Staging: android: add timed_gpio driver

driver for GPIOs that turn back off after a delay

From: Mike Lockwood <lockwood@android.com>
Signed-off-by: Brian Swetland <swetland@google.com>
Cc: Robert Love <rlove@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 214 insertions, 0 deletions

diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index 7728b84bf07c..502c283eedcc 100644
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -72,4 +72,9 @@ config ANDROID_RAM_CONSOLE_EARLY_SIZE
         default 0
         depends on ANDROID_RAM_CONSOLE_EARLY_INIT
 
+config ANDROID_TIMED_GPIO
+        tristate "Android timed gpio driver"
+        depends on GENERIC_GPIO
+        default n
+
 endmenu
diff --git a/drivers/staging/android/Makefile b/drivers/staging/android/Makefile
index 357abd73142a..d9b1525550f7 100644
--- a/drivers/staging/android/Makefile
+++ b/drivers/staging/android/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_ANDROID)			+= android.o
 obj-$(CONFIG_ANDROID_BINDER_IPC)        += binder.o
 obj-$(CONFIG_ANDROID_LOGGER)            += logger.o
 obj-$(CONFIG_ANDROID_RAM_CONSOLE)       += ram_console.o
+obj-$(CONFIG_ANDROID_TIMED_GPIO)        += timed_gpio.o
diff --git a/drivers/staging/android/android_timed_gpio.h b/drivers/staging/android/android_timed_gpio.h
new file mode 100644
index 000000000000..a38a96c2b378
--- /dev/null
+++ b/drivers/staging/android/android_timed_gpio.h
@@ -0,0 +1,31 @@
+/* include/linux/android_timed_gpio.h
+ *
+ * Copyright (C) 2008 Google, Inc.
+ *
+ * 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_ANDROID_TIMED_GPIO_H
+#define _LINUX_ANDROID_TIMED_GPIO_H
+
+struct timed_gpio {
+        const char *name;
+        unsigned        gpio;
+        int     max_timeout;
+        u8              active_low;
+};
+
+struct timed_gpio_platform_data {
+        int             num_gpios;
+        struct timed_gpio *gpios;
+};
+
+#endif
diff --git a/drivers/staging/android/timed_gpio.c b/drivers/staging/android/timed_gpio.c
new file mode 100644
index 000000000000..faaead1a7124
--- /dev/null
+++ b/drivers/staging/android/timed_gpio.c
@@ -0,0 +1,177 @@
+/* drivers/android/timed_gpio.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/platform_device.h>
+#include <linux/hrtimer.h>
+#include <linux/err.h>
+#include <asm/arch/gpio.h>
+
+#include "android_timed_gpio.h"
+
+
+static struct class *timed_gpio_class;
+
+struct timed_gpio_data {
+        struct device *dev;
+        struct hrtimer timer;
+        spinlock_t lock;
+        unsigned        gpio;
+        int             max_timeout;
+        u8              active_low;
+};
+
+static enum hrtimer_restart gpio_timer_func(struct hrtimer *timer)
+{
+        struct timed_gpio_data *gpio_data = container_of(timer, struct timed_gpio_data, timer);
+
+        gpio_direction_output(gpio_data->gpio, gpio_data->active_low ? 1 : 0);
+        return HRTIMER_NORESTART;
+}
+
+static ssize_t gpio_enable_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct timed_gpio_data *gpio_data = dev_get_drvdata(dev);
+        int remaining;
+
+        if (hrtimer_active(&gpio_data->timer)) {
+                ktime_t r = hrtimer_get_remaining(&gpio_data->timer);
+                remaining = r.tv.sec * 1000 + r.tv.nsec / 1000000;
+        } else
+                remaining = 0;
+
+        return sprintf(buf, "%d\n", remaining);
+}
+
+static ssize_t gpio_enable_store(
+                struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t size)
+{
+        struct timed_gpio_data *gpio_data = dev_get_drvdata(dev);
+        int value;
+        unsigned long   flags;
+
+        sscanf(buf, "%d", &value);
+
+        spin_lock_irqsave(&gpio_data->lock, flags);
+
+        /* cancel previous timer and set GPIO according to value */
