| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Driver for Elan 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 elan_i2c_hid_chip_data { |
| unsigned int post_gpio_reset_delay_ms; |
| unsigned int post_power_delay_ms; |
| u16 hid_descriptor_address; |
| }; |
| |
| struct i2c_hid_of_elan { |
| struct i2chid_ops ops; |
| |
| struct regulator *vcc33; |
| struct regulator *vccio; |
| struct gpio_desc *reset_gpio; |
| const struct elan_i2c_hid_chip_data *chip_data; |
| }; |
| |
| static int elan_i2c_hid_power_up(struct i2chid_ops *ops) |
| { |
| struct i2c_hid_of_elan *ihid_elan = |
| container_of(ops, struct i2c_hid_of_elan, ops); |
| int ret; |
| |
| ret = regulator_enable(ihid_elan->vcc33); |
| if (ret) |
| return ret; |
| |
| ret = regulator_enable(ihid_elan->vccio); |
| if (ret) { |
| regulator_disable(ihid_elan->vcc33); |
| return ret; |
| } |
| |
| if (ihid_elan->chip_data->post_power_delay_ms) |
| msleep(ihid_elan->chip_data->post_power_delay_ms); |
| |
| gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0); |
| if (ihid_elan->chip_data->post_gpio_reset_delay_ms) |
| msleep(ihid_elan->chip_data->post_gpio_reset_delay_ms); |
| |
| return 0; |
| } |
| |
| static void elan_i2c_hid_power_down(struct i2chid_ops *ops) |
| { |
| struct i2c_hid_of_elan *ihid_elan = |
| container_of(ops, struct i2c_hid_of_elan, ops); |
| |
| gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1); |
| regulator_disable(ihid_elan->vccio); |
| regulator_disable(ihid_elan->vcc33); |
| } |
| |
| static int i2c_hid_of_elan_probe(struct i2c_client *client) |
| { |
| struct i2c_hid_of_elan *ihid_elan; |
| |
| ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL); |
| if (!ihid_elan) |
| return -ENOMEM; |
| |
| ihid_elan->ops.power_up = elan_i2c_hid_power_up; |
| ihid_elan->ops.power_down = elan_i2c_hid_power_down; |
| |
| /* Start out with reset asserted */ |
| ihid_elan->reset_gpio = |
| devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH); |
| if (IS_ERR(ihid_elan->reset_gpio)) |
| return PTR_ERR(ihid_elan->reset_gpio); |
| |
| ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio"); |
| if (IS_ERR(ihid_elan->vccio)) |
| return PTR_ERR(ihid_elan->vccio); |
| |
| ihid_elan->vcc33 = devm_regulator_get(&client->dev, "vcc33"); |
| if (IS_ERR(ihid_elan->vcc33)) |
| return PTR_ERR(ihid_elan->vcc33); |
| |
| ihid_elan->chip_data = device_get_match_data(&client->dev); |
| |
| return i2c_hid_core_probe(client, &ihid_elan->ops, |
| ihid_elan->chip_data->hid_descriptor_address, 0); |
| } |
| |
| static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = { |
| .post_power_delay_ms = 1, |
| .post_gpio_reset_delay_ms = 300, |
| .hid_descriptor_address = 0x0001, |
| }; |
| |
| static const struct of_device_id elan_i2c_hid_of_match[] = { |
| { .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data }, |
| { } |
| }; |
| MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match); |
| |
| static struct i2c_driver elan_i2c_hid_ts_driver = { |
| .driver = { |
| .name = "i2c_hid_of_elan", |
| .pm = &i2c_hid_core_pm, |
| .probe_type = PROBE_PREFER_ASYNCHRONOUS, |
| .of_match_table = of_match_ptr(elan_i2c_hid_of_match), |
| }, |
| .probe_new = i2c_hid_of_elan_probe, |
| .remove = i2c_hid_core_remove, |
| .shutdown = i2c_hid_core_shutdown, |
| }; |
| module_i2c_driver(elan_i2c_hid_ts_driver); |
| |
| MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>"); |
| MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver"); |
| MODULE_LICENSE("GPL"); |