summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/input/misc/soc_button_array.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/drivers/input/misc/soc_button_array.c')
-rw-r--r--kernel/drivers/input/misc/soc_button_array.c222
1 files changed, 222 insertions, 0 deletions
diff --git a/kernel/drivers/input/misc/soc_button_array.c b/kernel/drivers/input/misc/soc_button_array.c
new file mode 100644
index 000000000..e8e010a85
--- /dev/null
+++ b/kernel/drivers/input/misc/soc_button_array.c
@@ -0,0 +1,222 @@
+/*
+ * 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/platform_device.h>
+#include <linux/acpi.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, GPIOD_ASIS);
+ 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 platform_device *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);
+ 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 = 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 int soc_button_remove(struct platform_device *pdev)
+{
+ struct soc_button_data *priv = platform_get_drvdata(pdev);
+
+ int i;
+
+ for (i = 0; i < BUTTON_TYPES; i++)
+ if (priv->children[i])
+ platform_device_unregister(priv->children[i]);
+
+ return 0;
+}
+
+static int soc_button_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ const struct acpi_device_id *id;
+ struct soc_button_info *button_info;
+ struct soc_button_data *priv;
+ struct platform_device *pd;
+ int i;
+ int error;
+
+ id = acpi_match_device(dev->driver->acpi_match_table, dev);
+ if (!id)
+ return -ENODEV;
+
+ button_info = (struct soc_button_info *)id->driver_data;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ platform_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;
+ }
+ continue;
+ }
+
+ 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_LEFTMETA, 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 acpi_device_id soc_button_acpi_match[] = {
+ { "PNP0C40", (unsigned long)soc_button_PNP0C40 },
+ { }
+};
+
+MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);
+
+static struct platform_driver soc_button_driver = {
+ .probe = soc_button_probe,
+ .remove = soc_button_remove,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .acpi_match_table = ACPI_PTR(soc_button_acpi_match),
+ },
+};
+module_platform_driver(soc_button_driver);
+
+MODULE_LICENSE("GPL");