rockchip: correctly set vop0 or vop1

[Patrick Wildt]

On Mon, Jun 08, 2020 at 10:18:19AM +0200, Arnaud Patard wrote:
> Patrick Wildt <patrick at blueri.se> writes:
> 
> Hi,
> 
> > The EDP_LCDC_SEL bit has to be set correctly to select vop0 or
> > vop1, but so far we have set it in both conditions, which is not
> > correct.
> >
> > Can someone verify this is the correct way round?  vop1 -> set,
> > vop0 -> clear?
> >
> > Signed-off-by: Patrick Wildt <patrick at blueri.se>
> >
> > diff --git a/drivers/video/rockchip/rk_edp.c b/drivers/video/rockchip/rk_edp.c
> > index 92188be9275..000bd481408 100644
> > --- a/drivers/video/rockchip/rk_edp.c
> > +++ b/drivers/video/rockchip/rk_edp.c
> > @@ -1062,7 +1062,8 @@ static int rk_edp_probe(struct udevice *dev)
> >  	rk_setreg(&priv->grf->soc_con12, 1 << 4);
> >  
> >  	/* select epd signal from vop0 or vop1 */
> > -	rk_setreg(&priv->grf->soc_con6, (vop_id == 1) ? (1 << 5) : (1 << 5));
> > +	rk_clrsetreg(&priv->grf->soc_con6, (1 << 5),
> > +	    (vop_id == 1) ? (1 << 5) : (0 << 5));
> 
> While working on PBP EDP support, found this too but I'm not sure it's
> fine or not. For rk3399, my (not yet published) patch is doing:
> 
> +       if (vop_id == 0)
> +               rk_clrreg(&priv->grf->soc_con20, (1 << 5));
> +       else
> +               rk_setreg(&priv->grf->soc_con20, (1 << 5));
> 
> I believe that the rk3288 may need similar treatment but I've yet to
> look at the rk3288 manual.
> 
> Arnaud

Yes, it does.  If you look at the linux code, they have:

static const struct rockchip_dp_chip_data rk3399_edp = {
        .lcdsel_grf_reg = RK3399_GRF_SOC_CON20,
        .lcdsel_big = HIWORD_UPDATE(0, RK3399_EDP_LCDC_SEL),
        .lcdsel_lit = HIWORD_UPDATE(RK3399_EDP_LCDC_SEL, RK3399_EDP_LCDC_SEL),
        .chip_type = RK3399_EDP,
};

static const struct rockchip_dp_chip_data rk3288_dp = {
        .lcdsel_grf_reg = RK3288_GRF_SOC_CON6,
        .lcdsel_big = HIWORD_UPDATE(0, RK3288_EDP_LCDC_SEL),
        .lcdsel_lit = HIWORD_UPDATE(RK3288_EDP_LCDC_SEL, RK3288_EDP_LCDC_SEL),
        .chip_type = RK3288_DP,
};

which indicates that for rk3399 *and* rk3288 the bit has to be set to
select "lit".  Now your diff looks equivalent to mine, apart from using
a different operation to achieve the same goal.

The linux code does

        ret = drm_of_encoder_active_endpoint_id(dp->dev->of_node, encoder);
        if (ret < 0)
                return;

        if (ret)
                val = dp->data->lcdsel_lit;
        else
                val = dp->data->lcdsel_big;

Assuming that endpoint_id essentiall returns vop id 0 or vop id 1, this
would mean that vop1 -> lit -> set bit and vop0 -> big -> clr bit.

That said, my diff seems to be fine, and your RK3399 code as well.  Do
you agree?

Patrick