serial: Introduce new mcux lpuart shim driver

Adds a shim layer around the mcux lpuart driver to adapt it to the Zephyr
serial interface.

NXP has multiple uart hardware blocks that implement different features
and have different register maps. The k64 has a uart block called
'uart', while the kw41 has a uart block called 'lpuart' (low power
uart). The MCUXpresso SDK provides separate drivers for each type of
uart block but with similar software interfaces. As a result, there are
also separate shim drivers in Zephyr. There is a 1:1:1 relationship
between hardware block, mcux driver, and mcux shim driver.

Because we now have two mcux shim drivers for the uart interface, a new
naming convention is created:

	<interface>_mcux_<hw block>

Where <interface> is the name of the Zephyr interface, in this case
'uart'. This convention is not new.

<hw block> is the name of the NXP hardware block, in this case 'lpuart'.
This is the new part, and distinguishes different hardware blocks
for the same interface.

Change-Id: I3a80b9bffa116bbb2b02ee950d4bdd79a19a4edc
Signed-off-by: Maureen Helm <maureen.helm@nxp.com>

4 files changed, 350 insertions, 0 deletions

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 3e404f0bb..4ab911ccc 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -59,6 +59,8 @@ source "drivers/serial/Kconfig.ns16550"
 
 source "drivers/serial/Kconfig.mcux"
 
+source "drivers/serial/Kconfig.mcux_lpuart"
+
 source "drivers/serial/Kconfig.stellaris"
 
 source "drivers/serial/Kconfig.nsim"
diff --git a/drivers/serial/Kconfig.mcux_lpuart b/drivers/serial/Kconfig.mcux_lpuart
new file mode 100644
index 000000000..36dfb9c68
--- /dev/null
+++ b/drivers/serial/Kconfig.mcux_lpuart
@@ -0,0 +1,40 @@
+# Kconfig - MCUXpresso SDK LPUART
+#
+# Copyright (c) 2017, NXP
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+menuconfig UART_MCUX_LPUART
+	bool "MCUX LPUART driver"
+	depends on HAS_MCUX && HAS_LPUART
+	default n
+	select SERIAL_HAS_DRIVER
+	help
+	  Enable the MCUX LPUART driver.
+
+if UART_MCUX_LPUART
+
+menuconfig UART_MCUX_LPUART_0
+	bool "UART 0"
+	default n
+	help
+	  Enable UART 0.
+
+if UART_MCUX_LPUART_0
+
+config UART_MCUX_LPUART_0_NAME
+	string "UART 0 driver name"
+	default "UART_0"
+
+config UART_MCUX_LPUART_0_IRQ_PRI
+	int "UART 0 interrupt priority"
+	default 0
+
+config UART_MCUX_LPUART_0_BAUD_RATE
+	int "UART 0 baud rate"
+	default 115200
+
+endif # UART_MCUX_LPUART_0
+
+endif # UART_MCUX_LPUART
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 7aaa48f35..17ce4af93 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -3,6 +3,7 @@ ccflags-y +=-I$(srctree)/drivers
 
