drivers: i2c: mcux: lpi2c: add bus recovery support

Add I2C bus recovery support to the NXP MCUX LPI2C driver. Since the LPI2C
peripheral block does not natively support I2C bus recovery, recovery is
performed using GPIO bitbanging.

Fixes: #42574

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>

drivers/i2c/Kconfig

@@ -107,6 +107,13 @@ config I2C_MCUX_LPI2C
 	help
 	  Enable the mcux LPI2C driver.
 
+config I2C_MCUX_LPI2C_BUS_RECOVERY
+	bool "Bus recovery support"
+	depends on I2C_MCUX_LPI2C && PINCTRL
+	select I2C_BITBANG
+	help
+	  Enable LPI2C driver bus recovery support via GPIO bitbanging.
+
 config I2C_IMX
 	bool "i.MX I2C driver"
 	depends on HAS_IMX_I2C

drivers/i2c/i2c_mcux_lpi2c.c

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2016 Freescale Semiconductor, Inc.
  * Copyright (c) 2019, NXP
+ * Copyright (c) 2022 Vestas Wind Systems A/S
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -16,6 +17,11 @@
 #include <zephyr/drivers/pinctrl.h>
 #endif /* CONFIG_PINCTRL */
 
+#ifdef CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY
+#include "i2c_bitbang.h"
+#include <zephyr/drivers/gpio.h>
+#endif /* CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY */
+
 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(mcux_lpi2c);
 
@@ -36,6 +42,10 @@ struct mcux_lpi2c_config {
 #ifdef CONFIG_PINCTRL
 	const struct pinctrl_dev_config *pincfg;
 #endif /* CONFIG_PINCTRL */
+#ifdef CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY
+	struct gpio_dt_spec scl;
+	struct gpio_dt_spec sda;
+#endif /* CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY */
 };
 
 struct mcux_lpi2c_data {
@@ -202,6 +212,89 @@ static int mcux_lpi2c_transfer(const struct device *dev, struct i2c_msg *msgs,
 	return ret;
 }
 
+#if CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY
+static void mcux_lpi2c_bitbang_set_scl(void *io_context, int state)
+{
+	const struct mcux_lpi2c_config *config = io_context;
+
+	gpio_pin_set_dt(&config->scl, state);
+}
+
+static void mcux_lpi2c_bitbang_set_sda(void *io_context, int state)
+{
+	const struct mcux_lpi2c_config *config = io_context;
+
+	gpio_pin_set_dt(&config->sda, state);
+}
+
+static int mcux_lpi2c_bitbang_get_sda(void *io_context)
+{
+	const struct mcux_lpi2c_config *config = io_context;
+
+	return gpio_pin_get_dt(&config->sda) == 0 ? 0 : 1;
+}
+
+static int mcux_lpi2c_recover_bus(const struct device *dev)
+{
+	const struct mcux_lpi2c_config *config = dev->config;
+	struct mcux_lpi2c_data *data = dev->data;
+	struct i2c_bitbang bitbang_ctx;
+	struct i2c_bitbang_io bitbang_io = {
+		.set_scl = mcux_lpi2c_bitbang_set_scl,
+		.set_sda = mcux_lpi2c_bitbang_set_sda,
+		.get_sda = mcux_lpi2c_bitbang_get_sda,
+	};
+	uint32_t bitrate_cfg;
+	int error = 0;
+
+	if (!device_is_ready(config->scl.port)) {
+		LOG_ERR("SCL GPIO device not ready");
+		return -EIO;
+	}
+
+	if (!device_is_ready(config->sda.port)) {
+		LOG_ERR("SDA GPIO device not ready");
+		return -EIO;
+	}
+
+	k_sem_take(&data->lock, K_FOREVER);
+
+	error = gpio_pin_configure_dt(&config->scl, GPIO_OUTPUT_HIGH);
+	if (error != 0) {
+		LOG_ERR("failed to configure SCL GPIO (err %d)", error);
+		goto restore;
+	}
+
+	error = gpio_pin_configure_dt(&config->sda, GPIO_OUTPUT_HIGH);
+	if (error != 0) {
+		LOG_ERR("failed to configure SDA GPIO (err %d)", error);
+		goto restore;
+	}
+
+	i2c_bitbang_init(&bitbang_ctx, &bitbang_io, (void *)config);
+
+	bitrate_cfg = i2c_map_dt_bitrate(config->bitrate) | I2C_MODE_MASTER;
+	error = i2c_bitbang_configure(&bitbang_ctx, bitrate_cfg);
+	if (error != 0) {
+		LOG_ERR("failed to configure I2C bitbang (err %d)", error);
+		goto restore;
+	}
+
+	error = i2c_bitbang_recover_bus(&bitbang_ctx);
+	if (error != 0) {
+		LOG_ERR("failed to recover bus (err %d)", error);
+		goto restore;
+	}
+
+restore:
+	(void)pinctrl_apply_state(config->pincfg, PINCTRL_STATE_DEFAULT);
+
+	k_sem_give(&data->lock);
+
+	return error;
+}
+#endif /* CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY */
+
 static void mcux_lpi2c_isr(const struct device *dev)
 {
 	const struct mcux_lpi2c_config *config = dev->config;
@@ -256,6 +349,9 @@ static int mcux_lpi2c_init(const struct device *dev)
 static const struct i2c_driver_api mcux_lpi2c_driver_api = {
 	.configure = mcux_lpi2c_configure,
 	.transfer = mcux_lpi2c_transfer,
+#if CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY
+	.recover_bus = mcux_lpi2c_recover_bus,
+#endif /* CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY */
 };
 
