On Thu 21 Oct 10:40 PDT 2021, Vinod Koul wrote:

On 16-10-21, 16:21, Bjorn Andersson wrote:

quoted

Many recent Qualcomm platforms comes with native DP and eDP support.
This consists of a controller in the MDSS and a QMP-like PHY.

While similar to the well known QMP block, the eDP PHY only has TX lanes
and the programming sequences are slightly different. Rather than
continuing the trend of parameterize the QMP driver to pieces, this
introduces the support as a new driver.

The registration of link and pixel clocks are borrowed from the QMP
driver. The non-DP link frequencies are omitted for now.

The eDP PHY is very similar to the dedicated (non-USB) DP PHY, but only
the prior is supported for now.

since this is QMP phy, pls add an explanation why common QMP driver
is not used here?

Looked at this again, doesn't the second paragraph answer that?

quoted

+static int qcom_edp_phy_init(struct phy *phy)
+{

[..]

quoted

+	writel(0x00, edp->edp + DP_PHY_AUX_CFG0);
+	writel(0x13, edp->edp + DP_PHY_AUX_CFG1);
+	writel(0x24, edp->edp + DP_PHY_AUX_CFG2);
+	writel(0x00, edp->edp + DP_PHY_AUX_CFG3);
+	writel(0x0a, edp->edp + DP_PHY_AUX_CFG4);
+	writel(0x26, edp->edp + DP_PHY_AUX_CFG5);
+	writel(0x0a, edp->edp + DP_PHY_AUX_CFG6);
+	writel(0x03, edp->edp + DP_PHY_AUX_CFG7);
+	writel(0x37, edp->edp + DP_PHY_AUX_CFG8);
+	writel(0x03, edp->edp + DP_PHY_AUX_CFG9);

In qmp phy we use a table for this, that looks very elegant and I am
sure next rev will have different magic numbers, so should we go the
table approach here on as well..?

Comparing the v3 and v4 USB/DP combo phy and this, the only number that
differs is CFG_AUX2 and CFG_AUX8.

CFG_AUX8 is 0x37 for eDP and 0xb7 for DP and AUX_CFG2 seems better to
mask together, but I don't fully understand the content yet.

I did check two other platforms and they have the same sequence, except
one additional bit in AUX_CFG2. There also seem to be a few additional
permutations of this value, so I don't think tables are the solution.


So I think it's better if we leave this as proposed and then
parameterize the two individual entries as needed when we go forward -
or determine that I missed something.

Regards,
Bjorn

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