On Tue, 2022-04-26 at 09:58 +0800, CK Hu wrote:
> Hi, Yongqiang:
>
> On Wed, 2022-04-20 at 21:06 +0800, Yongqiang Niu wrote:
> > From: Yongqiang Niu <yongqiang.niu@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > >
> >
> > mt8183 gamma module usage is different with before soc,
> > gamma odd(index start from 0) lut value set to hardware
> > register should be
> > the difference of current lut value with last lut value.
> >
> > gamma function support both increase and decrease lut.
>
> How to set decrease lut?
>
> Original lut:
> 12 10 8 6 4 2
>
> Does diff lut look like this?
> 12 [2] 8 [2] 4 [2]
>
yes
> How does hardware know that this is increase lut or decrease lut?
gamma register 0x20 , bit 2,
if this bit set to 1, hardware will know lut is decrease.
this bit default is 0, that means lut is increase
>
> > chrome os app set increase lut normally.
> >
> > for increase lut example, chrome os user space set lut
> > like this(only r chanel for example):
> > 2 4 6 8 10 12.
> > 1) mt8183 gamma driver should set the gamma lut to hardware
> > register like this:
> > 2 [2] 6 [8] 10 [2]
>
> 2 [2] 6 [2] 10 [2]
>
> > the value with [] is the difference value
> > 2) gamma hardware will restore the lut when apply gamma
> > function to display
>
> I don't know why do you mention the 'restore', any modification is
> related to this?
>
that means gamma
hardware process display data with original lut
> >
> > Signed-off-by: Yongqiang Niu <
> > yongqiang.niu@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/mediatek/mtk_disp_aal.c | 4 ++-
> > drivers/gpu/drm/mediatek/mtk_disp_drv.h | 2 +-
> > drivers/gpu/drm/mediatek/mtk_disp_gamma.c | 34 +++++++++++++++++++
> > ----
> > 3 files changed, 32 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_aal.c
> > b/drivers/gpu/drm/mediatek/mtk_disp_aal.c
> > index f46d4ab73d6a..e6378b074a17 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_aal.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_aal.c
> > @@ -23,6 +23,7 @@
> >
> > struct mtk_disp_aal_data {
> > bool has_gamma;
> > + bool lut_diff;
> > };
> >
> > /**
> > @@ -66,7 +67,7 @@ void mtk_aal_gamma_set(struct device *dev, struct
> > drm_crtc_state *state)
> > struct mtk_disp_aal *aal = dev_get_drvdata(dev);
> >
> > if (aal->data && aal->data->has_gamma)
> > - mtk_gamma_set_common(aal->regs, state);
> > + mtk_gamma_set_common(aal->regs, state, aal->data-
> > > lut_diff);
>
> gamma in aal does not support diff lut, so this would make things
> simple.
>
> mtk_gamma_set_common(aal->regs, state, false);
fix next version
>
> Regards,
> CK
>
> > }
> >
> > void mtk_aal_start(struct device *dev)
> > @@ -148,6 +149,7 @@ static int mtk_disp_aal_remove(struct
> > platform_device *pdev)
> >
> > static const struct mtk_disp_aal_data mt8173_aal_driver_data = {
> > .has_gamma = true,
> > + .lut_diff = false,
> > };
> >
> > static const struct of_device_id mtk_disp_aal_driver_dt_match[] =
> > {
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > b/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > index 86c3068894b1..3380651c6707 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_drv.h
> > @@ -51,7 +51,7 @@ void mtk_gamma_config(struct device *dev,
> > unsigned
> > int w,
> > unsigned int h, unsigned int vrefresh,
> > unsigned int bpc, struct cmdq_pkt *cmdq_pkt);
> > void mtk_gamma_set(struct device *dev, struct drm_crtc_state
