--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Himax hx83112b touchscreens
+ *
+ * Copyright (C) 2022 Job Noorman <job@noorman.info>
+ *
+ * This code is based on "Himax Android Driver Sample Code for QCT platform":
+ *
+ * Copyright (C) 2017 Himax Corporation.
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/regmap.h>
+
+#define HIMAX_ID_83112B 0x83112b
+
+#define HIMAX_MAX_POINTS 10
+
+#define HIMAX_REG_CFG_SET_ADDR 0x00
+#define HIMAX_REG_CFG_INIT_READ 0x0c
+#define HIMAX_REG_CFG_READ_VALUE 0x08
+#define HIMAX_REG_READ_EVENT 0x30
+
+#define HIMAX_CFG_PRODUCT_ID 0x900000d0
+
+#define HIMAX_INVALID_COORD 0xffff
+
+struct himax_event_point {
+ __be16 x;
+ __be16 y;
+} __packed;
+
+struct himax_event {
+ struct himax_event_point points[HIMAX_MAX_POINTS];
+ u8 majors[HIMAX_MAX_POINTS];
+ u8 pad0[2];
+ u8 num_points;
+ u8 pad1[2];
+ u8 checksum_fix;
+} __packed;
+
+static_assert(sizeof(struct himax_event) == 56);
+
+struct himax_ts_data {
+ struct gpio_desc *gpiod_rst;
+ struct input_dev *input_dev;
+ struct i2c_client *client;
+ struct regmap *regmap;
+ struct touchscreen_properties props;
+};
+
+static const struct regmap_config himax_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 32,
+ .val_format_endian = REGMAP_ENDIAN_LITTLE,
+};
+
+static int himax_read_config(struct himax_ts_data *ts, u32 address, u32 *dst)
+{
+ int error;
+
+ error = regmap_write(ts->regmap, HIMAX_REG_CFG_SET_ADDR, address);
+ if (error)
+ return error;
+
+ error = regmap_write(ts->regmap, HIMAX_REG_CFG_INIT_READ, 0x0);
+ if (error)
+ return error;
+
+ error = regmap_read(ts->regmap, HIMAX_REG_CFG_READ_VALUE, dst);
+ if (error)
+ return error;
+
+ return 0;
+}
+
+static void himax_reset(struct himax_ts_data *ts)
+{
+ gpiod_set_value_cansleep(ts->gpiod_rst, 1);
+
+ /* Delay copied from downstream driver */
+ msleep(20);
+ gpiod_set_value_cansleep(ts->gpiod_rst, 0);
+
+ /*
+ * The downstream driver doesn't contain this delay but is seems safer
+ * to include it. The range is just a guess that seems to work well.
+ */
+ usleep_range(1000, 1100);
+}
+
+static int himax_read_product_id(struct himax_ts_data *ts, u32 *product_id)
+{
+ int error;
+
+ error = himax_read_config(ts, HIMAX_CFG_PRODUCT_ID, product_id);
+ if (error)
+ return error;
+
+ *product_id >>= 8;
+ return 0;
+}
+
+static int himax_check_product_id(struct himax_ts_data *ts)
+{
+ int error;
+ u32 product_id;
+
+ error = himax_read_product_id(ts, &product_id);
+ if (error)
+ return error;
+
+ dev_dbg(&ts->client->dev, "Product id: %x\n", product_id);
+
+ switch (product_id) {
+ case HIMAX_ID_83112B:
+ return 0;
+
+ default:
+ dev_err(&ts->client->dev,
+ "Unknown product id: %x\n", product_id);
+ return -EINVAL;
+ }
+}
+
+static int himax_input_register(struct himax_ts_data *ts)
+{
+ int error;
+
+ ts->input_dev = devm_input_allocate_device(&ts->client->dev);
+ if (!ts->input_dev) {
+ dev_err(&ts->client->dev, "Failed to allocate input device\n");
+ return -ENOMEM;
+ }
+
+ ts->input_dev->name = "Himax Touchscreen";
+
+ input_set_capability(ts->input_dev, EV_ABS, ABS_MT_POSITION_X);
+ input_set_capability(ts->input_dev, EV_ABS, ABS_MT_POSITION_Y);
+ input_set_abs_params(ts->input_dev, ABS_MT_WIDTH_MAJOR, 0, 200, 0, 0);
+ input_set_abs_params(ts->input_dev, ABS_MT_TOUCH_MAJOR, 0, 200, 0, 0);
+
+ touchscreen_parse_properties(ts->input_dev, true, &ts->props);
+
+ error = input_mt_init_slots(ts->input_dev, HIMAX_MAX_POINTS,
+ INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
+ if (error) {
+ dev_err(&ts->client->dev,
+ "Failed to initialize MT slots: %d\n", error);
+ return error;
+ }
+
+ error = input_register_device(ts->input_dev);
+ if (error) {
+ dev_err(&ts->client->dev,
+ "Failed to register input device: %d\n", error);
+ return error;
+ }
+
+ return 0;
+}
+
+static u8 himax_event_get_num_points(const struct himax_event *event)
+{
+ if (event->num_points == 0xff)
+ return 0;
+ else
+ return event->num_points & 0x0f;
+}
+
+static bool himax_process_event_point(struct himax_ts_data *ts,
+ const struct himax_event *event,
+ int point_index)
+{
+ const struct himax_event_point *point = &event->points[point_index];
+ u16 x = be16_to_cpu(point->x);
+ u16 y = be16_to_cpu(point->y);
+ u8 w = event->majors[point_index];
