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/*
* Supports for the button array on SoC tablets originally running
* Windows 8.
*
* (C) Copyright 2014 Intel Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2
* of the License.
*/
#include <linux/module.h>
#include <linux/input.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio_keys.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>
/*
* Definition of buttons on the tablet. The ACPI index of each button
* is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
* Platforms"
*/
#define MAX_NBUTTONS 5
struct soc_button_info {
const char *name;
int acpi_index;
unsigned int event_type;
unsigned int event_code;
bool autorepeat;
bool wakeup;
};
/*
* 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
struct soc_button_data {
struct platform_device *children[BUTTON_TYPES];
};
/*
* Get the Nth GPIO number from the ACPI object.
*/
static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
{
struct gpio_desc *desc;
int gpio;
desc = gpiod_get_index(dev, KBUILD_MODNAME, 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 *
soc_button_device_create(struct platform_device *pdev,
const struct soc_button_info *button_info,
bool autorepeat)
{
const struct soc_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(&pdev->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 = soc_button_lookup_gpio(&pdev->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 = 1;
gpio_keys[n_buttons].desc = info->name;
gpio_keys[n_buttons].wakeup = info->wakeup;
/* These devices often use cheap buttons, use 50 ms debounce */
gpio_keys[n_buttons].debounce_interval = 50;
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(&pdev->dev, gpio_keys_pdata);
return ERR_PTR(error);
}
static int soc_button_remove(struct platform_device *pdev)
{
struct soc_button_data *priv = platform_get_drvdata(pdev);
int i;
for (i = 0; i < BUTTON_TYPES; i++)
if (priv->children[i])
platform_device_unregister(priv->children[i]);
return 0;
}
static int soc_button_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
const struct acpi_device_id *id;
struct soc_button_info *button_info;
struct soc_button_data *priv;
struct platform_device *pd;
int i;
int error;
id = acpi_match_device(dev->driver->acpi_match_table, dev);
if (!id)
return -ENODEV;
button_info = (struct soc_button_info *)id->driver_data;
if (gpiod_count(dev, KBUILD_MODNAME) <= 0) {
dev_dbg(dev, "no GPIO attached, ignoring...\n");
return -ENODEV;
}
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
platform_set_drvdata(pdev, priv);
for (i = 0; i < BUTTON_TYPES; i++) {
pd = soc_button_device_create(pdev, button_info, i == 0);
if (IS_ERR(pd)) {
error = PTR_ERR(pd);
if (error != -ENODEV) {
soc_button_remove(pdev);
return error;
}
continue;
}
priv->children[i] = pd;
}
if (!priv->children[0] && !priv->children[1])
return -ENODEV;
return 0;
}
static struct soc_button_info soc_button_PNP0C40[] = {
{ "power", 0, EV_KEY, KEY_POWER, false, true },
{ "home", 1, EV_KEY, KEY_LEFTMETA, false, true },
{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
{ "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false },
{ "rotation_lock", 4, EV_SW, SW_ROTATE_LOCK, false, false },
{ }
};
static const struct acpi_device_id soc_button_acpi_match[] = {
{ "PNP0C40", (unsigned long)soc_button_PNP0C40 },
{ }
};
MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);
static struct platform_driver soc_button_driver = {
.probe = soc_button_probe,
.remove = soc_button_remove,
.driver = {
.name = KBUILD_MODNAME,
.acpi_match_table = ACPI_PTR(soc_button_acpi_match),
},
};
module_platform_driver(soc_button_driver);
MODULE_LICENSE("GPL");
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