399 lines
10 KiB
C
399 lines
10 KiB
C
/*
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* Supports for the button array on SoC tablets originally running
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* Windows 8.
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*
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* (C) Copyright 2014 Intel Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*/
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#include <linux/module.h>
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#include <linux/input.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/acpi.h>
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#include <linux/gpio/consumer.h>
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#include <linux/gpio_keys.h>
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#include <linux/gpio.h>
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#include <linux/platform_device.h>
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struct soc_button_info {
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const char *name;
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int acpi_index;
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unsigned int event_type;
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unsigned int event_code;
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bool autorepeat;
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bool wakeup;
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};
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/*
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* Some of the buttons like volume up/down are auto repeat, while others
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* are not. To support both, we register two platform devices, and put
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* buttons into them based on whether the key should be auto repeat.
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*/
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#define BUTTON_TYPES 2
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struct soc_button_data {
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struct platform_device *children[BUTTON_TYPES];
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};
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/*
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* Get the Nth GPIO number from the ACPI object.
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*/
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static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
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{
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struct gpio_desc *desc;
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int gpio;
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desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS);
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if (IS_ERR(desc))
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return PTR_ERR(desc);
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gpio = desc_to_gpio(desc);
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gpiod_put(desc);
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return gpio;
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}
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static struct platform_device *
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soc_button_device_create(struct platform_device *pdev,
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const struct soc_button_info *button_info,
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bool autorepeat)
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{
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const struct soc_button_info *info;
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struct platform_device *pd;
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struct gpio_keys_button *gpio_keys;
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struct gpio_keys_platform_data *gpio_keys_pdata;
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int n_buttons = 0;
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int gpio;
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int error;
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for (info = button_info; info->name; info++)
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if (info->autorepeat == autorepeat)
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n_buttons++;
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gpio_keys_pdata = devm_kzalloc(&pdev->dev,
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sizeof(*gpio_keys_pdata) +
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sizeof(*gpio_keys) * n_buttons,
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GFP_KERNEL);
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if (!gpio_keys_pdata)
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return ERR_PTR(-ENOMEM);
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gpio_keys = (void *)(gpio_keys_pdata + 1);
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n_buttons = 0;
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for (info = button_info; info->name; info++) {
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if (info->autorepeat != autorepeat)
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continue;
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gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
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if (!gpio_is_valid(gpio))
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continue;
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gpio_keys[n_buttons].type = info->event_type;
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gpio_keys[n_buttons].code = info->event_code;
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gpio_keys[n_buttons].gpio = gpio;
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gpio_keys[n_buttons].active_low = 1;
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gpio_keys[n_buttons].desc = info->name;
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gpio_keys[n_buttons].wakeup = info->wakeup;
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/* These devices often use cheap buttons, use 50 ms debounce */
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gpio_keys[n_buttons].debounce_interval = 50;
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n_buttons++;
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}
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if (n_buttons == 0) {
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error = -ENODEV;
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goto err_free_mem;
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}
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gpio_keys_pdata->buttons = gpio_keys;
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gpio_keys_pdata->nbuttons = n_buttons;
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gpio_keys_pdata->rep = autorepeat;
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pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO);
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if (!pd) {
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error = -ENOMEM;
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goto err_free_mem;
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}
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error = platform_device_add_data(pd, gpio_keys_pdata,
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sizeof(*gpio_keys_pdata));
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if (error)
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goto err_free_pdev;
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error = platform_device_add(pd);
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if (error)
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goto err_free_pdev;
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return pd;
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err_free_pdev:
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platform_device_put(pd);
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err_free_mem:
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devm_kfree(&pdev->dev, gpio_keys_pdata);
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return ERR_PTR(error);
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}
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static int soc_button_get_acpi_object_int(const union acpi_object *obj)
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{
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if (obj->type != ACPI_TYPE_INTEGER)
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return -1;
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return obj->integer.value;
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}
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/* Parse a single ACPI0011 _DSD button descriptor */
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static int soc_button_parse_btn_desc(struct device *dev,
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const union acpi_object *desc,
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int collection_uid,
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struct soc_button_info *info)
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{
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int upage, usage;
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if (desc->type != ACPI_TYPE_PACKAGE ||
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desc->package.count != 5 ||
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/* First byte should be 1 (control) */
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soc_button_get_acpi_object_int(&desc->package.elements[0]) != 1 ||
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/* Third byte should be collection uid */
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soc_button_get_acpi_object_int(&desc->package.elements[2]) !=
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collection_uid) {
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dev_err(dev, "Invalid ACPI Button Descriptor\n");
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return -ENODEV;
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}
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info->event_type = EV_KEY;
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info->acpi_index =
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soc_button_get_acpi_object_int(&desc->package.elements[1]);
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upage = soc_button_get_acpi_object_int(&desc->package.elements[3]);
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usage = soc_button_get_acpi_object_int(&desc->package.elements[4]);
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/*
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* The UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e descriptors use HID
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* usage page and usage codes, but otherwise the device is not HID
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* compliant: it uses one irq per button instead of generating HID
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* input reports and some buttons should generate wakeups where as
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* others should not, so we cannot use the HID subsystem.
