i2c-designware: split of i2c-designware.c into core and bus specific parts

This patch splits i2c-designware.c into three pieces:
     i2c-designware-core.c, contains the code that interacts directly
     with the core.

     i2c-designware-platdrv.c, contains the code specific to the
     platform driver using the core.

     i2c-designware-core.h contains the definitions and declareations
     shared by i2c-designware-core.c and i2c-designware-platdrv.c.

This patch is the first in a set to allow multiple instances of the
designware I2C core in the system.

Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 562 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
new file mode 100644
index 00000000000..38d5a6b22a8
--- /dev/null
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -0,0 +1,562 @@
+/*
+ * Synopsys DesignWare I2C adapter driver (master only).
+ *
+ * Based on the TI DAVINCI I2C adapter driver.
+ *
+ * Copyright (C) 2006 Texas Instruments.
+ * Copyright (C) 2007 MontaVista Software Inc.
+ * Copyright (C) 2009 Provigent Ltd.
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * ----------------------------------------------------------------------------
+ *
+ */
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include "i2c-designware-core.h"
+
+static char *abort_sources[] = {
+	[ABRT_7B_ADDR_NOACK] =
+		"slave address not acknowledged (7bit mode)",
+	[ABRT_10ADDR1_NOACK] =
+		"first address byte not acknowledged (10bit mode)",
+	[ABRT_10ADDR2_NOACK] =
+		"second address byte not acknowledged (10bit mode)",
+	[ABRT_TXDATA_NOACK] =
+		"data not acknowledged",
+	[ABRT_GCALL_NOACK] =
+		"no acknowledgement for a general call",
+	[ABRT_GCALL_READ] =
+		"read after general call",
+	[ABRT_SBYTE_ACKDET] =
+		"start byte acknowledged",
+	[ABRT_SBYTE_NORSTRT] =
+		"trying to send start byte when restart is disabled",
+	[ABRT_10B_RD_NORSTRT] =
+		"trying to read when restart is disabled (10bit mode)",
+	[ABRT_MASTER_DIS] =
+		"trying to use disabled adapter",
+	[ARB_LOST] =
+		"lost arbitration",
+};
+
+u32 dw_readl(struct dw_i2c_dev *dev, int offset)
+{
+	u32 value = readl(dev->base + offset);
+
+	if (dev->swab)
+		return swab32(value);
+	else
+		return value;
+}
+
+void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)
+{
+	if (dev->swab)
+		b = swab32(b);
+
+	writel(b, dev->base + offset);
+}
+
+static u32
+i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
+{
+	/*
+	 * DesignWare I2C core doesn't seem to have solid strategy to meet
+	 * the tHD;STA timing spec.  Configuring _HCNT based on tHIGH spec
+	 * will result in violation of the tHD;STA spec.
+	 */
+	if (cond)
+		/*
+		 * Conditional expression:
+		 *
+		 *   IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH
+		 *
+		 * This is based on the DW manuals, and represents an ideal
+		 * configuration.  The resulting I2C bus speed will be
+		 * faster than any of the others.
+		 *
+		 * If your hardware is free from tHD;STA issue, try this one.
+		 */
+		return (ic_clk * tSYMBOL + 5000) / 10000 - 8 + offset;
+	else
+		/*
+		 * Conditional expression:
+		 *
+		 *   IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf)
+		 *
+		 * This is just experimental rule; the tHD;STA period turned
+		 * out to be proportinal to (_HCNT + 3).  With this setting,
+		 * we could meet both tHIGH and tHD;STA timing specs.
+		 *
+		 * If unsure, you'd better to take this alternative.
+		 *
+		 * The reason why we need to take into account "tf" here,
+		 * is the same as described in i2c_dw_scl_lcnt().
+		 */
+		return (ic_clk * (tSYMBOL + tf) + 5000) / 10000 - 3 + offset;
+}
+
+static u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
+{
+	/*
+	 * Conditional expression:
+	 *
+	 *   IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf)
+	 *
+	 * DW I2C core starts counting the SCL CNTs for the LOW period
+	 * of the SCL clock (tLOW) as soon as it pulls the SCL line.
+	 * In order to meet the tLOW timing spec, we need to take into
+	 * account the fall time of SCL signal (tf).  Default tf value
+	 * should be 0.3 us, for safety.
+	 */
+	return ((ic_clk * (tLOW + tf) + 5000) / 10000) - 1 + offset;
+}
+
+/**
+ * i2c_dw_init() - initialize the designware i2c master hardware
+ * @dev: device private data
+ *
+ * This functions configures and enables the I2C master.
+ * This function is called during I2C init function, and in case of timeout at
+ * run time.
