Introduce support for the Hynitron CST816X touchscreen controller used for 240×240 1.28-inch Round LCD Display Module manufactured by Waveshare Electronics. The driver is designed based on an Arduino implementation marked as under MIT License. This driver is written for a particular round display based on the CST816S controller, which is not compatiable with existing driver for Hynitron controllers. Signed-off-by: Oleh Kuzhylnyi <kuzhylol@xxxxxxxxx> --- Changes in v6: - No code changes Changes in v5: - Update commit based on Dmitry's feedback: - Make GPIO reset optional - Combine declaration and initialization for i2c_xfer - Return 0 explicitly where possible - Rename rc (return code) to error - Make Touch processing call return boolean - Improve error handling for i2c_transfer - Use get_unaligned_be16 for getting coordinates - Move touch event completeness upper to irq callback Changes in v4: - Update commit based on Dmitry's feedback: - Move abs_x and abs_y to u16 - Remove __packed qualifier for touch_info struct - Hide tiny touch irq context to stack - Extend cst816x_i2c_read_register() with buf and buf_size - Remove loop from event lookup Changes in v3: - Drop timer and delayed work - Process touch in threaded IRQ context - Fix chip reset sequence - Move input_register() before devm_request_threaded_irq() - Re-arrange and document input reporting - Set u16 data type for event_code - Remove double tap event to prevent continuous double side sliding Changes in v2: - Apply dev_err_probe() for better error handling - Remove redundant printing, remove dev_warn() message spamming - Get rid of PM since the touchscreen goes into sleep mode automatically - Get rid of IRQ control and IRQF_NO_AUTOEN flag - Reduce timer timeout up to 10ms to handle touch events faster - Skip registering of non-gesture CST816X_SWIPE event - Shift input_register_device() as a final call in probe() callback - Specify name of i2c_device_id explicitly - Update module description and fix typo - Add necessary spaces between lines drivers/input/touchscreen/Kconfig | 12 + drivers/input/touchscreen/Makefile | 1 + drivers/input/touchscreen/hynitron-cst816x.c | 259 +++++++++++++++++++ 3 files changed, 272 insertions(+) create mode 100644 drivers/input/touchscreen/hynitron-cst816x.c diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig index c821fe3ee794..02f40d0fbac0 100644 --- a/drivers/input/touchscreen/Kconfig +++ b/drivers/input/touchscreen/Kconfig @@ -481,6 +481,18 @@ config TOUCHSCREEN_HYNITRON_CSTXXX To compile this driver as a module, choose M here: the module will be called hynitron-cstxxx. +config TOUCHSCREEN_HYNITRON_CST816X + tristate "Hynitron CST816X touchscreen support" + depends on I2C + help + Say Y here if you have a touchscreen using a Hynitron + CST816X touchscreen controller. + + If unsure, say N. + + To compile this driver as a module, choose M here: the + module will be called hynitron-cst816x. + config TOUCHSCREEN_ILI210X tristate "Ilitek ILI210X based touchscreen" depends on I2C diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile index a81cb5aa21a5..a92a87417a97 100644 --- a/drivers/input/touchscreen/Makefile +++ b/drivers/input/touchscreen/Makefile @@ -51,6 +51,7 @@ obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_CORE) += goodix_berlin_core.o obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_I2C) += goodix_berlin_i2c.o obj-$(CONFIG_TOUCHSCREEN_GOODIX_BERLIN_SPI) += goodix_berlin_spi.o