Re: [PATCH v3 07/15] drm/bridge: analogix_dp: Add support for phy configuration.

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Hi Dmitry,

On 2024/12/20 13:37, Dmitry Baryshkov wrote:
On Fri, 20 Dec 2024 at 05:37, Damon Ding <damon.ding@xxxxxxxxxxxxxx> wrote:

Hi Dmitry,

On 2024/12/20 8:13, Dmitry Baryshkov wrote:
On Thu, Dec 19, 2024 at 04:05:56PM +0800, Damon Ding wrote:
Add support to configurate link rate, lane count, voltage swing and
pre-emphasis with phy_configure(). It is helpful in application scenarios
where analogix controller is mixed with the phy of other vendors.

Signed-off-by: Damon Ding <damon.ding@xxxxxxxxxxxxxx>

---

Changes in v2:
- remove needless assignments for phy_configure()
- remove unnecessary changes for phy_power_on()/phy_power_off()
---
   .../drm/bridge/analogix/analogix_dp_core.c    |  1 +
   .../gpu/drm/bridge/analogix/analogix_dp_reg.c | 56 +++++++++++++++++++
   2 files changed, 57 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 6f10d88a34c5..9429c50cc1bc 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1696,6 +1696,7 @@ int analogix_dp_resume(struct analogix_dp_device *dp)
      if (dp->plat_data->power_on)
              dp->plat_data->power_on(dp->plat_data);

+    phy_set_mode(dp->phy, PHY_MODE_DP);
      phy_power_on(dp->phy);

      analogix_dp_init_dp(dp);
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 3afc73c858c4..613ce504bea6 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -11,6 +11,7 @@
   #include <linux/gpio/consumer.h>
   #include <linux/io.h>
   #include <linux/iopoll.h>
+#include <linux/phy/phy.h>

   #include <drm/bridge/analogix_dp.h>

@@ -513,10 +514,25 @@ void analogix_dp_enable_sw_function(struct analogix_dp_device *dp)
   void analogix_dp_set_link_bandwidth(struct analogix_dp_device *dp, u32 bwtype)
   {
      u32 reg;
+    int ret;

      reg = bwtype;
      if ((bwtype == DP_LINK_BW_2_7) || (bwtype == DP_LINK_BW_1_62))
              writel(reg, dp->reg_base + ANALOGIX_DP_LINK_BW_SET);
+
+    if (dp->phy) {
+            union phy_configure_opts phy_cfg = {0};
+
+            phy_cfg.dp.lanes = dp->link_train.lane_count;

Should not be necessary, you are only setting the .set_rate.

Indeed, this can be dropped.


+            phy_cfg.dp.link_rate =
+                    drm_dp_bw_code_to_link_rate(dp->link_train.link_rate) / 100;
+            phy_cfg.dp.set_rate = true;
+            ret = phy_configure(dp->phy, &phy_cfg);
+            if (ret && ret != -EOPNOTSUPP) {
+                    dev_err(dp->dev, "%s: phy_configure() failed: %d\n", __func__, ret);
+                    return;
+            }
+    }
   }

   void analogix_dp_get_link_bandwidth(struct analogix_dp_device *dp, u32 *bwtype)
@@ -530,9 +546,22 @@ void analogix_dp_get_link_bandwidth(struct analogix_dp_device *dp, u32 *bwtype)
   void analogix_dp_set_lane_count(struct analogix_dp_device *dp, u32 count)
   {
      u32 reg;
+    int ret;

      reg = count;
      writel(reg, dp->reg_base + ANALOGIX_DP_LANE_COUNT_SET);
+
+    if (dp->phy) {
+            union phy_configure_opts phy_cfg = {0};
+
+            phy_cfg.dp.lanes = dp->link_train.lane_count;
+            phy_cfg.dp.set_lanes = true;
+            ret = phy_configure(dp->phy, &phy_cfg);
+            if (ret && ret != -EOPNOTSUPP) {
+                    dev_err(dp->dev, "%s: phy_configure() failed: %d\n", __func__, ret);
+                    return;
+            }
+    }
   }

   void analogix_dp_get_lane_count(struct analogix_dp_device *dp, u32 *count)
@@ -546,10 +575,37 @@ void analogix_dp_get_lane_count(struct analogix_dp_device *dp, u32 *count)
   void analogix_dp_set_lane_link_training(struct analogix_dp_device *dp)
   {
      u8 lane;
+    int ret;

      for (lane = 0; lane < dp->link_train.lane_count; lane++)
              writel(dp->link_train.training_lane[lane],
                     dp->reg_base + ANALOGIX_DP_LN0_LINK_TRAINING_CTL + 4 * lane);
+
+    if (dp->phy) {
+            union phy_configure_opts phy_cfg = {0};
+
+            for (lane = 0; lane < dp->link_train.lane_count; lane++) {
+                    u8 training_lane = dp->link_train.training_lane[lane];
+                    u8 vs, pe;
+
+                    vs = (training_lane & DP_TRAIN_VOLTAGE_SWING_MASK) >>
+                         DP_TRAIN_VOLTAGE_SWING_SHIFT;
+                    pe = (training_lane & DP_TRAIN_PRE_EMPHASIS_MASK) >>
+                         DP_TRAIN_PRE_EMPHASIS_SHIFT;
+                    phy_cfg.dp.voltage[lane] = vs;
+                    phy_cfg.dp.pre[lane] = pe;
+            }
+
+            phy_cfg.dp.lanes = dp->link_train.lane_count;
+            phy_cfg.dp.link_rate =
+                    drm_dp_bw_code_to_link_rate(dp->link_train.link_rate) / 100;

This two should not be necessary, please drop them.

These two are necessary for rk_hdptx_phy_set_voltage(), so they cannot
be dropped.

Please review the documentation for struct phy_configure_opts_dp and
fix your PHY driver to skip the values for which the .set_foo isn't
set. Then you might have to change this part.
You are setting just .set_voltages. It means that the rate and .lanes
shouldn't be changed and can be used as they were set by the previous
calls to phy_configure().


Indeed, I will store the previous &phy_configure_opts.dp.link_rate and &phy_configure_opts.dp.lanes in the struct rk_hdptx_phy, and will not use both of them during the configuration process of the &phy_cfg.dp.voltage[] and &phy_cfg.dp.pre[] in next version.



+            phy_cfg.dp.set_voltages = true;
+            ret = phy_configure(dp->phy, &phy_cfg);
+            if (ret && ret != -EOPNOTSUPP) {
+                    dev_err(dp->dev, "%s: phy_configure() failed: %d\n", __func__, ret);
+                    return;
+            }
+    }
   }

   u32 analogix_dp_get_lane_link_training(struct analogix_dp_device *dp, u8 lane)
--
2.34.1



Best regards,
Damon





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