+ */
+int i2c_dw_init(struct dw_i2c_dev *dev)
+{
+	u32 input_clock_khz = clk_get_rate(dev->clk) / 1000;
+	u32 ic_con, hcnt, lcnt;
+	u32 reg;
+
+	/* Configure register endianess access */
+	reg = dw_readl(dev, DW_IC_COMP_TYPE);
+	if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
+		dev->swab = 1;
+		reg = DW_IC_COMP_TYPE_VALUE;
+	}
+
+	if (reg != DW_IC_COMP_TYPE_VALUE) {
+		dev_err(dev->dev, "Unknown Synopsys component type: "
+			"0x%08x\n", reg);
+		return -ENODEV;
+	}
+
+	/* Disable the adapter */
+	dw_writel(dev, 0, DW_IC_ENABLE);
+
+	/* set standard and fast speed deviders for high/low periods */
+
+	/* Standard-mode */
+	hcnt = i2c_dw_scl_hcnt(input_clock_khz,
+				40,	/* tHD;STA = tHIGH = 4.0 us */
+				3,	/* tf = 0.3 us */
+				0,	/* 0: DW default, 1: Ideal */
+				0);	/* No offset */
+	lcnt = i2c_dw_scl_lcnt(input_clock_khz,
+				47,	/* tLOW = 4.7 us */
+				3,	/* tf = 0.3 us */
+				0);	/* No offset */
+	dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT);
+	dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
+	dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
+
+	/* Fast-mode */
+	hcnt = i2c_dw_scl_hcnt(input_clock_khz,
+				6,	/* tHD;STA = tHIGH = 0.6 us */
+				3,	/* tf = 0.3 us */
+				0,	/* 0: DW default, 1: Ideal */
+				0);	/* No offset */
+	lcnt = i2c_dw_scl_lcnt(input_clock_khz,
+				13,	/* tLOW = 1.3 us */
+				3,	/* tf = 0.3 us */
+				0);	/* No offset */
+	dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT);
+	dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
+	dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
+
+	/* Configure Tx/Rx FIFO threshold levels */
+	dw_writel(dev, dev->tx_fifo_depth - 1, DW_IC_TX_TL);
+	dw_writel(dev, 0, DW_IC_RX_TL);
+
+	/* configure the i2c master */
+	ic_con = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
+		DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST;
+	dw_writel(dev, ic_con, DW_IC_CON);
+	return 0;
+}
+
+/*
+ * Waiting for bus not busy
+ */
+static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
+{
+	int timeout = TIMEOUT;
+
+	while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
+		if (timeout <= 0) {
+			dev_warn(dev->dev, "timeout waiting for bus ready\n");
+			return -ETIMEDOUT;
+		}
+		timeout--;
+		mdelay(1);
+	}
+
+	return 0;
+}
+
+static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
+{
+	struct i2c_msg *msgs = dev->msgs;
+	u32 ic_con;
+
+	/* Disable the adapter */
+	dw_writel(dev, 0, DW_IC_ENABLE);
+
+	/* set the slave (target) address */
+	dw_writel(dev, msgs[dev->msg_write_idx].addr, DW_IC_TAR);
+
+	/* if the slave address is ten bit address, enable 10BITADDR */
+	ic_con = dw_readl(dev, DW_IC_CON);
+	if (msgs[dev->msg_write_idx].flags & I2C_M_TEN)
+		ic_con |= DW_IC_CON_10BITADDR_MASTER;
+	else
+		ic_con &= ~DW_IC_CON_10BITADDR_MASTER;
+	dw_writel(dev, ic_con, DW_IC_CON);
+
+	/* Enable the adapter */
+	dw_writel(dev, 1, DW_IC_ENABLE);
+
+	/* Enable interrupts */
+	dw_writel(dev, DW_IC_INTR_DEFAULT_MASK, DW_IC_INTR_MASK);
+}
+
+/*
+ * Initiate (and continue) low level master read/write transaction.
+ * This function is only called from i2c_dw_isr, and pumping i2c_msg
+ * messages into the tx buffer.  Even if the size of i2c_msg data is
+ * longer than the size of the tx buffer, it handles everything.