> > *state);
> > -void mtk_gamma_set_common(void __iomem *regs, struct
> > drm_crtc_state
> > *state);
> > +void mtk_gamma_set_common(void __iomem *regs, struct
> > drm_crtc_state
> > *state, bool lut_diff);
> > void mtk_gamma_start(struct device *dev);
> > void mtk_gamma_stop(struct device *dev);
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> > b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> > index 3a5815ab4079..fec2e9a5b60d 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> > @@ -27,6 +27,7 @@
> >
> > struct mtk_disp_gamma_data {
> > bool has_dither;
> > + bool lut_diff;
> > };
> >
> > /*
> > @@ -53,12 +54,13 @@ void mtk_gamma_clk_disable(struct device *dev)
> > clk_disable_unprepare(gamma->clk);
> > }
> >
> > -void mtk_gamma_set_common(void __iomem *regs, struct
> > drm_crtc_state
> > *state)
> > +void mtk_gamma_set_common(void __iomem *regs, struct
> > drm_crtc_state
> > *state, bool lut_diff)
> > {
> > unsigned int i, reg;
> > struct drm_color_lut *lut;
> > void __iomem *lut_base;
> > u32 word;
> > + u32 diff[3] = {0};
> >
> > if (state->gamma_lut) {
> > reg = readl(regs + DISP_GAMMA_CFG);
> > @@ -67,9 +69,20 @@ void mtk_gamma_set_common(void __iomem *regs,
> > struct drm_crtc_state *state)
> > lut_base = regs + DISP_GAMMA_LUT;
> > lut = (struct drm_color_lut *)state->gamma_lut->data;
> > for (i = 0; i < MTK_LUT_SIZE; i++) {
> > - word = (((lut[i].red >> 6) & LUT_10BIT_MASK) <<
> > 20) +
> > - (((lut[i].green >> 6) & LUT_10BIT_MASK)
> > << 10) +
> > - ((lut[i].blue >> 6) & LUT_10BIT_MASK);
> > +
> > + if (!lut_diff || (i % 2 == 0)) {
> > + word = (((lut[i].red >> 6) &
> > LUT_10BIT_MASK) << 20) +
> > + (((lut[i].green >> 6) &
> > LUT_10BIT_MASK) << 10) +
> > + ((lut[i].blue >> 6) &
> > LUT_10BIT_MASK);
> > + } else {
> > + diff[0] = abs((lut[i].red >> 6) -
> > (lut[i - 1].red >> 6));
> > + diff[1] = abs((lut[i].green >> 6) -
> > (lut[i - 1].green >> 6));
> > + diff[2] = abs((lut[i].blue >> 6) -
> > (lut[i - 1].blue >> 6));
> > +
> > + word = ((diff[0] & LUT_10BIT_MASK) <<
> > 20) +
> > + ((diff[1] & LUT_10BIT_MASK) <<
> > 10) +
> > + (diff[2] & LUT_10BIT_MASK);
> > + }
> > writel(word, (lut_base + i * 4));
> > }
> > }
> > @@ -78,8 +91,12 @@ void mtk_gamma_set_common(void __iomem *regs,
> > struct drm_crtc_state *state)
> > void mtk_gamma_set(struct device *dev, struct drm_crtc_state
> > *state)
> > {
> > struct mtk_disp_gamma *gamma = dev_get_drvdata(dev);
> > + bool lut_diff = false;
> > +
> > + if (gamma->data)
> > + lut_diff = gamma->data->lut_diff;
> >
> > - mtk_gamma_set_common(gamma->regs, state);
> > + mtk_gamma_set_common(gamma->regs, state, lut_diff);
> > }
> >
> > void mtk_gamma_config(struct device *dev, unsigned int w,
> > @@ -176,10 +193,15 @@ static const struct mtk_disp_gamma_data
> > mt8173_gamma_driver_data = {
> > .has_dither = true,
> > };
> >
> > +static const struct mtk_disp_gamma_data mt8183_gamma_driver_data =
> > {
> > + .lut_diff = true,
> > +};
> > +
> > static const struct of_device_id mtk_disp_gamma_driver_dt_match[]
> > =
> > {
> > { .compatible = "mediatek,mt8173-disp-gamma",
> > .data = &mt8173_gamma_driver_data},
> > - { .compatible = "mediatek,mt8183-disp-gamma"},
> > + { .compatible = "mediatek,mt8183-disp-gamma",
> > + .data = &mt8183_gamma_driver_data},
> > {},
> > };
> > MODULE_DEVICE_TABLE(of, mtk_disp_gamma_driver_dt_match);
>
>
