From: Koji Matsuoka <koji.matsuoka...@renesas.com>

The ADV7481 Register Control Manual states that bit 2 in the Video
Standard Selection register is reserved with the value of 1.

The bit is otherwise undocumented, and currently cleared by the driver
when setting the video standard selection.

Define the bit as reserved, and ensure that it is always set when
writing to the SDP_VID_SEL register.

Reviewed-by: Kieran Bingham <kieran.bingham+rene...@ideasonboard.com>
Signed-off-by: Koji Matsuoka <koji.matsuoka...@renesas.com>
[Kieran: Updated commit message, utilised BIT macro]
Signed-off-by: Kieran Bingham <kieran.bingham+rene...@ideasonboard.com>
---
 drivers/media/i2c/adv748x/adv748x-afe.c | 3 ++-
 drivers/media/i2c/adv748x/adv748x.h     | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/i2c/adv748x/adv748x-afe.c 
b/drivers/media/i2c/adv748x/adv748x-afe.c
index 71714634efb0..c4d9ffc50702 100644
--- a/drivers/media/i2c/adv748x/adv748x-afe.c
+++ b/drivers/media/i2c/adv748x/adv748x-afe.c
@@ -151,7 +151,8 @@ static void adv748x_afe_set_video_standard(struct 
adv748x_state *state,
                                          int sdpstd)
 {
        sdp_clrset(state, ADV748X_SDP_VID_SEL, ADV748X_SDP_VID_SEL_MASK,
-                  (sdpstd & 0xf) << ADV748X_SDP_VID_SEL_SHIFT);
+                  (sdpstd & 0xf) << ADV748X_SDP_VID_SEL_SHIFT |
+                  ADV748X_SDP_VID_RESERVED_BIT);
 }
 
 static int adv748x_afe_s_input(struct adv748x_afe *afe, unsigned int input)
diff --git a/drivers/media/i2c/adv748x/adv748x.h 
b/drivers/media/i2c/adv748x/adv748x.h
index b482c7fe6957..778aa55a741a 100644
--- a/drivers/media/i2c/adv748x/adv748x.h
+++ b/drivers/media/i2c/adv748x/adv748x.h
@@ -265,6 +265,7 @@ struct adv748x_state {
 #define ADV748X_SDP_INSEL              0x00    /* user_map_rw_reg_00 */
 
 #define ADV748X_SDP_VID_SEL            0x02    /* user_map_rw_reg_02 */
+#define ADV748X_SDP_VID_RESERVED_BIT   BIT(2)  /* undocumented reserved bit */
 #define ADV748X_SDP_VID_SEL_MASK       0xf0
 #define ADV748X_SDP_VID_SEL_SHIFT      4
 
-- 
2.17.1

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