+ */
+void
+i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
+{
+	struct i2c_msg *msgs = dev->msgs;
+	u32 intr_mask;
+	int tx_limit, rx_limit;
+	u32 addr = msgs[dev->msg_write_idx].addr;
+	u32 buf_len = dev->tx_buf_len;
+	u8 *buf = dev->tx_buf;
+
+	intr_mask = DW_IC_INTR_DEFAULT_MASK;
+
+	for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) {
+		/*
+		 * if target address has changed, we need to
+		 * reprogram the target address in the i2c
+		 * adapter when we are done with this transfer
+		 */
+		if (msgs[dev->msg_write_idx].addr != addr) {
+			dev_err(dev->dev,
+				"%s: invalid target address\n", __func__);
+			dev->msg_err = -EINVAL;
+			break;
+		}
+
+		if (msgs[dev->msg_write_idx].len == 0) {
+			dev_err(dev->dev,
+				"%s: invalid message length\n", __func__);
+			dev->msg_err = -EINVAL;
+			break;
+		}
+
+		if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
+			/* new i2c_msg */
+			buf = msgs[dev->msg_write_idx].buf;
+			buf_len = msgs[dev->msg_write_idx].len;
+		}
+
+		tx_limit = dev->tx_fifo_depth - dw_readl(dev, DW_IC_TXFLR);
+		rx_limit = dev->rx_fifo_depth - dw_readl(dev, DW_IC_RXFLR);
+
+		while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
+			if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {
+				dw_writel(dev, 0x100, DW_IC_DATA_CMD);
+				rx_limit--;
+			} else
+				dw_writel(dev, *buf++, DW_IC_DATA_CMD);
+			tx_limit--; buf_len--;
+		}
+
+		dev->tx_buf = buf;
+		dev->tx_buf_len = buf_len;
+
+		if (buf_len > 0) {
+			/* more bytes to be written */
+			dev->status |= STATUS_WRITE_IN_PROGRESS;
+			break;
+		} else
+			dev->status &= ~STATUS_WRITE_IN_PROGRESS;
+	}
+
+	/*
+	 * If i2c_msg index search is completed, we don't need TX_EMPTY
+	 * interrupt any more.
+	 */
+	if (dev->msg_write_idx == dev->msgs_num)
+		intr_mask &= ~DW_IC_INTR_TX_EMPTY;
+
+	if (dev->msg_err)
+		intr_mask = 0;
+
+	dw_writel(dev, intr_mask,  DW_IC_INTR_MASK);
+}
+
+static void
+i2c_dw_read(struct dw_i2c_dev *dev)
+{
+	struct i2c_msg *msgs = dev->msgs;
+	int rx_valid;
+
+	for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) {
+		u32 len;
+		u8 *buf;
+
+		if (!(msgs[dev->msg_read_idx].flags & I2C_M_RD))
+			continue;
+
+		if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
+			len = msgs[dev->msg_read_idx].len;
+			buf = msgs[dev->msg_read_idx].buf;
+		} else {
+			len = dev->rx_buf_len;
+			buf = dev->rx_buf;
+		}
+
+		rx_valid = dw_readl(dev, DW_IC_RXFLR);
+
+		for (; len > 0 && rx_valid > 0; len--, rx_valid--)
+			*buf++ = dw_readl(dev, DW_IC_DATA_CMD);
+
+		if (len > 0) {
+			dev->status |= STATUS_READ_IN_PROGRESS;
+			dev->rx_buf_len = len;
+			dev->rx_buf = buf;
+			return;
+		} else
+			dev->status &= ~STATUS_READ_IN_PROGRESS;
+	}
+}
+
+static int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev)
+{
+	unsigned long abort_source = dev->abort_source;
+	int i;
+
+	if (abort_source & DW_IC_TX_ABRT_NOACK) {
+		for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
+			dev_dbg(dev->dev,
+				"%s: %s\n", __func__, abort_sources[i]);
+		return -EREMOTEIO;
+	}
+
+	for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
+		dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]);
+
+	if (abort_source & DW_IC_TX_ARB_LOST)
+		return -EAGAIN;
+	else if (abort_source & DW_IC_TX_ABRT_GCALL_READ)
+		return -EINVAL; /* wrong msgs[] data */
+	else
+		return -EIO;
+}
+
+/*
+ * Prepare controller for a transaction and call i2c_dw_xfer_msg
+ */
+int
+i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+	int ret;
+
+	dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
+
+	mutex_lock(&dev->lock);
+
+	INIT_COMPLETION(dev->cmd_complete);
+	dev->msgs = msgs;
+	dev->msgs_num = num;
+	dev->cmd_err = 0;
+	dev->msg_write_idx = 0;
+	dev->msg_read_idx = 0;
+	dev->msg_err = 0;
+	dev->status = STATUS_IDLE;
+	dev->abort_source = 0;
+
+	ret = i2c_dw_wait_bus_not_busy(dev);
+	if (ret < 0)
+		goto done;
+
+	/* start the transfers */
+	i2c_dw_xfer_init(dev);
+
+	/* wait for tx to complete */
+	ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, HZ);
+	if (ret == 0) {
+		dev_err(dev->dev, "controller timed out\n");
+		i2c_dw_init(dev);
+		ret = -ETIMEDOUT;
+		goto done;
+	} else if (ret < 0)
+		goto done;
+
+	if (dev->msg_err) {
+		ret = dev->msg_err;
+		goto done;
+	}
+
+	/* no error */
+	if (likely(!dev->cmd_err)) {
+		/* Disable the adapter */
+		dw_writel(dev, 0, DW_IC_ENABLE);
+		ret = num;
+		goto done;
+	}
+
+	/* We have an error */
+	if (dev->cmd_err == DW_IC_ERR_TX_ABRT) {
+		ret = i2c_dw_handle_tx_abort(dev);
+		goto done;
+	}
+	ret = -EIO;
+
+done:
+	mutex_unlock(&dev->lock);
+
+	return ret;
+}
+
+u32 i2c_dw_func(struct i2c_adapter *adap)
+{
+	return	I2C_FUNC_I2C |
+		I2C_FUNC_10BIT_ADDR |
+		I2C_FUNC_SMBUS_BYTE |
+		I2C_FUNC_SMBUS_BYTE_DATA |
+		I2C_FUNC_SMBUS_WORD_DATA |
+		I2C_FUNC_SMBUS_I2C_BLOCK;
+}
+
+static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
+{
+	u32 stat;
+
+	/*
+	 * The IC_INTR_STAT register just indicates "enabled" interrupts.
