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
+		if (ret) {
+			dev_err(&spi->dev, "failed to request cs gpio\n");
+			return ret;
+		}
+	}
+
+out_gpio:
+	ret = gpio_direction_output(spi->cs_gpio,
+			!(spi->mode & SPI_CS_HIGH));
+
+	return ret;
+}
+
+static void meson_spicc_cleanup(struct spi_device *spi)
+{
+	if (gpio_is_valid(spi->cs_gpio))
+		gpio_free(spi->cs_gpio);
+
+	spi->controller_state = NULL;
+}
+
+static int meson_spicc_probe(struct platform_device *pdev)
+{
+	struct spi_master *master;
+	struct meson_spicc_device *spicc;
+	struct resource *res;
+	int ret, irq, rate;
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*spicc));
+	if (!master) {
+		dev_err(&pdev->dev, "master allocation failed\n");
+		return -ENOMEM;
+	}
+	spicc = spi_master_get_devdata(master);
+	spicc->master = master;
+
+	spicc->pdev = pdev;
+	platform_set_drvdata(pdev, spicc);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	spicc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(spicc->base)) {
+		dev_err(&pdev->dev, "io resource mapping failed\n");
+		ret = PTR_ERR(spicc->base);
+		goto out_master;
+	}
+
+	/* Disable all IRQs */
+	writel_relaxed(0, spicc->base + SPICC_INTREG);
+
+	irq = platform_get_irq(pdev, 0);
+	ret = devm_request_irq(&pdev->dev, irq, meson_spicc_irq,
+			       0, NULL, spicc);
+	if (ret) {
+		dev_err(&pdev->dev, "irq request failed\n");
+		goto out_master;
+	}
+
+	spicc->core = devm_clk_get(&pdev->dev, "core");
+	if (IS_ERR(spicc->core)) {
+		dev_err(&pdev->dev, "core clock request failed\n");
+		ret = PTR_ERR(spicc->core);
+		goto out_master;
+	}
+
+	ret = clk_prepare_enable(spicc->core);
+	if (ret) {
+		dev_err(&pdev->dev, "core clock enable failed\n");
+		goto out_master;
+	}
+	rate = clk_get_rate(spicc->core);
+
+	device_reset_optional(&pdev->dev);
+
+	master->num_chipselect = 4;
+	master->dev.of_node = pdev->dev.of_node;
+	master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH;
+	master->bits_per_word_mask = SPI_BPW_MASK(32) |
+				     SPI_BPW_MASK(24) |
+				     SPI_BPW_MASK(16) |
+				     SPI_BPW_MASK(8);
+	master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
+	master->min_speed_hz = rate >> 9;
+	master->setup = meson_spicc_setup;
+	master->cleanup = meson_spicc_cleanup;
+	master->prepare_message = meson_spicc_prepare_message;
+	master->unprepare_transfer_hardware = meson_spicc_unprepare_transfer;
+	master->transfer_one = meson_spicc_transfer_one;
+
+	/* Setup max rate according to the Meson GX datasheet */
+	if ((rate >> 2) > SPICC_MAX_FREQ)
+		master->max_speed_hz = SPICC_MAX_FREQ;
+	else
+		master->max_speed_hz = rate >> 2;
+
+	ret = devm_spi_register_master(&pdev->dev, master);
+	if (!ret)
+		return 0;
+
+	dev_err(&pdev->dev, "spi master registration failed\n");
+
+out_master:
+	spi_master_put(master);
+
+	return ret;
+}
+
+static int meson_spicc_remove(struct platform_device *pdev)
+{
+	struct meson_spicc_device *spicc = platform_get_drvdata(pdev);
+
+	/* Disable SPI */
+	writel(0, spicc->base + SPICC_CONREG);
+
+	clk_disable_unprepare(spicc->core);
+
+	return 0;
+}
+
+static const struct of_device_id meson_spicc_of_match[] = {
+	{ .compatible = "amlogic,meson-gx-spicc", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, meson_spicc_of_match);
+
+static struct platform_driver meson_spicc_driver = {
+	.probe   = meson_spicc_probe,
+	.remove  = meson_spicc_remove,
+	.driver  = {
+		.name = "meson-spicc",
+		.of_match_table = of_match_ptr(meson_spicc_of_match),
+	},
+};
+
+module_platform_driver(meson_spicc_driver);
+
+MODULE_DESCRIPTION("Meson SPI Communication Controller driver");
+MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 7275223dbcd4..e048268d8ba2 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -1412,9 +1412,6 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
 		sprintf(mcspi->dma_channels[i].dma_tx_ch_name, "tx%d", i);
 	}
 
-	if (status < 0)
-		goto free_master;
-
 	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
 	pm_runtime_enable(&pdev->dev);
diff --git a/drivers/spi/spi-orion.c b/drivers/spi/spi-orion.c
index be2e87ee8b31..28fc9f161b9d 100644
--- a/drivers/spi/spi-orion.c
+++ b/drivers/spi/spi-orion.c
@@ -22,6 +22,7 @@
 #include <linux/of_device.h>
 #include <linux/clk.h>
 #include <linux/sizes.h>
+#include <linux/gpio.h>
 #include <asm/unaligned.h>
 