 #ifdef CONFIG_PINCTRL
@@ -266,6 +362,14 @@ static const struct i2c_driver_api mcux_lpi2c_driver_api = {
 #define I2C_MCUX_LPI2C_PINCTRL_INIT(n)
 #endif /* CONFIG_PINCTRL */
 
+#if CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY
+#define I2C_MCUX_LPI2C_SCL_INIT(n) .scl = GPIO_DT_SPEC_INST_GET_OR(n, scl_gpios, {0}),
+#define I2C_MCUX_LPI2C_SDA_INIT(n) .sda = GPIO_DT_SPEC_INST_GET_OR(n, sda_gpios, {0}),
+#else
+#define I2C_MCUX_LPI2C_SCL_INIT(n)
+#define I2C_MCUX_LPI2C_SDA_INIT(n)
+#endif /* CONFIG_I2C_MCUX_LPI2C_BUS_RECOVERY */
+
 #define I2C_MCUX_LPI2C_INIT(n)						\
 	I2C_MCUX_LPI2C_PINCTRL_DEFINE(n)				\
 									\
@@ -279,6 +383,8 @@ static const struct i2c_driver_api mcux_lpi2c_driver_api = {
 		.irq_config_func = mcux_lpi2c_config_func_##n,		\
 		.bitrate = DT_INST_PROP(n, clock_frequency),		\
 		I2C_MCUX_LPI2C_PINCTRL_INIT(n)				\
+		I2C_MCUX_LPI2C_SCL_INIT(n)				\
+		I2C_MCUX_LPI2C_SDA_INIT(n)				\
 		.bus_idle_timeout_ns =					\
 			UTIL_AND(DT_INST_NODE_HAS_PROP(n, bus_idle_timeout),\
 				 DT_INST_PROP(n, bus_idle_timeout)),	\

dts/bindings/i2c/nxp,imx-lpi2c.yaml

@@ -18,3 +18,15 @@ properties:
       required: false
       type: int
       description: Bus idle timeout in nanoseconds
+
+    scl-gpios:
+      type: phandle-array
+      required: false
+      description: |
+        GPIO to which the I2C SCL signal is routed. This is only needed for I2C bus recovery support.
+
+    sda-gpios:
+      type: phandle-array
+      required: false
+      description: |
+        GPIO to which the I2C SDA signal is routed. This is only needed for I2C bus recovery support.