224 lines
5.1 KiB
C
224 lines
5.1 KiB
C
/*
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* Supports for the button array on SoC tablets originally running
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* Windows 8.
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*
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* (C) Copyright 2014 Intel Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*/
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#include <linux/module.h>
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#include <linux/input.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/acpi.h>
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#include <linux/gpio/consumer.h>
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#include <linux/gpio_keys.h>
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#include <linux/platform_device.h>
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#include <linux/acpi.h>
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/*
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* Definition of buttons on the tablet. The ACPI index of each button
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* is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
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* Platforms"
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*/
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#define MAX_NBUTTONS 5
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struct soc_button_info {
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const char *name;
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int acpi_index;
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unsigned int event_type;
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unsigned int event_code;
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bool autorepeat;
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bool wakeup;
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};
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/*
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* Some of the buttons like volume up/down are auto repeat, while others
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* are not. To support both, we register two platform devices, and put
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* buttons into them based on whether the key should be auto repeat.
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*/
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#define BUTTON_TYPES 2
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struct soc_button_data {
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struct platform_device *children[BUTTON_TYPES];
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};
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/*
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* Get the Nth GPIO number from the ACPI object.
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*/
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static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
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{
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struct gpio_desc *desc;
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int gpio;
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desc = gpiod_get_index(dev, KBUILD_MODNAME, acpi_index, GPIOD_ASIS);
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if (IS_ERR(desc))
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return PTR_ERR(desc);
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gpio = desc_to_gpio(desc);
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gpiod_put(desc);
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return gpio;
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}
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static struct platform_device *
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soc_button_device_create(struct platform_device *pdev,
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const struct soc_button_info *button_info,
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bool autorepeat)
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{
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const struct soc_button_info *info;
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struct platform_device *pd;
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struct gpio_keys_button *gpio_keys;
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struct gpio_keys_platform_data *gpio_keys_pdata;
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int n_buttons = 0;
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int gpio;
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int error;
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gpio_keys_pdata = devm_kzalloc(&pdev->dev,
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sizeof(*gpio_keys_pdata) +
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sizeof(*gpio_keys) * MAX_NBUTTONS,
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GFP_KERNEL);
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if (!gpio_keys_pdata)
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return ERR_PTR(-ENOMEM);
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gpio_keys = (void *)(gpio_keys_pdata + 1);
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for (info = button_info; info->name; info++) {
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if (info->autorepeat != autorepeat)
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continue;
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gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
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if (gpio < 0)
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continue;
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gpio_keys[n_buttons].type = info->event_type;
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gpio_keys[n_buttons].code = info->event_code;
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gpio_keys[n_buttons].gpio = gpio;
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gpio_keys[n_buttons].active_low = 1;
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gpio_keys[n_buttons].desc = info->name;
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gpio_keys[n_buttons].wakeup = info->wakeup;
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n_buttons++;
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}
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if (n_buttons == 0) {
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error = -ENODEV;
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goto err_free_mem;
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}
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gpio_keys_pdata->buttons = gpio_keys;
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gpio_keys_pdata->nbuttons = n_buttons;
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gpio_keys_pdata->rep = autorepeat;
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pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO);
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if (!pd) {
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error = -ENOMEM;
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goto err_free_mem;
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}
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error = platform_device_add_data(pd, gpio_keys_pdata,
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sizeof(*gpio_keys_pdata));
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if (error)
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goto err_free_pdev;
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error = platform_device_add(pd);
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if (error)
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goto err_free_pdev;
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return pd;
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err_free_pdev:
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platform_device_put(pd);
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err_free_mem:
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devm_kfree(&pdev->dev, gpio_keys_pdata);
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return ERR_PTR(error);
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}
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static int soc_button_remove(struct platform_device *pdev)
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{
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struct soc_button_data *priv = platform_get_drvdata(pdev);
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int i;
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for (i = 0; i < BUTTON_TYPES; i++)
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if (priv->children[i])
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platform_device_unregister(priv->children[i]);
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return 0;
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}
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static int soc_button_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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const struct acpi_device_id *id;
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struct soc_button_info *button_info;
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struct soc_button_data *priv;
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struct platform_device *pd;
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int i;
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int error;
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id = acpi_match_device(dev->driver->acpi_match_table, dev);
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if (!id)
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return -ENODEV;
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button_info = (struct soc_button_info *)id->driver_data;
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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platform_set_drvdata(pdev, priv);
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for (i = 0; i < BUTTON_TYPES; i++) {
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pd = soc_button_device_create(pdev, button_info, i == 0);
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if (IS_ERR(pd)) {
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error = PTR_ERR(pd);
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if (error != -ENODEV) {
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soc_button_remove(pdev);
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return error;
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}
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continue;
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}
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priv->children[i] = pd;
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}
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if (!priv->children[0] && !priv->children[1])
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return -ENODEV;
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return 0;
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}
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static struct soc_button_info soc_button_PNP0C40[] = {
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{ "power", 0, EV_KEY, KEY_POWER, false, true },
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{ "home", 1, EV_KEY, KEY_HOME, false, true },
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{ "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
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{ "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false },
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{ "rotation_lock", 4, EV_SW, SW_ROTATE_LOCK, false, false },
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{ }
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};
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static const struct acpi_device_id soc_button_acpi_match[] = {
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{ "PNP0C40", (unsigned long)soc_button_PNP0C40 },
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{ }
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};
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MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);
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static struct platform_driver soc_button_driver = {
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.probe = soc_button_probe,
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.remove = soc_button_remove,
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.driver = {
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.name = KBUILD_MODNAME,
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.owner = THIS_MODULE,
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.acpi_match_table = ACPI_PTR(soc_button_acpi_match),
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},
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};
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module_platform_driver(soc_button_driver);
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MODULE_LICENSE("GPL");
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