// 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");
