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// 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 int himax_read_mcu(struct himax_ts_data *ts, u32 address, u32 *dst)
{
int error;
error = himax_bus_read(ts, address, dst, sizeof(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_mcu(ts, HIMAX_REG_ADDR_ICID, 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");