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linux/drivers/input/touchscreen/st1232.c
Geert Uytterhoeven f605be6a57 Input: st1232 - wait until device is ready before reading resolution 
According to the st1232 datasheet, the host has to wait for the device
to change into Normal state before accessing registers other than the
Status Register.

If the reset GPIO is wired, the device is powered on during driver
probe, just before reading the resolution.  However, the latter may
happen before the device is ready, leading to a probe failure:

    st1232-ts 1-0055: Failed to read resolution: -6

Fix this by waiting until the device is ready, by trying to read the
Status Register until it indicates so, or until timeout.

On Armadillo 800 EVA, typically the first read fails with an I2C
transfer error, while the second read indicates the device is ready.

Fixes: 3a54a21541 ("Input: st1232 - add support resolution reading")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20201229162601.2154566-4-geert+renesas@glider.be
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2021-01-01 22:19:03 -08:00

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// SPDX-License-Identifier: GPL-2.0
/*
* ST1232 Touchscreen Controller Driver
*
* Copyright (C) 2010 Renesas Solutions Corp.
* Tony SIM <chinyeow.sim.xt@renesas.com>
*
* Using code from:
* - android.git.kernel.org: projects/kernel/common.git: synaptics_i2c_rmi.c
* Copyright (C) 2007 Google, Inc.
*/
#include <linux/delay.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/module.h>
#include <linux/of.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/types.h>
#define ST1232_TS_NAME "st1232-ts"
#define ST1633_TS_NAME "st1633-ts"
#define REG_STATUS 0x01 /* Device Status | Error Code */
#define STATUS_NORMAL 0x00
#define STATUS_INIT 0x01
#define STATUS_ERROR 0x02
#define STATUS_AUTO_TUNING 0x03
#define STATUS_IDLE 0x04
#define STATUS_POWER_DOWN 0x05
#define ERROR_NONE 0x00
#define ERROR_INVALID_ADDRESS 0x10
#define ERROR_INVALID_VALUE 0x20
#define ERROR_INVALID_PLATFORM 0x30
#define REG_XY_RESOLUTION 0x04
#define REG_XY_COORDINATES 0x12
#define ST_TS_MAX_FINGERS 10
struct st_chip_info {
bool have_z;
u16 max_area;
u16 max_fingers;
};
struct st1232_ts_data {
struct i2c_client *client;
struct input_dev *input_dev;
struct touchscreen_properties prop;
struct dev_pm_qos_request low_latency_req;
struct gpio_desc *reset_gpio;
const struct st_chip_info *chip_info;
int read_buf_len;
u8 *read_buf;
};
static int st1232_ts_read_data(struct st1232_ts_data *ts, u8 reg,
unsigned int n)
{
struct i2c_client *client = ts->client;
struct i2c_msg msg[] = {
{
.addr = client->addr,
.len = sizeof(reg),
.buf = &reg,
},
{
.addr = client->addr,
.flags = I2C_M_RD | I2C_M_DMA_SAFE,
.len = n,
.buf = ts->read_buf,
}
};
int ret;
ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
if (ret != ARRAY_SIZE(msg))
return ret < 0 ? ret : -EIO;
return 0;
}
static int st1232_ts_wait_ready(struct st1232_ts_data *ts)
{
unsigned int retries;
int error;
for (retries = 10; retries; retries--) {
error = st1232_ts_read_data(ts, REG_STATUS, 1);
if (!error && ts->read_buf[0] == (STATUS_NORMAL | ERROR_NONE))
return 0;
usleep_range(1000, 2000);
}
return -ENXIO;
}
static int st1232_ts_read_resolution(struct st1232_ts_data *ts, u16 *max_x,
u16 *max_y)
{
u8 *buf;