+        hrtimer_cancel(&gpio_data->timer);
+        gpio_direction_output(gpio_data->gpio, gpio_data->active_low ? !value : !!value);
+
+        if (value > 0) {
+                if (value > gpio_data->max_timeout)
+                        value = gpio_data->max_timeout;
+
+                hrtimer_start(&gpio_data->timer,
+                                                ktime_set(value / 1000, (value % 1000) * 1000000),
+                                                HRTIMER_MODE_REL);
+        }
+
+        spin_unlock_irqrestore(&gpio_data->lock, flags);
+
+        return size;
+}
+
+static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, gpio_enable_show, gpio_enable_store);
+
+static int android_timed_gpio_probe(struct platform_device *pdev)
+{
+        struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;
+        struct timed_gpio *cur_gpio;
+        struct timed_gpio_data *gpio_data, *gpio_dat;
+        int i, ret = 0;
+
+        if (!pdata)
+                return -EBUSY;
+
+        gpio_data = kzalloc(sizeof(struct timed_gpio_data) * pdata->num_gpios, GFP_KERNEL);
+        if (!gpio_data)
+                return -ENOMEM;
+
+        for (i = 0; i < pdata->num_gpios; i++) {
+                cur_gpio = &pdata->gpios[i];
+                gpio_dat = &gpio_data[i];
+
+                hrtimer_init(&gpio_dat->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+                gpio_dat->timer.function = gpio_timer_func;
+                spin_lock_init(&gpio_dat->lock);
+
+                gpio_dat->gpio = cur_gpio->gpio;
+                gpio_dat->max_timeout = cur_gpio->max_timeout;
+                gpio_dat->active_low = cur_gpio->active_low;
+                gpio_direction_output(gpio_dat->gpio, gpio_dat->active_low);
+
+                gpio_dat->dev = device_create(timed_gpio_class, &pdev->dev, 0, "%s", cur_gpio->name);
+                if (unlikely(IS_ERR(gpio_dat->dev)))
+                        return PTR_ERR(gpio_dat->dev);
+
+                dev_set_drvdata(gpio_dat->dev, gpio_dat);
+                ret = device_create_file(gpio_dat->dev, &dev_attr_enable);
+                if (ret)
+                        return ret;
+        }
+
+        platform_set_drvdata(pdev, gpio_data);
+
+        return 0;
+}
+
+static int android_timed_gpio_remove(struct platform_device *pdev)
+{
+        struct timed_gpio_platform_data *pdata = pdev->dev.platform_data;
+        struct timed_gpio_data *gpio_data = platform_get_drvdata(pdev);
+        int i;
+
+        for (i = 0; i < pdata->num_gpios; i++) {
+                device_remove_file(gpio_data[i].dev, &dev_attr_enable);
+                device_unregister(gpio_data[i].dev);
+        }
+
+        kfree(gpio_data);
+
+        return 0;
+}
+
+static struct platform_driver android_timed_gpio_driver = {
+        .probe          = android_timed_gpio_probe,
+        .remove         = android_timed_gpio_remove,
+        .driver         = {
+                .name           = "android-timed-gpio",
+                .owner          = THIS_MODULE,
+        },
+};
+
+static int __init android_timed_gpio_init(void)
+{
+        timed_gpio_class = class_create(THIS_MODULE, "timed_output");
+        if (IS_ERR(timed_gpio_class))
+                return PTR_ERR(timed_gpio_class);
+        return platform_driver_register(&android_timed_gpio_driver);
+}
+
+static void __exit android_timed_gpio_exit(void)
+{
+        class_destroy(timed_gpio_class);
+        platform_driver_unregister(&android_timed_gpio_driver);
+}
+
+module_init(android_timed_gpio_init);
+module_exit(android_timed_gpio_exit);
+
+MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
+MODULE_DESCRIPTION("Android timed gpio driver");
+MODULE_LICENSE("GPL");