Re: [PATCH 6/8] phy: allwinner: phy-sun6i-mipi-dphy: Set enable bit last

[Paul Kocialkowski <paul.kocialkowski@bootlin.com>]

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Hi Samuel,

On Fri 12 Aug 22, 17:31, Samuel Holland wrote:
> Hi Paul,
> 
> On 8/12/22 7:03 AM, Paul Kocialkowski wrote:
> > On Fri 12 Aug 22, 02:56, Samuel Holland wrote:
> >> The A100 variant of the DPHY requires configuring the analog registers
> >> before setting the global enable bit. Since this order also works on the
> >> other variants, always use it, to minimize the differences between them.
> > 
> > Did you get a chance to actually test this with either DSI/CSI-2 hardware?
> 
> I have tested DSI output with the Clockwork DevTerm (D1 SoC) and Pine64
> PinePhone (A64 SoC). I do not have any MIPI CSI hardware to test with.

Sounds good to me then!

> > I vaguely remember that the order mattered. Do you have an idea of what the
> > Allwinner BSP does too?
> 
> The Allwinner BSP makes the same change as this commit in its "lowlevel_v2x"
> copy of the code, which is used for R40 and T7 (original DPHY) and A100 and D1
> (updated DPHY). It does not make the change in "lowlevel_sun50iw1" (A64 SoC,
> original DPHY), but I tested A64 with this change, and it works fine.

Great, thanks for details.

> > Otherwise I could give it a try, at least with my MIPI CSI-2 setup
> > that uses the driver.
> 
> This commit only changes sun6i_dphy_tx_power_on(). The code for RX is unchanged
> -- in fact, it already sets SUN6I_DPHY_GCTL_REG last.

Ah yes you're right, actually I remember being tempted to change this too when
adding the rx path, but didn't have hardware to easily test.

Thanks for the details, this is:

Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>

Cheers,

Paul

> Regards,
> Samuel
> 
> >> Signed-off-by: Samuel Holland <samuel@sholland.org>
> >> ---
> >>
> >>  drivers/phy/allwinner/phy-sun6i-mipi-dphy.c | 8 ++++----
> >>  1 file changed, 4 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c b/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
> >> index 625c6e1e9990..9698d68d0db7 100644
> >> --- a/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
> >> +++ b/drivers/phy/allwinner/phy-sun6i-mipi-dphy.c
> >> @@ -183,10 +183,6 @@ static int sun6i_dphy_tx_power_on(struct sun6i_dphy *dphy)
> >>  		     SUN6I_DPHY_TX_TIME4_HS_TX_ANA0(3) |
> >>  		     SUN6I_DPHY_TX_TIME4_HS_TX_ANA1(3));
> >>  
> >> -	regmap_write(dphy->regs, SUN6I_DPHY_GCTL_REG,
> >> -		     SUN6I_DPHY_GCTL_LANE_NUM(dphy->config.lanes) |
> >> -		     SUN6I_DPHY_GCTL_EN);
> >> -
> >>  	regmap_write(dphy->regs, SUN6I_DPHY_ANA0_REG,
> >>  		     SUN6I_DPHY_ANA0_REG_PWS |
> >>  		     SUN6I_DPHY_ANA0_REG_DMPC |
> >> @@ -244,6 +240,10 @@ static int sun6i_dphy_tx_power_on(struct sun6i_dphy *dphy)
> >>  			   SUN6I_DPHY_ANA2_EN_P2S_CPU_MASK,
> >>  			   SUN6I_DPHY_ANA2_EN_P2S_CPU(lanes_mask));
> >>  
> >> +	regmap_write(dphy->regs, SUN6I_DPHY_GCTL_REG,
> >> +		     SUN6I_DPHY_GCTL_LANE_NUM(dphy->config.lanes) |
> >> +		     SUN6I_DPHY_GCTL_EN);
> >> +
> >>  	return 0;
> >>  }
> >>  
> >> -- 
> >> 2.35.1
> >>
> > 
> 

-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com

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