[PATCH v2 02/15] media: microchip-isc: mask WB offset and gain register fields
From: Balakrishnan Sambath <hidden>
Date: 2026-05-12 15:43:50
Also in:
linux-media, lkml
Subsystem:
media input infrastructure (v4l/dvb), microchip isc driver, the rest · Maintainers:
Mauro Carvalho Chehab, Eugen Hristev, Linus Torvalds
ISC_WB_O_* and ISC_WB_G_* pack two 13-bit fields per register. Sign
extension from negative offsets corrupts the upper field. Mask both
fields to 13 bits before packing.
Fixes: 3308bec11098 ("at91: isc: integrate pipeline")
Cc: stable@vger.kernel.org
Signed-off-by: Balakrishnan Sambath <redacted>
---
.../platform/microchip/microchip-isc-base.c | 21 ++++++++++++-------
1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index a7cdc743fda7..45b94f1e89d8 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c@@ -61,18 +61,23 @@ static inline void isc_update_awb_ctrls(struct isc_device *isc) /* In here we set our actual hw pipeline config */ + /* + * Mask offset fields to 13 bits. Sign extension of negative s32 + * values would otherwise corrupt the adjacent field. + */ regmap_write(isc->regmap, ISC_WB_O_RGR, - ((ctrls->offset[ISC_HIS_CFG_MODE_R])) | - ((ctrls->offset[ISC_HIS_CFG_MODE_GR]) << 16)); + ((u32)ctrls->offset[ISC_HIS_CFG_MODE_R] & GENMASK(12, 0)) | + (((u32)ctrls->offset[ISC_HIS_CFG_MODE_GR] & GENMASK(12, 0)) << 16)); regmap_write(isc->regmap, ISC_WB_O_BGB, - ((ctrls->offset[ISC_HIS_CFG_MODE_B])) | - ((ctrls->offset[ISC_HIS_CFG_MODE_GB]) << 16)); + ((u32)ctrls->offset[ISC_HIS_CFG_MODE_B] & GENMASK(12, 0)) | + (((u32)ctrls->offset[ISC_HIS_CFG_MODE_GB] & GENMASK(12, 0)) << 16)); + /* Gains are 13-bit unsigned fields [12:0] and [28:16] */ regmap_write(isc->regmap, ISC_WB_G_RGR, - ctrls->gain[ISC_HIS_CFG_MODE_R] | - (ctrls->gain[ISC_HIS_CFG_MODE_GR] << 16)); + (ctrls->gain[ISC_HIS_CFG_MODE_R] & GENMASK(12, 0)) | + ((ctrls->gain[ISC_HIS_CFG_MODE_GR] & GENMASK(12, 0)) << 16)); regmap_write(isc->regmap, ISC_WB_G_BGB, - ctrls->gain[ISC_HIS_CFG_MODE_B] | - (ctrls->gain[ISC_HIS_CFG_MODE_GB] << 16)); + (ctrls->gain[ISC_HIS_CFG_MODE_B] & GENMASK(12, 0)) | + ((ctrls->gain[ISC_HIS_CFG_MODE_GB] & GENMASK(12, 0)) << 16)); } static inline void isc_reset_awb_ctrls(struct isc_device *isc)
--
2.34.1