Input: rpi_ft5406 - add enable sysfs attribute

Add enable sysfs attribute for disable/enable the touchscreen input.
This feature is required to turn the touch screen display on or off.

Change-Id: I4d5250c32cc2118f0f19a8a3cfb76ea8574f6937
Signed-off-by: KwangCheol Lee <kclee@dignsys.com>

1 files changed, 76 insertions, 3 deletions

diff --git a/drivers/input/touchscreen/rpi-ft5406.c b/drivers/input/touchscreen/rpi-ft5406.c
index 4115b4666211..c47555f40f82 100644
--- a/drivers/input/touchscreen/rpi-ft5406.c
+++ b/drivers/input/touchscreen/rpi-ft5406.c
@@ -53,6 +53,8 @@ struct ft5406 {
 	void __iomem		*ts_base;
 	dma_addr_t		bus_addr;
 	struct task_struct	*thread;
+	bool                     enable;
+	struct mutex             sysfs_mutex;
 
 	uint16_t	max_x;
 	uint16_t	max_y;
@@ -160,6 +162,62 @@ static int ft5406_thread(void *arg)
 	return 0;
 }
 
+static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct ft5406 *ts = (struct ft5406 *)dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", ts->enable);
+}
+
+static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	struct ft5406 *ts = (struct ft5406 *)dev_get_drvdata(dev);
+	unsigned int val;
+	int error;
+
+	error = kstrtouint(buf, 0, &val);
+	if (error)
+		return error;
+
+	mutex_lock(&ts->sysfs_mutex);
+
+	if (ts->enable == !!val)
+		goto out;
+
+	if (val) {
+		ts->thread = kthread_run(ft5406_thread, ts, "ft5406");
+		if (IS_ERR(ts->thread)) {
+			dev_err(dev, "Failed to create kernel thread");
+			goto out;
+		}
+	} else {
+		error = kthread_stop(ts->thread);
+		if (unlikely(error)) {
+			dev_err(dev, "Failed to stop kernel thread");
+			goto out;
+		}
+	}
+	ts->enable = !!val;
+
+out:
+	mutex_unlock(&ts->sysfs_mutex);
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(enable);
+
+static struct attribute *rpi_ft5406_attrs[] = {
+	&dev_attr_enable.attr,
+	NULL
+};
+
+static const struct attribute_group rpi_ft5406_attr_group = {
+	.attrs = rpi_ft5406_attrs,
+};
+
 static int ft5406_probe(struct platform_device *pdev)
 {
 	int err = 0;
@@ -296,16 +354,28 @@ static int ft5406_probe(struct platform_device *pdev)
 		goto out;
 	}
 
+	ts->enable = true;
+	mutex_init(&ts->sysfs_mutex);
+
+	err = sysfs_create_group(&dev->kobj, &rpi_ft5406_attr_group);
+	if (err) {
+		dev_err(dev, "failed to create sysfs group: %d\n", err);
+		goto out;
+	}
+
 	/* create thread that polls the touch events */
 	ts->thread = kthread_run(ft5406_thread, ts, "ft5406");
-	if (ts->thread == NULL) {
+	if (IS_ERR(ts->thread))
+	{
 		dev_err(dev, "Failed to create kernel thread");
 		err = -ENOMEM;
-		goto out;
+		goto out_sysfs;
 	}
 
 	return 0;
 
+out_sysfs:
+	sysfs_remove_group(&dev->kobj, &rpi_ft5406_attr_group);
 out:
 	if (ts->bus_addr) {
 		dma_free_coherent(dev, PAGE_SIZE, ts->ts_base, ts->bus_addr);
@@ -329,7 +399,10 @@ static int ft5406_remove(struct platform_device *pdev)
 
 	dev_info(dev, "Removing rpi-ft5406\n");
 
-	kthread_stop(ts->thread);
+	sysfs_remove_group(&dev->kobj, &rpi_ft5406_attr_group);
+
+	if (ts->enable)
+		kthread_stop(ts->thread);
 
 	if (ts->bus_addr)
 		dma_free_coherent(dev, PAGE_SIZE, ts->ts_base, ts->bus_addr);