| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Driver for Himax hx83112b touchscreens |
| * |
| * Copyright (C) 2022 Job Noorman <job@noorman.info> |
| * |
| * HX83100A support |
| * Copyright (C) 2024 Felix Kaechele <felix@kaechele.ca> |
| * |
| * 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_MAX_POINTS 10 |
| |
| #define HIMAX_AHB_ADDR_BYTE_0 0x00 |
| #define HIMAX_AHB_ADDR_RDATA_BYTE_0 0x08 |
| #define HIMAX_AHB_ADDR_ACCESS_DIRECTION 0x0c |
| #define HIMAX_AHB_ADDR_INCR4 0x0d |
| #define HIMAX_AHB_ADDR_CONTI 0x13 |
| #define HIMAX_AHB_ADDR_EVENT_STACK 0x30 |
| |
| #define HIMAX_AHB_CMD_ACCESS_DIRECTION_READ 0x00 |
| #define HIMAX_AHB_CMD_INCR4 0x10 |
| #define HIMAX_AHB_CMD_CONTI 0x31 |
| |
| #define HIMAX_REG_ADDR_ICID 0x900000d0 |
| |
| #define HX83100A_REG_FW_EVENT_STACK 0x90060000 |
| |
| #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 himax_chip { |
| u32 id; |
| int (*check_id)(struct himax_ts_data *ts); |
| int (*read_events)(struct himax_ts_data *ts, struct himax_event *event, |
| size_t length); |
| }; |
| |
| struct himax_ts_data { |
| const struct himax_chip *chip; |
| 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_bus_enable_burst(struct himax_ts_data *ts) |
| { |
| int error; |
| |
| error = regmap_write(ts->regmap, HIMAX_AHB_ADDR_CONTI, |
| HIMAX_AHB_CMD_CONTI); |
| if (error) |
| return error; |
| |
| error = regmap_write(ts->regmap, HIMAX_AHB_ADDR_INCR4, |
| HIMAX_AHB_CMD_INCR4); |
| if (error) |
| return error; |
| |
| return 0; |
| } |
| |
| static int himax_bus_read(struct himax_ts_data *ts, u32 address, void *dst, |
| size_t length) |
| { |
| int error; |
| |
| if (length > 4) { |
| error = himax_bus_enable_burst(ts); |
| if (error) |
| return error; |
| } |
| |
| error = regmap_write(ts->regmap, HIMAX_AHB_ADDR_BYTE_0, address); |
| if (error) |
| return error; |
| |
| error = regmap_write(ts->regmap, HIMAX_AHB_ADDR_ACCESS_DIRECTION, |
| HIMAX_AHB_CMD_ACCESS_DIRECTION_READ); |
| if (error) |
| return error; |
| |
| if (length > 4) |
| error = regmap_noinc_read(ts->regmap, HIMAX_AHB_ADDR_RDATA_BYTE_0, |
| dst, length); |
| else |
| error = regmap_read(ts->regmap, HIMAX_AHB_ADDR_RDATA_BYTE_0, |
| 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_bus_read(ts, HIMAX_REG_ADDR_ICID, product_id, |
| sizeof(*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); |
| |
| if (product_id == ts->chip->id) |
| return 0; |
| |
| 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_read_events(struct himax_ts_data *ts, |
| struct himax_event *event, size_t length) |
| { |
| return regmap_raw_read(ts->regmap, HIMAX_AHB_ADDR_EVENT_STACK, event, |
| length); |
| } |
| |
| static int hx83100a_read_events(struct himax_ts_data *ts, |
| struct himax_event *event, size_t length) |
| { |
| return himax_bus_read(ts, HX83100A_REG_FW_EVENT_STACK, event, length); |
| }; |
| |
| static int himax_handle_input(struct himax_ts_data *ts) |
| { |
| int error; |
| struct himax_event event; |
| |
| error = ts->chip->read_events(ts, &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) |
| { |
| 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->chip = i2c_get_match_data(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); |
| |
| if (ts->chip->check_id) { |
| 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 himax_chip hx83100a_chip = { |
| .read_events = hx83100a_read_events, |
| }; |
| |
| static const struct himax_chip hx83112b_chip = { |
| .id = 0x83112b, |
| .check_id = himax_check_product_id, |
| .read_events = himax_read_events, |
| }; |
| |
| static const struct i2c_device_id himax_ts_id[] = { |
| { "hx83100a", (kernel_ulong_t)&hx83100a_chip }, |
| { "hx83112b", (kernel_ulong_t)&hx83112b_chip }, |
| { /* sentinel */ } |
| }; |
| MODULE_DEVICE_TABLE(i2c, himax_ts_id); |
| |
| #ifdef CONFIG_OF |
| static const struct of_device_id himax_of_match[] = { |
| { .compatible = "himax,hx83100a", .data = &hx83100a_chip }, |
| { .compatible = "himax,hx83112b", .data = &hx83112b_chip }, |
| { /* 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"); |