[PATCH v2 12/15] media: microchip-isc: reset pipeline state on kernel AWB enable

[Balakrishnan Sambath <balakrishnan.s@microchip.com>]

gamma_lut_override and cc_coeff[] persist across control writes. When
kernel AWB is enabled after userspace has customized the gamma curve or
color correction matrix, the stale settings produce incorrect color.

Clear gamma_lut_override and reset cc_coeff[] to identity when
V4L2_CID_AUTO_WHITE_BALANCE is set to 1.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../platform/microchip/microchip-isc-base.c      | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index 3749f473c3c6..e6386f8852e5 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1730,10 +1730,22 @@ static int isc_s_awb_ctrl(struct v4l2_ctrl *ctrl)
 
 	switch (ctrl->id) {
 	case V4L2_CID_AUTO_WHITE_BALANCE:
-		if (ctrl->val == 1)
+		if (ctrl->val == 1) {
 			ctrls->awb = ISC_WB_AUTO;
-		else
+			/*
+			 * Reset gamma and CC to defaults when enabling kernel
+			 * AWB so it starts with a clean pipeline.
+			 */
+			ctrls->gamma_lut_override = false;
+			memset(ctrls->cc_coeff, 0, sizeof(ctrls->cc_coeff));
+			ctrls->cc_coeff[0] = 256; /* RR */
+			ctrls->cc_coeff[4] = 256; /* GG */
+			ctrls->cc_coeff[8] = 256; /* BB */
+			memset(ctrls->cc_offset, 0, sizeof(ctrls->cc_offset));
+			ctrls->cc_dirty = true;
+		} else {
 			ctrls->awb = ISC_WB_NONE;
+		}
 
 		/* configure the controls with new values from v4l2 */
 		if (ctrl->cluster[ISC_CTRL_R_GAIN]->is_new)
-- 
2.34.1