[media] s5p-fimc: Add runtime PM support in the mem-to-mem driver

Add runtime PM and system sleep support in the memory-to-memory
driver. It's required to enable the FIMC operation on Exynos4
SoCs. This patch prevents system boot failure when the driver
is compiled in, as it now tries to access its I/O memory without
first enabling the corresponding power domain.

The camera capture device suspend/resume is not fully covered,
the capture device is just powered on/off during the video
node open/close. However this enables it's normal operation
on Exynos4 SoCs.

[mchehab@redhat.com: fix a small checkpatch error]
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/Kconfig

@@ -950,7 +950,7 @@ config VIDEO_MX2
 
 config  VIDEO_SAMSUNG_S5P_FIMC
 	tristate "Samsung S5P and EXYNOS4 camera host interface driver"
-	depends on VIDEO_DEV && VIDEO_V4L2 && PLAT_S5P
+	depends on VIDEO_V4L2 && PLAT_S5P && PM_RUNTIME
 	select VIDEOBUF2_DMA_CONTIG
 	select V4L2_MEM2MEM_DEV
 	---help---

drivers/media/video/s5p-fimc/fimc-capture.c

@@ -17,6 +17,7 @@
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/clk.h>
@@ -271,6 +272,16 @@ static int stop_streaming(struct vb2_queue *q)
 	return fimc_stop_capture(fimc);
 }
 
+int fimc_capture_suspend(struct fimc_dev *fimc)
+{
+	return -EBUSY;
+}
+
+int fimc_capture_resume(struct fimc_dev *fimc)
+{
+	return 0;
+}
+
 static unsigned int get_plane_size(struct fimc_frame *fr, unsigned int plane)
 {
 	if (!fr || plane >= fr->fmt->memplanes)
@@ -396,9 +407,14 @@ static int fimc_capture_open(struct file *file)
 	if (fimc_m2m_active(fimc))
 		return -EBUSY;
 
+	ret = pm_runtime_get_sync(&fimc->pdev->dev);
+	if (ret)
+		return ret;
+
 	if (++fimc->vid_cap.refcnt == 1) {
 		ret = fimc_isp_subdev_init(fimc, 0);
 		if (ret) {
+			pm_runtime_put_sync(&fimc->pdev->dev);
 			fimc->vid_cap.refcnt--;
 			return -EIO;
 		}
@@ -426,6 +442,8 @@ static int fimc_capture_close(struct file *file)
 		fimc_subdev_unregister(fimc);
 	}
 
+	pm_runtime_put(&fimc->pdev->dev);
+
 	return 0;
 }