[PATCH v6 12/16] media: ov2740: release group hold after gain write errors

[Maurizio Casciano]

Digital-gain updates start a register group before writing the red,
green and blue gains. The current error paths return immediately when
one of those writes fails, leaving the group open and never issuing its
end and launch commands. Later control updates can then be accumulated
in an unfinished group instead of taking effect.

Once group hold has started, always attempt both commands needed to end
and launch the group. Preserve the first gain-write error; report an end
or launch error only when all gain writes succeeded.

Signed-off-by: Maurizio Casciano <mauriziocasciano7@xxxxxxxxx>
Assisted-by: LLM sparse
---
 drivers/media/i2c/ov2740.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/media/i2c/ov2740.c b/drivers/media/i2c/ov2740.c
index f3d91c87b3d5..5f381b7972bf 100644
--- a/drivers/media/i2c/ov2740.c
+++ b/drivers/media/i2c/ov2740.c
@@ -696,7 +696,7 @@ static int ov2740_identify_module(struct ov2740 *ov2740)
 
 static int ov2740_update_digital_gain(struct ov2740 *ov2740, u32 d_gain)
 {
-	int ret;
+	int end_ret, launch_ret, ret;
 
 	ret = ov2740_write_reg(ov2740, OV2740_REG_GROUP_ACCESS, 1,
 			       OV2740_GROUP_HOLD_START);
@@ -705,24 +705,21 @@ static int ov2740_update_digital_gain(struct ov2740 *ov2740, u32 d_gain)
 
 	ret = ov2740_write_reg(ov2740, OV2740_REG_MWB_R_GAIN, 2, d_gain);
 	if (ret)
-		return ret;
+		goto release_group;
 
 	ret = ov2740_write_reg(ov2740, OV2740_REG_MWB_G_GAIN, 2, d_gain);
 	if (ret)
-		return ret;
+		goto release_group;
 
 	ret = ov2740_write_reg(ov2740, OV2740_REG_MWB_B_GAIN, 2, d_gain);
-	if (ret)
-		return ret;
 
-	ret = ov2740_write_reg(ov2740, OV2740_REG_GROUP_ACCESS, 1,
-			       OV2740_GROUP_HOLD_END);
-	if (ret)
-		return ret;
+release_group:
+	end_ret = ov2740_write_reg(ov2740, OV2740_REG_GROUP_ACCESS, 1,
+				   OV2740_GROUP_HOLD_END);
+	launch_ret = ov2740_write_reg(ov2740, OV2740_REG_GROUP_ACCESS, 1,
+				      OV2740_GROUP_HOLD_LAUNCH);
 
-	ret = ov2740_write_reg(ov2740, OV2740_REG_GROUP_ACCESS, 1,
-			       OV2740_GROUP_HOLD_LAUNCH);
-	return ret;
+	return ret ?: end_ret ?: launch_ret;
 }
 
 static int ov2740_test_pattern(struct ov2740 *ov2740, u32 pattern)
-- 
2.53.0