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 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 | 306 +++++++++++++++++++
3 files changed, 319 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..86715c3d1872
--- /dev/null
+++ b/drivers/input/touchscreen/hynitron-cst816x.c
@@ -0,0 +1,306 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for I2C connected Hynitron CST816X Touchscreen
+ *
+ * Copyright (C) 2024 Oleh Kuzhylnyi <kuzhylol@xxxxxxxxx>
+ */
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/of_irq.h>
+#include <linux/timer.h>
+
+#define CST816X_MAX_X 240
+#define CST816X_MAX_Y CST816X_MAX_X
+
+#define CST816X_EVENT_TIMEOUT_MS 10
+
+enum cst816x_registers {
+ CST816X_FRAME = 0x01,
+ CST816X_MOTION = 0xEC,
+};
+
+enum cst816_gesture_code {
+ CST816X_SWIPE = 0x00,
+ CST816X_SWIPE_UP = 0x01,
+ CST816X_SWIPE_DOWN = 0x02,
+ CST816X_SWIPE_LEFT = 0x03,
+ CST816X_SWIPE_RIGHT = 0x04,
+ CST816X_SINGLE_TAP = 0x05,
+ CST816X_DOUBLE_TAP = 0x0B,
+ CST816X_LONG_PRESS = 0x0C,
+};
+
+struct cst816x_info {
+ u8 gesture;
+ u8 x;
+ u8 y;
+};
+
+struct cst816x_priv {
+ struct device *dev;
+ struct i2c_client *client;
+ struct gpio_desc *reset;
+ struct input_dev *input;
+ struct timer_list timer;
+ struct delayed_work dw;
+ struct cst816x_info info;
+
+ u8 rxtx[8];
+};
+
+struct cst816x_gesture_mapping {
+ enum cst816_gesture_code gesture_code;
+ size_t event_code;
+};
+
+static const struct cst816x_gesture_mapping cst816x_gesture_map[] = {
+ {CST816X_SWIPE, KEY_UNKNOWN},
+ {CST816X_SWIPE_UP, KEY_UP},
+ {CST816X_SWIPE_DOWN, KEY_DOWN},
+ {CST816X_SWIPE_LEFT, KEY_LEFT},
+ {CST816X_SWIPE_RIGHT, KEY_RIGHT},
+ {CST816X_SINGLE_TAP, BTN_TOUCH},
+ {CST816X_DOUBLE_TAP, BTN_TOOL_DOUBLETAP},
+ {CST816X_LONG_PRESS, BTN_TOOL_TRIPLETAP}
+};
+
+static int cst816x_i2c_write_reg(struct cst816x_priv *priv, u8 reg, u8 cmd)
+{
+ struct i2c_client *client;
+ struct i2c_msg xfer;
+ int rc;
+
+ client = priv->client;
+
+ priv->rxtx[0] = reg;
+ priv->rxtx[1] = cmd;
+
+ xfer.addr = client->addr;
+ xfer.flags = 0;
+ xfer.len = 2;
+ xfer.buf = priv->rxtx;
+
+ rc = i2c_transfer(client->adapter, &xfer, 1);
+ if (rc != 1) {
+ if (rc >= 0)
+ rc = -EIO;
+ } else {
+ rc = 0;
+ }
+
+ if (rc < 0)
+ dev_err(&client->dev, "i2c tx err: %d\n", rc);
+
+ return rc;
+}
+
+static int cst816x_i2c_read_reg(struct cst816x_priv *priv, u8 reg)
+{
+ struct i2c_client *client;
+ struct i2c_msg xfer[2];
+ int rc;
+
+ client = priv->client;
+
+ xfer[0].addr = client->addr;
+ xfer[0].flags = 0;
+ xfer[0].len = sizeof(reg);
+ xfer[0].buf = ®
+
+ xfer[1].addr = client->addr;
+ xfer[1].flags = I2C_M_RD;
+ xfer[1].len = sizeof(priv->rxtx);
+ xfer[1].buf = priv->rxtx;
+
+ rc = i2c_transfer(client->adapter, xfer, ARRAY_SIZE(xfer));
+ if (rc != ARRAY_SIZE(xfer)) {
+ if (rc >= 0)
+ rc = -EIO;
+ } else {
+ rc = 0;
+ }
+
+ if (rc < 0)
+ dev_err(&client->dev, "i2c rx err: %d\n", rc);
+
+ return rc;
+}
+
+static int cst816x_setup_regs(struct cst816x_priv *priv)
+{
+ return cst816x_i2c_write_reg(priv, CST816X_MOTION, CST816X_DOUBLE_TAP);
+}
+
+static void report_gesture_event(const struct cst816x_priv *priv,
+ enum cst816_gesture_code gesture_code,
+ bool state)
+{
+ const struct cst816x_gesture_mapping *lookup = NULL;
+
+ for (u8 i = CST816X_SWIPE_UP; i < ARRAY_SIZE(cst816x_gesture_map); i++) {