+
+ if (x == HIMAX_INVALID_COORD || y == HIMAX_INVALID_COORD)
+ return false;
+
+ input_mt_slot(ts->input_dev, point_index);
+ input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, true);
+ touchscreen_report_pos(ts->input_dev, &ts->props, x, y, true);
+ input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR, w);
+ input_report_abs(ts->input_dev, ABS_MT_WIDTH_MAJOR, w);
+ return true;
+}
+
+static void himax_process_event(struct himax_ts_data *ts,
+ const struct himax_event *event)
+{
+ int i;
+ int num_points_left = himax_event_get_num_points(event);
+
+ for (i = 0; i < HIMAX_MAX_POINTS && num_points_left > 0; i++) {
+ if (himax_process_event_point(ts, event, i))
+ num_points_left--;
+ }
+
+ input_mt_sync_frame(ts->input_dev);
+ input_sync(ts->input_dev);
+}
+
+static bool himax_verify_checksum(struct himax_ts_data *ts,
+ const struct himax_event *event)
+{
+ u8 *data = (u8 *)event;
+ int i;
+ u16 checksum = 0;
+
+ for (i = 0; i < sizeof(*event); i++)
+ checksum += data[i];
+
+ if ((checksum & 0x00ff) != 0) {
+ dev_err(&ts->client->dev, "Wrong event checksum: %04x\n",
+ checksum);
+ return false;
+ }
+
+ return true;
+}
+
+static int himax_handle_input(struct himax_ts_data *ts)
+{
+ int error;
+ struct himax_event event;
+
+ error = regmap_raw_read(ts->regmap, HIMAX_REG_READ_EVENT, &event,
+ sizeof(event));
+ if (error) {
+ dev_err(&ts->client->dev, "Failed to read input event: %d\n",
+ error);
+ return error;
+ }
+
+ /*
+ * Only process the current event when it has a valid checksum but
+ * don't consider it a fatal error when it doesn't.
+ */
+ if (himax_verify_checksum(ts, &event))
+ himax_process_event(ts, &event);
+
+ return 0;
+}
+
+static irqreturn_t himax_irq_handler(int irq, void *dev_id)
+{
+ int error;
+ struct himax_ts_data *ts = dev_id;
+
+ error = himax_handle_input(ts);
+ if (error)
+ return IRQ_NONE;
+
+ return IRQ_HANDLED;
+}
+
+static int himax_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int error;
+ struct device *dev = &client->dev;
+ struct himax_ts_data *ts;
+
+ if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+ dev_err(dev, "I2C check functionality failed\n");
+ return -ENXIO;
+ }
+
+ ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
+ if (!ts)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, ts);
+ ts->client = client;
+
+ ts->regmap = devm_regmap_init_i2c(client, &himax_regmap_config);
+ error = PTR_ERR_OR_ZERO(ts->regmap);
+ if (error) {
+ dev_err(dev, "Failed to initialize regmap: %d\n", error);
+ return error;
+ }
+
+ ts->gpiod_rst = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+ error = PTR_ERR_OR_ZERO(ts->gpiod_rst);
+ if (error) {
+ dev_err(dev, "Failed to get reset GPIO: %d\n", error);
+ return error;
+ }
+
+ himax_reset(ts);
+
+ error = himax_check_product_id(ts);
+ if (error)
+ return error;
+
+ error = himax_input_register(ts);
+ if (error)
+ return error;
+
+ error = devm_request_threaded_irq(dev, client->irq, NULL,
+ himax_irq_handler, IRQF_ONESHOT,
+ client->name, ts);
+ if (error)
+ return error;
+
+ return 0;
+}
+
+static int himax_suspend(struct device *dev)
+{
+ struct himax_ts_data *ts = dev_get_drvdata(dev);
+
+ disable_irq(ts->client->irq);
+ return 0;
+}
+
+static int himax_resume(struct device *dev)
+{
+ struct himax_ts_data *ts = dev_get_drvdata(dev);
+
+ enable_irq(ts->client->irq);
+ return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(himax_pm_ops, himax_suspend, himax_resume);
+
+static const struct i2c_device_id himax_ts_id[] = {
+ { "hx83112b", 0 },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, himax_ts_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id himax_of_match[] = {
+ { .compatible = "himax,hx83112b" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, himax_of_match);
+#endif
+
+static struct i2c_driver himax_ts_driver = {
+ .probe = himax_probe,
+ .id_table = himax_ts_id,
+ .driver = {
+ .name = "Himax-hx83112b-TS",
+ .of_match_table = of_match_ptr(himax_of_match),
+ .pm = pm_sleep_ptr(&himax_pm_ops),
+ },
+};
+module_i2c_driver(himax_ts_driver);
+
+MODULE_AUTHOR("Job Noorman <job@noorman.info>");
+MODULE_DESCRIPTION("Himax hx83112b touchscreen driver");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-rpi.git / commitdiff