Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Doug Anderson | 682 | 100.00% | 3 | 100.00% |
Total | 682 | 3 |
// 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); } 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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