diff options
Diffstat (limited to 'drivers/platform/x86/surface3_button.c')
| -rw-r--r-- | drivers/platform/x86/surface3_button.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/platform/x86/surface3_button.c b/drivers/platform/x86/surface3_button.c new file mode 100644 index 000000000000..8bfd7f613d36 --- /dev/null +++ b/drivers/platform/x86/surface3_button.c @@ -0,0 +1,250 @@ +/* + * 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 <linux/module.h> +#include <linux/input.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/i2c.h> +#include <linux/slab.h> +#include <linux/acpi.h> +#include <linux/gpio/consumer.h> +#include <linux/gpio_keys.h> +#include <linux/gpio.h> +#include <linux/platform_device.h> + + +#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; + + 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; + + 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 <benjamin.tissoires@gmail.com>"); +MODULE_DESCRIPTION("surface3 button array driver"); +MODULE_LICENSE("GPL v2"); |