blob: 05946fee4fd440a6a284e53584cf0b16d8194ab3 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for Hynitron cstxxx Touchscreen
*
* Copyright (c) 2022 Chris Morgan <macromorgan@hotmail.com>
*
* This code is based on hynitron_core.c authored by Hynitron.
* Note that no datasheet was available, so much of these registers
* are undocumented. This is essentially a cleaned-up version of the
* vendor driver with support removed for hardware I cannot test and
* device-specific functions replated with generic functions wherever
* possible.
*/
#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/mod_devicetable.h>
#include <linux/module.h>
#include <linux/property.h>
#include <asm/unaligned.h>
/* Per chip data */
struct hynitron_ts_chip_data {
unsigned int max_touch_num;
u32 ic_chkcode;
int (*firmware_info)(struct i2c_client *client);
int (*bootloader_enter)(struct i2c_client *client);
int (*init_input)(struct i2c_client *client);
void (*report_touch)(struct i2c_client *client);
};
/* Data generic to all (supported and non-supported) controllers. */
struct hynitron_ts_data {
const struct hynitron_ts_chip_data *chip;
struct i2c_client *client;
struct input_dev *input_dev;
struct touchscreen_properties prop;
struct gpio_desc *reset_gpio;
};
/*
* Since I have no datasheet, these values are guessed and/or assumed
* based on observation and testing.
*/
#define CST3XX_FIRMWARE_INFO_START_CMD 0x01d1
#define CST3XX_FIRMWARE_INFO_END_CMD 0x09d1
#define CST3XX_FIRMWARE_CHK_CODE_REG 0xfcd1
#define CST3XX_FIRMWARE_VERSION_REG 0x08d2
#define CST3XX_FIRMWARE_VER_INVALID_VAL 0xa5a5a5a5
#define CST3XX_BOOTLDR_PROG_CMD 0xaa01a0
#define CST3XX_BOOTLDR_PROG_CHK_REG 0x02a0
#define CST3XX_BOOTLDR_CHK_VAL 0xac
#define CST3XX_TOUCH_DATA_PART_REG 0x00d0
#define CST3XX_TOUCH_DATA_FULL_REG 0x07d0
#define CST3XX_TOUCH_DATA_CHK_VAL 0xab
#define CST3XX_TOUCH_DATA_TOUCH_VAL 0x03
#define CST3XX_TOUCH_DATA_STOP_CMD 0xab00d0
#define CST3XX_TOUCH_COUNT_MASK GENMASK(6, 0)
/*
* Hard coded reset delay value of 20ms not IC dependent in
* vendor driver.
*/
static void hyn_reset_proc(struct i2c_client *client, int delay)
{
struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
gpiod_set_value_cansleep(ts_data->reset_gpio, 1);
msleep(20);
gpiod_set_value_cansleep(ts_data->reset_gpio, 0);
if (delay)
fsleep(delay * 1000);
}
static irqreturn_t hyn_interrupt_handler(int irq, void *dev_id)
{
struct i2c_client *client = dev_id;
struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
ts_data->chip->report_touch(client);
return IRQ_HANDLED;
}
/*
* The vendor driver would retry twice before failing to read or write
* to the i2c device.
*/
static int cst3xx_i2c_write(struct i2c_client *client,
unsigned char *buf, int len)
{
int ret;
int retries = 0;
while (retries < 2) {
ret = i2c_master_send(client, buf, len);
if (ret == len)
return 0;
if (ret <= 0)
retries++;
else
break;
}
return ret < 0 ? ret : -EIO;
}
static int cst3xx_i2c_read_register(struct i2c_client *client, u16 reg,
u8 *val, u16 len)
{
__le16 buf = cpu_to_le16(reg);
struct i2c_msg msgs[] = {
{
.addr = client->addr,
.flags = 0,
.len = 2,
.buf = (u8 *)&buf,
},
{
.addr = client->addr,
.flags = I2C_M_RD,
.len = len,
.buf = val,
}
};
int err;
int ret;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret == ARRAY_SIZE(msgs))
return 0;
err = ret < 0 ? ret : -EIO;
dev_err(&client->dev, "Error reading %d bytes from 0x%04x: %d (%d)\n",
len, reg, err, ret);
return err;
}
static int cst3xx_firmware_info(struct i2c_client *client)
{
struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
int err;
u32 tmp;
unsigned char buf[4];
/*
* Tests suggest this command needed to read firmware regs.
*/
put_unaligned_le16(CST3XX_FIRMWARE_INFO_START_CMD, buf);
err = cst3xx_i2c_write(client, buf, 2);
if (err)
return err;
usleep_range(10000, 11000);
/*
* Read register for check-code to determine if device detected
* correctly.
