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_delay_ms;
  22         unsigned int post_power_delay_ms;
  23         u16 hid_descriptor_address;
  24 };
  25
  26 struct i2c_hid_of_elan {
  27         struct i2chid_ops ops;
  28
  29         struct regulator *vcc33;
  30         struct regulator *vccio;
  31         struct gpio_desc *reset_gpio;
  32         const struct elan_i2c_hid_chip_data *chip_data;
  33 };
  34
  35 static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
  36 {
  37         struct i2c_hid_of_elan *ihid_elan =
  38                 container_of(ops, struct i2c_hid_of_elan, ops);
  39         int ret;
  40
  41         ret = regulator_enable(ihid_elan->vcc33);
  42         if (ret)
  43                 return ret;
  44
  45         ret = regulator_enable(ihid_elan->vccio);
  46         if (ret) {
  47                 regulator_disable(ihid_elan->vcc33);
  48                 return ret;
  49         }
  50
  51         if (ihid_elan->chip_data->post_power_delay_ms)
  52                 msleep(ihid_elan->chip_data->post_power_delay_ms);
  53
  54         gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
  55         if (ihid_elan->chip_data->post_gpio_reset_delay_ms)
  56                 msleep(ihid_elan->chip_data->post_gpio_reset_delay_ms);
  57
  58         return 0;
  59 }
  60
  61 static void elan_i2c_hid_power_down(struct i2chid_ops *ops)
  62 {
  63         struct i2c_hid_of_elan *ihid_elan =
  64                 container_of(ops, struct i2c_hid_of_elan, ops);
  65
  66         gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
  67         regulator_disable(ihid_elan->vccio);
  68         regulator_disable(ihid_elan->vcc33);
  69 }
  70
  71 static int i2c_hid_of_elan_probe(struct i2c_client *client,
  72                                  const struct i2c_device_id *id)
  73 {
  74         struct i2c_hid_of_elan *ihid_elan;
  75
  76         ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL);
  77         if (!ihid_elan)
  78                 return -ENOMEM;
  79
  80         ihid_elan->ops.power_up = elan_i2c_hid_power_up;
  81         ihid_elan->ops.power_down = elan_i2c_hid_power_down;
  82
  83         /* Start out with reset asserted */
  84         ihid_elan->reset_gpio =
  85                 devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
  86         if (IS_ERR(ihid_elan->reset_gpio))
  87                 return PTR_ERR(ihid_elan->reset_gpio);
  88
  89         ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio");
  90         if (IS_ERR(ihid_elan->vccio))
  91                 return PTR_ERR(ihid_elan->vccio);
  92
  93         ihid_elan->vcc33 = devm_regulator_get(&client->dev, "vcc33");
  94         if (IS_ERR(ihid_elan->vcc33))
  95                 return PTR_ERR(ihid_elan->vcc33);
  96
  97         ihid_elan->chip_data = device_get_match_data(&client->dev);
  98
  99         return i2c_hid_core_probe(client, &ihid_elan->ops,
 100                                   ihid_elan->chip_data->hid_descriptor_address, 0);
 101 }
 102
 103 static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = {
 104         .post_power_delay_ms = 1,
 105         .post_gpio_reset_delay_ms = 300,
 106         .hid_descriptor_address = 0x0001,
 107 };
 108
 109 static const struct of_device_id elan_i2c_hid_of_match[] = {
 110         { .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },
 111         { }
 112 };
 113 MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);
 114
 115 static struct i2c_driver elan_i2c_hid_ts_driver = {
 116         .driver = {
 117                 .name   = "i2c_hid_of_elan",
 118                 .pm     = &i2c_hid_core_pm,
 119                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
 120                 .of_match_table = of_match_ptr(elan_i2c_hid_of_match),
 121         },
 122         .probe          = i2c_hid_of_elan_probe,
 123         .remove         = i2c_hid_core_remove,
 124         .shutdown       = i2c_hid_core_shutdown,
 125 };
 126 module_i2c_driver(elan_i2c_hid_ts_driver);
 127
 128 MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");
 129 MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver");
 130 MODULE_LICENSE("GPL");