V4L/DVB: soc-camera: add runtime pm support for subdevices
To save power soc-camera powers subdevices down, when they are not in use,
if this is supported by the platform. However, the V4L standard dictates,
that video nodes shall preserve configuration between uses. This requires
runtime power management, which is implemented by this patch. It allows
subdevice drivers to specify their runtime power-management methods, by
assigning a type to the video device.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/soc_camera.c b/drivers/media/video/soc_camera.c
index a24174d..0c65031 100644
--- a/drivers/media/video/soc_camera.c
+++ b/drivers/media/video/soc_camera.c
@@ -25,6 +25,7 @@
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
+#include <linux/pm_runtime.h>
#include <linux/vmalloc.h>
#include <media/soc_camera.h>
@@ -388,6 +389,11 @@
goto eiciadd;
}
+ pm_runtime_enable(&icd->vdev->dev);
+ ret = pm_runtime_resume(&icd->vdev->dev);
+ if (ret < 0 && ret != -ENOSYS)
+ goto eresume;
+
/*
* Try to configure with default parameters. Notice: this is the
* very first open, so, we cannot race against other calls,
@@ -409,10 +415,12 @@
return 0;
/*
- * First five errors are entered with the .video_lock held
+ * First four errors are entered with the .video_lock held
* and use_count == 1
*/
esfmt:
+ pm_runtime_disable(&icd->vdev->dev);
+eresume:
ici->ops->remove(icd);
eiciadd:
if (icl->power)
@@ -437,7 +445,11 @@
if (!icd->use_count) {
struct soc_camera_link *icl = to_soc_camera_link(icd);
+ pm_runtime_suspend(&icd->vdev->dev);
+ pm_runtime_disable(&icd->vdev->dev);
+
ici->ops->remove(icd);
+
if (icl->power)
icl->power(icd->pdev, 0);
}
@@ -1319,6 +1331,7 @@
*/
static int soc_camera_video_start(struct soc_camera_device *icd)
{
+ struct device_type *type = icd->vdev->dev.type;
int ret;
if (!icd->dev.parent)
@@ -1335,6 +1348,9 @@
return ret;
}
+ /* Restore device type, possibly set by the subdevice driver */
+ icd->vdev->dev.type = type;
+
return 0;
}