Thread (20 messages) 20 messages, 7 authors, 2025-09-05

Re: [PATCH v4 5/6] phy: qcom: qmp-combo: register a typec mux to change the QMPPHY_MODE

From: Dmitry Baryshkov <hidden>
Date: 2025-08-11 10:55:53
Also in: linux-arm-msm, linux-phy, lkml

On Mon, Aug 11, 2025 at 12:37:00PM +0200, Konrad Dybcio wrote:
On 8/9/25 10:13 AM, Dmitry Baryshkov wrote:
quoted
On Thu, Aug 07, 2025 at 06:33:23PM +0200, Konrad Dybcio wrote:
quoted
From: Neil Armstrong <neil.armstrong@linaro.org>

Register a typec mux in order to change the PHY mode on the Type-C
mux events depending on the mode and the svid when in Altmode setup.

The DisplayPort phy should be left enabled if is still powered on
by the DRM DisplayPort controller, so bail out until the DisplayPort
PHY is not powered off.

The Type-C Mode/SVID only changes on plug/unplug, and USB SAFE states
will be set in between of USB-Only, Combo and DisplayPort Only so
this will leave enough time to the DRM DisplayPort controller to
turn of the DisplayPort PHY.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
[konrad: renaming, rewording, bug fixes]
Signed-off-by: Konrad Dybcio <redacted>
---
 drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 118 ++++++++++++++++++++++++++++--
 1 file changed, 113 insertions(+), 5 deletions(-)

+
+	if (qmp->qmpphy_mode != QMPPHY_MODE_USB3_ONLY && qmp->dp_powered_on) {
+		dev_dbg(qmp->dev, "typec_mux_set: DP PHY is still in use, delaying switch\n");
+		return 0;
+	}
I can't say that I'm fully happy about it, nevertheless:

Reviewed-by: Dmitry Baryshkov <redacted>
IIUC we'll be able to get rid of it after the dp rework?
Which one? The HPD? not really. My unhappiness is about the sync between
USB and DP. I'm unsure whether we need higher level of sync for
USB-or-DP PHYs.

-- 
With best wishes
Dmitry
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