Re: [PATCH v6 5/9] phy: rockchip-samsung-dcphy: Move block-level setup to runtime resume

[Michael Riesch]

Hi Jason,

Thanks for the patch!

On 11/10/26 09:18, Jason Yang wrote:
> The APB reset and the BIAS references have to be treated as block-level
> [1]: both the transmitter and the receiver need them, and they only have
> to be programmed once. They are programmed from the transmitter's
> power-on path today.
> 
> A later change registers one struct phy for each of them, and a second
> consumer coming up would then reset the block underneath a PHY that is
> already running.
> 
> Program them from runtime resume instead, where whichever of the two
> comes up first brings the block up and a second one no longer resets it.
> 
> This puts the BIAS writes ahead of the per-PHY reset assert, where the
> TRM's worked example has them after [1]. That is safe: neither M_RESETN
> nor S_RESETN covers the BIAS registers, and the values written are those
> registers' reset defaults.
> 
> [1] RK3588 TRM: sections 22.4.1 (address map), 22.4.2 (reset values),
>     22.6.1.2 (reset) and 22.6.4.1 (D-PHY transmitter start-up)
> 
> Signed-off-by: Jason Yang <jason98166@xxxxxxxxx>

Reviewed-by: Michael Riesch <michael.riesch@xxxxxxxxxxxxx>

Best regards,
Michael

> ---
>  drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c b/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
> index 7a009d87a665..d6acc3e2d448 100644
> --- a/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
> +++ b/drivers/phy/rockchip/phy-rockchip-samsung-dcphy.c
> @@ -1346,7 +1346,6 @@ static int samsung_mipi_dphy_power_on(struct samsung_mipi_dcphy *samsung)
>  
>  	reset_control_assert(samsung->m_phy_rst);
>  
> -	samsung_mipi_dcphy_bias_block_enable(samsung);
>  	samsung_mipi_dcphy_pll_configure(samsung);
>  	samsung_mipi_dphy_clk_lane_timing_init(samsung);
>  	samsung_mipi_dphy_data_lane_timing_init(samsung);
> @@ -1373,10 +1372,6 @@ static int samsung_mipi_dcphy_power_on(struct phy *phy)
>  {
>  	struct samsung_mipi_dcphy *samsung = phy_get_drvdata(phy);
>  
> -	reset_control_assert(samsung->apb_rst);
> -	udelay(1);
> -	reset_control_deassert(samsung->apb_rst);
> -
>  	switch (samsung->type) {
>  	case PHY_TYPE_DPHY:
>  		return samsung_mipi_dphy_power_on(samsung);
> @@ -1667,6 +1662,12 @@ static __maybe_unused int samsung_mipi_dcphy_runtime_resume(struct device *dev)
>  		return ret;
>  	}
>  
> +	reset_control_assert(samsung->apb_rst);
> +	udelay(1);
> +	reset_control_deassert(samsung->apb_rst);
> +
> +	samsung_mipi_dcphy_bias_block_enable(samsung);
> +
>  	return 0;
>  }
>  
>