Hi James,
On Mon, Sep 30, 2019 at 04:54:41AM +0000, james qian wang (Arm Technology China) wrote:
This function is used to convert drm_color_ctm S31.32 sign-magnitude value to komeda required Q2.12 2's complement
Signed-off-by: james qian wang (Arm Technology China) james.qian.wang@arm.com
.../arm/display/komeda/komeda_color_mgmt.c | 27 +++++++++++++++++++ .../arm/display/komeda/komeda_color_mgmt.h | 1 + 2 files changed, 28 insertions(+)
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c index c180ce70c26c..c92c82eebddb 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c @@ -117,3 +117,30 @@ void drm_lut_to_fgamma_coeffs(struct drm_property_blob *lut_blob, u32 *coeffs) { drm_lut_to_coeffs(lut_blob, coeffs, sector_tbl, ARRAY_SIZE(sector_tbl)); }
+/* Convert from S31.32 sign-magnitude to HW Q2.12 2's complement */ +static s32 drm_ctm_s31_32_to_q2_12(u64 input) +{
- u64 mag = (input & ~BIT_ULL(63)) >> 20;
- bool negative = !!(input & BIT_ULL(63));
- u32 val;
- /* the range of signed 2s complement is [-2^n, 2^n - 1] */
- val = clamp_val(mag, 0, negative ? BIT(14) : BIT(14) - 1);
- return negative ? 0 - val : val;
+}
This function looks generally useful. Should it be in DRM core (assuming there isn't already one there)?
You can use a parameter to determine the number of bits desired in the output.
Thanks, -Brian
+void drm_ctm_to_coeffs(struct drm_property_blob *ctm_blob, u32 *coeffs) +{
- struct drm_color_ctm *ctm;
- u32 i;
- if (!ctm_blob)
return;- ctm = ctm_blob->data;
- for (i = 0; i < KOMEDA_N_CTM_COEFFS; i++)
coeffs[i] = drm_ctm_s31_32_to_q2_12(ctm->matrix[i]);+} diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h index 08ab69281648..2f4668466112 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h +++ b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h @@ -18,6 +18,7 @@ #define KOMEDA_N_CTM_COEFFS 9
void drm_lut_to_fgamma_coeffs(struct drm_property_blob *lut_blob, u32 *coeffs); +void drm_ctm_to_coeffs(struct drm_property_blob *ctm_blob, u32 *coeffs);
const s32 *komeda_select_yuv2rgb_coeffs(u32 color_encoding, u32 color_range);
-- 2.20.1