int error;
/* select resolution register */
error = st1232_ts_read_data(ts, REG_XY_RESOLUTION, 3);
if (error)
return error;
buf = ts->read_buf;
*max_x = (((buf[0] & 0x0070) << 4) | buf[1]) - 1;
*max_y = (((buf[0] & 0x0007) << 8) | buf[2]) - 1;
return 0;
}
static int st1232_ts_parse_and_report(struct st1232_ts_data *ts)
{
struct input_dev *input = ts->input_dev;
struct input_mt_pos pos[ST_TS_MAX_FINGERS];
u8 z[ST_TS_MAX_FINGERS];
int slots[ST_TS_MAX_FINGERS];
int n_contacts = 0;
int i;
for (i = 0; i < ts->chip_info->max_fingers; i++) {
u8 *buf = &ts->read_buf[i * 4];
if (buf[0] & BIT(7)) {
unsigned int x = ((buf[0] & 0x70) << 4) | buf[1];
unsigned int y = ((buf[0] & 0x07) << 8) | buf[2];
touchscreen_set_mt_pos(&pos[n_contacts],
&ts->prop, x, y);
/* st1232 includes a z-axis / touch strength */
if (ts->chip_info->have_z)
z[n_contacts] = ts->read_buf[i + 6];
n_contacts++;
}
}
input_mt_assign_slots(input, slots, pos, n_contacts, 0);
for (i = 0; i < n_contacts; i++) {
input_mt_slot(input, slots[i]);
input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
input_report_abs(input, ABS_MT_POSITION_X, pos[i].x);
input_report_abs(input, ABS_MT_POSITION_Y, pos[i].y);
if (ts->chip_info->have_z)
input_report_abs(input, ABS_MT_TOUCH_MAJOR, z[i]);
}
input_mt_sync_frame(input);
input_sync(input);
return n_contacts;
}
static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
{
struct st1232_ts_data *ts = dev_id;
int count;
int error;
error = st1232_ts_read_data(ts, REG_XY_COORDINATES, ts->read_buf_len);
if (error)
goto out;
count = st1232_ts_parse_and_report(ts);
if (!count) {
if (ts->low_latency_req.dev) {
dev_pm_qos_remove_request(&ts->low_latency_req);
ts->low_latency_req.dev = NULL;
}
} else if (!ts->low_latency_req.dev) {
/* First contact, request 100 us latency. */
dev_pm_qos_add_ancestor_request(&ts->client->dev,
&ts->low_latency_req,
DEV_PM_QOS_RESUME_LATENCY, 100);
}
out:
return IRQ_HANDLED;
}
static void st1232_ts_power(struct st1232_ts_data *ts, bool poweron)
{
if (ts->reset_gpio)
gpiod_set_value_cansleep(ts->reset_gpio, !poweron);
}
static void st1232_ts_power_off(void *data)
{
st1232_ts_power(data, false);
}
static const struct st_chip_info st1232_chip_info = {
.have_z = true,
.max_area = 0xff,
.max_fingers = 2,
};
static const struct st_chip_info st1633_chip_info = {
.have_z = false,
.max_area = 0x00,
.max_fingers = 5,
};
static int st1232_ts_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
const struct st_chip_info *match;
struct st1232_ts_data *ts;
struct input_dev *input_dev;
u16 max_x, max_y;
int error;
match = device_get_match_data(&client->dev);
if (!match && id)
match = (const void *)id->driver_data;
if (!match) {
dev_err(&client->dev, "unknown device model\n");
return -ENODEV;
}
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
dev_err(&client->dev, "need I2C_FUNC_I2C\n");
return -EIO;
}
if (!client->irq) {
dev_err(&client->dev, "no IRQ?\n");
return -EINVAL;
}
ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
if (!ts)
return -ENOMEM;
ts->chip_info = match;
/* allocate a buffer according to the number of registers to read */
ts->read_buf_len = ts->chip_info->max_fingers * 4;
ts->read_buf = devm_kzalloc(&client->dev, ts->read_buf_len, GFP_KERNEL);
if (!ts->read_buf)
return -ENOMEM;
input_dev = devm_input_allocate_device(&client->dev);
if (!input_dev)