 obj-$(CONFIG_UART_NS16550)	+= uart_ns16550.o
 obj-$(CONFIG_UART_MCUX)		+= uart_mcux.o
+obj-$(CONFIG_UART_MCUX_LPUART)	+= uart_mcux_lpuart.o
 obj-$(CONFIG_UART_STELLARIS)	+= uart_stellaris.o
 obj-$(CONFIG_UART_NSIM)		+= uart_nsim.o
 obj-$(CONFIG_UART_ATMEL_SAM3)	+= uart_atmel_sam3.o
diff --git a/drivers/serial/uart_mcux_lpuart.c b/drivers/serial/uart_mcux_lpuart.c
new file mode 100644
index 000000000..133c22f6b
--- /dev/null
+++ b/drivers/serial/uart_mcux_lpuart.c
@@ -0,0 +1,307 @@
+/*
+ * Copyright (c) 2017, NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <errno.h>
+#include <device.h>
+#include <uart.h>
+#include <fsl_lpuart.h>
+#include <fsl_clock.h>
+#include <soc.h>
+
+struct mcux_lpuart_config {
+	LPUART_Type *base;
+	clock_name_t clock_source;
+	uint32_t baud_rate;
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+	void (*irq_config_func)(struct device *dev);
+#endif
+};
+
+struct mcux_lpuart_data {
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+	uart_irq_callback_t callback;
+#endif
+};
+
+static int mcux_lpuart_poll_in(struct device *dev, unsigned char *c)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t flags = LPUART_GetStatusFlags(config->base);
+	int ret = -1;
+
+	if (flags & kLPUART_RxDataRegFullFlag) {
+		*c = LPUART_ReadByte(config->base);
+		ret = 0;
+	}
+
+	return ret;
+}
+
+static unsigned char mcux_lpuart_poll_out(struct device *dev, unsigned char c)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+
+	while (!(LPUART_GetStatusFlags(config->base)
+		& kLPUART_TxDataRegEmptyFlag))
+		;
+
+	LPUART_WriteByte(config->base, c);
+
+	return c;
+}
+
+static int mcux_lpuart_err_check(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t flags = LPUART_GetStatusFlags(config->base);
+	int err = 0;
+
+	if (flags & kLPUART_RxOverrunFlag) {
+		err |= UART_ERROR_OVERRUN;
+	}
+
+	if (flags & kLPUART_ParityErrorFlag) {
+		err |= UART_ERROR_PARITY;
+	}
+
+	if (flags & kLPUART_FramingErrorFlag) {
+		err |= UART_ERROR_FRAMING;
+	}
+
+	LPUART_ClearStatusFlags(config->base, kLPUART_RxOverrunFlag |
+					      kLPUART_ParityErrorFlag |
+					      kLPUART_FramingErrorFlag);
+
+	return err;
+}
+
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+static int mcux_lpuart_fifo_fill(struct device *dev, const uint8_t *tx_data,
+			       int len)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint8_t num_tx = 0;
+
+	while ((len - num_tx > 0) &&
+	       (LPUART_GetStatusFlags(config->base)
+		& kLPUART_TxDataRegEmptyFlag)) {
+
+		LPUART_WriteByte(config->base, tx_data[num_tx++]);
+	}
+
+	return num_tx;
+}
+
+static int mcux_lpuart_fifo_read(struct device *dev, uint8_t *rx_data,
+			       const int len)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint8_t num_rx = 0;
+
+	while ((len - num_rx > 0) &&
+	       (LPUART_GetStatusFlags(config->base)
+		& kLPUART_RxDataRegFullFlag)) {
+
+		rx_data[num_rx++] = LPUART_ReadByte(config->base);
+	}
+
+	return num_rx;
+}
+
+static void mcux_lpuart_irq_tx_enable(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t mask = kLPUART_TxDataRegEmptyInterruptEnable;
+
+	LPUART_EnableInterrupts(config->base, mask);
+}
+
+static void mcux_lpuart_irq_tx_disable(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t mask = kLPUART_TxDataRegEmptyInterruptEnable;
+
+	LPUART_DisableInterrupts(config->base, mask);
+}
+
+static int mcux_lpuart_irq_tx_empty(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t flags = LPUART_GetStatusFlags(config->base);
+
+	return (flags & kLPUART_TxDataRegEmptyFlag) != 0;
+}
+
+static int mcux_lpuart_irq_tx_ready(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t mask = kLPUART_TxDataRegEmptyInterruptEnable;
+
+	return (LPUART_GetEnabledInterrupts(config->base) & mask)
+		&& mcux_lpuart_irq_tx_empty(dev);
+}
+
+static void mcux_lpuart_irq_rx_enable(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t mask = kLPUART_RxDataRegFullInterruptEnable;
+
+	LPUART_EnableInterrupts(config->base, mask);
+}
+
+static void mcux_lpuart_irq_rx_disable(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t mask = kLPUART_RxDataRegFullInterruptEnable;
+
