/* * 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_SW, SW_ROTATE_LOCK, 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");