return -ENOMEM;
ts->client = client;
ts->input_dev = input_dev;
ts->reset_gpio = devm_gpiod_get_optional(&client->dev, NULL,
GPIOD_OUT_HIGH);
if (IS_ERR(ts->reset_gpio)) {
error = PTR_ERR(ts->reset_gpio);
dev_err(&client->dev, "Unable to request GPIO pin: %d.\n",
error);
return error;
}
st1232_ts_power(ts, true);
error = devm_add_action_or_reset(&client->dev, st1232_ts_power_off, ts);
if (error) {
dev_err(&client->dev,
"Failed to install power off action: %d\n", error);
return error;
}
input_dev->name = "st1232-touchscreen";
input_dev->id.bustype = BUS_I2C;
/* Wait until device is ready */
error = st1232_ts_wait_ready(ts);
if (error)
return error;
/* Read resolution from the chip */
error = st1232_ts_read_resolution(ts, &max_x, &max_y);
if (error) {
dev_err(&client->dev,
"Failed to read resolution: %d\n", error);
return error;
}
if (ts->chip_info->have_z)
input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0,
ts->chip_info->max_area, 0, 0);
input_set_abs_params(input_dev, ABS_MT_POSITION_X,
0, max_x, 0, 0);
input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
0, max_y, 0, 0);
touchscreen_parse_properties(input_dev, true, &ts->prop);
error = input_mt_init_slots(input_dev, ts->chip_info->max_fingers,
INPUT_MT_DIRECT | INPUT_MT_TRACK |
INPUT_MT_DROP_UNUSED);
if (error) {
dev_err(&client->dev, "failed to initialize MT slots\n");
return error;
}
error = devm_request_threaded_irq(&client->dev, client->irq,
NULL, st1232_ts_irq_handler,
IRQF_ONESHOT,
client->name, ts);
if (error) {
dev_err(&client->dev, "Failed to register interrupt\n");
return error;
}
error = input_register_device(ts->input_dev);
if (error) {
dev_err(&client->dev, "Unable to register %s input device\n",
input_dev->name);
return error;
}
i2c_set_clientdata(client, ts);
return 0;
}
static int __maybe_unused st1232_ts_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct st1232_ts_data *ts = i2c_get_clientdata(client);
disable_irq(client->irq);
if (!device_may_wakeup(&client->dev))
st1232_ts_power(ts, false);
return 0;
}
static int __maybe_unused st1232_ts_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct st1232_ts_data *ts = i2c_get_clientdata(client);
if (!device_may_wakeup(&client->dev))
st1232_ts_power(ts, true);
enable_irq(client->irq);
return 0;
}
static SIMPLE_DEV_PM_OPS(st1232_ts_pm_ops,
st1232_ts_suspend, st1232_ts_resume);
static const struct i2c_device_id st1232_ts_id[] = {
{ ST1232_TS_NAME, (unsigned long)&st1232_chip_info },
{ ST1633_TS_NAME, (unsigned long)&st1633_chip_info },
{ }
};
MODULE_DEVICE_TABLE(i2c, st1232_ts_id);
static const struct of_device_id st1232_ts_dt_ids[] = {
{ .compatible = "sitronix,st1232", .data = &st1232_chip_info },
{ .compatible = "sitronix,st1633", .data = &st1633_chip_info },
{ }
};
MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
static struct i2c_driver st1232_ts_driver = {
.probe = st1232_ts_probe,
.id_table = st1232_ts_id,
.driver = {
.name = ST1232_TS_NAME,
.of_match_table = st1232_ts_dt_ids,
.pm = &st1232_ts_pm_ops,
},
};
module_i2c_driver(st1232_ts_driver);
MODULE_AUTHOR("Tony SIM <chinyeow.sim.xt@renesas.com>");
MODULE_AUTHOR("Martin Kepplinger <martin.kepplinger@ginzinger.com>");
MODULE_DESCRIPTION("SITRONIX ST1232 Touchscreen Controller Driver");
MODULE_LICENSE("GPL v2");
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