 #define DRIVER_NAME			"orion_spi"
@@ -320,12 +321,18 @@ orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 static void orion_spi_set_cs(struct spi_device *spi, bool enable)
 {
 	struct orion_spi *orion_spi;
+	int cs;
+
+	if (gpio_is_valid(spi->cs_gpio))
+		cs = 0;
+	else
+		cs = spi->chip_select;
 
 	orion_spi = spi_master_get_devdata(spi->master);
 
 	orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, ORION_SPI_CS_MASK);
 	orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG,
-				ORION_SPI_CS(spi->chip_select));
+				ORION_SPI_CS(cs));
 
 	/* Chip select logic is inverted from spi_set_cs */
 	if (!enable)
@@ -606,6 +613,7 @@ static int orion_spi_probe(struct platform_device *pdev)
 	master->setup = orion_spi_setup;
 	master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
 	master->auto_runtime_pm = true;
+	master->flags = SPI_MASTER_GPIO_SS;
 
 	platform_set_drvdata(pdev, master);
 
diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c
index 2ce15ca97782..c304c7167866 100644
--- a/drivers/spi/spi-sh-msiof.c
+++ b/drivers/spi/spi-sh-msiof.c
@@ -2,7 +2,8 @@
  * SuperH MSIOF SPI Master Interface
  *
  * Copyright (c) 2009 Magnus Damm
- * Copyright (C) 2014 Glider bvba
+ * Copyright (C) 2014 Renesas Electronics Corporation
+ * Copyright (C) 2014-2017 Glider bvba
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -33,7 +34,6 @@
 
 #include <asm/unaligned.h>
 
-
 struct sh_msiof_chipdata {
 	u16 tx_fifo_size;
 	u16 rx_fifo_size;
@@ -53,6 +53,7 @@ struct sh_msiof_spi_priv {
 	void *rx_dma_page;
 	dma_addr_t tx_dma_addr;
 	dma_addr_t rx_dma_addr;
+	bool slave_aborted;
 };
 
 #define TMDR1	0x00	/* Transmit Mode Register 1 */
@@ -337,7 +338,10 @@ static void sh_msiof_spi_set_pin_regs(struct sh_msiof_spi_priv *p,
 	tmp |= !cs_high << MDR1_SYNCAC_SHIFT;
 	tmp |= lsb_first << MDR1_BITLSB_SHIFT;
 	tmp |= sh_msiof_spi_get_dtdl_and_syncdl(p);
-	sh_msiof_write(p, TMDR1, tmp | MDR1_TRMD | TMDR1_PCON);
+	if (spi_controller_is_slave(p->master))
+		sh_msiof_write(p, TMDR1, tmp | TMDR1_PCON);
+	else
+		sh_msiof_write(p, TMDR1, tmp | MDR1_TRMD | TMDR1_PCON);
 	if (p->master->flags & SPI_MASTER_MUST_TX) {
 		/* These bits are reserved if RX needs TX */
 		tmp &= ~0x0000ffff;
@@ -564,17 +568,19 @@ static int sh_msiof_prepare_message(struct spi_master *master,
 
 static int sh_msiof_spi_start(struct sh_msiof_spi_priv *p, void *rx_buf)
 {
-	int ret;
+	bool slave = spi_controller_is_slave(p->master);
+	int ret = 0;
 
 	/* setup clock and rx/tx signals */
-	ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TSCKE);
+	if (!slave)
+		ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TSCKE);
 	if (rx_buf && !ret)
 		ret = sh_msiof_modify_ctr_wait(p, 0, CTR_RXE);
 	if (!ret)
 		ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TXE);
 
 	/* start by setting frame bit */
-	if (!ret)
+	if (!ret && !slave)
 		ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TFSE);
 
 	return ret;
@@ -582,20 +588,49 @@ static int sh_msiof_spi_start(struct sh_msiof_spi_priv *p, void *rx_buf)
 
 static int sh_msiof_spi_stop(struct sh_msiof_spi_priv *p, void *rx_buf)
 {
-	int ret;
+	bool slave = spi_controller_is_slave(p->master);
+	int ret = 0;
 
 	/* shut down frame, rx/tx and clock signals */
-	ret = sh_msiof_modify_ctr_wait(p, CTR_TFSE, 0);
+	if (!slave)
+		ret = sh_msiof_modify_ctr_wait(p, CTR_TFSE, 0);
 	if (!ret)
 		ret = sh_msiof_modify_ctr_wait(p, CTR_TXE, 0);
 	if (rx_buf && !ret)
 		ret = sh_msiof_modify_ctr_wait(p, CTR_RXE, 0);
-	if (!ret)
+	if (!ret && !slave)
 		ret = sh_msiof_modify_ctr_wait(p, CTR_TSCKE, 0);
 
 	return ret;
 }
 
+static int sh_msiof_slave_abort(struct spi_master *master)
+{
+	struct sh_msiof_spi_priv *p = spi_master_get_devdata(master);
+
+	p->slave_aborted = true;
+	complete(&p->done);
+	return 0;
+}
+
+static int sh_msiof_wait_for_completion(struct sh_msiof_spi_priv *p)
+{
+	if (spi_controller_is_slave(p->master)) {
+		if (wait_for_completion_interruptible(&p->done) ||
+		    p->slave_aborted) {
+			dev_dbg(&p->pdev->dev, "interrupted\n");
+			return -EINTR;
+		}
+	} else {
+		if (!wait_for_completion_timeout(&p->done, HZ)) {
+			dev_err(&p->pdev->dev, "timeout\n");
+			return -ETIMEDOUT;
+		}
+	}
+
+	return 0;
+}
+
 static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
 				  void (*tx_fifo)(struct sh_msiof_spi_priv *,
 						  const void *, int, int),
@@ -628,6 +663,7 @@ static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
 		tx_fifo(p, tx_buf, words, fifo_shift);
 
 	reinit_completion(&p->done);
+	p->slave_aborted = false;
 
 	ret = sh_msiof_spi_start(p, rx_buf);
 	if (ret) {
@@ -636,11 +672,9 @@ static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
 	}
 
