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247 lines
6.0 KiB
247 lines
6.0 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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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#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 <[email protected]>"); |
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MODULE_DESCRIPTION("surface3 button array driver"); |
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MODULE_LICENSE("GPL v2");
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