diff options
Diffstat (limited to 'drivers/input/misc/soc_button_array.c')
| -rw-r--r-- | drivers/input/misc/soc_button_array.c | 218 |
1 files changed, 218 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 00000000000..5a6334be30b --- /dev/null +++ b/drivers/input/misc/soc_button_array.c @@ -0,0 +1,218 @@ +/* + * 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/platform_device.h> +#include <linux/pnp.h> + +/* + * 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); + 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 pnp_dev *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); + 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 < 0) + 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; + 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 void soc_button_remove(struct pnp_dev *pdev) +{ + struct soc_button_data *priv = pnp_get_drvdata(pdev); + int i; + + for (i = 0; i < BUTTON_TYPES; i++) + if (priv->children[i]) + platform_device_unregister(priv->children[i]); +} + +static int soc_button_pnp_probe(struct pnp_dev *pdev, + const struct pnp_device_id *id) +{ + const struct soc_button_info *button_info = (void *)id->driver_data; + struct soc_button_data *priv; + struct platform_device *pd; + int i; + int error; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + pnp_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_HOME, 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 pnp_device_id soc_button_pnp_match[] = { + { .id = "PNP0C40", .driver_data = (long)soc_button_PNP0C40 }, + { .id = "" } +}; +MODULE_DEVICE_TABLE(pnp, soc_button_pnp_match); + +static struct pnp_driver soc_button_pnp_driver = { + .name = KBUILD_MODNAME, + .id_table = soc_button_pnp_match, + .probe = soc_button_pnp_probe, + .remove = soc_button_remove, +}; + +static int __init soc_button_init(void) +{ + return pnp_register_driver(&soc_button_pnp_driver); +} + +static void __exit soc_button_exit(void) +{ + pnp_unregister_driver(&soc_button_pnp_driver); +} + +module_init(soc_button_init); +module_exit(soc_button_exit); + +MODULE_LICENSE("GPL"); |