 	/* wait for tx fifo to be emptied / rx fifo to be filled */
-	if (!wait_for_completion_timeout(&p->done, HZ)) {
-		dev_err(&p->pdev->dev, "PIO timeout\n");
-		ret = -ETIMEDOUT;
+	ret = sh_msiof_wait_for_completion(p);
+	if (ret)
 		goto stop_reset;
-	}
 
 	/* read rx fifo */
 	if (rx_buf)
@@ -732,6 +766,7 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx,
 	sh_msiof_write(p, IER, ier_bits);
 
 	reinit_completion(&p->done);
+	p->slave_aborted = false;
 
 	/* Now start DMA */
 	if (rx)
@@ -746,11 +781,9 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx,
 	}
 
 	/* wait for tx fifo to be emptied / rx fifo to be filled */
-	if (!wait_for_completion_timeout(&p->done, HZ)) {
-		dev_err(&p->pdev->dev, "DMA timeout\n");
-		ret = -ETIMEDOUT;
+	ret = sh_msiof_wait_for_completion(p);
+	if (ret)
 		goto stop_reset;
-	}
 
 	/* clear status bits */
 	sh_msiof_reset_str(p);
@@ -843,7 +876,8 @@ static int sh_msiof_transfer_one(struct spi_master *master,
 	int ret;
 
 	/* setup clocks (clock already enabled in chipselect()) */
-	sh_msiof_spi_set_clk_regs(p, clk_get_rate(p->clk), t->speed_hz);
+	if (!spi_controller_is_slave(p->master))
+		sh_msiof_spi_set_clk_regs(p, clk_get_rate(p->clk), t->speed_hz);
 
 	while (master->dma_tx && len > 15) {
 		/*
@@ -998,8 +1032,12 @@ static struct sh_msiof_spi_info *sh_msiof_spi_parse_dt(struct device *dev)
 	if (!info)
 		return NULL;
 
+	info->mode = of_property_read_bool(np, "spi-slave") ? MSIOF_SPI_SLAVE
+							    : MSIOF_SPI_MASTER;
+
 	/* Parse the MSIOF properties */
-	of_property_read_u32(np, "num-cs", &num_cs);
+	if (info->mode == MSIOF_SPI_MASTER)
+		of_property_read_u32(np, "num-cs", &num_cs);
 	of_property_read_u32(np, "renesas,tx-fifo-size",
 					&info->tx_fifo_override);
 	of_property_read_u32(np, "renesas,rx-fifo-size",
@@ -1159,34 +1197,40 @@ static int sh_msiof_spi_probe(struct platform_device *pdev)
 	struct spi_master *master;
 	const struct sh_msiof_chipdata *chipdata;
 	const struct of_device_id *of_id;
+	struct sh_msiof_spi_info *info;
 	struct sh_msiof_spi_priv *p;
 	int i;
 	int ret;
 
-	master = spi_alloc_master(&pdev->dev, sizeof(struct sh_msiof_spi_priv));
-	if (master == NULL)
-		return -ENOMEM;
-
-	p = spi_master_get_devdata(master);
-
-	platform_set_drvdata(pdev, p);
-	p->master = master;
-
 	of_id = of_match_device(sh_msiof_match, &pdev->dev);
 	if (of_id) {
 		chipdata = of_id->data;
-		p->info = sh_msiof_spi_parse_dt(&pdev->dev);
+		info = sh_msiof_spi_parse_dt(&pdev->dev);
 	} else {
 		chipdata = (const void *)pdev->id_entry->driver_data;
-		p->info = dev_get_platdata(&pdev->dev);
+		info = dev_get_platdata(&pdev->dev);
 	}
 
-	if (!p->info) {
+	if (!info) {
 		dev_err(&pdev->dev, "failed to obtain device info\n");
-		ret = -ENXIO;
-		goto err1;
+		return -ENXIO;
 	}
 
+	if (info->mode == MSIOF_SPI_SLAVE)
+		master = spi_alloc_slave(&pdev->dev,
+					 sizeof(struct sh_msiof_spi_priv));
+	else
+		master = spi_alloc_master(&pdev->dev,
+					  sizeof(struct sh_msiof_spi_priv));
+	if (master == NULL)
+		return -ENOMEM;
+
+	p = spi_master_get_devdata(master);
+
+	platform_set_drvdata(pdev, p);
+	p->master = master;
+	p->info = info;
+
 	init_completion(&p->done);
 