obj-$(CONFIG_TOUCHSCREEN_HIDEEP) += hideep.o +obj-$(CONFIG_TOUCHSCREEN_HYNITRON_CST816X) += hynitron-cst816x.o obj-$(CONFIG_TOUCHSCREEN_HYNITRON_CSTXXX) += hynitron_cstxxx.o obj-$(CONFIG_TOUCHSCREEN_ILI210X) += ili210x.o obj-$(CONFIG_TOUCHSCREEN_ILITEK) += ilitek_ts_i2c.o diff --git a/drivers/input/touchscreen/hynitron-cst816x.c b/drivers/input/touchscreen/hynitron-cst816x.c new file mode 100644 index 000000000000..3886617e6a71 --- /dev/null +++ b/drivers/input/touchscreen/hynitron-cst816x.c @@ -0,0 +1,259 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Driver for I2C connected Hynitron CST816X Touchscreen + * + * Copyright (C) 2024 Oleh Kuzhylnyi <kuzhylol@xxxxxxxxx> + */ +#include <asm/unaligned.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/input.h> +#include <linux/interrupt.h> +#include <linux/module.h> + +enum cst816x_registers { + CST816X_FRAME = 0x01, + CST816X_MOTION = 0xEC, +}; + +enum cst816x_gestures { + CST816X_SWIPE_UP = 0x01, + CST816X_SWIPE_DOWN = 0x02, + CST816X_SWIPE_LEFT = 0x03, + CST816X_SWIPE_RIGHT = 0x04, + CST816X_SINGLE_TAP = 0x05, + CST816X_LONG_PRESS = 0x0C, + CST816X_RESERVED = 0xFF, +}; + +struct cst816x_touch_info { + u8 gesture; + u8 touch; + u16 abs_x; + u16 abs_y; +}; + +struct cst816x_priv { + struct device *dev; + struct i2c_client *client; + struct gpio_desc *reset; + struct input_dev *input; +}; + +struct cst816x_event_mapping { + enum cst816x_gestures gesture; + u16 code; +}; + +static const struct cst816x_event_mapping event_map[16] = { + {CST816X_SWIPE_UP, BTN_FORWARD}, + {CST816X_SWIPE_DOWN, BTN_BACK}, + {CST816X_SWIPE_LEFT, BTN_LEFT}, + {CST816X_SWIPE_RIGHT, BTN_RIGHT}, + {CST816X_SINGLE_TAP, BTN_TOUCH}, + {CST816X_LONG_PRESS, BTN_TOOL_TRIPLETAP}, + {CST816X_RESERVED, KEY_RESERVED}, + {CST816X_RESERVED, KEY_RESERVED}, + {CST816X_RESERVED, KEY_RESERVED}, + {CST816X_RESERVED, KEY_RESERVED}, + {CST816X_RESERVED, KEY_RESERVED}, + {CST816X_RESERVED, KEY_RESERVED}, + {CST816X_RESERVED, KEY_RESERVED}, + {CST816X_RESERVED, KEY_RESERVED}, + {CST816X_RESERVED, KEY_RESERVED}, + {CST816X_RESERVED, KEY_RESERVED}, +}; + +static int cst816x_i2c_read_register(struct cst816x_priv *priv, u8 reg, + void *buf, size_t len) +{ + int rc; + struct i2c_msg xfer[] = { + { + .addr = priv->client->addr, + .flags = 0, + .buf = ®, + .len = sizeof(reg), + }, + { + .addr = priv->client->addr, + .flags = I2C_M_RD, + .buf = buf, + .len = len, + }, + }; + + rc = i2c_transfer(priv->client->adapter, xfer, ARRAY_SIZE(xfer)); + if (rc != ARRAY_SIZE(xfer)) { + rc = rc < 0 ? rc : -EIO; + dev_err(&priv->client->dev, "i2c rx err: %d\n", rc); + return rc; + } + + return 0; +} + +static bool cst816x_process_touch(struct cst816x_priv *priv, + struct cst816x_touch_info *info) +{ + u8 raw[8]; + + if (cst816x_i2c_read_register(priv, CST816X_FRAME, raw, sizeof(raw))) + return false; + + info->gesture = raw[0]; + info->touch = raw[1]; + info->abs_x = get_unaligned_be16(&raw[2]) & GENMASK(11, 0); + info->abs_y = get_unaligned_be16(&raw[4]) & GENMASK(11, 0); + + dev_dbg(priv->dev, "x: %d, y: %d, t: %d, g: 0x%x\n", info->abs_x, + info->abs_y, info->touch, info->gesture); + + return true; +} + +static int cst816x_register_input(struct cst816x_priv *priv) +{ + priv->input = devm_input_allocate_device(priv->dev); + if (!priv->input) + return -ENOMEM; + + priv->input->name = "Hynitron CST816X Touchscreen"; + priv->input->phys = "input/ts"; + priv->input->id.bustype = BUS_I2C; + input_set_drvdata(priv->input, priv); + + for (unsigned int i = 0; i < ARRAY_SIZE(event_map); i++) + input_set_capability(priv->input, EV_KEY, event_map[i].code); + + input_set_abs_params(priv->input, ABS_X, 0, 240, 0, 0); + input_set_abs_params(priv->input, ABS_Y, 0, 240, 0, 0); + + return input_register_device(priv->input); +} + +static void cst816x_reset(struct cst816x_priv *priv) +{ + if (priv->reset) { + gpiod_set_value_cansleep(priv->reset, 1); + msleep(50); + gpiod_set_value_cansleep(priv->reset, 0); + msleep(100); + } +} + +static void report_gesture_event(const struct cst816x_priv *priv, + enum cst816x_gestures gesture, bool touch) +{ + u16 key = event_map[gesture & 0x0F].code; + + if (key != KEY_RESERVED) + input_report_key(priv->input, key, touch); +} + +/* + * Supports five gestures: TOUCH, LEFT, RIGHT, FORWARD, BACK, and LONG_PRESS. + * Reports surface interaction, sliding coordinates and finger detachment. + * + * 1. TOUCH Gesture Scenario: + * + * [x/y] [touch] [gesture] [Action] [Report ABS] [Report Key] + * x y true 0x00 Touch ABS_X_Y BTN_TOUCH + * x y true 0x00 Slide ABS_X_Y + * x y false 0x05 Gesture BTN_TOUCH + * + * 2. LEFT, RIGHT, FORWARD, BACK, and LONG_PRESS Gestures Scenario: + * + * [x/y] [touch] [gesture] [Action] [Report ABS] [Report Key] + * x y true 0x00 Touch ABS_X_Y BTN_TOUCH + * x y true 0x01 Gesture ABS_X_Y BTN_FORWARD + * x y true 0x01 Slide ABS_X_Y + * x y false 0x01 Detach BTN_FORWARD | BTN_TOUCH + */ +static irqreturn_t cst816x_irq_cb(int irq, void *cookie) +{ + struct cst816x_priv *priv = cookie; + struct cst816x_touch_info info; + + if (!cst816x_process_touch(priv, &info)) + goto out; + + if (info.touch) { + input_report_abs(priv->input, ABS_X, info.abs_x); + input_report_abs(priv->input, ABS_Y, info.abs_y); + input_report_key(priv->input, BTN_TOUCH, 1); + } + + if (info.gesture) { + report_gesture_event(priv, info.gesture, info.touch); + + if (!info.touch) + input_report_key(priv->input, BTN_TOUCH, 0); + } + + input_sync(priv->input); + +out: + return IRQ_HANDLED; +} + +static int cst816x_probe(struct i2c_client *client) +{ + struct cst816x_priv *priv; + struct device *dev = &client->dev; + int error; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->dev = dev; + priv->client = client; + + priv->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(priv->reset)) + return dev_err_probe(dev, PTR_ERR(priv->reset), + "reset gpio not found\n"); + + cst816x_reset(priv); + + error = cst816x_register_input(priv); + if (error) + return dev_err_probe(dev, error, "input register failed\n"); + + error = devm_request_threaded_irq(dev, client->irq, NULL, cst816x_irq_cb, + IRQF_ONESHOT, dev->driver->name, priv); + if (error) + return dev_err_probe(dev, error, "irq request failed\n"); + + return 0; +} + +static const struct i2c_device_id cst816x_id[] = { + { .name = "cst816s", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, cst816x_id); + +static const struct of_device_id cst816x_of_match[] = { + { .compatible = "hynitron,cst816s", }, + { } +}; +MODULE_DEVICE_TABLE(of, cst816x_of_match); + +static struct i2c_driver cst816x_driver = { + .driver = { + .name = "cst816x", + .of_match_table = cst816x_of_match, + }, + .id_table = cst816x_id, + .probe = cst816x_probe, +}; + +module_i2c_driver(cst816x_driver); + +MODULE_AUTHOR("Oleh Kuzhylnyi <kuzhylol@xxxxxxxxx>"); +MODULE_DESCRIPTION("Hynitron CST816X Touchscreen Driver"); +MODULE_LICENSE("GPL"); -- 2.34.1