*/
err = cst3xx_i2c_read_register(client, CST3XX_FIRMWARE_CHK_CODE_REG,
buf, 4);
if (err)
return err;
tmp = get_unaligned_le32(buf);
if ((tmp & 0xffff0000) != ts_data->chip->ic_chkcode) {
dev_err(&client->dev, "%s ic mismatch, chkcode is %u\n",
__func__, tmp);
return -ENODEV;
}
usleep_range(10000, 11000);
/* Read firmware version and test if firmware missing. */
err = cst3xx_i2c_read_register(client, CST3XX_FIRMWARE_VERSION_REG,
buf, 4);
if (err)
return err;
tmp = get_unaligned_le32(buf);
if (tmp == CST3XX_FIRMWARE_VER_INVALID_VAL) {
dev_err(&client->dev, "Device firmware missing\n");
return -ENODEV;
}
/*
* Tests suggest cmd required to exit reading firmware regs.
*/
put_unaligned_le16(CST3XX_FIRMWARE_INFO_END_CMD, buf);
err = cst3xx_i2c_write(client, buf, 2);
if (err)
return err;
usleep_range(5000, 6000);
return 0;
}
static int cst3xx_bootloader_enter(struct i2c_client *client)
{
int err;
u8 retry;
u32 tmp = 0;
unsigned char buf[3];
for (retry = 0; retry < 5; retry++) {
hyn_reset_proc(client, (7 + retry));
/* set cmd to enter program mode */
put_unaligned_le24(CST3XX_BOOTLDR_PROG_CMD, buf);
err = cst3xx_i2c_write(client, buf, 3);
if (err)
continue;
usleep_range(2000, 2500);
/* check whether in program mode */
err = cst3xx_i2c_read_register(client,
CST3XX_BOOTLDR_PROG_CHK_REG,
buf, 1);
if (err)
continue;
tmp = get_unaligned(buf);
if (tmp == CST3XX_BOOTLDR_CHK_VAL)
break;
}
if (tmp != CST3XX_BOOTLDR_CHK_VAL) {
dev_err(&client->dev, "%s unable to enter bootloader mode\n",
__func__);
return -ENODEV;
}
hyn_reset_proc(client, 40);
return 0;
}
static void cst3xx_report_contact(struct hynitron_ts_data *ts_data,
u8 id, unsigned int x, unsigned int y, u8 w)
{
input_mt_slot(ts_data->input_dev, id);
input_mt_report_slot_state(ts_data->input_dev, MT_TOOL_FINGER, 1);
touchscreen_report_pos(ts_data->input_dev, &ts_data->prop, x, y, true);
input_report_abs(ts_data->input_dev, ABS_MT_TOUCH_MAJOR, w);
}
static int cst3xx_finish_touch_read(struct i2c_client *client)
{
unsigned char buf[3];
int err;
put_unaligned_le24(CST3XX_TOUCH_DATA_STOP_CMD, buf);
err = cst3xx_i2c_write(client, buf, 3);
if (err) {
dev_err(&client->dev,
"send read touch info ending failed: %d\n", err);
return err;
}
return 0;
}
/*
* Handle events from IRQ. Note that for cst3xx it appears that IRQ
* fires continuously while touched, otherwise once every 1500ms
* when not touched (assume touchscreen waking up periodically).
* Note buffer is sized for 5 fingers, if more needed buffer must
* be increased. The buffer contains 5 bytes for each touch point,
* a touch count byte, a check byte, and then a second check byte after
* all other touch points.
*
* For example 1 touch would look like this:
* touch1[5]:touch_count[1]:chk_byte[1]
*
* 3 touches would look like this:
* touch1[5]:touch_count[1]:chk_byte[1]:touch2[5]:touch3[5]:chk_byte[1]
*/
static void cst3xx_touch_report(struct i2c_client *client)
{
struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
u8 buf[28];
u8 finger_id, sw, w;
unsigned int x, y;
unsigned int touch_cnt, end_byte;
unsigned int idx = 0;
unsigned int i;
int err;
/* Read and validate the first bits of input data. */
err = cst3xx_i2c_read_register(client, CST3XX_TOUCH_DATA_PART_REG,
buf, 28);
if (err ||
buf[6] != CST3XX_TOUCH_DATA_CHK_VAL ||
buf[0] == CST3XX_TOUCH_DATA_CHK_VAL) {
dev_err(&client->dev, "cst3xx touch read failure\n");
return;
}
/* Report to the device we're done reading the touch data. */
err = cst3xx_finish_touch_read(client);
if (err)
return;
touch_cnt = buf[5] & CST3XX_TOUCH_COUNT_MASK;
/*
* Check the check bit of the last touch slot. The check bit is
* always present after touch point 1 for valid data, and then
* appears as the last byte after all other touch data.
