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[2/2] media: imx258: Limit the max analogue gain to 480

Message ID 20210723112233.1361319-3-umang.jain@ideasonboard.com
State Accepted
Commit f809665ee75fff3f4ea8907f406a66d380aeb184
Headers show
Series IMX258 driver fixes | expand

Commit Message

Umang Jain July 23, 2021, 11:22 a.m. UTC 
The range for analog gain mentioned in the datasheet is [0, 480].
The real gain formula mentioned in the datasheet is:

	Gain = 512 / (512 – X)

Hence, values larger than 511 clearly makes no sense. The gain
register field is also documented to be of 9-bits in the datasheet.

Certainly, it is enough to infer that, the kernel driver currently
advertises an arbitrary analog gain max. Fix it by rectifying the
value as per the data sheet i.e. 480.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
---
 drivers/media/i2c/imx258.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/media/i2c/imx258.c b/drivers/media/i2c/imx258.c
index 4e695096e5d0..81cdf37216ca 100644
--- a/drivers/media/i2c/imx258.c
+++ b/drivers/media/i2c/imx258.c
@@ -47,7 +47,7 @@ 
 /* Analog gain control */
 #define IMX258_REG_ANALOG_GAIN		0x0204
 #define IMX258_ANA_GAIN_MIN		0
-#define IMX258_ANA_GAIN_MAX		0x1fff
+#define IMX258_ANA_GAIN_MAX		480
 #define IMX258_ANA_GAIN_STEP		1
 #define IMX258_ANA_GAIN_DEFAULT		0x0