 	p->clk = devm_clk_get(&pdev->dev, NULL);
@@ -1237,6 +1281,7 @@ static int sh_msiof_spi_probe(struct platform_device *pdev)
 	master->num_chipselect = p->info->num_chipselect;
 	master->setup = sh_msiof_spi_setup;
 	master->prepare_message = sh_msiof_prepare_message;
+	master->slave_abort = sh_msiof_slave_abort;
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32);
 	master->auto_runtime_pm = true;
 	master->transfer_one = sh_msiof_transfer_one;
diff --git a/drivers/spi/spi-slave-system-control.c b/drivers/spi/spi-slave-system-control.c
new file mode 100644
index 000000000000..c0257e937995
--- /dev/null
+++ b/drivers/spi/spi-slave-system-control.c
@@ -0,0 +1,154 @@
+/*
+ * SPI slave handler controlling system state
+ *
+ * This SPI slave handler allows remote control of system reboot, power off,
+ * halt, and suspend.
+ *
+ * Copyright (C) 2016-2017 Glider bvba
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Usage (assuming /dev/spidev2.0 corresponds to the SPI master on the remote
+ * system):
+ *
+ *   # reboot='\x7c\x50'
+ *   # poweroff='\x71\x3f'
+ *   # halt='\x38\x76'
+ *   # suspend='\x1b\x1b'
+ *   # spidev_test -D /dev/spidev2.0 -p $suspend # or $reboot, $poweroff, $halt
+ */
+
+#include <linux/completion.h>
+#include <linux/module.h>
+#include <linux/reboot.h>
+#include <linux/suspend.h>
+#include <linux/spi/spi.h>
+
+/*
+ * The numbers are chosen to display something human-readable on two 7-segment
+ * displays connected to two 74HC595 shift registers
+ */
+#define CMD_REBOOT	0x7c50	/* rb */
+#define CMD_POWEROFF	0x713f	/* OF */
+#define CMD_HALT	0x3876	/* HL */
+#define CMD_SUSPEND	0x1b1b	/* ZZ */
+
+struct spi_slave_system_control_priv {
+	struct spi_device *spi;
+	struct completion finished;
+	struct spi_transfer xfer;
+	struct spi_message msg;
+	__be16 cmd;
+};
+
+static
+int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv);
+
+static void spi_slave_system_control_complete(void *arg)
+{
+	struct spi_slave_system_control_priv *priv = arg;
+	u16 cmd;
+	int ret;
+
+	if (priv->msg.status)
+		goto terminate;
+
+	cmd = be16_to_cpu(priv->cmd);
+	switch (cmd) {
+	case CMD_REBOOT:
+		dev_info(&priv->spi->dev, "Rebooting system...\n");
+		kernel_restart(NULL);
+
+	case CMD_POWEROFF:
+		dev_info(&priv->spi->dev, "Powering off system...\n");
+		kernel_power_off();
+		break;
+
+	case CMD_HALT:
+		dev_info(&priv->spi->dev, "Halting system...\n");
+		kernel_halt();
+		break;
+
+	case CMD_SUSPEND:
+		dev_info(&priv->spi->dev, "Suspending system...\n");
+		pm_suspend(PM_SUSPEND_MEM);
+		break;
+
+	default:
+		dev_warn(&priv->spi->dev, "Unknown command 0x%x\n", cmd);
+		break;
+	}
+
+	ret = spi_slave_system_control_submit(priv);
+	if (ret)
+		goto terminate;
+
+	return;
+
+terminate:
+	dev_info(&priv->spi->dev, "Terminating\n");
+	complete(&priv->finished);
+}
+
+static
+int spi_slave_system_control_submit(struct spi_slave_system_control_priv *priv)
+{
+	int ret;
+
+	spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1);
+
+	priv->msg.complete = spi_slave_system_control_complete;
+	priv->msg.context = priv;
+
+	ret = spi_async(priv->spi, &priv->msg);
+	if (ret)
+		dev_err(&priv->spi->dev, "spi_async() failed %d\n", ret);
+
+	return ret;
+}
+
+static int spi_slave_system_control_probe(struct spi_device *spi)
+{
+	struct spi_slave_system_control_priv *priv;
+	int ret;
+
+	priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->spi = spi;
+	init_completion(&priv->finished);
+	priv->xfer.rx_buf = &priv->cmd;
+	priv->xfer.len = sizeof(priv->cmd);
+
+	ret = spi_slave_system_control_submit(priv);
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, priv);
+	return 0;
+}
+
+static int spi_slave_system_control_remove(struct spi_device *spi)
+{
+	struct spi_slave_system_control_priv *priv = spi_get_drvdata(spi);
+
+	spi_slave_abort(spi);
+	wait_for_completion(&priv->finished);
+	return 0;
+}
+
+static struct spi_driver spi_slave_system_control_driver = {
+	.driver = {
+		.name	= "spi-slave-system-control",
+	},
+	.probe		= spi_slave_system_control_probe,
+	.remove		= spi_slave_system_control_remove,
+};
+module_spi_driver(spi_slave_system_control_driver);
+
+MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
+MODULE_DESCRIPTION("SPI slave handler controlling system state");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/spi/spi-slave-time.c b/drivers/spi/spi-slave-time.c
new file mode 100644
index 000000000000..f2e07a392d68
--- /dev/null
+++ b/drivers/spi/spi-slave-time.c
@@ -0,0 +1,129 @@
+/*
+ * SPI slave handler reporting uptime at reception of previous SPI message
+ *
+ * This SPI slave handler sends the time of reception of the last SPI message
+ * as two 32-bit unsigned integers in binary format and in network byte order,
+ * representing the number of seconds and fractional seconds (in microseconds)
+ * since boot up.
+ *
+ * Copyright (C) 2016-2017 Glider bvba
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Usage (assuming /dev/spidev2.0 corresponds to the SPI master on the remote
+ * system):
+ *
+ *   # spidev_test -D /dev/spidev2.0 -p dummy-8B
+ *   spi mode: 0x0
+ *   bits per word: 8
+ *   max speed: 500000 Hz (500 KHz)
+ *   RX | 00 00 04 6D 00 09 5B BB ...
+ *		^^^^^    ^^^^^^^^
+ *		seconds  microseconds
+ */
+
+#include <linux/completion.h>
+#include <linux/module.h>
+#include <linux/sched/clock.h>
+#include <linux/spi/spi.h>
+
+
+struct spi_slave_time_priv {
+	struct spi_device *spi;
+	struct completion finished;
+	struct spi_transfer xfer;
+	struct spi_message msg;
+	__be32 buf[2];
+};
+
+static int spi_slave_time_submit(struct spi_slave_time_priv *priv);
+
+static void spi_slave_time_complete(void *arg)
+{
+	struct spi_slave_time_priv *priv = arg;
+	int ret;
+
+	ret = priv->msg.status;
+	if (ret)
+		goto terminate;
+
+	ret = spi_slave_time_submit(priv);
+	if (ret)
+		goto terminate;
+
+	return;
+
+terminate:
+	dev_info(&priv->spi->dev, "Terminating\n");
+	complete(&priv->finished);
+}
+
+static int spi_slave_time_submit(struct spi_slave_time_priv *priv)
+{
+	u32 rem_us;
+	int ret;
+	u64 ts;
+
+	ts = local_clock();
+	rem_us = do_div(ts, 1000000000) / 1000;
+
+	priv->buf[0] = cpu_to_be32(ts);
+	priv->buf[1] = cpu_to_be32(rem_us);
+
+	spi_message_init_with_transfers(&priv->msg, &priv->xfer, 1);
+
+	priv->msg.complete = spi_slave_time_complete;
+	priv->msg.context = priv;
+
+	ret = spi_async(priv->spi, &priv->msg);
+	if (ret)
+		dev_err(&priv->spi->dev, "spi_async() failed %d\n", ret);
+
+	return ret;
+}
+
+static int spi_slave_time_probe(struct spi_device *spi)
+{
+	struct spi_slave_time_priv *priv;
+	int ret;
+
+	priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->spi = spi;
+	init_completion(&priv->finished);
+	priv->xfer.tx_buf = priv->buf;
+	priv->xfer.len = sizeof(priv->buf);
+
+	ret = spi_slave_time_submit(priv);
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, priv);
+	return 0;
+}
+
+static int spi_slave_time_remove(struct spi_device *spi)
+{
+	struct spi_slave_time_priv *priv = spi_get_drvdata(spi);
+
+	spi_slave_abort(spi);
+	wait_for_completion(&priv->finished);
+	return 0;
+}
+
+static struct spi_driver spi_slave_time_driver = {
+	.driver = {
+		.name	= "spi-slave-time",
+	},
+	.probe		= spi_slave_time_probe,
+	.remove		= spi_slave_time_remove,
+};
+module_spi_driver(spi_slave_time_driver);
+
+MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
+MODULE_DESCRIPTION("SPI slave reporting uptime at previous SPI message");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/spi/spi-st-ssc4.c b/drivers/spi/spi-st-ssc4.c
index e54b59638458..a4e43fc19ece 100644
--- a/drivers/spi/spi-st-ssc4.c
+++ b/drivers/spi/spi-st-ssc4.c
@@ -229,42 +229,42 @@ static int spi_st_setup(struct spi_device *spi)
 		"setting baudrate:target= %u hz, actual= %u hz, sscbrg= %u\n",
 		hz, spi_st->baud, sscbrg);
 
