Re: [PATCH v12 05/10] drm/mediatek: Add MT8195 Embedded DisplayPort driver

[CK Hu]

Hi, Bo-Chen:

On Mon, 2022-06-27 at 16:03 +0800, Bo-Chen Chen wrote:
> From: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
> 
> This patch adds a embedded displayport driver for the MediaTek mt8195
> SoC.
> 
> It supports the MT8195, the embedded DisplayPort units. It offers
> DisplayPort 1.4 with up to 4 lanes.
> 
> The driver creates a child device for the phy. The child device will
> never exist without the parent being active. As they are sharing a
> register range, the parent passes a regmap pointer to the child so
> that
> both can work with the same register range. The phy driver sets
> device
> data that is read by the parent to get the phy device that can be
> used
> to control the phy properties.
> 
> This driver is based on an initial version by
> Jitao shi <jitao.shi@xxxxxxxxxxxx>
> 
> Signed-off-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
> Signed-off-by: Guillaume Ranquet <granquet@xxxxxxxxxxxx>
> [Bo-Chen: Cleanup the drivers and modify comments from reviewers]
> Signed-off-by: Bo-Chen Chen <rex-bc.chen@xxxxxxxxxxxx>
> ---

[snip]

> +
> +static void mtk_dp_power_enable(struct mtk_dp *mtk_dp)
> +{
> +	mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_RESET_AND_PROBE,
> +			   0, SW_RST_B_PHYD);
> +
> +	/* Wait for power enable */
> +	usleep_range(10, 200);
> +
> +	mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_RESET_AND_PROBE,
> +			   SW_RST_B_PHYD, SW_RST_B_PHYD);
> +	mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> +			   DP_PWR_STATE_BANDGAP_TPLL,
> DP_PWR_STATE_MASK);
> +}
> +
> +static void mtk_dp_power_disable(struct mtk_dp *mtk_dp)
> +{
> +	mtk_dp_write(mtk_dp, MTK_DP_TOP_PWR_STATE, 0);
> +
> +	mtk_dp_write(mtk_dp, MTK_DP_0034,
> +		     DA_CKM_CKTX0_EN_FORCE_EN |
> +		     DA_CKM_BIAS_LPF_EN_FORCE_VAL |
> +		     DA_CKM_BIAS_EN_FORCE_VAL |
> +		     DA_XTP_GLB_LDO_EN_FORCE_VAL |
> +		     DA_XTP_GLB_AVD10_ON_FORCE_VAL);
> +
> +	/* Disable RX */
> +	mtk_dp_write(mtk_dp, MTK_DP_1040, 0);

MTK_DP_1040 is set to 0 in mtk_dp_power_disable(), but it is not set to
other value in mtk_dp_power_enable(). Does any thing would be wrong
when mtk_dp_power_disable() and mtk_dp_power_enable()?

Regards,
CK

> +	mtk_dp_write(mtk_dp, MTK_DP_TOP_MEM_PD,
> +		     0x550 | BIT(FUSE_SEL_SHIFT) |
> BIT(MEM_ISO_EN_SHIFT));
> +}
> +