[PATCH] drm: atmel-hlcdc: fix atmel_xlcdc_plane_setup_scaler()

[Dmitry Baryshkov]

On Mon, Oct 14, 2024 at 03:19:42PM +0530, Manikandan Muralidharan wrote:
> From: Cyrille Pitchen <cyrille.pitchen at microchip.com>
> 
> On SoCs, like the SAM9X75, which embed the XLCDC ip, the registers that
> configure the unified scaling engine were not filled with proper values.
> 
> Indeed, for YCbCr formats, the VXSCFACT bitfield of the HEOCFG25
> register and the HXSCFACT bitfield of the HEOCFG27 register were
> incorrect.
> 
> For 4:2:0 formats, both vertical and horizontal factors for
> chroma chanels should be divided by 2 from the factors for the luma
> channel. Hence:
> 
> HEOCFG24.VXSYFACT = VFACTOR
> HEOCFG25.VSXCFACT = VFACTOR / 2
> HEOCFG26.HXSYFACT = HFACTOR
> HEOCFG27.HXSCFACT = HFACTOR / 2
> 
> However, for 4:2:2 formats, only the horizontal factor for chroma
> chanels should be divided by 2 from the factor for the luma channel;
> the vertical factor is the same for all the luma and chroma channels.
> Hence:
> 
> HEOCFG24.VXSYFACT = VFACTOR
> HEOCFG25.VXSCFACT = VFACTOR
> HEOCFG26.HXSYFACT = HFACTOR
> HEOCFG27.HXSCFACT = HFACTOR / 2
> 
> Fixes: d498771b0b83 ("drm: atmel_hlcdc: Add support for XLCDC using IP specific driver ops")
> Signed-off-by: Cyrille Pitchen <cyrille.pitchen at microchip.com>
> ---
>  .../gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c   | 27 ++++++++++++++++---
>  1 file changed, 24 insertions(+), 3 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>

-- 
With best wishes
Dmitry