Re: [PATCH v11 05/10] drm/mediatek: Add MT8195 Embedded DisplayPort driver
From: CK Hu <hidden>
Date: 2022-06-15 03:07:02
Also in:
dri-devel, linux-arm-kernel, linux-devicetree, linux-mediatek, lkml
Hi, Bo-Chen: On Fri, 2022-06-10 at 18:55 +0800, Bo-Chen Chen wrote:
From: Markus Schneider-Pargmann <msp@baylibre.com> 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 [off-list ref] Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com> Signed-off-by: Guillaume Ranquet <redacted> [Bo-Chen: Cleanup the drivers and modify comments from reviewers] Signed-off-by: Bo-Chen Chen <redacted> ---
[snip]
quoted hunk ↗ jump to hunk
+ +static int mtk_dp_parse_capabilities(struct mtk_dp *mtk_dp) +{ + u8 val; + struct mtk_dp_train_info *train_info = &mtk_dp->train_info; + + drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER, DP_SET_POWER_D0); + usleep_range(2000, 5000); + + drm_dp_read_dpcd_caps(&mtk_dp->aux, mtk_dp->rx_cap); + + mtk_dp->rx_cap[DP_TRAINING_AUX_RD_INTERVAL] &= DP_TRAINING_AUX_RD_MASK; + + train_info->link_rate = min_t(int, mtk_dp->max_linkrate, + mtk_dp->rx_cap[mtk_dp-quoted
max_linkrate]);+ train_info->lane_count = min_t(int, mtk_dp->max_lanes, + drm_dp_max_lane_count(mtk_dp-quoted
rx_cap));+ + train_info->tps3 = drm_dp_tps3_supported(mtk_dp->rx_cap); + train_info->tps4 = drm_dp_tps4_supported(mtk_dp->rx_cap); + + train_info->sink_ssc = !!(mtk_dp->rx_cap[DP_MAX_DOWNSPREAD] & + DP_MAX_DOWNSPREAD_0_5);
I think this is redundant because next statement would set sink_scc to false. Regards, CK
+
+ train_info->sink_ssc = false;
+
+ drm_dp_dpcd_readb(&mtk_dp->aux, DP_MSTM_CAP, &val);
+ if (val & DP_MST_CAP) {
+ /* Clear DP_DEVICE_SERVICE_IRQ_VECTOR_ESI0 */
+ drm_dp_dpcd_readb(&mtk_dp->aux,
+ DP_DEVICE_SERVICE_IRQ_VECTOR_ESI0,
&val);
+ if (val)
+ drm_dp_dpcd_writeb(&mtk_dp->aux,
+ DP_DEVICE_SERVICE_IRQ_VECTOR
_ESI0,
+ val);
+ }
+
+ return 0;
+}