drivers: kscan: add support for cst816s touch panel driver

Add touch panel driver support for pinetime

Signed-off-by: Qingsong Gou <gouqs@hotmail.com>

boards/arm/pinetime_devkit0/Kconfig.defconfig

@@ -21,4 +21,7 @@ config ST7789V
 
 endif # DISPLAY
 
+config I2C
+	default y if KSCAN
+
 endif # BOARD_PINETIME_DEVKIT0

boards/arm/pinetime_devkit0/pinetime_devkit0.dts

@@ -32,6 +32,7 @@
 		led2 = &blled2;	/* backlight high */
 		led3 = &statusled;	/* status led, may be not populated */
 		sw0 = &key_in;  /* key in */
+		kscan0 = &cst816s;
 	};
 
 	leds {
@@ -108,7 +109,7 @@
 
 	/* Hynitron CST816S Capacitive Touch Controller (400KHz) */
 	cst816s: cst816s@15 {
-		compatible = "hynitron-cst816s";
+		compatible = "hynitron,cst816s";
 		reg = <0x15>;
 		label = "CST816S";
 		irq-gpios = <&gpio0 28 GPIO_ACTIVE_LOW>;

boards/arm/pinetime_devkit0/pinetime_devkit0.yaml

@@ -8,3 +8,5 @@ toolchain:
   - xtools
 ram: 64
 flash: 512
+supported:
+  - kscan:touch

drivers/kscan/CMakeLists.txt

@@ -7,5 +7,6 @@ zephyr_library_sources_ifdef(CONFIG_KSCAN_ITE_IT8XXX2	kscan_ite_it8xxx2.c)
 zephyr_library_sources_ifdef(CONFIG_KSCAN_XEC		kscan_mchp_xec.c)
 zephyr_library_sources_ifdef(CONFIG_KSCAN_SDL		kscan_sdl.c)
 zephyr_library_sources_ifdef(CONFIG_KSCAN_HT16K33	kscan_ht16k33.c)
+zephyr_library_sources_ifdef(CONFIG_KSCAN_CST816S	kscan_cst816s.c)
 
 zephyr_library_sources_ifdef(CONFIG_USERSPACE	    kscan_handlers.c)

drivers/kscan/Kconfig

@@ -15,6 +15,7 @@ source "drivers/kscan/Kconfig.it8xxx2"
 source "drivers/kscan/Kconfig.xec"
 source "drivers/kscan/Kconfig.sdl"
 source "drivers/kscan/Kconfig.ht16k33"
+source "drivers/kscan/Kconfig.cst816s"
 
 module = KSCAN
 module-str = kscan

drivers/kscan/Kconfig.cst816s

@@ -0,0 +1,29 @@
+# Copyright (c) 2020 Qingsong Gou <gouqs@hotmail.com>
+# SPDX-License-Identifier: Apache-2.0
+
+DT_COMPAT_HYNITRON_CST816S := hynitron,cst816s
+
+menuconfig KSCAN_CST816S
+	bool "CST816S capacitive touch panel driver"
+	default $(dt_compat_enabled,$(DT_COMPAT_HYNITRON_CST816S))
+	depends on I2C
+	help
+	  Enable driver for hynitron cst816s touch panel.
+
+if KSCAN_CST816S
+
+config KSCAN_CST816S_PERIOD
+	int "Sample period"
+	depends on !KSCAN_CST816S_INTERRUPT
+	default 20
+	help
+	  Sample period in milliseconds when in polling mode.
+
+config KSCAN_CST816S_INTERRUPT
+	bool "Enable interrupt support"
+	default y
+	depends on GPIO
+	help
+	  Enable interrupt support (requires GPIO).
+
+endif # KSCAN_CST816S

