Re: [PATCH] drm/msm/dsi/phy: fix 7nm v4.0 settings for C-PHY mode

[Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>]

On 2/16/2022 4:08 PM, Dmitry Baryshkov wrote:
> The dsi_7nm_phy_enable() disagrees with downstream for
> glbl_str_swi_cal_sel_ctrl and glbl_hstx_str_ctrl_0 values. Update
> programmed settings to match downstream driver. To remove the
> possibility for such errors in future drop less_than_1500_mhz
> assignment and specify settings explicitly.
>
> Fixes: 5ac178381d26 ("drm/msm/dsi: support CPHY mode for 7nm pll/phy")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Yes, this matches what we have downstream
Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> ---
>   drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c | 22 ++++++++++++++--------
>   1 file changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> index 36eb6109cb88..6e506feb111f 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> @@ -864,20 +864,26 @@ static int dsi_7nm_phy_enable(struct msm_dsi_phy *phy,
>   	/* Alter PHY configurations if data rate less than 1.5GHZ*/
>   	less_than_1500_mhz = (clk_req->bitclk_rate <= 1500000000);
>   
> -	/* For C-PHY, no low power settings for lower clk rate */
> -	if (phy->cphy_mode)
> -		less_than_1500_mhz = false;
> -
>   	if (phy->cfg->quirks & DSI_PHY_7NM_QUIRK_V4_1) {
>   		vreg_ctrl_0 = less_than_1500_mhz ? 0x53 : 0x52;
> -		glbl_rescode_top_ctrl = less_than_1500_mhz ? 0x3d :  0x00;
> -		glbl_rescode_bot_ctrl = less_than_1500_mhz ? 0x39 :  0x3c;
> +		if (phy->cphy_mode) {
> +			glbl_rescode_top_ctrl = 0x00;
> +			glbl_rescode_bot_ctrl = 0x3c;
> +		} else {
> +			glbl_rescode_top_ctrl = less_than_1500_mhz ? 0x3d :  0x00;
> +			glbl_rescode_bot_ctrl = less_than_1500_mhz ? 0x39 :  0x3c;
> +		}
>   		glbl_str_swi_cal_sel_ctrl = 0x00;
>   		glbl_hstx_str_ctrl_0 = 0x88;
>   	} else {
>   		vreg_ctrl_0 = less_than_1500_mhz ? 0x5B : 0x59;
> -		glbl_str_swi_cal_sel_ctrl = less_than_1500_mhz ? 0x03 : 0x00;
> -		glbl_hstx_str_ctrl_0 = less_than_1500_mhz ? 0x66 : 0x88;
> +		if (phy->cphy_mode) {
> +			glbl_str_swi_cal_sel_ctrl = 0x03;
> +			glbl_hstx_str_ctrl_0 = 0x66;
> +		} else {
> +			glbl_str_swi_cal_sel_ctrl = less_than_1500_mhz ? 0x03 : 0x00;
> +			glbl_hstx_str_ctrl_0 = less_than_1500_mhz ? 0x66 : 0x88;
> +		}
>   		glbl_rescode_top_ctrl = 0x03;
>   		glbl_rescode_bot_ctrl = 0x3c;
>   	}