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*
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* Luckily all devices only use a few usage page + usage combinations,
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* so we can simply check for the known combinations here.
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*/
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if (upage == 0x01 && usage == 0x81) {
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info->name = "power";
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info->event_code = KEY_POWER;
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info->wakeup = true;
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} else if (upage == 0x07 && usage == 0xe3) {
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info->name = "home";
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info->event_code = KEY_LEFTMETA;
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info->wakeup = true;
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} else if (upage == 0x0c && usage == 0xe9) {
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info->name = "volume_up";
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info->event_code = KEY_VOLUMEUP;
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info->autorepeat = true;
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} else if (upage == 0x0c && usage == 0xea) {
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info->name = "volume_down";
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info->event_code = KEY_VOLUMEDOWN;
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info->autorepeat = true;
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} else {
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dev_warn(dev, "Unknown button index %d upage %02x usage %02x, ignoring\n",
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info->acpi_index, upage, usage);
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info->name = "unknown";
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info->event_code = KEY_RESERVED;
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}
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return 0;
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}
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/* ACPI0011 _DSD btns descriptors UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e */
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static const u8 btns_desc_uuid[16] = {
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0x25, 0xd6, 0x6b, 0xfa, 0xe8, 0x9c, 0x0d, 0x47,
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0xa2, 0xc7, 0xb3, 0xca, 0x36, 0xc4, 0x28, 0x2e
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};
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/* Parse ACPI0011 _DSD button descriptors */
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static struct soc_button_info *soc_button_get_button_info(struct device *dev)
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{
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struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
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const union acpi_object *desc, *el0, *uuid, *btns_desc = NULL;
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struct soc_button_info *button_info;
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acpi_status status;
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int i, btn, collection_uid = -1;
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status = acpi_evaluate_object_typed(ACPI_HANDLE(dev), "_DSD", NULL,
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&buf, ACPI_TYPE_PACKAGE);
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if (ACPI_FAILURE(status)) {
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dev_err(dev, "ACPI _DSD object not found\n");
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return ERR_PTR(-ENODEV);
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}
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/* Look for the Button Descriptors UUID */
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desc = buf.pointer;
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for (i = 0; (i + 1) < desc->package.count; i += 2) {
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uuid = &desc->package.elements[i];
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if (uuid->type != ACPI_TYPE_BUFFER ||
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uuid->buffer.length != 16 ||
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desc->package.elements[i + 1].type != ACPI_TYPE_PACKAGE) {
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break;
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}
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if (memcmp(uuid->buffer.pointer, btns_desc_uuid, 16) == 0) {
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btns_desc = &desc->package.elements[i + 1];
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break;
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}
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}
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if (!btns_desc) {
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dev_err(dev, "ACPI Button Descriptors not found\n");
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button_info = ERR_PTR(-ENODEV);
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goto out;
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}
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/* The first package describes the collection */
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el0 = &btns_desc->package.elements[0];
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if (el0->type == ACPI_TYPE_PACKAGE &&
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el0->package.count == 5 &&
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/* First byte should be 0 (collection) */
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soc_button_get_acpi_object_int(&el0->package.elements[0]) == 0 &&
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/* Third byte should be 0 (top level collection) */
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soc_button_get_acpi_object_int(&el0->package.elements[2]) == 0) {
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collection_uid = soc_button_get_acpi_object_int(
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&el0->package.elements[1]);
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}
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if (collection_uid == -1) {
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dev_err(dev, "Invalid Button Collection Descriptor\n");
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button_info = ERR_PTR(-ENODEV);
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goto out;
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}
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/* There are package.count - 1 buttons + 1 terminating empty entry */
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button_info = devm_kcalloc(dev, btns_desc->package.count,
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sizeof(*button_info), GFP_KERNEL);
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if (!button_info) {
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button_info = ERR_PTR(-ENOMEM);
