drivers: i2c: pca9542a: Initial driver support

The PCA9542A is a 1-of-2 bidirectional translating multiplexer, controlled via the I 2 C-bus.

Signed-off-by: Alan Shaju <[email protected]>

drivers/i2c/CMakeLists.txt

@@ -80,6 +80,7 @@ zephyr_library_sources_ifdef(CONFIG_I2C_ENE_KB1200	i2c_ene_kb1200.c)
 zephyr_library_sources_ifdef(CONFIG_GPIO_I2C_SWITCH	gpio_i2c_switch.c)
 zephyr_library_sources_ifdef(CONFIG_I2C_NUMAKER		i2c_numaker.c)
 zephyr_library_sources_ifdef(CONFIG_I2C_MAX32		i2c_max32.c)
+zephyr_library_sources_ifdef(CONFIG_I2C_PCA9542A	i2c_pca9542a.c)
 
 zephyr_library_sources_ifdef(CONFIG_I2C_STM32_V1
 	i2c_ll_stm32_v1.c

drivers/i2c/Kconfig

@@ -129,6 +129,7 @@ source "drivers/i2c/Kconfig.numaker"
 source "drivers/i2c/Kconfig.mcux"
 source "drivers/i2c/Kconfig.ene"
 source "drivers/i2c/Kconfig.max32"
+source "drivers/i2c/Kconfig.pca9542a"
 
 config I2C_INIT_PRIORITY
 	int "Init priority"

drivers/i2c/Kconfig.pca9542a

@@ -0,0 +1,27 @@
+# pca9542a
+
+# Copyright (c) 2024 tinyVision.ai Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+menuconfig I2C_PCA9542A
+	bool "NXP PCA9542A 2-channel multiplexer"
+	default y
+	depends on DT_HAS_NXP_PCA9542A_ENABLED
+	help
+	  Enable NXP PCA9542A 2-channel multiplexer
+
+if I2C_PCA9542A
+
+config I2C_PCA9542A_ROOT_INIT_PRIO
+	int "PCA9542A root driver init priority"
+	default I2C_INIT_PRIORITY
+	help
+	  Should be lower than `I2C_PCA9542A_CHANNEL_INIT_PRIO`
+
+config I2C_PCA9542A_CHANNEL_INIT_PRIO
+	int "PCA9542A channel driver init priority"
+	default I2C_INIT_PRIORITY
+	help
+	  Should be higher than `I2C_PCA9542A_ROOT_INIT_PRIO`
+
+endif