+	LPUART_DisableInterrupts(config->base, mask);
+}
+
+static int mcux_lpuart_irq_rx_full(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t flags = LPUART_GetStatusFlags(config->base);
+
+	return (flags & kLPUART_RxDataRegFullFlag) != 0;
+}
+
+static int mcux_lpuart_irq_rx_ready(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t mask = kLPUART_RxDataRegFullInterruptEnable;
+
+	return (LPUART_GetEnabledInterrupts(config->base) & mask)
+		&& mcux_lpuart_irq_rx_full(dev);
+}
+
+static void mcux_lpuart_irq_err_enable(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t mask = kLPUART_NoiseErrorInterruptEnable |
+			kLPUART_FramingErrorInterruptEnable |
+			kLPUART_ParityErrorInterruptEnable;
+
+	LPUART_EnableInterrupts(config->base, mask);
+}
+
+static void mcux_lpuart_irq_err_disable(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	uint32_t mask = kLPUART_NoiseErrorInterruptEnable |
+			kLPUART_FramingErrorInterruptEnable |
+			kLPUART_ParityErrorInterruptEnable;
+
+	LPUART_DisableInterrupts(config->base, mask);
+}
+
+static int mcux_lpuart_irq_is_pending(struct device *dev)
+{
+	return (mcux_lpuart_irq_tx_ready(dev)
+		|| mcux_lpuart_irq_rx_ready(dev));
+}
+
+static int mcux_lpuart_irq_update(struct device *dev)
+{
+	return 1;
+}
+
+static void mcux_lpuart_irq_callback_set(struct device *dev,
+				       uart_irq_callback_t cb)
+{
+	struct mcux_lpuart_data *data = dev->driver_data;
+
+	data->callback = cb;
+}
+
+static void mcux_lpuart_isr(void *arg)
+{
+	struct device *dev = arg;
+	struct mcux_lpuart_data *data = dev->driver_data;
+
+	if (data->callback) {
+		data->callback(dev);
+	}
+}
+#endif /* CONFIG_UART_INTERRUPT_DRIVEN */
+
+static int mcux_lpuart_init(struct device *dev)
+{
+	const struct mcux_lpuart_config *config = dev->config->config_info;
+	lpuart_config_t uart_config;
+	uint32_t clock_freq;
+
+	clock_freq = CLOCK_GetFreq(config->clock_source);
+
+	LPUART_GetDefaultConfig(&uart_config);
+	uart_config.enableTx = true;
+	uart_config.enableRx = true;
+	uart_config.baudRate_Bps = config->baud_rate;
+
+	LPUART_Init(config->base, &uart_config, clock_freq);
+
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+	config->irq_config_func(dev);
+#endif
+
+	return 0;
+}
+
+static const struct uart_driver_api mcux_lpuart_driver_api = {
+	.poll_in = mcux_lpuart_poll_in,
+	.poll_out = mcux_lpuart_poll_out,
+	.err_check = mcux_lpuart_err_check,
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+	.fifo_fill = mcux_lpuart_fifo_fill,
+	.fifo_read = mcux_lpuart_fifo_read,
+	.irq_tx_enable = mcux_lpuart_irq_tx_enable,
+	.irq_tx_disable = mcux_lpuart_irq_tx_disable,
+	.irq_tx_empty = mcux_lpuart_irq_tx_empty,
+	.irq_tx_ready = mcux_lpuart_irq_tx_ready,
+	.irq_rx_enable = mcux_lpuart_irq_rx_enable,
+	.irq_rx_disable = mcux_lpuart_irq_rx_disable,
+	.irq_rx_ready = mcux_lpuart_irq_rx_ready,
+	.irq_err_enable = mcux_lpuart_irq_err_enable,
+	.irq_err_disable = mcux_lpuart_irq_err_disable,
+	.irq_is_pending = mcux_lpuart_irq_is_pending,
+	.irq_update = mcux_lpuart_irq_update,
+	.irq_callback_set = mcux_lpuart_irq_callback_set,
+#endif
+};
+
+#ifdef CONFIG_UART_MCUX_LPUART_0
+
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+static void mcux_lpuart_config_func_0(struct device *dev);
+#endif
+
+static const struct mcux_lpuart_config mcux_lpuart_0_config = {
+	.base = LPUART0,
+	.clock_source = LPUART0_CLK_SRC,
+	.baud_rate = CONFIG_UART_MCUX_LPUART_0_BAUD_RATE,
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+	.irq_config_func = mcux_lpuart_config_func_0,
+#endif
+};
+
+static struct mcux_lpuart_data mcux_lpuart_0_data;
+
+DEVICE_AND_API_INIT(uart_0, CONFIG_UART_MCUX_LPUART_0_NAME,
+		    &mcux_lpuart_init,
+		    &mcux_lpuart_0_data, &mcux_lpuart_0_config,
+		    PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
+		    &mcux_lpuart_driver_api);
+
+#ifdef CONFIG_UART_INTERRUPT_DRIVEN
+static void mcux_lpuart_config_func_0(struct device *dev)
+{
+	IRQ_CONNECT(IRQ_LPUART0, CONFIG_UART_MCUX_LPUART_0_IRQ_PRI,
+		    mcux_lpuart_isr, DEVICE_GET(uart_0), 0);
+
+	irq_enable(IRQ_LPUART0);
+}
+#endif
+
+#endif /* CONFIG_UART_MCUX_LPUART_0 */