drivers: input: CHSC6X Driver

Added a driver for the CHSC6X chip used on the
Seeed Studio Round Display for Xiao

Signed-off-by: Nicolas Goualard <nicolas.goualard@sfr.fr>

drivers/input/CMakeLists.txt

@@ -9,6 +9,7 @@ zephyr_library_sources_ifdef(CONFIG_INPUT_ANALOG_AXIS input_analog_axis.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_ANALOG_AXIS_SETTINGS input_analog_axis_settings.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_CAP1203 input_cap1203.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_CF1133 input_cf1133.c)
+zephyr_library_sources_ifdef(CONFIG_INPUT_CHSC6X input_chsc6x.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_CST816S input_cst816s.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_ESP32_TOUCH_SENSOR input_esp32_touch_sensor.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_FT5336 input_ft5336.c)

drivers/input/Kconfig

@@ -10,6 +10,7 @@ source "drivers/input/Kconfig.adc_keys"
 source "drivers/input/Kconfig.analog_axis"
 source "drivers/input/Kconfig.cap1203"
 source "drivers/input/Kconfig.cf1133"
+source "drivers/input/Kconfig.chsc6x"
 source "drivers/input/Kconfig.cst816s"
 source "drivers/input/Kconfig.esp32"
 source "drivers/input/Kconfig.evdev"

drivers/input/Kconfig.chsc6x

@@ -0,0 +1,11 @@
+# Copyright (c) 2024 Nicolas Goualard <nicolas.goualard@sfr.fr>
+# SPDX-License-Identifier: Apache-2.0
+
+config INPUT_CHSC6X
+	bool "Use out of tree CHSC6X capacitive touch panel driver"
+	default y
+	depends on DT_HAS_SEEED_CHSC6X_ENABLED
+	select GPIO
+	select I2C
+	help
+	  Enable out of tree driver for CHSC6X touch panel.

