// SPDX-License-Identifier: GPL-2.0-only/* * Supports for the button array on the Surface tablets. * * (C) Copyright 2016 Red Hat, Inc * * Based on soc_button_array.c: * * {C} Copyright 2014 Intel Corporation */ #include <linux/module.h>#include <linux/input.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/i2c.h>#include <linux/slab.h>#include <linux/acpi.h>#include <linux/gpio/consumer.h>#include <linux/gpio_keys.h>#include <linux/gpio.h>#include <linux/platform_device.h>  #define SURFACE_BUTTON_OBJ_NAME		"TEV2"#define MAX_NBUTTONS			4 /* * Some of the buttons like volume up/down are auto repeat, while others * are not. To support both, we register two platform devices, and put * buttons into them based on whether the key should be auto repeat. */#define BUTTON_TYPES			2 /* * Power button, Home button, Volume buttons support is supposed to * be covered by drivers/input/misc/soc_button_array.c, which is implemented * according to "Windows ACPI Design Guide for SoC Platforms". * However surface 3 seems not to obey the specs, instead it uses * device TEV2(MSHW0028) for declaring the GPIOs. The gpios are also slightly * different in which the Home button is active high. * Compared to surfacepro3_button.c which also handles MSHW0028, the Surface 3 * is a reduce platform and thus uses GPIOs, not ACPI events. * We choose an I2C driver here because we need to access the resources * declared under the device node, while surfacepro3_button.c only needs * the ACPI companion node. */static const struct acpi_device_id surface3_acpi_match[] = {	{ "MSHW0028", 0 },	{ }};MODULE_DEVICE_TABLE(acpi, surface3_acpi_match); struct surface3_button_info {	const char *name;	int acpi_index;	unsigned int event_type;	unsigned int event_code;	bool autorepeat;	bool wakeup;	bool active_low;}; struct surface3_button_data {	struct platform_device *children[BUTTON_TYPES];}; /* * Get the Nth GPIO number from the ACPI object. */static int surface3_button_lookup_gpio(struct device *dev, int acpi_index){	struct gpio_desc *desc;	int gpio; 	desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS);	if (IS_ERR(desc))		return PTR_ERR(desc); 	gpio = desc_to_gpio(desc); 	gpiod_put(desc); 	return gpio;} static struct platform_device *surface3_button_device_create(struct i2c_client *client,			      const struct surface3_button_info *button_info,			      bool autorepeat){	const struct surface3_button_info *info;	struct platform_device *pd;	struct gpio_keys_button *gpio_keys;	struct gpio_keys_platform_data *gpio_keys_pdata;	int n_buttons = 0;	int gpio;	int error; 	gpio_keys_pdata = devm_kzalloc(&client->dev,				       sizeof(*gpio_keys_pdata) +				       sizeof(*gpio_keys) * MAX_NBUTTONS,				       GFP_KERNEL);	if (!gpio_keys_pdata)		return ERR_PTR(-ENOMEM); 	gpio_keys = (void *)(gpio_keys_pdata + 1); 	for (info = button_info; info->name; info++) {		if (info->autorepeat != autorepeat)			continue; 		gpio = surface3_button_lookup_gpio(&client->dev,						   info->acpi_index);		if (!gpio_is_valid(gpio))			continue; 		gpio_keys[n_buttons].type = info->event_type;		gpio_keys[n_buttons].code = info->event_code;		gpio_keys[n_buttons].gpio = gpio;		gpio_keys[n_buttons].active_low = info->active_low;		gpio_keys[n_buttons].desc = info->name;		gpio_keys[n_buttons].wakeup = info->wakeup;		n_buttons++;	} 	if (n_buttons == 0) {		error = -ENODEV;		goto err_free_mem;	} 	gpio_keys_pdata->buttons = gpio_keys;	gpio_keys_pdata->nbuttons = n_buttons;	gpio_keys_pdata->rep = autorepeat; 	pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO);	if (!pd) {		error = -ENOMEM;		goto err_free_mem;	} 	error = platform_device_add_data(pd, gpio_keys_pdata,					 sizeof(*gpio_keys_pdata));	if (error)		goto err_free_pdev; 	error = platform_device_add(pd);	if (error)		goto err_free_pdev; 	return pd; err_free_pdev:	platform_device_put(pd);err_free_mem:	devm_kfree(&client->dev, gpio_keys_pdata);	return ERR_PTR(error);} static int surface3_button_remove(struct i2c_client *client){	struct surface3_button_data *priv = i2c_get_clientdata(client); 	int i; 	for (i = 0; i < BUTTON_TYPES; i++)		if (priv->children[i])			platform_device_unregister(priv->children[i]); 	return 0;} static struct surface3_button_info surface3_button_surface3[] = {	{ "power", 0, EV_KEY, KEY_POWER, false, true, true },	{ "home", 1, EV_KEY, KEY_LEFTMETA, false, true, false },	{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false, true },	{ "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false, true },	{ }}; static int surface3_button_probe(struct i2c_client *client,				 const struct i2c_device_id *id){	struct device *dev = &client->dev;	struct surface3_button_data *priv;	struct platform_device *pd;	int i;	int error; 	if (strncmp(acpi_device_bid(ACPI_COMPANION(&client->dev)),		    SURFACE_BUTTON_OBJ_NAME,		    strlen(SURFACE_BUTTON_OBJ_NAME)))		return -ENODEV; 	error = gpiod_count(dev, NULL);	if (error < 0) {		dev_dbg(dev, "no GPIO attached, ignoring...\n");		return error;	} 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);	if (!priv)		return -ENOMEM; 	i2c_set_clientdata(client, priv); 	for (i = 0; i < BUTTON_TYPES; i++) {		pd = surface3_button_device_create(client,						   surface3_button_surface3,						   i == 0);		if (IS_ERR(pd)) {			error = PTR_ERR(pd);			if (error != -ENODEV) {				surface3_button_remove(client);				return error;			}			continue;		} 		priv->children[i] = pd;	} 	if (!priv->children[0] && !priv->children[1])		return -ENODEV; 	return 0;} static const struct i2c_device_id surface3_id[] = {	{ }};MODULE_DEVICE_TABLE(i2c, surface3_id); static struct i2c_driver surface3_driver = {	.probe = surface3_button_probe,	.remove = surface3_button_remove,	.id_table = surface3_id,	.driver = {		.name = "surface3",		.acpi_match_table = ACPI_PTR(surface3_acpi_match),	},};module_i2c_driver(surface3_driver); MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");MODULE_DESCRIPTION("surface3 button array driver");MODULE_LICENSE("GPL v2");