staging: android: switch: switch class and GPIO drivers.

This adds the Android switch driver code to the staging tree.

[Note, this code was located in drivers/switch/ in the Android kernel
releases, but as that api wasn't generally accepted, and the interface
is working toward changing to the newly proposed extcon inteface, this
driver was placed here until the extcon code is merged into mainline and
the Android userspace code is converted over to using it. - gregkh]

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Mike Lockwood <lockwood@android.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Donggeun Kim <dg77.kim@samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: MyungJoo Ham <myungjoo.ham@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: NeilBrown <neilb@suse.de>
Cc: Morten CHRISTIANSEN <morten.christiansen@stericsson.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/android/Kconfig

@@ -90,6 +90,8 @@ config ANDROID_LOW_MEMORY_KILLER
 	---help---
 	  Register processes to be killed when memory is low
 
+source "drivers/staging/android/switch/Kconfig"
+
 endif # if ANDROID
 
 endmenu

drivers/staging/android/Makefile

@@ -4,3 +4,4 @@ obj-$(CONFIG_ANDROID_RAM_CONSOLE)	+= ram_console.o
 obj-$(CONFIG_ANDROID_TIMED_OUTPUT)	+= timed_output.o
 obj-$(CONFIG_ANDROID_TIMED_GPIO)	+= timed_gpio.o
 obj-$(CONFIG_ANDROID_LOW_MEMORY_KILLER)	+= lowmemorykiller.o
+obj-$(CONFIG_ANDROID_SWITCH)		+= switch/

drivers/staging/android/switch/Kconfig

@@ -0,0 +1,11 @@
+menuconfig ANDROID_SWITCH
+	tristate "Android Switch class support"
+	help
+	  Say Y here to enable Android switch class support. This allows
+	  monitoring switches by userspace via sysfs and uevent.
+
+config ANDROID_SWITCH_GPIO
+	tristate "Android GPIO Switch support"
+	depends on GENERIC_GPIO && ANDROID_SWITCH
+	help
+	  Say Y here to enable GPIO based switch support.

drivers/staging/android/switch/Makefile

@@ -0,0 +1,4 @@
+# Android Switch Class Driver
+obj-$(CONFIG_ANDROID_SWITCH)		+= switch_class.o
+obj-$(CONFIG_ANDROID_SWITCH_GPIO)	+= switch_gpio.o
+

drivers/staging/android/switch/switch.h

@@ -0,0 +1,53 @@
+/*
+ *  Switch class driver
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+*/
+
+#ifndef __LINUX_SWITCH_H__
+#define __LINUX_SWITCH_H__
+
+struct switch_dev {
+	const char	*name;
+	struct device	*dev;
+	int		index;
+	int		state;
+
+	ssize_t	(*print_name)(struct switch_dev *sdev, char *buf);
+	ssize_t	(*print_state)(struct switch_dev *sdev, char *buf);
+};
+
+struct gpio_switch_platform_data {
+	const char *name;
+	unsigned 	gpio;
+
+	/* if NULL, switch_dev.name will be printed */
+	const char *name_on;
+	const char *name_off;
+	/* if NULL, "0" or "1" will be printed */
+	const char *state_on;
+	const char *state_off;
+};
+
+extern int switch_dev_register(struct switch_dev *sdev);
+extern void switch_dev_unregister(struct switch_dev *sdev);
+
+static inline int switch_get_state(struct switch_dev *sdev)
+{
+	return sdev->state;
+}
+
+extern void switch_set_state(struct switch_dev *sdev, int state);
+
+#endif /* __LINUX_SWITCH_H__ */

