driver: i2c: Add TCA9546a I2C switch driver

The driver only support use case where the channels are used in mutual
exclusion.
Origin: Original

Signed-off-by: Guillaume Lager <g.lager@innoseis.com>

CODEOWNERS

@@ -345,6 +345,7 @@
 /drivers/i2c/i2c_rv32m1_lpi2c*            @henrikbrixandersen
 /drivers/i2c/*sam0*                       @Sizurka
 /drivers/i2c/i2c_dw*                      @dcpleung
+/drivers/i2c/*tca9546a*                   @kurddt
 /drivers/*/*xec*                          @franciscomunoz @albertofloyd @scottwcpg
 /drivers/watchdog/*gecko*                 @oanerer
 /drivers/watchdog/*sifive*                @katsuster

drivers/i2c/CMakeLists.txt

@@ -33,6 +33,7 @@ zephyr_library_sources_ifdef(CONFIG_I2C_NPCX		i2c_npcx_controller.c)
 zephyr_library_sources_ifdef(CONFIG_I2C_NPCX		i2c_npcx_port.c)
 zephyr_library_sources_ifdef(CONFIG_I2C_DW		i2c_dw.c)
 zephyr_library_sources_ifdef(CONFIG_I2C_RCAR		i2c_rcar.c)
+zephyr_library_sources_ifdef(CONFIG_I2C_TCA9546A	i2c_tca9546a.c)
 
 zephyr_library_sources_ifdef(CONFIG_I2C_STM32_V1
 	i2c_ll_stm32_v1.c

drivers/i2c/Kconfig

@@ -42,6 +42,7 @@ source "drivers/i2c/Kconfig.lpc11u6x"
 source "drivers/i2c/Kconfig.npcx"
 source "drivers/i2c/Kconfig.test"
 source "drivers/i2c/Kconfig.rcar"
+source "drivers/i2c/Kconfig.tca9546a"
 
 config I2C_INIT_PRIORITY
 	int "Init priority"

drivers/i2c/Kconfig.tca9546a

@@ -0,0 +1,19 @@
+# Copyright (c) 2020 Innoseis BV
+# SPDX-License-Identifier: Apache-2.0
+
+menuconfig I2C_TCA9546A
+	bool "I2C addressable switch"
+	help
+	  Enable TCA9546A i2C bus switch
+
+if I2C_TCA9546A
+
+config I2C_TCA9546_ROOT_INIT_PRIO
+	int "TCA9546a root driver init priority"
+	default I2C_INIT_PRIORITY
+
+config I2C_TCA9546_CHANNEL_INIT_PRIO
+	int "TCA9546a channel driver init priority"
+	default I2C_INIT_PRIORITY
+
+endif

