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"); 156