drivers/staging/android/switch/switch_class.c

@@ -0,0 +1,174 @@
+/*
+ * switch_class.c
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+*/
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/err.h>
+#include "switch.h"
+
+struct class *switch_class;
+static atomic_t device_count;
+
+static ssize_t state_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct switch_dev *sdev = (struct switch_dev *)
+		dev_get_drvdata(dev);
+
+	if (sdev->print_state) {
+		int ret = sdev->print_state(sdev, buf);
+		if (ret >= 0)
+			return ret;
+	}
+	return sprintf(buf, "%d\n", sdev->state);
+}
+
+static ssize_t name_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct switch_dev *sdev = (struct switch_dev *)
+		dev_get_drvdata(dev);
+
+	if (sdev->print_name) {
+		int ret = sdev->print_name(sdev, buf);
+		if (ret >= 0)
+			return ret;
+	}
+	return sprintf(buf, "%s\n", sdev->name);
+}
+
+static DEVICE_ATTR(state, S_IRUGO | S_IWUSR, state_show, NULL);
+static DEVICE_ATTR(name, S_IRUGO | S_IWUSR, name_show, NULL);
+
+void switch_set_state(struct switch_dev *sdev, int state)
+{
+	char name_buf[120];
+	char state_buf[120];
+	char *prop_buf;
+	char *envp[3];
+	int env_offset = 0;
+	int length;
+
+	if (sdev->state != state) {
+		sdev->state = state;
+
+		prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
+		if (prop_buf) {
+			length = name_show(sdev->dev, NULL, prop_buf);
+			if (length > 0) {
+				if (prop_buf[length - 1] == '\n')
+					prop_buf[length - 1] = 0;
+				snprintf(name_buf, sizeof(name_buf),
+					"SWITCH_NAME=%s", prop_buf);
+				envp[env_offset++] = name_buf;
+			}
+			length = state_show(sdev->dev, NULL, prop_buf);
+			if (length > 0) {
+				if (prop_buf[length - 1] == '\n')
+					prop_buf[length - 1] = 0;
+				snprintf(state_buf, sizeof(state_buf),
+					"SWITCH_STATE=%s", prop_buf);
+				envp[env_offset++] = state_buf;
+			}
+			envp[env_offset] = NULL;
+			kobject_uevent_env(&sdev->dev->kobj, KOBJ_CHANGE, envp);
+			free_page((unsigned long)prop_buf);
+		} else {
+			printk(KERN_ERR "out of memory in switch_set_state\n");
+			kobject_uevent(&sdev->dev->kobj, KOBJ_CHANGE);
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(switch_set_state);
+
+static int create_switch_class(void)
+{
+	if (!switch_class) {
+		switch_class = class_create(THIS_MODULE, "switch");
+		if (IS_ERR(switch_class))
+			return PTR_ERR(switch_class);
+		atomic_set(&device_count, 0);
+	}
+
+	return 0;
+}
+
+int switch_dev_register(struct switch_dev *sdev)
+{
+	int ret;
+
+	if (!switch_class) {
+		ret = create_switch_class();
+		if (ret < 0)
+			return ret;
+	}
+
+	sdev->index = atomic_inc_return(&device_count);
+	sdev->dev = device_create(switch_class, NULL,
+		MKDEV(0, sdev->index), NULL, sdev->name);
+	if (IS_ERR(sdev->dev))
+		return PTR_ERR(sdev->dev);
+
+	ret = device_create_file(sdev->dev, &dev_attr_state);
+	if (ret < 0)
+		goto err_create_file_1;
+	ret = device_create_file(sdev->dev, &dev_attr_name);
+	if (ret < 0)
+		goto err_create_file_2;
+
+	dev_set_drvdata(sdev->dev, sdev);
+	sdev->state = 0;
+	return 0;
+
+err_create_file_2:
+	device_remove_file(sdev->dev, &dev_attr_state);
+err_create_file_1:
+	device_destroy(switch_class, MKDEV(0, sdev->index));
+	printk(KERN_ERR "switch: Failed to register driver %s\n", sdev->name);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(switch_dev_register);
+
+void switch_dev_unregister(struct switch_dev *sdev)
+{
+	device_remove_file(sdev->dev, &dev_attr_name);
+	device_remove_file(sdev->dev, &dev_attr_state);
+	device_destroy(switch_class, MKDEV(0, sdev->index));
+	dev_set_drvdata(sdev->dev, NULL);
+}
+EXPORT_SYMBOL_GPL(switch_dev_unregister);
+
+static int __init switch_class_init(void)
+{
+	return create_switch_class();
+}
+
+static void __exit switch_class_exit(void)
+{
+	class_destroy(switch_class);
+}
+
+module_init(switch_class_init);
+module_exit(switch_class_exit);
+
+MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
+MODULE_DESCRIPTION("Switch class driver");
+MODULE_LICENSE("GPL");