diff options
Diffstat (limited to 'drivers/input/touchscreen/hynitron-cst816x.c')
| -rw-r--r-- | drivers/input/touchscreen/hynitron-cst816x.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/hynitron-cst816x.c b/drivers/input/touchscreen/hynitron-cst816x.c new file mode 100644 index 000000000000..b64d7928e18f --- /dev/null +++ b/drivers/input/touchscreen/hynitron-cst816x.c @@ -0,0 +1,253 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Driver for I2C connected Hynitron CST816x Series Touchscreen + * + * Copyright (C) 2025 Oleh Kuzhylnyi <kuzhylol@gmail.com> + */ + +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/input.h> +#include <linux/unaligned.h> +#include <linux/interrupt.h> +#include <linux/module.h> + +#define CST816X_RD_REG 0x01 +#define CST816X_NUM_KEYS 5 + +struct cst816x_touch { + u8 gest; + u8 active; + u16 abs_x; + u16 abs_y; +} __packed; + +struct cst816x_priv { + struct i2c_client *client; + struct gpio_desc *reset; + struct input_dev *input; + unsigned int keycode[CST816X_NUM_KEYS]; + unsigned int keycodemax; +}; + +static int cst816x_parse_keycodes(struct device *dev, struct cst816x_priv *priv) +{ + int count; + int error; + + if (device_property_present(dev, "linux,keycodes")) { + count = device_property_count_u32(dev, "linux,keycodes"); + if (count < 0) { + error = count; + dev_err(dev, "failed to count keys: %d\n", error); + return error; + } else if (count > ARRAY_SIZE(priv->keycode)) { + dev_err(dev, "too many keys defined: %d\n", count); + return -EINVAL; + } + priv->keycodemax = count; + + error = device_property_read_u32_array(dev, "linux,keycodes", + priv->keycode, + priv->keycodemax); + if (error) { + dev_err(dev, "failed to read keycodes: %d\n", error); + return error; + } + } + + return 0; +} + +static int cst816x_i2c_read_register(struct cst816x_priv *priv, u8 reg, + void *buf, size_t len) +{ + 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, + }, + }; + int error; + int ret; + + ret = i2c_transfer(priv->client->adapter, xfer, ARRAY_SIZE(xfer)); + if (ret != ARRAY_SIZE(xfer)) { + error = ret < 0 ? ret : -EIO; + dev_err(&priv->client->dev, "i2c rx err: %d\n", error); + return error; + } + + return 0; +} + +static u8 cst816x_gest_idx(u8 gest) +{ + u8 index; + + switch (gest) { + case 0x01: /* Slide up gesture */ + case 0x02: /* Slide down gesture */ + case 0x03: /* Slide left gesture */ + case 0x04: /* Slide right gesture */ + index = gest; + break; + case 0x0c: /* Long press gesture */ + default: + index = CST816X_NUM_KEYS; + break; + } + + return index - 1; +} + +static bool cst816x_process_touch(struct cst816x_priv *priv, + struct cst816x_touch *tch) +{ + if (cst816x_i2c_read_register(priv, CST816X_RD_REG, tch, sizeof(*tch))) + return false; + + tch->abs_x = get_unaligned_be16(&tch->abs_x) & GENMASK(11, 0); + tch->abs_y = get_unaligned_be16(&tch->abs_y) & GENMASK(11, 0); + + dev_dbg(&priv->client->dev, "x: %u, y: %u, t: %u, g: 0x%x\n", + tch->abs_x, tch->abs_y, tch->active, tch->gest); + + return true; +} + +static int cst816x_register_input(struct cst816x_priv *priv) +{ + priv->input = devm_input_allocate_device(&priv->client->dev); + if (!priv->input) + return -ENOMEM; + + priv->input->name = "Hynitron CST816x Series Touchscreen"; + priv->input->phys = "input/ts"; + priv->input->id.bustype = BUS_I2C; + + input_set_drvdata(priv->input, priv); + + input_set_abs_params(priv->input, ABS_X, 0, 240, 0, 0); + input_set_abs_params(priv->input, ABS_Y, 0, 240, 0, 0); + input_set_capability(priv->input, EV_KEY, BTN_TOUCH); + + priv->input->keycode = priv->keycode; + priv->input->keycodesize = sizeof(priv->keycode[0]); + priv->input->keycodemax = priv->keycodemax; + + for (int i = 0; i < priv->keycodemax; i++) { + if (priv->keycode[i] == KEY_RESERVED) + continue; + + input_set_capability(priv->input, EV_KEY, priv->keycode[i]); + } + + return input_register_device(priv->input); +} + +static void cst816x_reset(struct cst816x_priv *priv) +{ + gpiod_set_value_cansleep(priv->reset, 1); + msleep(50); + gpiod_set_value_cansleep(priv->reset, 0); + msleep(100); +} + +static irqreturn_t cst816x_irq_cb(int irq, void *cookie) +{ + struct cst816x_priv *priv = cookie; + struct cst816x_touch tch; + + if (!cst816x_process_touch(priv, &tch)) + return IRQ_HANDLED; + + input_report_abs(priv->input, ABS_X, tch.abs_x); + input_report_abs(priv->input, ABS_Y, tch.abs_y); + + if (tch.gest) + input_report_key(priv->input, + priv->keycode[cst816x_gest_idx(tch.gest)], + tch.active); + + input_report_key(priv->input, BTN_TOUCH, tch.active); + + input_sync(priv->input); + + return IRQ_HANDLED; +} + +static int cst816x_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct cst816x_priv *priv; + int error; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + 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), + "gpio reset request failed\n"); + + if (priv->reset) + cst816x_reset(priv); + + error = cst816x_parse_keycodes(dev, priv); + if (error) + dev_warn(dev, "no gestures found in dt\n"); + + 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_string(dev), 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@gmail.com>"); +MODULE_DESCRIPTION("Hynitron CST816x Series Touchscreen Driver"); +MODULE_LICENSE("GPL"); |