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"); 131