On Gen3 the CSI-2 routing is controlled by the VnCSI_IFMD register. One
feature of this register is that it's only present in the VIN0 and VIN4
instances. The register in VIN0 controls the routing for VIN0-3 and the
register in VIN4 controls routing for VIN4-7.

To be able to control routing from a media device these functions need
to control runtime PM for the subgroup master (VIN0 and VIN4). The
subgroup master must be switched on before the register is manipulated,
once the operation is complete it's safe to switch the master off and
the new routing will still be in effect.

Signed-off-by: Niklas Söderlund <niklas.soderlund+rene...@ragnatech.se>
---
 drivers/media/platform/rcar-vin/rcar-dma.c | 43 ++++++++++++++++++++++++++++++
 drivers/media/platform/rcar-vin/rcar-vin.h |  3 +++
 2 files changed, 46 insertions(+)

diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c 
b/drivers/media/platform/rcar-vin/rcar-dma.c
index 7fecb616b6c45a32..fef31aac0ed40979 100644
--- a/drivers/media/platform/rcar-vin/rcar-dma.c
+++ b/drivers/media/platform/rcar-vin/rcar-dma.c
@@ -16,6 +16,7 @@
 
 #include <linux/delay.h>
 #include <linux/interrupt.h>
+#include <linux/pm_runtime.h>
 
 #include <media/videobuf2-dma-contig.h>
 
@@ -1240,3 +1241,45 @@ int rvin_dma_probe(struct rvin_dev *vin, int irq)
 
        return ret;
 }
+
+/* 
-----------------------------------------------------------------------------
+ * Gen3 CHSEL manipulation
+ */
+
+int rvin_set_chsel(struct rvin_dev *vin, u8 chsel)
+{
+       u32 ifmd;
+
+       pm_runtime_get_sync(vin->dev);
+
+       /*
+        * Undocumented feature: Writing to VNCSI_IFMD_REG will go
+        * through and on read back look correct but won't have
+        * any effect if VNMC_REG is not first set to 0.
+        */
+       rvin_write(vin, 0, VNMC_REG);
+
+       ifmd = VNCSI_IFMD_DES2 | VNCSI_IFMD_DES1 | VNCSI_IFMD_DES0 |
+               VNCSI_IFMD_CSI_CHSEL(chsel);
+
+       rvin_write(vin, ifmd, VNCSI_IFMD_REG);
+
+       vin_dbg(vin, "Set IFMD 0x%x\n", ifmd);
+
+       pm_runtime_put(vin->dev);
+
+       return 0;
+}
+
+int rvin_get_chsel(struct rvin_dev *vin)
+{
+       int chsel;
+
+       pm_runtime_get_sync(vin->dev);
+
+       chsel = rvin_read(vin, VNCSI_IFMD_REG) & VNCSI_IFMD_CSI_CHSEL_MASK;
+
+       pm_runtime_put(vin->dev);
+
+       return chsel;
+}
diff --git a/drivers/media/platform/rcar-vin/rcar-vin.h 
b/drivers/media/platform/rcar-vin/rcar-vin.h
index 09fc70e192699f35..b1cd0abba9ca9c94 100644
--- a/drivers/media/platform/rcar-vin/rcar-vin.h
+++ b/drivers/media/platform/rcar-vin/rcar-vin.h
@@ -163,4 +163,7 @@ void rvin_v4l2_remove(struct rvin_dev *vin);
 
 const struct rvin_video_format *rvin_format_from_pixel(u32 pixelformat);
 
+int rvin_set_chsel(struct rvin_dev *vin, u8 chsel);
+int rvin_get_chsel(struct rvin_dev *vin);
+
 #endif
-- 
2.12.2

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