+ if (cst816x_gesture_map[i].gesture_code == gesture_code) {
+ lookup = &cst816x_gesture_map[i];
+ break;
+ }
+ }
+
+ if (lookup)
+ input_report_key(priv->input, lookup->event_code, state);
+}
+
+static int cst816x_process_touch(struct cst816x_priv *priv)
+{
+ u8 *raw;
+ int rc;
+
+ rc = cst816x_i2c_read_reg(priv, CST816X_FRAME);
+ if (!rc) {
+ raw = priv->rxtx;
+
+ priv->info.gesture = raw[0];
+ priv->info.x = ((raw[2] & 0x0F) << 8) | raw[3];
+ priv->info.y = ((raw[4] & 0x0F) << 8) | raw[5];
+
+ dev_dbg(priv->dev, "x: %d, y: %d, gesture: 0x%x\n",
+ priv->info.x, priv->info.y, priv->info.gesture);
+ }
+
+ return rc;
+}
+
+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 (u8 i = CST816X_SWIPE_UP; i < ARRAY_SIZE(cst816x_gesture_map); i++) {
+ input_set_capability(priv->input, EV_KEY,
+ cst816x_gesture_map[i].event_code);
+ }
+
+ input_set_abs_params(priv->input, ABS_X, 0, CST816X_MAX_X, 0, 0);
+ input_set_abs_params(priv->input, ABS_Y, 0, CST816X_MAX_Y, 0, 0);
+ input_set_capability(priv->input, EV_ABS, ABS_X);
+ input_set_capability(priv->input, EV_ABS, ABS_Y);
+
+ return input_register_device(priv->input);
+}
+
+static void cst816x_reset(struct cst816x_priv *priv)
+{
+ gpiod_set_value_cansleep(priv->reset, 0);
+ msleep(100);
+ gpiod_set_value_cansleep(priv->reset, 1);
+ msleep(100);
+}
+
+static void cst816x_timer_cb(struct timer_list *timer)
+{
+ struct cst816x_priv *priv = from_timer(priv, timer, timer);
+
+ report_gesture_event(priv, priv->info.gesture, false);
+ input_sync(priv->input);
+}
+
+static void cst816x_dw_cb(struct work_struct *work)
+{
+ struct cst816x_priv *priv =
+ container_of(work, struct cst816x_priv, dw.work);
+
+ if (!cst816x_process_touch(priv)) {
+ input_report_abs(priv->input, ABS_X, priv->info.x);
+ input_report_abs(priv->input, ABS_Y, priv->info.y);
+ report_gesture_event(priv, priv->info.gesture, true);
+ input_sync(priv->input);
+
+ mod_timer(&priv->timer,
+ jiffies + msecs_to_jiffies(CST816X_EVENT_TIMEOUT_MS));
+ }
+}
+
+static irqreturn_t cst816x_irq_cb(int irq, void *cookie)
+{
+ struct cst816x_priv *priv = (struct cst816x_priv *)cookie;
+
+ schedule_delayed_work(&priv->dw, 0);
+
+ return IRQ_HANDLED;
+}
+
+static int cst816x_probe(struct i2c_client *client)
+{
+ struct cst816x_priv *priv;
+ struct device *dev = &client->dev;
+ int rc;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = dev;
+ priv->client = client;
+
+ INIT_DELAYED_WORK(&priv->dw, cst816x_dw_cb);
+ timer_setup(&priv->timer, cst816x_timer_cb, 0);
+
+ priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(priv->reset))
+ return dev_err_probe(dev, PTR_ERR(priv->reset),
+ "reset gpio not found\n");
+
+ if (priv->reset)
+ cst816x_reset(priv);
+
+ rc = cst816x_setup_regs(priv);
+ if (rc)
+ return dev_err_probe(dev, rc, "regs setup failed\n");
+
+ client->irq = of_irq_get(dev->of_node, 0);
+ if (client->irq <= 0)
+ return dev_err_probe(dev, client->irq, "irq lookup failed\n");
+
+ rc = devm_request_threaded_irq(dev, client->irq, NULL, cst816x_irq_cb,
+ IRQF_ONESHOT, dev->driver->name, priv);
+ if (rc)
+ return dev_err_probe(dev, client->irq, "irq request failed\n");
+
+ return cst816x_register_input(priv);
+}
+
+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");
--
2.30.2
