diff options
Diffstat (limited to 'drivers/gpu/drm/drm_color_mgmt.c')
| -rw-r--r-- | drivers/gpu/drm/drm_color_mgmt.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c index 789b4c65cd69..cc23b9a505c0 100644 --- a/drivers/gpu/drm/drm_color_mgmt.c +++ b/drivers/gpu/drm/drm_color_mgmt.c @@ -88,6 +88,30 @@ */ /** + * drm_color_lut_extract - clamp and round LUT entries + * @user_input: input value + * @bit_precision: number of bits the hw LUT supports + * + * Extract a degamma/gamma LUT value provided by user (in the form of + * &drm_color_lut entries) and round it to the precision supported by the + * hardware. + */ +uint32_t drm_color_lut_extract(uint32_t user_input, uint32_t bit_precision) +{ + uint32_t val = user_input; + uint32_t max = 0xffff >> (16 - bit_precision); + + /* Round only if we're not using full precision. */ + if (bit_precision < 16) { + val += 1UL << (16 - bit_precision - 1); + val >>= 16 - bit_precision; + } + + return clamp_val(val, 0, max); +} +EXPORT_SYMBOL(drm_color_lut_extract); + +/** * drm_crtc_enable_color_mgmt - enable color management properties * @crtc: DRM CRTC * @degamma_lut_size: the size of the degamma lut (before CSC) |