/* * Supports for the button array on the Surface tablets. * * (C) Copyright 2016 Red Hat, Inc * * Based on soc_button_array.c: * * {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 #include #include #define SURFACE_BUTTON_OBJ_NAME "TEV2" #define MAX_NBUTTONS 4 /* * 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 /* * Power button, Home button, Volume buttons support is supposed to * be covered by drivers/input/misc/soc_button_array.c, which is implemented * according to "Windows ACPI Design Guide for SoC Platforms". * However surface 3 seems not to obey the specs, instead it uses * device TEV2(MSHW0028) for declaring the GPIOs. The gpios are also slightly * different in which the Home button is active high. * Compared to surfacepro3_button.c which also handles MSHW0028, the Surface 3 * is a reduce platform and thus uses GPIOs, not ACPI events. * We choose an I2C driver here because we need to access the resources * declared under the device node, while surfacepro3_button.c only needs * the ACPI companion node. */ static const struct acpi_device_id surface3_acpi_match[] = { { "MSHW0028", 0 }, { } }; MODULE_DEVICE_TABLE(acpi, surface3_acpi_match); struct surface3_button_info { const char *name; int acpi_index; unsigned int event_type; unsigned int event_code; bool autorepeat; bool wakeup; bool active_low; }; struct surface3_button_data { struct platform_device *children[BUTTON_TYPES]; }; /* * Get the Nth GPIO number from the ACPI object. */ static int surface3_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 * surface3_button_device_create(struct i2c_client *client, const struct surface3_button_info *button_info, bool autorepeat) { const struct surface3_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(&client->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 = surface3_button_lookup_gpio(&client->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 = info->active_low; gpio_keys[n_buttons].desc = info->name; gpio_keys[n_buttons].wakeup = info->wakeup; 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(&client->dev, gpio_keys_pdata); return ERR_PTR(error); } static int surface3_button_remove(struct i2c_client *client) { struct surface3_button_data *priv = i2c_get_clientdata(client); int i; for (i = 0; i < BUTTON_TYPES; i++) if (priv->children[i]) platform_device_unregister(priv->children[i]); return 0; } static struct surface3_button_info surface3_button_surface3[] = { { "power", 0, EV_KEY, KEY_POWER, false, true, true }, { "home", 1, EV_KEY, KEY_LEFTMETA, false, true, false }, { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false, true }, { "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false, true }, { } }; static int surface3_button_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct device *dev = &client->dev; struct surface3_button_data *priv; struct platform_device *pd; int i; int error; if (strncmp(acpi_device_bid(ACPI_COMPANION(&client->dev)), SURFACE_BUTTON_OBJ_NAME, strlen(SURFACE_BUTTON_OBJ_NAME))) return -ENODEV; error = gpiod_count(dev, NULL); if (error < 0) { dev_dbg(dev, "no GPIO attached, ignoring...\n"); return error; } priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; i2c_set_clientdata(client, priv); for (i = 0; i < BUTTON_TYPES; i++) { pd = surface3_button_device_create(client, surface3_button_surface3, i == 0); if (IS_ERR(pd)) { error = PTR_ERR(pd); if (error != -ENODEV) { surface3_button_remove(client); return error; } continue; } priv->children[i] = pd; } if (!priv->children[0] && !priv->children[1]) return -ENODEV; return 0; } static const struct i2c_device_id surface3_id[] = { { } }; MODULE_DEVICE_TABLE(i2c, surface3_id); static struct i2c_driver surface3_driver = { .probe = surface3_button_probe, .remove = surface3_button_remove, .id_table = surface3_id, .driver = { .name = "surface3", .acpi_match_table = ACPI_PTR(surface3_acpi_match), }, }; module_i2c_driver(surface3_driver); MODULE_AUTHOR("Benjamin Tissoires "); MODULE_DESCRIPTION("surface3 button array driver"); MODULE_LICENSE("GPL v2");