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 000000000000..08ead2aaede5
--- /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/input.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;
+                        }
+                }
+
+                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");