drivers/kscan/kscan_cst816s.c

@@ -0,0 +1,327 @@
+/*
+ * Copyright (c) 2021 Qingsong Gou <gouqs@hotmail.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT hynitron_cst816s
+
+#include <sys/byteorder.h>
+#include <drivers/kscan.h>
+#include <drivers/i2c.h>
+#include <drivers/gpio.h>
+#include <logging/log.h>
+
+LOG_MODULE_REGISTER(cst816s, CONFIG_KSCAN_LOG_LEVEL);
+
+#define CST816S_CHIP_ID                 0xB4
+
+#define CST816S_REG_DATA                0x00
+#define CST816S_REG_GESTURE_ID          0x01
+#define CST816S_REG_FINGER_NUM          0x02
+#define CST816S_REG_XPOS_H              0x03
+#define CST816S_REG_XPOS_L              0x04
+#define CST816S_REG_YPOS_H              0x05
+#define CST816S_REG_YPOS_L              0x06
+#define CST816S_REG_BPC0H               0xB0
+#define CST816S_REG_BPC0L               0xB1
+#define CST816S_REG_BPC1H               0xB2
+#define CST816S_REG_BPC1L               0xB3
+#define CST816S_REG_POWER_MODE          0xA5
+#define CST816S_REG_CHIP_ID             0xA7
+#define CST816S_REG_PROJ_ID             0xA8
+#define CST816S_REG_FW_VERSION          0xA9
+#define CST816S_REG_MOTION_MASK         0xEC
+#define CST816S_REG_IRQ_PULSE_WIDTH     0xED
+#define CST816S_REG_NOR_SCAN_PER        0xEE
+#define CST816S_REG_MOTION_S1_ANGLE     0xEF
+#define CST816S_REG_LP_SCAN_RAW1H       0xF0
+#define CST816S_REG_LP_SCAN_RAW1L       0xF1
+#define CST816S_REG_LP_SCAN_RAW2H       0xF2
+#define CST816S_REG_LP_SCAN_RAW2L       0xF3
+#define CST816S_REG_LP_AUTO_WAKEUP_TIME 0xF4
+#define CST816S_REG_LP_SCAN_TH          0xF5
+#define CST816S_REG_LP_SCAN_WIN         0xF6
+#define CST816S_REG_LP_SCAN_FREQ        0xF7
+#define CST816S_REG_LP_SCAN_I_DAC       0xF8
+#define CST816S_REG_AUTOSLEEP_TIME      0xF9
+#define CST816S_REG_IRQ_CTL             0xFA
+#define CST816S_REG_DEBOUNCE_TIME       0xFB
+#define CST816S_REG_LONG_PRESS_TIME     0xFC
+#define CST816S_REG_IOCTL               0xFD
+#define CST816S_REG_DIS_AUTO_SLEEP      0xFE
+
+#define CST816S_MOTION_EN_CON_LR      BIT(2)
+#define CST816S_MOTION_EN_CON_UR      BIT(1)
+#define CST816S_MOTION_EN_DCLICK      BIT(0)
+
+#define CST816S_IRQ_EN_TEST           BIT(7)
+#define CST816S_IRQ_EN_TOUCH          BIT(6)
+#define CST816S_IRQ_EN_CHANGE         BIT(5)
+#define CST816S_IRQ_EN_MOTION         BIT(4)
+#define CST816S_IRQ_ONCE_WLP          BIT(0)
+
+#define CST816S_IOCTL_SOFT_RTS        BIT(2)
+#define CST816S_IOCTL_IIC_OD          BIT(1)
+#define CST816S_IOCTL_EN_1V8          BIT(0)
+
+#define CST816S_POWER_MODE_SLEEP          (0x03)
+#define CST816S_POWER_MODE_EXPERIMENTAL   (0x05)
+
+#define CST816S_EVENT_BITS_POS        (0x06)
+
+#define CST816S_RESET_DELAY           (5) /* in ms */
+#define CST816S_WAIT_DELAY            (50) /* in ms */
+
+#define EVENT_PRESS_DOWN	0x00U
+#define EVENT_LIFT_UP		0x01U
+#define EVENT_CONTACT		0x02U
+#define EVENT_NONE		0x03U
+
+
+/** cst816s configuration (DT). */
+struct cst816s_config {
+	struct i2c_dt_spec i2c;
+	const struct gpio_dt_spec rst_gpio;
+#ifdef CONFIG_KSCAN_CST816S_INTERRUPT
+	const struct gpio_dt_spec int_gpio;
+#endif
+};
+
+/** cst816s data. */
+struct cst816s_data {
+	/** Device pointer. */
+	const struct device *dev;
+	/** KSCAN Callback. */
+	kscan_callback_t callback;
+	/** Work queue (for deferred read). */
+	struct k_work work;
+
+#ifdef CONFIG_KSCAN_CST816S_INTERRUPT
+	/** Interrupt GPIO callback. */
+	struct gpio_callback int_gpio_cb;
+#else
+	/** Timer (polling mode). */
+	struct k_timer timer;
+#endif
+};
+
+static int cst816s_process(const struct device *dev)
+{
+	const struct cst816s_config *cfg = dev->config;
+	struct cst816s_data *data = dev->data;
+
+	int r;
+	uint8_t event;
+	uint16_t row, col;
+	bool pressed;
+	uint16_t x;
+	uint16_t y;
+
+	r = i2c_burst_read_dt(&cfg->i2c, CST816S_REG_XPOS_H, (uint8_t *)&x, sizeof(x));
+	if (r < 0) {
+		LOG_ERR("Could not read x data");
+		return r;
+	}
+
+	r = i2c_burst_read_dt(&cfg->i2c, CST816S_REG_YPOS_H, (uint8_t *)&y, sizeof(y));
+	if (r < 0) {
+		LOG_ERR("Could not read y data");
+		return r;
+	}
+	col = sys_be16_to_cpu(x) & 0x0fff;
+	row = sys_be16_to_cpu(y) & 0x0fff;
+
+	event = (x & 0xff) >> CST816S_EVENT_BITS_POS;
+	pressed = (event == EVENT_PRESS_DOWN) || (event == EVENT_CONTACT);
+
+	LOG_DBG("event: %d, row: %d, col: %d", event, row, col);
+
+	if (data->callback) {
+		data->callback(dev, row, col, pressed);
+	}
+	return r;
+}
+
+static void cst816s_work_handler(struct k_work *work)
+{
+	struct cst816s_data *data = CONTAINER_OF(work, struct cst816s_data, work);
+
+	cst816s_process(data->dev);
+}
+
+#ifdef CONFIG_KSCAN_CST816S_INTERRUPT
+static void cst816s_isr_handler(const struct device *dev,
+				struct gpio_callback *cb, uint32_t pins)
+{
+	struct cst816s_data *data = CONTAINER_OF(cb, struct cst816s_data, int_gpio_cb);
+
+	k_work_submit(&data->work);
+}
+#else
+static void cst816s_timer_handler(struct k_timer *timer)
+{
+	struct cst816s_data *data = CONTAINER_OF(timer, struct cst816s_data, timer);
+
+	k_work_submit(&data->work);
+}
+#endif
+
+static int cst816s_configure(const struct device *dev,
+			     kscan_callback_t callback)
+{
+	struct cst816s_data *data = dev->data;
+
+	if (!callback) {
+		LOG_ERR("Invalid callback (NULL)");
+		return -EINVAL;
+	}
+
+	data->callback = callback;
+
+	return 0;
+}
+
+static int cst816s_enable_callback(const struct device *dev)
+{
+	struct cst816s_data *data = dev->data;
+
+#ifdef CONFIG_KSCAN_CST816S_INTERRUPT
+	const struct cst816s_config *config = dev->config;
+
+	gpio_add_callback(config->int_gpio.port, &data->int_gpio_cb);
+#else
+	k_timer_start(&data->timer, K_MSEC(CONFIG_KSCAN_CST816S_PERIOD),
+		      K_MSEC(CONFIG_KSCAN_CST816S_PERIOD));
+#endif
+
+	return 0;
+}
+
+static int cst816s_disable_callback(const struct device *dev)
+{
+	struct cst816s_data *data = dev->data;
+
+#ifdef CONFIG_KSCAN_CST816S_INTERRUPT
+	const struct cst816s_config *config = dev->config;
+
+	gpio_remove_callback(config->int_gpio.port, &data->int_gpio_cb);
+#else
+	k_timer_stop(&data->timer);
+#endif
+
+	return 0;
+}
+
+static void cst816s_chip_reset(const struct device *dev)
+{
+	const struct cst816s_config *config = dev->config;
+	int ret;
+
+	if (device_is_ready(config->rst_gpio.port)) {
+		ret = gpio_pin_configure_dt(&config->rst_gpio,
+					    GPIO_OUTPUT_INACTIVE);
+		if (ret < 0) {
+			LOG_ERR("Could not configure reset GPIO pin");
+			return;
+		}
+		gpio_pin_set_dt(&config->rst_gpio, 1);
+		k_msleep(CST816S_RESET_DELAY);
+		gpio_pin_set_dt(&config->rst_gpio, 0);
+		k_msleep(CST816S_WAIT_DELAY);
+	}
+}
+
+static int cst816s_chip_init(const struct device *dev)
+{
+	const struct cst816s_config *cfg = dev->config;
+	int ret = 0;
+	uint8_t chip_id = 0;
+
+	cst816s_chip_reset(dev);
+
+	if (!device_is_ready(cfg->i2c.bus)) {
