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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>
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, 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 *
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;
for (info = button_info; info->name; info++)
if (info->autorepeat == autorepeat)
n_buttons++;
gpio_keys_pdata = devm_kzalloc(&pdev->dev,
sizeof(*gpio_keys_pdata) +
sizeof(*gpio_keys) * n_buttons,
GFP_KERNEL);
if (!gpio_keys_pdata)
return ERR_PTR(-ENOMEM);
gpio_keys = (void *)(gpio_keys_pdata + 1);
n_buttons = 0;
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_get_acpi_object_int(const union acpi_object *obj)
{
if (obj->type != ACPI_TYPE_INTEGER)
return -1;
return obj->integer.value;
}
/* Parse a single ACPI0011 _DSD button descriptor */
static int soc_button_parse_btn_desc(struct device *dev,
const union acpi_object *desc,
int collection_uid,
struct soc_button_info *info)
{
int upage, usage;
if (desc->type != ACPI_TYPE_PACKAGE ||
desc->package.count != 5 ||
/* First byte should be 1 (control) */
soc_button_get_acpi_object_int(&desc->package.elements[0]) != 1 ||
/* Third byte should be collection uid */
soc_button_get_acpi_object_int(&desc->package.elements[2]) !=
collection_uid) {
dev_err(dev, "Invalid ACPI Button Descriptor\n");
return -ENODEV;
}
info->event_type = EV_KEY;
info->acpi_index =
soc_button_get_acpi_object_int(&desc->package.elements[1]);
upage = soc_button_get_acpi_object_int(&desc->package.elements[3]);
usage = soc_button_get_acpi_object_int(&desc->package.elements[4]);
/*
* The UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e descriptors use HID
* usage page and usage codes, but otherwise the device is not HID
* compliant: it uses one irq per button instead of generating HID
* input reports and some buttons should generate wakeups where as
* others should not, so we cannot use the HID subsystem.
*
* Luckily all devices only use a few usage page + usage combinations,
* so we can simply check for the known combinations here.
*/
if (upage == 0x01 && usage == 0x81) {
info->name = "power";
info->event_code = KEY_POWER;
info->wakeup = true;
} else if (upage == 0x01 && usage == 0xca) {
info->name = "rotation lock switch";
info->event_type = EV_SW;
info->event_code = SW_ROTATE_LOCK;
} else if (upage == 0x07 && usage == 0xe3) {
info->name = "home";
info->event_code = KEY_LEFTMETA;
info->wakeup = true;
} else if (upage == 0x0c && usage == 0xe9) {
info->name = "volume_up";
info->event_code = KEY_VOLUMEUP;
info->autorepeat = true;
} else if (upage == 0x0c && usage == 0xea) {
info->name = "volume_down";
info->event_code = KEY_VOLUMEDOWN;
info->autorepeat = true;
} else {
dev_warn(dev, "Unknown button index %d upage %02x usage %02x, ignoring\n",
info->acpi_index, upage, usage);
info->name = "unknown";
info->event_code = KEY_RESERVED;
}
return 0;
}
/* ACPI0011 _DSD btns descriptors UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e */
static const u8 btns_desc_uuid[16] = {
0x25, 0xd6, 0x6b, 0xfa, 0xe8, 0x9c, 0x0d, 0x47,
0xa2, 0xc7, 0xb3, 0xca, 0x36, 0xc4, 0x28, 0x2e
};
/* Parse ACPI0011 _DSD button descriptors */
static struct soc_button_info *soc_button_get_button_info(struct device *dev)
{
struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
const union acpi_object *desc, *el0, *uuid, *btns_desc = NULL;
struct soc_button_info *button_info;
acpi_status status;
int i, btn, collection_uid = -1;
status = acpi_evaluate_object_typed(ACPI_HANDLE(dev), "_DSD", NULL,
&buf, ACPI_TYPE_PACKAGE);
if (ACPI_FAILURE(status)) {
dev_err(dev, "ACPI _DSD object not found\n");
return ERR_PTR(-ENODEV);
}
/* Look for the Button Descriptors UUID */
desc = buf.pointer;
for (i = 0; (i + 1) < desc->package.count; i += 2) {
uuid = &desc->package.elements[i];
if (uuid->type != ACPI_TYPE_BUFFER ||
uuid->buffer.length != 16 ||
desc->package.elements[i
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