--- /dev/null
+/*
+ * 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");
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff