diff options
Diffstat (limited to 'drivers/hid/i2c-hid/i2c-hid-of-goodix.c')
| -rw-r--r-- | drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c new file mode 100644 index 000000000..ec6c73f75 --- /dev/null +++ b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c @@ -0,0 +1,178 @@ +// 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 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; + + 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; + } + + 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; + + 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. + */ + ihid_goodix->nb.notifier_call = ihid_goodix_vdd_notify; + ret = devm_regulator_register_notifier(ihid_goodix->vdd, &ihid_goodix->nb); + if (ret) + 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... and temporarily bump the regulator reference count just to + * make sure it is impossible for this to race with our own notifier! + * We also 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)) { + ret = regulator_enable(ihid_goodix->vdd); + if (ret) + return ret; + goodix_i2c_hid_deassert_reset(ihid_goodix, true); + regulator_disable(ihid_goodix->vdd); + } + + 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"); |