diff options
Diffstat (limited to 'drivers/input/misc/soc_button_array.c')
| -rw-r--r-- | drivers/input/misc/soc_button_array.c | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/drivers/input/misc/soc_button_array.c b/drivers/input/misc/soc_button_array.c new file mode 100644 index 000000000..55cd6e0b4 --- /dev/null +++ b/drivers/input/misc/soc_button_array.c @@ -0,0 +1,398 @@ +/* + * 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 == 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 + 1].type != ACPI_TYPE_PACKAGE) { + break; + } + + if (memcmp(uuid->buffer.pointer, btns_desc_uuid, 16) == 0) { + btns_desc = &desc->package.elements[i + 1]; + break; + } + } + + if (!btns_desc) { + dev_err(dev, "ACPI Button Descriptors not found\n"); + button_info = ERR_PTR(-ENODEV); + goto out; + } + + /* The first package describes the collection */ + el0 = &btns_desc->package.elements[0]; + if (el0->type == ACPI_TYPE_PACKAGE && + el0->package.count == 5 && + /* First byte should be 0 (collection) */ + soc_button_get_acpi_object_int(&el0->package.elements[0]) == 0 && + /* Third byte should be 0 (top level collection) */ + soc_button_get_acpi_object_int(&el0->package.elements[2]) == 0) { + collection_uid = soc_button_get_acpi_object_int( + &el0->package.elements[1]); + } + if (collection_uid == -1) { + dev_err(dev, "Invalid Button Collection Descriptor\n"); + button_info = ERR_PTR(-ENODEV); + goto out; + } + + /* There are package.count - 1 buttons + 1 terminating empty entry */ + button_info = devm_kcalloc(dev, btns_desc->package.count, + sizeof(*button_info), GFP_KERNEL); + if (!button_info) { + button_info = ERR_PTR(-ENOMEM); + goto out; + } + + /* Parse the button descriptors */ + for (i = 1, btn = 0; i < btns_desc->package.count; i++, btn++) { + if (soc_button_parse_btn_desc(dev, + &btns_desc->package.elements[i], + collection_uid, + &button_info[btn])) { + button_info = ERR_PTR(-ENODEV); + goto out; + } + } + +out: + kfree(buf.pointer); + return button_info; +} + +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; + + if (!id->driver_data) { + button_info = soc_button_get_button_info(dev); + if (IS_ERR(button_info)) + return PTR_ERR(button_info); + } else { + button_info = (struct soc_button_info *)id->driver_data; + } + + error = gpiod_count(dev, NULL); + if (error < 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; + + if (!id->driver_data) + devm_kfree(dev, button_info); + + return 0; +} + +/* + * 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" + */ +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_KEY, KEY_ROTATE_LOCK_TOGGLE, false, false }, + { } +}; + +static const struct acpi_device_id soc_button_acpi_match[] = { + { "PNP0C40", (unsigned long)soc_button_PNP0C40 }, + { "ACPI0011", 0 }, + { } +}; + +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"); |