drivers/input/input_chsc6x.c

@@ -0,0 +1,139 @@
+/*
+ * Copyright (c) 2024 Nicolas Goualard <nicolas.goualard@sfr.fr>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT seeed_chsc6x
+
+#include <zephyr/sys/byteorder.h>
+#include <zephyr/input/input.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/logging/log.h>
+
+struct chsc6x_config {
+	struct i2c_dt_spec i2c;
+	const struct gpio_dt_spec int_gpio;
+};
+
+struct chsc6x_data {
+	const struct device *dev;
+	struct k_work work;
+	struct gpio_callback int_gpio_cb;
+};
+
+#define CHSC6X_READ_ADDR 0
+#define CHSC6X_READ_LENGTH 5
+#define CHSC6X_OUTPUT_POINTS_PRESSED 0
+#define CHSC6X_OUTPUT_COL 2
+#define CHSC6X_OUTPUT_ROW 4
+
+LOG_MODULE_REGISTER(chsc6x, CONFIG_INPUT_LOG_LEVEL);
+
+static int chsc6x_process(const struct device *dev)
+{
+	uint8_t output[CHSC6X_READ_LENGTH];
+	uint8_t row, col;
+	bool is_pressed;
+	int ret;
+
+	const struct chsc6x_config *cfg = dev->config;
+
+	ret = i2c_burst_read_dt(&cfg->i2c, CHSC6X_READ_ADDR, output, CHSC6X_READ_LENGTH);
+	if (ret < 0) {
+		LOG_ERR("Could not read data: %i", ret);
+		return -ENODATA;
+	}
+
+	is_pressed = output[CHSC6X_OUTPUT_POINTS_PRESSED];
+	col = output[CHSC6X_OUTPUT_COL];
+	row = output[CHSC6X_OUTPUT_ROW];
+
+	if (is_pressed) {
+		/* These events are generated for the LVGL touch implementation. */
+		input_report_abs(dev, INPUT_ABS_X, col, false, K_FOREVER);
+		input_report_abs(dev, INPUT_ABS_Y, row, false, K_FOREVER);
+		input_report_key(dev, INPUT_BTN_TOUCH, 1, true, K_FOREVER);
+	} else {
+		/* This event is generated for the LVGL touch implementation. */
+		input_report_key(dev, INPUT_BTN_TOUCH, 0, true, K_FOREVER);
+	}
+
+	return 0;
+}
+
+static void chsc6x_work_handler(struct k_work *work)
+{
+	struct chsc6x_data *data = CONTAINER_OF(work, struct chsc6x_data, work);
+
+	chsc6x_process(data->dev);
+}
+
+static void chsc6x_isr_handler(const struct device *dev, struct gpio_callback *cb, uint32_t mask)
+{
+	struct chsc6x_data *data = CONTAINER_OF(cb, struct chsc6x_data, int_gpio_cb);
+
+	k_work_submit(&data->work);
+}
+
+static int chsc6x_chip_init(const struct device *dev)
+{
+	const struct chsc6x_config *cfg = dev->config;
+
+	if (!i2c_is_ready_dt(&(cfg->i2c))) {
+		LOG_ERR("I2C bus %s not ready", cfg->i2c.bus->name);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int chsc6x_init(const struct device *dev)
+{
+	struct chsc6x_data *data = dev->data;
+	int ret;
+	data->dev = dev;
+	k_work_init(&data->work, chsc6x_work_handler);
+
+	const struct chsc6x_config *config = dev->config;
+
+	if (!gpio_is_ready_dt(&config->int_gpio)) {
+		LOG_ERR("GPIO port %s not ready", config->int_gpio.port->name);
+		return -ENODEV;
+	}
+
+	ret = gpio_pin_configure_dt(&config->int_gpio, GPIO_INPUT);
+	if (ret < 0) {
+		LOG_ERR("Could not configure interrupt GPIO pin: %d", ret);
+		return ret;
+	}
+
+	ret = gpio_pin_interrupt_configure_dt(&config->int_gpio, GPIO_INT_EDGE_TO_ACTIVE);
+	if (ret < 0) {
+		LOG_ERR("Could not configure interrupt GPIO interrupt: %d", ret);
+		return ret;
+	}
+
+	gpio_init_callback(&data->int_gpio_cb, chsc6x_isr_handler, BIT(config->int_gpio.pin));
+
+	ret = gpio_add_callback(config->int_gpio.port, &data->int_gpio_cb);
+	if (ret < 0) {
+		LOG_ERR("Could not set gpio callback: %d", ret);
+		return ret;
+	}
+
+	return chsc6x_chip_init(dev);
+};
+
+#define CHSC6X_DEFINE(index)                                                                       \
+	static const struct chsc6x_config chsc6x_config_##index = {                                \
+		.i2c = I2C_DT_SPEC_INST_GET(index),                                                \
+		.int_gpio = GPIO_DT_SPEC_INST_GET(index, irq_gpios),                               \
+	};                                                                                         \
+	static struct chsc6x_data chsc6x_data_##index;                                             \
+	DEVICE_DT_INST_DEFINE(index, chsc6x_init, NULL, &chsc6x_data_##index,                      \
+			      &chsc6x_config_##index, POST_KERNEL, CONFIG_INPUT_INIT_PRIORITY,     \
+			      NULL);
+
+DT_INST_FOREACH_STATUS_OKAY(CHSC6X_DEFINE)

dts/bindings/input/seeed,chsc6x.yaml

@@ -0,0 +1,14 @@
+description: CHSC6X touchscreen sensor
+
+compatible: "seeed,chsc6x"
+
+include: i2c-device.yaml
+
+properties:
+  irq-gpios:
+    type: phandle-array
+    required: true
+    description: |
+      The irq signal defaults to active low as produced by the
+      sensor. The property value should ensure the flags properly
+      describe the signal that is presented to the driver.

tests/drivers/build_all/input/app.overlay

@@ -218,6 +218,12 @@
 				int-gpios = <&test_gpio 0 0>;
 			};
 
+			chsc6x@7 {
+				compatible = "seeed,chsc6x";
+				reg = <0x7>;
+				irq-gpios = <&test_gpio 0 0>;
+			};
+
 			pinnacle@2a {
 				compatible = "cirque,pinnacle";
 				reg = <0x2a>;