+		LOG_ERR("I2C bus %s not ready", cfg->i2c.bus->name);
+		return -ENODEV;
+	}
+	ret = i2c_reg_read_byte_dt(&cfg->i2c, CST816S_REG_CHIP_ID, &chip_id);
+	if (ret < 0) {
+		LOG_ERR("failed reading chip id");
+		return ret;
+	}
+
+	if (chip_id != CST816S_CHIP_ID) {
+		LOG_ERR("CST816S wrong chip id: returned 0x%x", chip_id);
+		return -ENODEV;
+	}
+
+	ret = i2c_reg_update_byte_dt(&cfg->i2c,
+				     CST816S_REG_IRQ_CTL,
+				     CST816S_IRQ_EN_TOUCH | CST816S_IRQ_EN_CHANGE,
+				     CST816S_IRQ_EN_TOUCH | CST816S_IRQ_EN_CHANGE);
+	if (ret < 0) {
+		LOG_ERR("Could not enable irq");
+		return ret;
+	}
+	return ret;
+}
+
+static int cst816s_init(const struct device *dev)
+{
+	struct cst816s_data *data = dev->data;
+
+	data->dev = dev;
+	k_work_init(&data->work, cst816s_work_handler);
+
+#ifdef CONFIG_KSCAN_CST816S_INTERRUPT
+	const struct cst816s_config *config = dev->config;
+	int ret;
+
+	if (!device_is_ready(config->int_gpio.port)) {
+		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");
+		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.");
+		return ret;
+	}
+
+	gpio_init_callback(&data->int_gpio_cb, cst816s_isr_handler,
+			   BIT(config->int_gpio.pin));
+#else
+	k_timer_init(&data->timer, cst816s_timer_handler, NULL);
+#endif
+
+	return cst816s_chip_init(dev);
+}
+
+static const struct kscan_driver_api cst816s_driver_api = {
+	.config = cst816s_configure,
+	.enable_callback = cst816s_enable_callback,
+	.disable_callback = cst816s_disable_callback,
+};
+
+#define CST816S_DEFINE(index)                                                     \
+	static const struct cst816s_config cst816s_config_##index = {             \
+		.i2c = I2C_DT_SPEC_INST_GET(index),                               \
+		COND_CODE_1(CONFIG_KSCAN_CST816S_INTERRUPT,                       \
+			   (.int_gpio = GPIO_DT_SPEC_INST_GET(index, irq_gpios),),\
+			   ())                                                    \
+		.rst_gpio = GPIO_DT_SPEC_INST_GET_OR(index, rst_gpios, {}),       \
+	};                                                                        \
+	static struct cst816s_data cst816s_data_##index;                          \
+	DEVICE_DT_INST_DEFINE(index, cst816s_init, NULL,                          \
+			     &cst816s_data_##index, &cst816s_config_##index,      \
+			     POST_KERNEL, CONFIG_KSCAN_INIT_PRIORITY,             \
+			     &cst816s_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(CST816S_DEFINE)

dts/bindings/kscan/hynitron,cst816s.yaml

@@ -0,0 +1,25 @@
+# Copyright (c) 2021 Qingsong Gou <gouqs@hotmail.com>
+# SPDX-License-Identifier: Apache-2.0
+
+description: Hynitron CST816S touchscreen sensor
+
+compatible: "hynitron,cst816s"
+
+include: i2c-device.yaml
+
+properties:
+    irq-gpios:
+      type: phandle-array
+      required: false
+      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.
+
+    rst-gpios:
+      type: phandle-array
+      required: false
+      description: |
+        The reset signal defaults to active low to the
+        sensor. The property value should ensure the flags properly
+        describe the signal that is presented to the driver.

dts/bindings/vendor-prefixes.txt

@@ -258,6 +258,7 @@ hugsun	Shenzhen Hugsun Technology Co. Ltd.
 hwacom	HwaCom Systems Inc.
 hycon	Hycon Technology Corp.
 hydis	Hydis Technologies
+hynitron	Hynitron
 hyundai	Hyundai Technology
 i2se	I2SE GmbH
 ibm	International Business Machines (IBM)