*/
if (touch_cnt > 1) {
end_byte = touch_cnt * 5 + 2;
if (buf[end_byte] != CST3XX_TOUCH_DATA_CHK_VAL) {
dev_err(&client->dev, "cst3xx touch read failure\n");
return;
}
}
/* Parse through the buffer to capture touch data. */
for (i = 0; i < touch_cnt; i++) {
x = ((buf[idx + 1] << 4) | ((buf[idx + 3] >> 4) & 0x0f));
y = ((buf[idx + 2] << 4) | (buf[idx + 3] & 0x0f));
w = (buf[idx + 4] >> 3);
sw = (buf[idx] & 0x0f) >> 1;
finger_id = (buf[idx] >> 4) & 0x0f;
/* Sanity check we don't have more fingers than we expect */
if (ts_data->chip->max_touch_num < finger_id) {
dev_err(&client->dev, "cst3xx touch read failure\n");
break;
}
/* sw value of 0 means no touch, 0x03 means touch */
if (sw == CST3XX_TOUCH_DATA_TOUCH_VAL)
cst3xx_report_contact(ts_data, finger_id, x, y, w);
idx += 5;
/* Skip the 2 bytes between point 1 and point 2 */
if (i == 0)
idx += 2;
}
input_mt_sync_frame(ts_data->input_dev);
input_sync(ts_data->input_dev);
}
static int cst3xx_input_dev_int(struct i2c_client *client)
{
struct hynitron_ts_data *ts_data = i2c_get_clientdata(client);
int err;
ts_data->input_dev = devm_input_allocate_device(&client->dev);
if (!ts_data->input_dev) {
dev_err(&client->dev, "Failed to allocate input device\n");
return -ENOMEM;
}
ts_data->input_dev->name = "Hynitron cst3xx Touchscreen";
ts_data->input_dev->phys = "input/ts";
ts_data->input_dev->id.bustype = BUS_I2C;
input_set_drvdata(ts_data->input_dev, ts_data);
input_set_capability(ts_data->input_dev, EV_ABS, ABS_MT_POSITION_X);
input_set_capability(ts_data->input_dev, EV_ABS, ABS_MT_POSITION_Y);
input_set_abs_params(ts_data->input_dev, ABS_MT_TOUCH_MAJOR,
0, 255, 0, 0);
touchscreen_parse_properties(ts_data->input_dev, true, &ts_data->prop);
if (!ts_data->prop.max_x || !ts_data->prop.max_y) {
dev_err(&client->dev,
"Invalid x/y (%d, %d), using defaults\n",
ts_data->prop.max_x, ts_data->prop.max_y);
ts_data->prop.max_x = 1152;
ts_data->prop.max_y = 1920;
input_abs_set_max(ts_data->input_dev,
ABS_MT_POSITION_X, ts_data->prop.max_x);
input_abs_set_max(ts_data->input_dev,
ABS_MT_POSITION_Y, ts_data->prop.max_y);
}
err = input_mt_init_slots(ts_data->input_dev,
ts_data->chip->max_touch_num,
INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
if (err) {
dev_err(&client->dev,
"Failed to initialize input slots: %d\n", err);
return err;
}
err = input_register_device(ts_data->input_dev);
if (err) {
dev_err(&client->dev,
"Input device registration failed: %d\n", err);
return err;
}
return 0;
}
static int hyn_probe(struct i2c_client *client)
{
struct hynitron_ts_data *ts_data;
int err;
ts_data = devm_kzalloc(&client->dev, sizeof(*ts_data), GFP_KERNEL);
if (!ts_data)
return -ENOMEM;
ts_data->client = client;
i2c_set_clientdata(client, ts_data);
ts_data->chip = device_get_match_data(&client->dev);
if (!ts_data->chip)
return -EINVAL;
ts_data->reset_gpio = devm_gpiod_get(&client->dev,
"reset", GPIOD_OUT_LOW);
err = PTR_ERR_OR_ZERO(ts_data->reset_gpio);
if (err) {
dev_err(&client->dev, "request reset gpio failed: %d\n", err);
return err;
}
hyn_reset_proc(client, 60);
err = ts_data->chip->bootloader_enter(client);
if (err < 0)
return err;
err = ts_data->chip->init_input(client);
if (err < 0)
return err;
err = ts_data->chip->firmware_info(client);
if (err < 0)
return err;
err = devm_request_threaded_irq(&client->dev, client->irq,
NULL, hyn_interrupt_handler,
IRQF_ONESHOT,
"Hynitron Touch Int", client);
if (err) {
dev_err(&client->dev, "failed to request IRQ: %d\n", err);
return err;
}
return 0;
}
static const struct hynitron_ts_chip_data cst3xx_data = {
.max_touch_num = 5,
.ic_chkcode = 0xcaca0000,
.firmware_info = &cst3xx_firmware_info,
.bootloader_enter = &cst3xx_bootloader_enter,
.init_input = &cst3xx_input_dev_int,
.report_touch = &cst3xx_touch_report,
};
static const struct i2c_device_id hyn_tpd_id[] = {
{ .name = "hynitron_ts", 0 },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(i2c, hyn_tpd_id);
static const struct of_device_id hyn_dt_match[] = {
{ .compatible = "hynitron,cst340", .data = &cst3xx_data },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, hyn_dt_match);
static struct i2c_driver hynitron_i2c_driver = {
.driver = {
.name = "Hynitron-TS",
.of_match_table = hyn_dt_match,
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
},
.id_table = hyn_tpd_id,
.probe = hyn_probe,
};
module_i2c_driver(hynitron_i2c_driver);
MODULE_AUTHOR("Chris Morgan");
MODULE_DESCRIPTION("Hynitron Touchscreen Driver");
MODULE_LICENSE("GPL");