Re: [PATCH v3,1/4] drm/mediatek: Adjust the timing of mipi signal from LP00 to LP11

[xinlei.lee <xinlei.lee@mediatek.com>]

On Thu, 2022-03-17 at 19:13 +0800, Rex-BC Chen wrote:
> Hello Xinlei,
> 
> Thanks for your patch, and there are something I want to know:
> 
> On Thu, 2022-03-17 at 15:53 +0800, xinlei.lee@mediatek.com wrote:
> > From: Jitao Shi <jitao.shi@mediatek.com>
> > 
> > Old sequence:
> > 1. Pull the MIPI signal high
> > 2. Delay & Dsi_reset
> > 3. Set the dsi timing register
> > 4. dsi clk & lanes leave ulp mode and enter hs mode
> > 
> > New sequence:
> > 1. Set the dsi timing register
> > 2. Pull the MIPI signal high
> > 3. Delay & Dsi_reset
> > 4. dsi clk & lanes leave ulp mode and enter hs mode
> > 
> 
> Could you explain why you want to change original power on sequence?
> From this commit message, I don't know why you want to do this.
> If the reason is in cover letter, I think you should move them here.
> 
> > In the new sequence 2 & 3 & 4 will be moved to dsi_enbale in later
> > patch.
> 
> I think this is no need to describe here.
> 
> BRs,
> Rex
> > 
> > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> > Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dsi.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index ccb0511b9cd5..262c027d8c2f 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -649,14 +649,14 @@ static int mtk_dsi_poweron(struct mtk_dsi
> > *dsi)
> >  	mtk_dsi_reset_engine(dsi);
> >  	mtk_dsi_phy_timconfig(dsi);
> >  
> > -	mtk_dsi_rxtx_control(dsi);
> > -	usleep_range(30, 100);
> > -	mtk_dsi_reset_dphy(dsi);
> >  	mtk_dsi_ps_control_vact(dsi);
> >  	mtk_dsi_set_vm_cmd(dsi);
> >  	mtk_dsi_config_vdo_timing(dsi);
> >  	mtk_dsi_set_interrupt_enable(dsi);
> >  
> > +	mtk_dsi_rxtx_control(dsi);
> > +	usleep_range(30, 100);
> > +	mtk_dsi_reset_dphy(dsi);
> >  	mtk_dsi_clk_ulp_mode_leave(dsi);
> >  	mtk_dsi_lane0_ulp_mode_leave(dsi);
> >  	mtk_dsi_clk_hs_mode(dsi, 0);
> 
> 
Hi Rex:

Thanks for your review!
Explain to you that this change does not actually affect the function
of dsi. We have verified this.
After this modification, it is convenient to move them into the if
(!dsi->lanes_ready) condition, which is just an adjustment action.
If you still have questions about my later explanation, please give
another suggestion.

Thanks!
xinlei