drivers/i2c/i2c_tca9546a.c

@@ -0,0 +1,168 @@
+/*
+ * Copyright (c) 2020 Innoseis BV
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT ti_tca9546a
+
+#include <zephyr.h>
+#include <device.h>
+#include <devicetree.h>
+#include <drivers/i2c.h>
+#include <logging/log.h>
+#include <stdint.h>
+
+LOG_MODULE_REGISTER(tca9546a, CONFIG_I2C_LOG_LEVEL);
+
+#define MAX_CHANNEL_MASK BIT_MASK(4)
+
+struct tca9546a_root_config {
+	const struct device *bus;
+	uint16_t slave_addr;
+};
+
+struct tca9546a_root_data {
+	struct k_mutex lock;
+	uint8_t selected_chan;
+};
+
+struct tca9546a_channel_config {
+	const struct device *root;
+	uint8_t chan_mask;
+};
+
+static inline struct tca9546a_root_data *
+get_root_data_from_channel(const struct device *dev)
+{
+	const struct tca9546a_channel_config *channel_config = dev->config;
+
+	return channel_config->root->data;
+}
+
+static inline const struct tca9546a_root_config *
+get_root_config_from_channel(const struct device *dev)
+{
+	const struct tca9546a_channel_config *channel_config = dev->config;
+
+	return channel_config->root->config;
+}
+
+static int tca9546a_configure(const struct device *dev, uint32_t dev_config)
+{
+	const struct tca9546a_root_config *cfg = get_root_config_from_channel(
+		dev);
+
+	return i2c_configure(cfg->bus, dev_config);
+}
+
+static int tca9546a_set_channel(const struct device *dev, uint8_t select_mask)
+{
+	int res = 0;
+	struct tca9546a_root_data *data = dev->data;
+	const struct tca9546a_root_config *cfg = dev->config;
+
+	if (data->selected_chan != select_mask) {
+		res = i2c_write(cfg->bus, &select_mask, 1, cfg->slave_addr);
+		if (res == 0) {
+			data->selected_chan = select_mask;
+		}
+	}
+	return res;
+}
+
+static int tca9546a_transfer(const struct device *dev,
+			     struct i2c_msg *msgs,
+			     uint8_t num_msgs,
+			     uint16_t addr)
+{
+	struct tca9546a_root_data *data = get_root_data_from_channel(dev);
+	const struct tca9546a_root_config *config = get_root_config_from_channel(
+		dev);
+	const struct tca9546a_channel_config *down_cfg = dev->config;
+	int res;
+
+	res = k_mutex_lock(&data->lock, K_MSEC(5000));
+	if (res != 0) {
+		return res;
+	}
+
+	res = tca9546a_set_channel(down_cfg->root, down_cfg->chan_mask);
+	if (res != 0) {
+		goto end_trans;
+	}
+
+	res = i2c_transfer(config->bus, msgs, num_msgs, addr);
+
+end_trans:
+	k_mutex_unlock(&data->lock);
+	return res;
+}
+
+static int tca9546_root_init(const struct device *dev)
+{
+	struct tca9546a_root_data *i2c_tca9546a = dev->data;
+	const struct tca9546a_root_config *config = dev->config;
+
+	if (!device_is_ready(config->bus)) {
+		LOG_ERR("I2C bus %s not ready", config->bus->name);
+		return -ENODEV;
+	}
+
+	i2c_tca9546a->selected_chan = 0;
+
+	return 0;
+}
+
+static int tca9546a_channel_init(const struct device *dev)
+{
+	const struct tca9546a_channel_config *cfg = dev->config;
+
+	if (!device_is_ready(cfg->root)) {
+		LOG_ERR("I2C mux root %s not ready", cfg->root->name);
+		return -ENODEV;
+	}
+
+	if (cfg->chan_mask > MAX_CHANNEL_MASK) {
+		LOG_ERR("Wrong DTS address provided for %s", dev->name);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+const struct i2c_driver_api tca9546a_api_funcs = {
+	.configure = tca9546a_configure,
+	.transfer = tca9546a_transfer,
+};
+
+#define TCA9546A_CHILD_DEFINE(node_id)					    \
+	static const struct tca9546a_channel_config			    \
+		tca9546a_down_config_##node_id = {			    \
+		.chan_mask = BIT(DT_REG_ADDR(node_id)),			    \
+		.root = DEVICE_DT_GET(DT_PARENT(node_id)),		    \
+	};								    \
+	DEVICE_DT_DEFINE(node_id,					    \
+			 tca9546a_channel_init,				    \
+			 NULL,						    \
+			 NULL,						    \
+			 &tca9546a_down_config_##node_id,		    \
+			 POST_KERNEL, CONFIG_I2C_TCA9546_CHANNEL_INIT_PRIO, \
+			 &tca9546a_api_funcs);
+
+#define TCA9546A_ROOT_CHILD_DEFINE(inst)				      \
+	static const struct tca9546a_root_config tca9546a_cfg_##inst = {      \
+		.slave_addr = DT_INST_REG_ADDR(inst),			      \
+		.bus = DEVICE_DT_GET(DT_INST_BUS(inst))			      \
+	};								      \
+	static struct tca9546a_root_data tca9546a_data_##inst = {	      \
+		.lock = Z_MUTEX_INITIALIZER(tca9546a_data_0.lock),	      \
+	};								      \
+	DEVICE_DT_INST_DEFINE(inst,					      \
+			      tca9546_root_init, NULL,			      \
+			      &tca9546a_data_##inst, &tca9546a_cfg_##inst,    \
+			      POST_KERNEL, CONFIG_I2C_TCA9546_ROOT_INIT_PRIO, \
+			      NULL);					      \
+	DT_INST_FOREACH_CHILD(inst, TCA9546A_CHILD_DEFINE);
+
+DT_INST_FOREACH_STATUS_OKAY(TCA9546A_ROOT_CHILD_DEFINE)