-	 /* Set SSC_CTL and enable SSC */
-	 var = readl_relaxed(spi_st->base + SSC_CTL);
-	 var |= SSC_CTL_MS;
+	/* Set SSC_CTL and enable SSC */
+	var = readl_relaxed(spi_st->base + SSC_CTL);
+	var |= SSC_CTL_MS;
 
-	 if (spi->mode & SPI_CPOL)
+	if (spi->mode & SPI_CPOL)
 		var |= SSC_CTL_PO;
-	 else
+	else
 		var &= ~SSC_CTL_PO;
 
-	 if (spi->mode & SPI_CPHA)
+	if (spi->mode & SPI_CPHA)
 		var |= SSC_CTL_PH;
-	 else
+	else
 		var &= ~SSC_CTL_PH;
 
-	 if ((spi->mode & SPI_LSB_FIRST) == 0)
+	if ((spi->mode & SPI_LSB_FIRST) == 0)
 		var |= SSC_CTL_HB;
-	 else
+	else
 		var &= ~SSC_CTL_HB;
 
-	 if (spi->mode & SPI_LOOP)
+	if (spi->mode & SPI_LOOP)
 		var |= SSC_CTL_LPB;
-	 else
+	else
 		var &= ~SSC_CTL_LPB;
 
-	 var &= ~SSC_CTL_DATA_WIDTH_MSK;
-	 var |= (spi->bits_per_word - 1);
+	var &= ~SSC_CTL_DATA_WIDTH_MSK;
+	var |= (spi->bits_per_word - 1);
 
-	 var |= SSC_CTL_EN_TX_FIFO | SSC_CTL_EN_RX_FIFO;
-	 var |= SSC_CTL_EN;
+	var |= SSC_CTL_EN_TX_FIFO | SSC_CTL_EN_RX_FIFO;
+	var |= SSC_CTL_EN;
 
-	 writel_relaxed(var, spi_st->base + SSC_CTL);
+	writel_relaxed(var, spi_st->base + SSC_CTL);
 
-	 /* Clear the status register */
-	 readl_relaxed(spi_st->base + SSC_RBUF);
+	/* Clear the status register */
+	readl_relaxed(spi_st->base + SSC_RBUF);
 
