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From:   Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
To:     linux-media@vger.kernel.org
Cc:     devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
        rahul.blr97@gmail.com, gregkh@linuxfoundation.org,
        mchehab@kernel.org, tian.shu.qiu@intel.com, bingbu.cao@intel.com,
        sakari.ailus@linux.intel.com, jeanmichel.hautbois@ideasonboard.com
Subject: [PATCH] media: intel-ipu3: Specify CCM values precision
Date:   Fri,  5 Feb 2021 17:38:19 +0100
Message-Id: <20210205163819.28439-1-jeanmichel.hautbois@ideasonboard.com>
MIME-Version: 1.0
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When trying to convert a CCM matrix for IPU3, extreme values for the
Color Correction Matrix.
Specify the precision to ease userspace integration.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
---
 drivers/staging/media/ipu3/include/intel-ipu3.h | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/media/ipu3/include/intel-ipu3.h b/drivers/staging/media/ipu3/include/intel-ipu3.h
index edd8edda0647..68f7d11ce52f 100644
--- a/drivers/staging/media/ipu3/include/intel-ipu3.h
+++ b/drivers/staging/media/ipu3/include/intel-ipu3.h
@@ -923,19 +923,21 @@ struct ipu3_uapi_dm_config {
 /**
  * struct ipu3_uapi_ccm_mat_config - Color correction matrix
  *
- * @coeff_m11: CCM 3x3 coefficient, range [-65536, 65535]
+ * @coeff_m11: CCM 3x3 coefficient, range [-32768, 32767]
  * @coeff_m12: CCM 3x3 coefficient, range [-8192, 8191]
- * @coeff_m13: CCM 3x3 coefficient, range [-32768, 32767]
+ * @coeff_m13: CCM 3x3 coefficient, range [-8192, 8191]
  * @coeff_o_r: Bias 3x1 coefficient, range [-8191, 8181]
- * @coeff_m21: CCM 3x3 coefficient, range [-32767, 32767]
- * @coeff_m22: CCM 3x3 coefficient, range [-8192, 8191]
- * @coeff_m23: CCM 3x3 coefficient, range [-32768, 32767]
+ * @coeff_m21: CCM 3x3 coefficient, range [-8192, 8191]
+ * @coeff_m22: CCM 3x3 coefficient, range [-32768, 32767]
+ * @coeff_m23: CCM 3x3 coefficient, range [-8192, 8191]
  * @coeff_o_g: Bias 3x1 coefficient, range [-8191, 8181]
- * @coeff_m31: CCM 3x3 coefficient, range [-32768, 32767]
+ * @coeff_m31: CCM 3x3 coefficient, range [-8192, 8191]
  * @coeff_m32: CCM 3x3 coefficient, range [-8192, 8191]
  * @coeff_m33: CCM 3x3 coefficient, range [-32768, 32767]
  * @coeff_o_b: Bias 3x1 coefficient, range [-8191, 8181]
  *
+ * Precision s3.13, range [-8, 8).
+ *
  * Transform sensor specific color space to standard sRGB by applying 3x3 matrix
  * and adding a bias vector O. The transformation is basically a rotation and
  * translation in the 3-dimensional color spaces. Here are the defaults:
-- 
2.27.0