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