dts/bindings/i2c/ti,tca9546a.yaml

@@ -0,0 +1,46 @@
+# Copyright (c) 2020, Innoseis BV
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+  TCA9546a I2C switch
+
+  Each channel is represented by a separate devicetree child node
+  with a "ti,tca9546a-channel" compatible.
+  The channel node can then be used as a standard i2c bus controller
+  like in the following simplified example:
+
+      /* The tca9546a node must be a child of an i2c controller */
+      mux: tca9546a@77 {
+          compatible = "ti,tca9546a";
+          reg = <0x77>;
+
+          mux_i2c@0 {
+              compatible = "ti,tca9546a-channel";
+              reg = <0>;
+
+              temp_sens_0: tmp116@49 {
+                  compatible = "ti,tmp116";
+                  reg = <0x49>;
+              };
+          };
+
+          mux_i2c@1 {
+              compatible = "ti,tca9546a-channel";
+              reg = <1>;
+
+              temp_sens_1: tmp116@49 {
+                  compatible = "ti,tmp116";
+                  reg = <0x49>;
+              };
+          };
+      };
+
+compatible: "ti,tca9546a"
+
+include: [i2c-device.yaml]
+
+child-binding:
+  description: TCA9546a I2C switch channel node
+  compatible: "ti,tca9546a-channel"
+  include: [i2c-controller.yaml]
+  on-bus: i2c

tests/drivers/i2c/i2c_tca9546a/CMakeLists.txt

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.13.1)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(i2c_tca9546a)
+
+FILE(GLOB app_sources src/*.c)
+target_sources(app PRIVATE ${app_sources})

tests/drivers/i2c/i2c_tca9546a/boards/nrf52840dk_nrf52840.overlay

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2020 Teslabs Engineering S.L.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&i2c0 {
+	status = "okay";
+	mux: tca9546a@77 {
+		compatible = "ti,tca9546a";
+		reg = <0x77>;
+		status = "okay";
+		label = "i2c_mux";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		ch0: mux_i2c@0 {
+			label = "mux_dw_0";
+			reg = <0>;
+			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "ti,tca9546a-channel";
+		};
+
+		ch1: mux_i2c@1 {
+			label = "mux_dw_1";
+			reg = <1>;
+			status = "okay";
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "ti,tca9546a-channel";
+        };
+	};
+};
+
+/{
+	aliases {
+		i2c-channel-0 = &ch0;
+		i2c-channel-1 = &ch1;
+	};
+};

tests/drivers/i2c/i2c_tca9546a/prj.conf

@@ -0,0 +1,3 @@
+CONFIG_ZTEST=y
+CONFIG_I2C=y
+CONFIG_I2C_TCA9546A=y

tests/drivers/i2c/i2c_tca9546a/src/main.c

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <ztest.h>
+#include <device.h>
+#include <drivers/i2c.h>
+
+#if DT_NODE_HAS_STATUS(DT_ALIAS(i2c_channel_0), okay)
+#define I2C_0_CTRL_NODE_ID      DT_ALIAS(i2c_channel_0)
+#define I2C_0_CTRL_DEV_NAME     DT_LABEL(I2C_0_CTRL_NODE_ID)
+#else
+#error "I2C 0 controller device not found"
+#endif
+
+#if DT_NODE_HAS_STATUS(DT_ALIAS(i2c_channel_1), okay)
+#define I2C_1_CTRL_NODE_ID      DT_ALIAS(i2c_channel_1)
+#define I2C_1_CTRL_DEV_NAME     DT_LABEL(I2C_1_CTRL_NODE_ID)
+#else
+#error "I2C 1 controller device not found"
+#endif
+
+
+
+
+/**
+ * @brief Test Asserts
+ *
+ * This test verifies various assert macros provided by ztest.
+ *
+ */
+static void test_tca9546a(void)
+{
+	uint8_t buff[1];
+
+	const struct device *i2c0 = DEVICE_DT_GET(I2C_0_CTRL_NODE_ID);
+	const struct device *i2c1 = DEVICE_DT_GET(I2C_1_CTRL_NODE_ID);
+
+	zassert_true(device_is_ready(i2c0), "I2C 0 not ready");
+	zassert_true(device_is_ready(i2c1), "I2C 1 not ready");
+
+	i2c_read(i2c0, buff, 1, 0x42);
+	i2c_read(i2c1, buff, 1, 0x42);
+}
+
+void test_main(void)
+{
+	ztest_test_suite(framework_tests,
+			 ztest_unit_test(test_tca9546a)
+			 );
+
+	ztest_run_test_suite(framework_tests);
+}

tests/drivers/i2c/i2c_tca9546a/testcase.yaml

@@ -0,0 +1,7 @@
+tests:
+  drivers.i2c:
+    build_only: true
+    tags: testing drivers
+    depends_on: i2c
+    filter: dt_compat_enabled("ti,tca9546a")
+    platform_allow: nrf52840dk_nrf52840