+	 * Ths unmasked raw version of interrupt status bits are available
+	 * in the IC_RAW_INTR_STAT register.
+	 *
+	 * That is,
+	 *   stat = dw_readl(IC_INTR_STAT);
+	 * equals to,
+	 *   stat = dw_readl(IC_RAW_INTR_STAT) & dw_readl(IC_INTR_MASK);
+	 *
+	 * The raw version might be useful for debugging purposes.
+	 */
+	stat = dw_readl(dev, DW_IC_INTR_STAT);
+
+	/*
+	 * Do not use the IC_CLR_INTR register to clear interrupts, or
+	 * you'll miss some interrupts, triggered during the period from
+	 * dw_readl(IC_INTR_STAT) to dw_readl(IC_CLR_INTR).
+	 *
+	 * Instead, use the separately-prepared IC_CLR_* registers.
+	 */
+	if (stat & DW_IC_INTR_RX_UNDER)
+		dw_readl(dev, DW_IC_CLR_RX_UNDER);
+	if (stat & DW_IC_INTR_RX_OVER)
+		dw_readl(dev, DW_IC_CLR_RX_OVER);
+	if (stat & DW_IC_INTR_TX_OVER)
+		dw_readl(dev, DW_IC_CLR_TX_OVER);
+	if (stat & DW_IC_INTR_RD_REQ)
+		dw_readl(dev, DW_IC_CLR_RD_REQ);
+	if (stat & DW_IC_INTR_TX_ABRT) {
+		/*
+		 * The IC_TX_ABRT_SOURCE register is cleared whenever
+		 * the IC_CLR_TX_ABRT is read.  Preserve it beforehand.
+		 */
+		dev->abort_source = dw_readl(dev, DW_IC_TX_ABRT_SOURCE);
+		dw_readl(dev, DW_IC_CLR_TX_ABRT);
+	}
+	if (stat & DW_IC_INTR_RX_DONE)
+		dw_readl(dev, DW_IC_CLR_RX_DONE);
+	if (stat & DW_IC_INTR_ACTIVITY)
+		dw_readl(dev, DW_IC_CLR_ACTIVITY);
+	if (stat & DW_IC_INTR_STOP_DET)
+		dw_readl(dev, DW_IC_CLR_STOP_DET);
+	if (stat & DW_IC_INTR_START_DET)
+		dw_readl(dev, DW_IC_CLR_START_DET);
+	if (stat & DW_IC_INTR_GEN_CALL)
+		dw_readl(dev, DW_IC_CLR_GEN_CALL);
+
+	return stat;
+}
+
+/*
+ * Interrupt service routine. This gets called whenever an I2C interrupt
+ * occurs.
+ */
+irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
+{
+	struct dw_i2c_dev *dev = dev_id;
+	u32 stat;
+
+	stat = i2c_dw_read_clear_intrbits(dev);
+	dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
+
+	if (stat & DW_IC_INTR_TX_ABRT) {
+		dev->cmd_err |= DW_IC_ERR_TX_ABRT;
+		dev->status = STATUS_IDLE;
+
+		/*
+		 * Anytime TX_ABRT is set, the contents of the tx/rx
+		 * buffers are flushed.  Make sure to skip them.
+		 */
+		dw_writel(dev, 0, DW_IC_INTR_MASK);
+		goto tx_aborted;
+	}
+
+	if (stat & DW_IC_INTR_RX_FULL)
+		i2c_dw_read(dev);
+
+	if (stat & DW_IC_INTR_TX_EMPTY)
+		i2c_dw_xfer_msg(dev);
+
+	/*
+	 * No need to modify or disable the interrupt mask here.
+	 * i2c_dw_xfer_msg() will take care of it according to
+	 * the current transmit status.
+	 */
+
+tx_aborted:
+	if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
+		complete(&dev->cmd_complete);
+
+	return IRQ_HANDLED;
+}