diff options
Diffstat (limited to 'drivers/hid/i2c-hid/i2c-hid-of-elan.c')
| -rw-r--r-- | drivers/hid/i2c-hid/i2c-hid-of-elan.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/drivers/hid/i2c-hid/i2c-hid-of-elan.c b/drivers/hid/i2c-hid/i2c-hid-of-elan.c new file mode 100644 index 000000000000..0215f217f6d8 --- /dev/null +++ b/drivers/hid/i2c-hid/i2c-hid-of-elan.c @@ -0,0 +1,215 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Driver for Elan touchscreens that use the i2c-hid protocol. + * + * Copyright 2020 Google LLC + */ + +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/gpio/consumer.h> +#include <linux/hid.h> +#include <linux/i2c.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/pm.h> +#include <linux/regulator/consumer.h> + +#include "i2c-hid.h" + +struct elan_i2c_hid_chip_data { + unsigned int post_gpio_reset_on_delay_ms; + unsigned int post_gpio_reset_off_delay_ms; + unsigned int post_power_delay_ms; + u16 hid_descriptor_address; + const char *main_supply_name; + bool power_after_backlight; +}; + +struct i2c_hid_of_elan { + struct i2chid_ops ops; + + struct regulator *vcc33; + struct regulator *vccio; + struct gpio_desc *reset_gpio; + bool no_reset_on_power_off; + const struct elan_i2c_hid_chip_data *chip_data; +}; + +static int elan_i2c_hid_power_up(struct i2chid_ops *ops) +{ + struct i2c_hid_of_elan *ihid_elan = + container_of(ops, struct i2c_hid_of_elan, ops); + int ret; + + gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1); + + if (ihid_elan->vcc33) { + ret = regulator_enable(ihid_elan->vcc33); + if (ret) + goto err_deassert_reset; + } + + ret = regulator_enable(ihid_elan->vccio); + if (ret) + goto err_disable_vcc33; + + if (ihid_elan->chip_data->post_power_delay_ms) + msleep(ihid_elan->chip_data->post_power_delay_ms); + + gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0); + if (ihid_elan->chip_data->post_gpio_reset_on_delay_ms) + msleep(ihid_elan->chip_data->post_gpio_reset_on_delay_ms); + + return 0; + +err_disable_vcc33: + if (ihid_elan->vcc33) + regulator_disable(ihid_elan->vcc33); +err_deassert_reset: + if (ihid_elan->no_reset_on_power_off) + gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0); + + return ret; +} + +static void elan_i2c_hid_power_down(struct i2chid_ops *ops) +{ + struct i2c_hid_of_elan *ihid_elan = + container_of(ops, struct i2c_hid_of_elan, ops); + + /* + * Do not assert reset when the hardware allows for it to remain + * deasserted regardless of the state of the (shared) power supply to + * avoid wasting power when the supply is left on. + */ + if (!ihid_elan->no_reset_on_power_off) + gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1); + + if (ihid_elan->chip_data->post_gpio_reset_off_delay_ms) + msleep(ihid_elan->chip_data->post_gpio_reset_off_delay_ms); + + regulator_disable(ihid_elan->vccio); + if (ihid_elan->vcc33) + regulator_disable(ihid_elan->vcc33); +} + +static int i2c_hid_of_elan_probe(struct i2c_client *client) +{ + struct i2c_hid_of_elan *ihid_elan; + int ret; + u32 quirks = 0; + + ihid_elan = devm_kzalloc(&client->dev, sizeof(*ihid_elan), GFP_KERNEL); + if (!ihid_elan) + return -ENOMEM; + + ihid_elan->ops.power_up = elan_i2c_hid_power_up; + ihid_elan->ops.power_down = elan_i2c_hid_power_down; + + /* Start out with reset asserted */ + ihid_elan->reset_gpio = + devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(ihid_elan->reset_gpio)) + return PTR_ERR(ihid_elan->reset_gpio); + + ihid_elan->no_reset_on_power_off = of_property_read_bool(client->dev.of_node, + "no-reset-on-power-off"); + + ihid_elan->vccio = devm_regulator_get(&client->dev, "vccio"); + if (IS_ERR(ihid_elan->vccio)) { + ret = PTR_ERR(ihid_elan->vccio); + goto err_deassert_reset; + } + + ihid_elan->chip_data = device_get_match_data(&client->dev); + + if (ihid_elan->chip_data->main_supply_name) { + ihid_elan->vcc33 = devm_regulator_get(&client->dev, + ihid_elan->chip_data->main_supply_name); + if (IS_ERR(ihid_elan->vcc33)) { + ret = PTR_ERR(ihid_elan->vcc33); + goto err_deassert_reset; + } + } + + if (ihid_elan->chip_data->power_after_backlight) + quirks = HID_QUIRK_POWER_ON_AFTER_BACKLIGHT; + + ret = i2c_hid_core_probe(client, &ihid_elan->ops, + ihid_elan->chip_data->hid_descriptor_address, + quirks); + if (ret) + goto err_deassert_reset; + + return 0; + +err_deassert_reset: + if (ihid_elan->no_reset_on_power_off) + gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0); + + return ret; +} + +static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = { + .post_power_delay_ms = 1, + .post_gpio_reset_on_delay_ms = 300, + .hid_descriptor_address = 0x0001, + .main_supply_name = "vcc33", + .power_after_backlight = true, +}; + +static const struct elan_i2c_hid_chip_data elan_ekth6a12nay_chip_data = { + .post_power_delay_ms = 10, + .post_gpio_reset_on_delay_ms = 300, + .hid_descriptor_address = 0x0001, + .main_supply_name = "vcc33", + .power_after_backlight = true, +}; + +static const struct elan_i2c_hid_chip_data ilitek_ili9882t_chip_data = { + .post_power_delay_ms = 1, + .post_gpio_reset_on_delay_ms = 200, + .post_gpio_reset_off_delay_ms = 65, + .hid_descriptor_address = 0x0001, + /* + * this touchscreen is tightly integrated with the panel and assumes + * that the relevant power rails (other than the IO rail) have already + * been turned on by the panel driver because we're a panel follower. + */ + .main_supply_name = NULL, +}; + +static const struct elan_i2c_hid_chip_data ilitek_ili2901_chip_data = { + .post_power_delay_ms = 10, + .post_gpio_reset_on_delay_ms = 100, + .hid_descriptor_address = 0x0001, + .main_supply_name = "vcc33", +}; + +static const struct of_device_id elan_i2c_hid_of_match[] = { + { .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data }, + { .compatible = "elan,ekth6a12nay", .data = &elan_ekth6a12nay_chip_data }, + { .compatible = "ilitek,ili9882t", .data = &ilitek_ili9882t_chip_data }, + { .compatible = "ilitek,ili2901", .data = &ilitek_ili2901_chip_data }, + { } +}; +MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match); + +static struct i2c_driver elan_i2c_hid_ts_driver = { + .driver = { + .name = "i2c_hid_of_elan", + .pm = &i2c_hid_core_pm, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + .of_match_table = of_match_ptr(elan_i2c_hid_of_match), + }, + .probe = i2c_hid_of_elan_probe, + .remove = i2c_hid_core_remove, + .shutdown = i2c_hid_core_shutdown, +}; +module_i2c_driver(elan_i2c_hid_ts_driver); + +MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>"); +MODULE_DESCRIPTION("Elan i2c-hid touchscreen driver"); +MODULE_LICENSE("GPL"); |