linux/drivers/input/misc/soc_button_array.c
Benjamin Tissoires 3d5a9437a6 Input: soc_button_array - bail out earlier if gpiod_count is zero
The PNP0C40 device of the Surface 3 doesn't have any GPIO attached to it.
Instead of trying to access the GPIO, request the count beforehand and
bail out if it is null or if an error is returned.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2016-11-25 11:39:50 -08:00

228 lines
5.2 KiB
C

/*
* 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;
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(&pdev->dev, KBUILD_MODNAME) <= 0) {
dev_dbg(&pdev->dev, "no GPIO attached, ignoring...\n");
return -ENODEV;
}
priv = devm_kzalloc(&pdev->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");