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1// SPDX-License-Identifier: GPL-2.02/*3 * Driver for Elan touchscreens that use the i2c-hid protocol.4 *5 * Copyright 2020 Google LLC6 */7 8#include <linux/delay.h>9#include <linux/device.h>10#include <linux/gpio/consumer.h>11#include <linux/i2c.h>12#include <linux/kernel.h>13#include <linux/module.h>14#include <linux/of.h>15#include <linux/pm.h>16#include <linux/regulator/consumer.h>17 18#include "i2c-hid.h"19 20struct elan_i2c_hid_chip_data {21 unsigned int post_gpio_reset_on_delay_ms;22 unsigned int post_gpio_reset_off_delay_ms;23 unsigned int post_power_delay_ms;24 u16 hid_descriptor_address;25 const char *main_supply_name;26};27 28struct i2c_hid_of_elan {29 struct i2chid_ops ops;30 31 struct regulator *vcc33;32 struct regulator *vccio;33 struct gpio_desc *reset_gpio;34 bool no_reset_on_power_off;35 const struct elan_i2c_hid_chip_data *chip_data;36};37 38static int elan_i2c_hid_power_up(struct i2chid_ops *ops)39{40 struct i2c_hid_of_elan *ihid_elan =41 container_of(ops, struct i2c_hid_of_elan, ops);42 int ret;43 44 gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);45 46 if (ihid_elan->vcc33) {47 ret = regulator_enable(ihid_elan->vcc33);48 if (ret)49 goto err_deassert_reset;50 }51 52 ret = regulator_enable(ihid_elan->vccio);53 if (ret)54 goto err_disable_vcc33;55 56 if (ihid_elan->chip_data->post_power_delay_ms)57 msleep(ihid_elan->chip_data->post_power_delay_ms);58 59 gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);60 if (ihid_elan->chip_data->post_gpio_reset_on_delay_ms)61 msleep(ihid_elan->chip_data->post_gpio_reset_on_delay_ms);62 63 return 0;64 65err_disable_vcc33:66 if (ihid_elan->vcc33)67 regulator_disable(ihid_elan->vcc33);68err_deassert_reset:69 if (ihid_elan->no_reset_on_power_off)70 gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);71 72 return ret;73}74 75static void elan_i2c_hid_power_down(struct i2chid_ops *ops)76{77 struct i2c_hid_of_elan *ihid_elan =78 container_of(ops, struct i2c_hid_of_elan, ops);79 80 /*81 * Do not assert reset when the hardware allows for it to remain82 * deasserted regardless of the state of the (shared) power supply to83 * avoid wasting power when the supply is left on.84 */85 if (!ihid_elan->no_reset_on_power_off)86 gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);87 88 if (ihid_elan->chip_data->post_gpio_reset_off_delay_ms)89 msleep(ihid_elan->chip_data->post_gpio_reset_off_delay_ms);90 91 regulator_disable(ihid_elan->vccio);92 if (ihid_elan->vcc33)93 regulator_disable(ihid_elan->vcc33);94}95 96static int i2c_hid_of_elan_probe(struct i2c_client *client)97{98 struct i2c_hid_of_elan *ihid_elan;99 int ret;100 101 ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL);102 if (!ihid_elan)103 return -ENOMEM;104 105 ihid_elan->ops.power_up = elan_i2c_hid_power_up;106 ihid_elan->ops.power_down = elan_i2c_hid_power_down;107 108 /* Start out with reset asserted */109 ihid_elan->reset_gpio =110 devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);111 if (IS_ERR(ihid_elan->reset_gpio))112 return PTR_ERR(ihid_elan->reset_gpio);113 114 ihid_elan->no_reset_on_power_off = of_property_read_bool(client->dev.of_node,115 "no-reset-on-power-off");116 117 ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio");118 if (IS_ERR(ihid_elan->vccio)) {119 ret = PTR_ERR(ihid_elan->vccio);120 goto err_deassert_reset;121 }122 123 ihid_elan->chip_data = device_get_match_data(&client->dev);124 125 if (ihid_elan->chip_data->main_supply_name) {126 ihid_elan->vcc33 = devm_regulator_get(&client->dev,127 ihid_elan->chip_data->main_supply_name);128 if (IS_ERR(ihid_elan->vcc33)) {129 ret = PTR_ERR(ihid_elan->vcc33);130 goto err_deassert_reset;131 }132 }133 134 ret = i2c_hid_core_probe(client, &ihid_elan->ops,135 ihid_elan->chip_data->hid_descriptor_address, 0);136 if (ret)137 goto err_deassert_reset;138 139 return 0;140 141err_deassert_reset:142 if (ihid_elan->no_reset_on_power_off)143 gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);144 145 return ret;146}147 148static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = {149 .post_power_delay_ms = 1,150 .post_gpio_reset_on_delay_ms = 300,151 .hid_descriptor_address = 0x0001,152 .main_supply_name = "vcc33",153};154 155static const struct elan_i2c_hid_chip_data elan_ekth6a12nay_chip_data = {156 .post_power_delay_ms = 10,157 .post_gpio_reset_on_delay_ms = 300,158 .hid_descriptor_address = 0x0001,159 .main_supply_name = "vcc33",160};161 162static const struct elan_i2c_hid_chip_data ilitek_ili9882t_chip_data = {163 .post_power_delay_ms = 1,164 .post_gpio_reset_on_delay_ms = 200,165 .post_gpio_reset_off_delay_ms = 65,166 .hid_descriptor_address = 0x0001,167 /*168 * this touchscreen is tightly integrated with the panel and assumes169 * that the relevant power rails (other than the IO rail) have already170 * been turned on by the panel driver because we're a panel follower.171 */172 .main_supply_name = NULL,173};174 175static const struct elan_i2c_hid_chip_data ilitek_ili2901_chip_data = {176 .post_power_delay_ms = 10,177 .post_gpio_reset_on_delay_ms = 100,178 .hid_descriptor_address = 0x0001,179 .main_supply_name = "vcc33",180};181 182static const struct of_device_id elan_i2c_hid_of_match[] = {183 { .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },184 { .compatible = "elan,ekth6a12nay", .data = &elan_ekth6a12nay_chip_data },185 { .compatible = "ilitek,ili9882t", .data = &ilitek_ili9882t_chip_data },186 { .compatible = "ilitek,ili2901", .data = &ilitek_ili2901_chip_data },187 { }188};189MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);190 191static struct i2c_driver elan_i2c_hid_ts_driver = {192 .driver = {193 .name = "i2c_hid_of_elan",194 .pm = &i2c_hid_core_pm,195 .probe_type = PROBE_PREFER_ASYNCHRONOUS,196 .of_match_table = of_match_ptr(elan_i2c_hid_of_match),197 },198 .probe = i2c_hid_of_elan_probe,199 .remove = i2c_hid_core_remove,200 .shutdown = i2c_hid_core_shutdown,201};202module_i2c_driver(elan_i2c_hid_ts_driver);203 204MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");205MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver");206MODULE_LICENSE("GPL");207