drivers/hid/i2c-hid/i2c-hid-of-elan.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Driver for Elan touchscreens that use the i2c-hid protocol.
   4  *
   5  * Copyright 2020 Google LLC
   6  */
   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
  20 struct 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
  28 struct 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         const struct elan_i2c_hid_chip_data *chip_data;
  35 };
  36
  37 static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
  38 {
  39         struct i2c_hid_of_elan *ihid_elan =
  40                 container_of(ops, struct i2c_hid_of_elan, ops);
  41         int ret;
  42
  43         if (ihid_elan->vcc33) {
  44                 ret = regulator_enable(ihid_elan->vcc33);
  45                 if (ret)
  46                         return ret;
  47         }
  48
  49         ret = regulator_enable(ihid_elan->vccio);
  50         if (ret) {
  51                 regulator_disable(ihid_elan->vcc33);
  52                 return ret;
  53         }
  54
  55         if (ihid_elan->chip_data->post_power_delay_ms)
  56                 msleep(ihid_elan->chip_data->post_power_delay_ms);
  57
  58         gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
  59         if (ihid_elan->chip_data->post_gpio_reset_on_delay_ms)
  60                 msleep(ihid_elan->chip_data->post_gpio_reset_on_delay_ms);
  61
  62         return 0;
  63 }
  64
  65 static void elan_i2c_hid_power_down(struct i2chid_ops *ops)
  66 {
  67         struct i2c_hid_of_elan *ihid_elan =
  68                 container_of(ops, struct i2c_hid_of_elan, ops);
  69
  70         gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
  71         if (ihid_elan->chip_data->post_gpio_reset_off_delay_ms)
  72                 msleep(ihid_elan->chip_data->post_gpio_reset_off_delay_ms);
  73
  74         regulator_disable(ihid_elan->vccio);
  75         if (ihid_elan->vcc33)
  76                 regulator_disable(ihid_elan->vcc33);
  77 }
  78
  79 static int i2c_hid_of_elan_probe(struct i2c_client *client)
  80 {
  81         struct i2c_hid_of_elan *ihid_elan;
  82
  83         ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL);
  84         if (!ihid_elan)
  85                 return -ENOMEM;
  86
  87         ihid_elan->ops.power_up = elan_i2c_hid_power_up;
  88         ihid_elan->ops.power_down = elan_i2c_hid_power_down;
  89
  90         /* Start out with reset asserted */
  91         ihid_elan->reset_gpio =
  92                 devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
  93         if (IS_ERR(ihid_elan->reset_gpio))
  94                 return PTR_ERR(ihid_elan->reset_gpio);
  95
  96         ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio");
  97         if (IS_ERR(ihid_elan->vccio))
  98                 return PTR_ERR(ihid_elan->vccio);
  99
 100         ihid_elan->chip_data = device_get_match_data(&client->dev);
 101
 102         if (ihid_elan->chip_data->main_supply_name) {
 103                 ihid_elan->vcc33 = devm_regulator_get(&client->dev,
 104                                                       ihid_elan->chip_data->main_supply_name);
 105                 if (IS_ERR(ihid_elan->vcc33))
 106                         return PTR_ERR(ihid_elan->vcc33);
 107         }
 108
 109         return i2c_hid_core_probe(client, &ihid_elan->ops,
 110                                   ihid_elan->chip_data->hid_descriptor_address, 0);
 111 }
 112
 113 static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = {
 114         .post_power_delay_ms = 1,
 115         .post_gpio_reset_on_delay_ms = 300,
 116         .hid_descriptor_address = 0x0001,
 117         .main_supply_name = "vcc33",
 118 };
 119
 120 static const struct elan_i2c_hid_chip_data ilitek_ili9882t_chip_data = {
 121         .post_power_delay_ms = 1,
 122         .post_gpio_reset_on_delay_ms = 200,
 123         .post_gpio_reset_off_delay_ms = 65,
 124         .hid_descriptor_address = 0x0001,
 125         /*
 126          * this touchscreen is tightly integrated with the panel and assumes
 127          * that the relevant power rails (other than the IO rail) have already
 128          * been turned on by the panel driver because we're a panel follower.
 129          */
 130         .main_supply_name = NULL,
 131 };
 132
 133 static const struct of_device_id elan_i2c_hid_of_match[] = {
 134         { .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },
 135         { .compatible = "ilitek,ili9882t", .data = &ilitek_ili9882t_chip_data },
 136         { }
 137 };
 138 MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);
 139
 140 static struct i2c_driver elan_i2c_hid_ts_driver = {
 141         .driver = {
 142                 .name   = "i2c_hid_of_elan",
 143                 .pm     = &i2c_hid_core_pm,
 144                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
 145                 .of_match_table = of_match_ptr(elan_i2c_hid_of_match),
 146         },
 147         .probe          = i2c_hid_of_elan_probe,
 148         .remove         = i2c_hid_core_remove,
 149         .shutdown       = i2c_hid_core_shutdown,
 150 };
 151 module_i2c_driver(elan_i2c_hid_ts_driver);
 152
 153 MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
 154 MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver");
 155 MODULE_LICENSE("GPL");