/* * 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 #include #include #include #include #include #include #include #include /* * 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; /* 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_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(dev, KBUILD_MODNAME) <= 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; 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");