-	 return 0;
+	return 0;
 
 out_free_gpio:
 	gpio_free(cs);
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 89254a55eb2e..c3f6b524b3ce 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -80,7 +80,7 @@ static ssize_t spi_master_##field##_show(struct device *dev,		\
 	return spi_statistics_##field##_show(&master->statistics, buf);	\
 }									\
 static struct device_attribute dev_attr_spi_master_##field = {		\
-	.attr = { .name = file, .mode = S_IRUGO },			\
+	.attr = { .name = file, .mode = 0444 },				\
 	.show = spi_master_##field##_show,				\
 };									\
 static ssize_t spi_device_##field##_show(struct device *dev,		\
@@ -91,7 +91,7 @@ static ssize_t spi_device_##field##_show(struct device *dev,		\
 	return spi_statistics_##field##_show(&spi->statistics, buf);	\
 }									\
 static struct device_attribute dev_attr_spi_device_##field = {		\
-	.attr = { .name = file, .mode = S_IRUGO },			\
+	.attr = { .name = file, .mode = 0444 },				\
 	.show = spi_device_##field##_show,				\
 }
 
@@ -1535,15 +1535,6 @@ static int of_spi_parse_dt(struct spi_master *master, struct spi_device *spi,
 	u32 value;
 	int rc;
 
-	/* Device address */
-	rc = of_property_read_u32(nc, "reg", &value);
-	if (rc) {
-		dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
-			nc->full_name, rc);
-		return rc;
-	}
-	spi->chip_select = value;
-
 	/* Mode (clock phase/polarity/etc.) */
 	if (of_find_property(nc, "spi-cpha", NULL))
 		spi->mode |= SPI_CPHA;
@@ -1593,6 +1584,24 @@ static int of_spi_parse_dt(struct spi_master *master, struct spi_device *spi,
 		}
 	}
 
+	if (spi_controller_is_slave(master)) {
+		if (strcmp(nc->name, "slave")) {
+			dev_err(&master->dev, "%s is not called 'slave'\n",
+				nc->full_name);
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	/* Device address */
+	rc = of_property_read_u32(nc, "reg", &value);
+	if (rc) {
+		dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
+			nc->full_name, rc);
+		return rc;
+	}
+	spi->chip_select = value;
+
 	/* Device speed */
 	rc = of_property_read_u32(nc, "spi-max-frequency", &value);
 	if (rc) {
@@ -1658,8 +1667,8 @@ err_out:
  * of_register_spi_devices() - Register child devices onto the SPI bus
  * @master:	Pointer to spi_master device
  *
- * Registers an spi_device for each child node of master node which has a 'reg'
- * property.
+ * Registers an spi_device for each child node of controller node which
+ * represents a valid SPI slave.
  */
 static void of_register_spi_devices(struct spi_master *master)
 {
@@ -1828,28 +1837,129 @@ static struct class spi_master_class = {
 	.dev_groups	= spi_master_groups,
 };
 
+#ifdef CONFIG_SPI_SLAVE
+/**
+ * spi_slave_abort - abort the ongoing transfer request on an SPI slave
+ *		     controller
+ * @spi: device used for the current transfer
+ */
+int spi_slave_abort(struct spi_device *spi)
+{
+	struct spi_master *master = spi->master;
+
+	if (spi_controller_is_slave(master) && master->slave_abort)
+		return master->slave_abort(master);
+
+	return -ENOTSUPP;
+}
+EXPORT_SYMBOL_GPL(spi_slave_abort);
+
+static int match_true(struct device *dev, void *data)
+{
+	return 1;
+}
+
+static ssize_t spi_slave_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct spi_master *ctlr = container_of(dev, struct spi_master, dev);
+	struct device *child;
+
+	child = device_find_child(&ctlr->dev, NULL, match_true);
+	return sprintf(buf, "%s\n",
+		       child ? to_spi_device(child)->modalias : NULL);
+}
+
+static ssize_t spi_slave_store(struct device *dev,
+			       struct device_attribute *attr, const char *buf,
+			       size_t count)
+{
+	struct spi_master *ctlr = container_of(dev, struct spi_master, dev);
+	struct spi_device *spi;
+	struct device *child;
+	char name[32];
+	int rc;
+
+	rc = sscanf(buf, "%31s", name);
+	if (rc != 1 || !name[0])
+		return -EINVAL;
+
+	child = device_find_child(&ctlr->dev, NULL, match_true);
+	if (child) {
+		/* Remove registered slave */
+		device_unregister(child);
+		put_device(child);
+	}
+
+	if (strcmp(name, "(null)")) {
+		/* Register new slave */
+		spi = spi_alloc_device(ctlr);
+		if (!spi)
+			return -ENOMEM;
+
+		strlcpy(spi->modalias, name, sizeof(spi->modalias));
+
+		rc = spi_add_device(spi);
+		if (rc) {
+			spi_dev_put(spi);
+			return rc;
+		}
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR(slave, 0644, spi_slave_show, spi_slave_store);
+
+static struct attribute *spi_slave_attrs[] = {
+	&dev_attr_slave.attr,
+	NULL,
+};
+
+static const struct attribute_group spi_slave_group = {
+	.attrs = spi_slave_attrs,
+};
+
+static const struct attribute_group *spi_slave_groups[] = {
+	&spi_master_statistics_group,
+	&spi_slave_group,
+	NULL,
+};
+
+static struct class spi_slave_class = {
+	.name		= "spi_slave",
+	.owner		= THIS_MODULE,
+	.dev_release	= spi_master_release,
+	.dev_groups	= spi_slave_groups,
+};
+#else
+extern struct class spi_slave_class;	/* dummy */
+#endif
 