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goto out;
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}
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/* Parse the button descriptors */
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for (i = 1, btn = 0; i < btns_desc->package.count; i++, btn++) {
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if (soc_button_parse_btn_desc(dev,
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&btns_desc->package.elements[i],
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collection_uid,
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&button_info[btn])) {
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button_info = ERR_PTR(-ENODEV);
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goto out;
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}
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}
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out:
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kfree(buf.pointer);
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return button_info;
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}
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static int soc_button_remove(struct platform_device *pdev)
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{
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struct soc_button_data *priv = platform_get_drvdata(pdev);
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int i;
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for (i = 0; i < BUTTON_TYPES; i++)
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if (priv->children[i])
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platform_device_unregister(priv->children[i]);
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return 0;
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}
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static int soc_button_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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const struct acpi_device_id *id;
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struct soc_button_info *button_info;
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struct soc_button_data *priv;
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struct platform_device *pd;
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int i;
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int error;
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id = acpi_match_device(dev->driver->acpi_match_table, dev);
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if (!id)
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return -ENODEV;
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if (!id->driver_data) {
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button_info = soc_button_get_button_info(dev);
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if (IS_ERR(button_info))
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return PTR_ERR(button_info);
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} else {
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button_info = (struct soc_button_info *)id->driver_data;
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}
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error = gpiod_count(dev, NULL);
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if (error < 0) {
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dev_dbg(dev, "no GPIO attached, ignoring...\n");
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return -ENODEV;
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}
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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platform_set_drvdata(pdev, priv);
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for (i = 0; i < BUTTON_TYPES; i++) {
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pd = soc_button_device_create(pdev, button_info, i == 0);
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if (IS_ERR(pd)) {
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error = PTR_ERR(pd);
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if (error != -ENODEV) {
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soc_button_remove(pdev);
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return error;
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}
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continue;
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}
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priv->children[i] = pd;
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}
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if (!priv->children[0] && !priv->children[1])
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return -ENODEV;
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if (!id->driver_data)
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devm_kfree(dev, button_info);
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return 0;
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}
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/*
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* Definition of buttons on the tablet. The ACPI index of each button
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* is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
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* Platforms"
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*/
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static struct soc_button_info soc_button_PNP0C40[] = {
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{ "power", 0, EV_KEY, KEY_POWER, false, true },
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{ "home", 1, EV_KEY, KEY_LEFTMETA, false, true },
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{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
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{ "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false },
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{ "rotation_lock", 4, EV_SW, SW_ROTATE_LOCK, false, false },
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{ }
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};
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static const struct acpi_device_id soc_button_acpi_match[] = {
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{ "PNP0C40", (unsigned long)soc_button_PNP0C40 },
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{ "ACPI0011", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);
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static struct platform_driver soc_button_driver = {
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.probe = soc_button_probe,
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.remove = soc_button_remove,
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.driver = {
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.name = KBUILD_MODNAME,
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.acpi_match_table = ACPI_PTR(soc_button_acpi_match),
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},
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};
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module_platform_driver(soc_button_driver);
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MODULE_LICENSE("GPL");
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