drivers/i2c/i2c_pca9542a.c

@@ -0,0 +1,165 @@
+/*
+ *
+ * Copyright (c) 2020 Innoseis BV
+ * Copyright (c) 2024 tinyVision.ai Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT nxp_pca9542a
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/logging/log.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#define BCD2BIN(bcd) (((10 * ((bcd) >> 4)) + ((bcd) & 0x0F)))
+
+LOG_MODULE_REGISTER(pca9542a, CONFIG_I2C_LOG_LEVEL);
+
+struct pca9542a_root_config {
+	struct i2c_dt_spec i2c;
+	uint8_t nchans;
+};
+
+struct pca9542a_root_data {
+	struct k_mutex lock;
+	uint8_t selected_chan;
+};
+
+struct pca9542a_channel_config {
+	const struct device *root;
+	uint8_t chan_mask;
+};
+
+static inline struct pca9542a_root_data *get_root_data_from_channel(const struct device *dev)
+{
+	const struct pca9542a_channel_config *channel_config = dev->config;
+
+	return channel_config->root->data;
+}
+
+static inline const struct pca9542a_root_config *
+get_root_config_from_channel(const struct device *dev)
+{
+	const struct pca9542a_channel_config *channel_config = dev->config;
+
+	return channel_config->root->config;
+}
+
+static int pca9542a_configure(const struct device *dev, uint32_t dev_config)
+{
+	const struct pca9542a_root_config *cfg = get_root_config_from_channel(dev);
+
+	return i2c_configure(cfg->i2c.bus, dev_config);
+}
+
+static int pca9542a_set_channel(const struct device *dev, uint8_t select_mask)
+{
+	int res = 0;
+	struct pca9542a_root_data *data = dev->data;
+	const struct pca9542a_root_config *cfg = dev->config;
+
+	/* Only select the channel if its different from the last channel */
+	if (data->selected_chan != select_mask) {
+		res = i2c_write_dt(&cfg->i2c, &select_mask, 1);
+		if (res == 0) {
+			data->selected_chan = select_mask;
+		} else {
+			LOG_DBG("pca9542a: failed to set channel");
+		}
+	}
+	return res;
+}
+
+static int pca9542a_transfer(const struct device *dev, struct i2c_msg *msgs, uint8_t num_msgs,
+			     uint16_t addr)
+{
+	struct pca9542a_root_data *data = get_root_data_from_channel(dev);
+	const struct pca9542a_root_config *config = get_root_config_from_channel(dev);
+	const struct pca9542a_channel_config *down_cfg = dev->config;
+	int res;
+
+	res = k_mutex_lock(&data->lock, K_MSEC(5000));
+	if (res != 0) {
+		return res;
+	}
+
+	res = pca9542a_set_channel(down_cfg->root, down_cfg->chan_mask);
+	if (res != 0) {
+		goto end_trans;
+	}
+
+	res = i2c_transfer(config->i2c.bus, msgs, num_msgs, addr);
+
+end_trans:
+	k_mutex_unlock(&data->lock);
+	return res;
+}
+
+static int pca9542a_root_init(const struct device *dev)
+{
+
+	struct pca9542a_root_data *i2c_pca9542a = dev->data;
+	const struct pca9542a_root_config *config = dev->config;
+	printf("inside root init...\n");
+	if (!device_is_ready(config->i2c.bus)) {
+		LOG_ERR("I2C bus %s not ready", config->i2c.bus->name);
+		return -ENODEV;
+	}
+
+	i2c_pca9542a->selected_chan = 0;
+
+	return 0;
+}
+
+static int pca9542a_channel_init(const struct device *dev)
+{
+	const struct pca9542a_channel_config *chan_cfg = dev->config;
+	const struct pca9542a_root_config *root_cfg = get_root_config_from_channel(dev);
+	if (!device_is_ready(chan_cfg->root)) {
+		LOG_ERR("I2C mux root %s not ready", chan_cfg->root->name);
+		return -ENODEV;
+	}
+
+	if (chan_cfg->chan_mask >= BCD2BIN(root_cfg->nchans + 4)) {
+		LOG_ERR("Wrong DTS address provided for %s", dev->name);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct i2c_driver_api pca9542a_api_funcs = {
+	.configure = pca9542a_configure,
+	.transfer = pca9542a_transfer,
+};
+
+BUILD_ASSERT(CONFIG_I2C_PCA9542A_CHANNEL_INIT_PRIO > CONFIG_I2C_PCA9542A_ROOT_INIT_PRIO,
+	     "I2C multiplexer channels must be initialized after their root");
+
+#define PCA9542A_CHILD_DEFINE(node_id)                                                             \
+	static const struct pca9542a_channel_config pca9542a_down_config_##node_id = {             \
+		.chan_mask = BCD2BIN(DT_REG_ADDR(node_id) + 4),                                    \
+		.root = DEVICE_DT_GET(DT_PARENT(node_id)),                                         \
+	};                                                                                         \
+	DEVICE_DT_DEFINE(node_id, pca9542a_channel_init, NULL, NULL,                               \
+			 &pca9542a_down_config_##node_id, POST_KERNEL,                             \
+			 CONFIG_I2C_PCA9542A_CHANNEL_INIT_PRIO, &pca9542a_api_funcs);
+
+#define PCA9542A_INIT(n)                                                                           \
+	static const struct pca9542a_root_config pca9542a_cfg_##n = {                              \
+		.i2c = I2C_DT_SPEC_INST_GET(n),                                                    \
+		.nchans = 2,                                                                       \
+	};                                                                                         \
+	static struct pca9542a_root_data pca9542a_data_##n = {                                     \
+		.lock = Z_MUTEX_INITIALIZER(pca9542a_data_##n.lock),                               \
+	};                                                                                         \
+	I2C_DEVICE_DT_DEFINE(DT_INST(n, nxp_pca9542a), pca9542a_root_init, NULL,                   \
+			     &pca9542a_data_##n, &pca9542a_cfg_##n, POST_KERNEL,                   \
+			     CONFIG_I2C_PCA9542A_ROOT_INIT_PRIO, NULL);                            \
+	DT_FOREACH_CHILD(DT_INST(n, nxp_pca9542a), PCA9542A_CHILD_DEFINE);
+
+DT_INST_FOREACH_STATUS_OKAY(PCA9542A_INIT)

dts/bindings/i2c/nxp,pca9542a.yaml

@@ -0,0 +1,13 @@
+# Copyright (c) 2024 tinyVision.ai Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+description: NXP PCA9542A 2-channel multiplexer
+
+compatible: "nxp,pca9542a"
+
+include: i2c-device.yaml
+
+child-binding:
+  compatible: "nxp,pca9542a-channel"
+  include: i2c-controller.yaml
+  on-bus: i2c