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// SPDX-License-Identifier: GPL-2.0
/*
* Driver for Goodix touchscreens that use the i2c-hid protocol.
*
* Copyright 2020 Google LLC
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/regulator/consumer.h>
#include "i2c-hid.h"
struct goodix_i2c_hid_timing_data {
unsigned int post_gpio_reset_delay_ms;
unsigned int post_power_delay_ms;
};
struct i2c_hid_of_goodix {
struct i2chid_ops ops;
struct regulator *vdd;
struct notifier_block nb;
struct mutex regulator_mutex;
struct gpio_desc *reset_gpio;
const struct goodix_i2c_hid_timing_data *timings;
};
static void goodix_i2c_hid_deassert_reset(struct i2c_hid_of_goodix *ihid_goodix,
bool regulator_just_turned_on)
{
if (regulator_just_turned_on && ihid_goodix->timings->post_power_delay_ms)
msleep(ihid_goodix->timings->post_power_delay_ms);
gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 0);
if (ihid_goodix->timings->post_gpio_reset_delay_ms)
msleep(ihid_goodix->timings->post_gpio_reset_delay_ms);
}
static int goodix_i2c_hid_power_up(struct i2chid_ops *ops)
{
struct i2c_hid_of_goodix *ihid_goodix =
container_of(ops, struct i2c_hid_of_goodix, ops);
return regulator_enable(ihid_goodix->vdd);
}
static void goodix_i2c_hid_power_down(struct i2chid_ops *ops)
{
struct i2c_hid_of_goodix *ihid_goodix =
container_of(ops, struct i2c_hid_of_goodix, ops);
regulator_disable(ihid_goodix->vdd);
}
static int ihid_goodix_vdd_notify(struct notifier_block *nb,
unsigned long event,
void *ignored)
{
struct i2c_hid_of_goodix *ihid_goodix =
container_of(nb, struct i2c_hid_of_goodix, nb);
int ret = NOTIFY_OK;
mutex_lock(&ihid_goodix->regulator_mutex);
switch (event) {
case REGULATOR_EVENT_PRE_DISABLE:
gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
break;
case REGULATOR_EVENT_ENABLE:
goodix_i2c_hid_deassert_reset(ihid_goodix, true);
break;
case REGULATOR_EVENT_ABORT_DISABLE:
goodix_i2c_hid_deassert_reset(ihid_goodix, false);
break;
default:
ret = NOTIFY_DONE;
break;
}
mutex_unlock(&ihid_goodix->regulator_mutex);
return ret;
}
static int i2c_hid_of_goodix_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_hid_of_goodix *ihid_goodix;
int ret;
ihid_goodix = devm_kzalloc(&client->dev, sizeof(*ihid_goodix),
GFP_KERNEL);
if (!ihid_goodix)
return -ENOMEM;
mutex_init(&ihid_goodix->regulator_mutex);
ihid_goodix->ops.power_up = goodix_i2c_hid_power_up;
ihid_goodix->ops.power_down = goodix_i2c_hid_power_down;
/* Start out with reset asserted */
ihid_goodix->reset_gpio =
devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(ihid_goodix->reset_gpio))
return PTR_ERR(ihid_goodix->reset_gpio);
ihid_goodix->vdd = devm_regulator_get(&client->dev, "vdd");
if (IS_ERR(ihid_goodix->vdd))
return PTR_ERR(ihid_goodix->vdd);
ihid_goodix->timings = device_get_match_data(&client->dev);
/*
* We need to control the "reset" line in lockstep with the regulator
* actually turning on an off instead of just when we make the request.
* This matters if the regulator is shared with another consumer.
* - If the regulator is off then we must assert reset. The reset
* line is active low and on some boards it could cause a current
* leak if left high.
* - If the regulator is on then we don't want reset asserted for very
* long. Holding the controller in reset apparently draws extra
* power.
*/
mutex_lock(&ihid_goodix->regulator_mutex);
ihid_goodix->nb.notifier_call = ihid_goodix_vdd_notify;
ret = devm_regulator_register_notifier(ihid_goodix->vdd, &ihid_goodix->nb);
if (ret) {
mutex_unlock(&ihid_goodix->regulator_mutex);
return dev_err_probe(&client->dev, ret,
"regulator notifier request failed\n");
}
/*
* If someone else is holding the regulator on (or the regulator is
* an always-on one) we might never be told to deassert reset. Do it
* now. Here we'll assume that someone else might have _just
* barely_ turned the regulator on so we'll do the full
* "post_power_delay" just in case.
*/
if (ihid_goodix->reset_gpio && regulator_is_enabled(ihid_goodix->vdd))
goodix_i2c_hid_deassert_reset(ihid_goodix, true);
mutex_unlock(&ihid_goodix->regulator_mutex);
return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001, 0);
}
static const struct goodix_i2c_hid_timing_data goodix_gt7375p_timing_data = {
.post_power_delay_ms = 10,
.post_gpio_reset_delay_ms = 180,
};
static const struct of_device_id goodix_i2c_hid_of_match[] = {
{ .compatible = "goodix,gt7375p", .data = &goodix_gt7375p_timing_data },
{ }
};
MODULE_DEVICE_TABLE(of, goodix_i2c_hid_of_match);
static struct i2c_driver goodix_i2c_hid_ts_driver = {
.driver = {
.name = "i2c_hid_of_goodix",
.pm = &i2c_hid_core_pm,
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = of_match_ptr(goodix_i2c_hid_of_match),
},
.probe = i2c_hid_of_goodix_probe,
.remove = i2c_hid_core_remove,
.shutdown = i2c_hid_core_shutdown,
};
module_i2c_driver(goodix_i2c_hid_ts_driver);
MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
MODULE_DESCRIPTION("Goodix i2c-hid touchscreen driver");
MODULE_LICENSE("GPL v2");
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