 /**
- * spi_alloc_master - allocate SPI master controller
+ * __spi_alloc_controller - allocate an SPI master or slave controller
  * @dev: the controller, possibly using the platform_bus
  * @size: how much zeroed driver-private data to allocate; the pointer to this
  *	memory is in the driver_data field of the returned device,
  *	accessible with spi_master_get_devdata().
+ * @slave: flag indicating whether to allocate an SPI master (false) or SPI
+ *	slave (true) controller
  * Context: can sleep
  *
- * This call is used only by SPI master controller drivers, which are the
+ * This call is used only by SPI controller drivers, which are the
  * only ones directly touching chip registers.  It's how they allocate
  * an spi_master structure, prior to calling spi_register_master().
  *
  * This must be called from context that can sleep.
  *
- * The caller is responsible for assigning the bus number and initializing
- * the master's methods before calling spi_register_master(); and (after errors
+ * The caller is responsible for assigning the bus number and initializing the
+ * controller's methods before calling spi_register_master(); and (after errors
  * adding the device) calling spi_master_put() to prevent a memory leak.
  *
- * Return: the SPI master structure on success, else NULL.
+ * Return: the SPI controller structure on success, else NULL.
  */
-struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
+struct spi_master *__spi_alloc_controller(struct device *dev,
+					  unsigned int size, bool slave)
 {
 	struct spi_master	*master;
 
@@ -1863,14 +1973,18 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
 	device_initialize(&master->dev);
 	master->bus_num = -1;
 	master->num_chipselect = 1;
-	master->dev.class = &spi_master_class;
+	master->slave = slave;
+	if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
+		master->dev.class = &spi_slave_class;
+	else
+		master->dev.class = &spi_master_class;
 	master->dev.parent = dev;
 	pm_suspend_ignore_children(&master->dev, true);
 	spi_master_set_devdata(master, &master[1]);
 
 	return master;
 }
-EXPORT_SYMBOL_GPL(spi_alloc_master);
+EXPORT_SYMBOL_GPL(__spi_alloc_controller);
 
 #ifdef CONFIG_OF
 static int of_spi_register_master(struct spi_master *master)
@@ -1946,9 +2060,11 @@ int spi_register_master(struct spi_master *master)
 	if (!dev)
 		return -ENODEV;
 
-	status = of_spi_register_master(master);
-	if (status)
-		return status;
+	if (!spi_controller_is_slave(master)) {
+		status = of_spi_register_master(master);
+		if (status)
+			return status;
+	}
 
 	/* even if it's just one always-selected device, there must
 	 * be at least one chipselect
@@ -1985,8 +2101,9 @@ int spi_register_master(struct spi_master *master)
 	status = device_add(&master->dev);
 	if (status < 0)
 		goto done;
-	dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
-			dynamic ? " (dynamic)" : "");
+	dev_dbg(dev, "registered %s %s%s\n",
+			spi_controller_is_slave(master) ? "slave" : "master",
+			dev_name(&master->dev), dynamic ? " (dynamic)" : "");
 
 	/* If we're using a queued driver, start the queue */
 	if (master->transfer)
@@ -2021,7 +2138,7 @@ static void devm_spi_unregister(struct device *dev, void *res)
 }
 
 /**
- * dev_spi_register_master - register managed SPI master controller
+ * devm_spi_register_master - register managed SPI master controller
  * @dev:    device managing SPI master
  * @master: initialized master, originally from spi_alloc_master()
  * Context: can sleep
@@ -3159,6 +3276,9 @@ static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
 
 	dev = class_find_device(&spi_master_class, NULL, node,
 				__spi_of_master_match);
+	if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
+		dev = class_find_device(&spi_slave_class, NULL, node,
+					__spi_of_master_match);
 	if (!dev)
 		return NULL;
 
@@ -3240,6 +3360,9 @@ static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
 
 	dev = class_find_device(&spi_master_class, NULL, adev,
 				spi_acpi_master_match);
+	if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
+		dev = class_find_device(&spi_slave_class, NULL, adev,
+					spi_acpi_master_match);
 	if (!dev)
 		return NULL;
 
@@ -3312,6 +3435,12 @@ static int __init spi_init(void)
 	if (status < 0)
 		goto err2;
 
+	if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
+		status = class_register(&spi_slave_class);
+		if (status < 0)
+			goto err3;
+	}
+
 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
 		WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
 	if (IS_ENABLED(CONFIG_ACPI))
@@ -3319,6 +3448,8 @@ static int __init spi_init(void)
 
 	return 0;
 
+err3:
+	class_unregister(&spi_master_class);
 err2:
 	bus_unregister(&spi_bus_type);
 err1:
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 9a2a79a871ba..d4d2d8d9f3e7 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -99,7 +99,6 @@ MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message");
 static ssize_t
 spidev_sync(struct spidev_data *spidev, struct spi_message *message)
 {
-	DECLARE_COMPLETION_ONSTACK(done);
 	int status;
 	struct spi_device *spi;
 
@@ -325,7 +324,6 @@ static struct spi_ioc_transfer *
 spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc,
 		unsigned *n_ioc)
 {
-	struct spi_ioc_transfer	*ioc;
 	u32	tmp;
 
