Commit c1ed18c1 authored by Douglas Anderson's avatar Douglas Anderson Committed by Benjamin Tissoires
Browse files

HID: i2c-hid: Introduce goodix-i2c-hid using i2c-hid core 



Goodix i2c-hid touchscreens are mostly i2c-hid compliant but have some
special power sequencing requirements, including the need to drive a
reset line during the sequencing.

Let's use the new rejiggering of i2c-hid to support this with a thin
wrapper driver to support the first Goodix i2c-hid touchscreen:
GT7375P

Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Signed-off-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
parent f9a056e0

drivers/hid/i2c-hid/Kconfig

+17 −2
Original line number Diff line number Diff line
@@ -32,10 +32,25 @@ config I2C_HID_OF 
	  will be called i2c-hid-of.  It will also build/depend on the

	  module i2c-hid.



config I2C_HID_OF_GOODIX

	tristate "Driver for Goodix hid-i2c based devices on OF systems"

	default n

	depends on I2C && INPUT && OF

	help

	  Say Y here if you want support for Goodix i2c devices that use

	  the i2c-hid protocol on Open Firmware (Device Tree)-based

	  systems.



	  If unsure, say N.



	  This support is also available as a module.  If so, the module

	  will be called i2c-hid-of-goodix.  It will also build/depend on

	  the module i2c-hid.



endmenu



config I2C_HID_CORE

	tristate

	default y if I2C_HID_ACPI=y || I2C_HID_OF=y

	default m if I2C_HID_ACPI=m || I2C_HID_OF=m

	default y if I2C_HID_ACPI=y || I2C_HID_OF=y || I2C_HID_OF_GOODIX=y

	default m if I2C_HID_ACPI=m || I2C_HID_OF=m || I2C_HID_OF_GOODIX=m

	select HID

drivers/hid/i2c-hid/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -10,3 +10,4 @@ i2c-hid-$(CONFIG_DMI) += i2c-hid-dmi-quirks.o 


obj-$(CONFIG_I2C_HID_ACPI)			+= i2c-hid-acpi.o

obj-$(CONFIG_I2C_HID_OF)			+= i2c-hid-of.o

obj-$(CONFIG_I2C_HID_OF_GOODIX)			+= i2c-hid-of-goodix.o

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

0 → 100644
+116 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Driver for Goodix 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/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 goodix_i2c_hid_timing_data {

	unsigned int post_gpio_reset_delay_ms;

	unsigned int post_power_delay_ms;

};



struct i2c_hid_of_goodix {

	struct i2chid_ops ops;



	struct regulator *vdd;

	struct gpio_desc *reset_gpio;

	const struct goodix_i2c_hid_timing_data *timings;

};



static int goodix_i2c_hid_power_up(struct i2chid_ops *ops)

{

	struct i2c_hid_of_goodix *ihid_goodix =

		container_of(ops, struct i2c_hid_of_goodix, ops);

	int ret;



	ret = regulator_enable(ihid_goodix->vdd);

	if (ret)

		return ret;



	if (ihid_goodix->timings->post_power_delay_ms)

		msleep(ihid_goodix->timings->post_power_delay_ms);



	gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 0);

	if (ihid_goodix->timings->post_gpio_reset_delay_ms)

		msleep(ihid_goodix->timings->post_gpio_reset_delay_ms);



	return 0;

}



static void goodix_i2c_hid_power_down(struct i2chid_ops *ops)

{

	struct i2c_hid_of_goodix *ihid_goodix =

		container_of(ops, struct i2c_hid_of_goodix, ops);



	gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);

	regulator_disable(ihid_goodix->vdd);

}



static int i2c_hid_of_goodix_probe(struct i2c_client *client,

				   const struct i2c_device_id *id)

{

	struct i2c_hid_of_goodix *ihid_goodix;



	ihid_goodix = devm_kzalloc(&client->dev, sizeof(*ihid_goodix),

				   GFP_KERNEL);

	if (!ihid_goodix)

		return -ENOMEM;



	ihid_goodix->ops.power_up = goodix_i2c_hid_power_up;

	ihid_goodix->ops.power_down = goodix_i2c_hid_power_down;



	/* Start out with reset asserted */

	ihid_goodix->reset_gpio =

		devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);

	if (IS_ERR(ihid_goodix->reset_gpio))

		return PTR_ERR(ihid_goodix->reset_gpio);



	ihid_goodix->vdd = devm_regulator_get(&client->dev, "vdd");

	if (IS_ERR(ihid_goodix->vdd))

		return PTR_ERR(ihid_goodix->vdd);



	ihid_goodix->timings = device_get_match_data(&client->dev);



	return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001);

}



static const struct goodix_i2c_hid_timing_data goodix_gt7375p_timing_data = {

	.post_power_delay_ms = 10,

	.post_gpio_reset_delay_ms = 180,

};



static const struct of_device_id goodix_i2c_hid_of_match[] = {

	{ .compatible = "goodix,gt7375p", .data = &goodix_gt7375p_timing_data },

	{ }

};

MODULE_DEVICE_TABLE(of, goodix_i2c_hid_of_match);



static struct i2c_driver goodix_i2c_hid_ts_driver = {

	.driver = {

		.name	= "i2c_hid_of_goodix",

		.pm	= &i2c_hid_core_pm,

		.probe_type = PROBE_PREFER_ASYNCHRONOUS,

		.of_match_table = of_match_ptr(goodix_i2c_hid_of_match),

	},

	.probe		= i2c_hid_of_goodix_probe,

	.remove		= i2c_hid_core_remove,

	.shutdown	= i2c_hid_core_shutdown,

};

module_i2c_driver(goodix_i2c_hid_ts_driver);



MODULE_AUTHOR("Douglas Anderson <dianders@chromium.org>");

MODULE_DESCRIPTION("Goodix i2c-hid touchscreen driver");

MODULE_LICENSE("GPL v2");