From 4b7444ff13250d2b10e940978bd72aef7a5561f2 Mon Sep 17 00:00:00 2001 From: Jean-Michel Hautbois Date: Fri, 17 Jun 2022 10:45:19 +0200 Subject: [PATCH] media: staging: ipu3-imgu: Fix BNR wb gain documentation The documentation states that the BNR factor is a multiplier coded as u3.13 and with a range of (0, 8). This is not correct, as the isp is adding 1.0 to the gain applied, ie Pout = { Pin * (1 + Gx) }. It means that a gain of 1.0 should be coded as 0. Signed-off-by: Jean-Michel Hautbois Reviewed-by: Kieran Bingham Signed-off-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- drivers/staging/media/ipu3/include/uapi/intel-ipu3.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h b/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h index dbdd015..caa358e 100644 --- a/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h +++ b/drivers/staging/media/ipu3/include/uapi/intel-ipu3.h @@ -626,8 +626,11 @@ struct ipu3_uapi_stats_3a { * @b: white balance gain for B channel. * @gb: white balance gain for Gb channel. * - * Precision u3.13, range [0, 8). White balance correction is done by applying - * a multiplicative gain to each color channels prior to BNR. + * For BNR parameters WB gain factor for the three channels [Ggr, Ggb, Gb, Gr]. + * Their precision is U3.13 and the range is (0, 8) and the actual gain is + * Gx + 1, it is typically Gx = 1. + * + * Pout = {Pin * (1 + Gx)}. */ struct ipu3_uapi_bnr_static_config_wb_gains_config { __u16 gr; -- 2.7.4