 	/* Check type, command number and direction */
@@ -342,14 +340,7 @@ spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc,
 		return NULL;
 
 	/* copy into scratch area */
-	ioc = kmalloc(tmp, GFP_KERNEL);
-	if (!ioc)
-		return ERR_PTR(-ENOMEM);
-	if (__copy_from_user(ioc, u_ioc, tmp)) {
-		kfree(ioc);
-		return ERR_PTR(-EFAULT);
-	}
-	return ioc;
+	return memdup_user(u_ioc, tmp);
 }
 
 static long
diff --git a/include/linux/spi/sh_msiof.h b/include/linux/spi/sh_msiof.h
index b087a85f5f72..f74b581f242f 100644
--- a/include/linux/spi/sh_msiof.h
+++ b/include/linux/spi/sh_msiof.h
@@ -1,10 +1,16 @@
 #ifndef __SPI_SH_MSIOF_H__
 #define __SPI_SH_MSIOF_H__
 
+enum {
+	MSIOF_SPI_MASTER,
+	MSIOF_SPI_SLAVE,
+};
+
 struct sh_msiof_spi_info {
 	int tx_fifo_override;
 	int rx_fifo_override;
 	u16 num_chipselect;
+	int mode;
 	unsigned int dma_tx_id;
 	unsigned int dma_rx_id;
 	u32 dtdl;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 935bd2854ff1..0a78745e5766 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -29,8 +29,8 @@ struct spi_transfer;
 struct spi_flash_read_message;
 
 /*
- * INTERFACES between SPI master-side drivers and SPI infrastructure.
- * (There's no SPI slave support for Linux yet...)
+ * INTERFACES between SPI master-side drivers and SPI slave protocol handlers,
+ * and SPI infrastructure.
  */
 extern struct bus_type spi_bus_type;
 
@@ -311,6 +311,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
  * @min_speed_hz: Lowest supported transfer speed
  * @max_speed_hz: Highest supported transfer speed
  * @flags: other constraints relevant to this driver
+ * @slave: indicates that this is an SPI slave controller
  * @max_transfer_size: function that returns the max transfer size for
  *	a &spi_device; may be %NULL, so the default %SIZE_MAX will be used.
  * @max_message_size: function that returns the max message size for
@@ -374,6 +375,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
  * @handle_err: the subsystem calls the driver to handle an error that occurs
  *		in the generic implementation of transfer_one_message().
  * @unprepare_message: undo any work done by prepare_message().
+ * @slave_abort: abort the ongoing transfer request on an SPI slave controller
  * @spi_flash_read: to support spi-controller hardwares that provide
  *                  accelerated interface to read from flash devices.
  * @spi_flash_can_dma: analogous to can_dma() interface, but for
@@ -447,6 +449,9 @@ struct spi_master {
 #define SPI_MASTER_MUST_TX      BIT(4)		/* requires tx */
 #define SPI_MASTER_GPIO_SS      BIT(5)		/* GPIO CS must select slave */
 
+	/* flag indicating this is an SPI slave controller */
+	bool			slave;
+
 	/*
 	 * on some hardware transfer / message size may be constrained
 	 * the limit may depend on device transfer settings
@@ -539,6 +544,7 @@ struct spi_master {
 			       struct spi_message *message);
 	int (*unprepare_message)(struct spi_master *master,
 				 struct spi_message *message);
+	int (*slave_abort)(struct spi_master *spi);
 	int (*spi_flash_read)(struct  spi_device *spi,
 			      struct spi_flash_read_message *msg);
 	bool (*spi_flash_can_dma)(struct spi_device *spi,
@@ -595,6 +601,11 @@ static inline void spi_master_put(struct spi_master *master)
 		put_device(&master->dev);
 }
 
+static inline bool spi_controller_is_slave(struct spi_master *ctlr)
+{
+	return IS_ENABLED(CONFIG_SPI_SLAVE) && ctlr->slave;
+}
+
 /* PM calls that need to be issued by the driver */
 extern int spi_master_suspend(struct spi_master *master);
 extern int spi_master_resume(struct spi_master *master);
@@ -605,8 +616,23 @@ extern void spi_finalize_current_message(struct spi_master *master);
 extern void spi_finalize_current_transfer(struct spi_master *master);
 
 /* the spi driver core manages memory for the spi_master classdev */
-extern struct spi_master *
-spi_alloc_master(struct device *host, unsigned size);
+extern struct spi_master *__spi_alloc_controller(struct device *host,
+						 unsigned int size, bool slave);
+
+static inline struct spi_master *spi_alloc_master(struct device *host,
+						  unsigned int size)
+{
+	return __spi_alloc_controller(host, size, false);
+}
+
+static inline struct spi_master *spi_alloc_slave(struct device *host,
+						 unsigned int size)
+{
+	if (!IS_ENABLED(CONFIG_SPI_SLAVE))
+		return NULL;
+
+	return __spi_alloc_controller(host, size, true);
+}
 
 extern int spi_register_master(struct spi_master *master);
 extern int devm_spi_register_master(struct device *dev,
@@ -912,6 +938,7 @@ extern int spi_setup(struct spi_device *spi);
 extern int spi_async(struct spi_device *spi, struct spi_message *message);
 extern int spi_async_locked(struct spi_device *spi,
 			    struct spi_message *message);
+extern int spi_slave_abort(struct spi_device *spi);
 
 static inline size_t
 spi_max_message_size(struct spi_device *spi)