Re: [PATCH v4 3/5] phy: qcom: edp: Add SC7280/SC8180X swing/pre-emphasis tables

From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
To: Yongxing Mou <yongxing.mou@oss.qualcomm.com>,
	Vinod Koul <vkoul@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Stephen Boyd <swboyd@chromium.org>,
	Bjorn Andersson <andersson@kernel.org>
Cc: linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 3/5] phy: qcom: edp: Add SC7280/SC8180X swing/pre-emphasis tables
Date: Wed, 22 Apr 2026 12:42:56 +0200	[thread overview]
Message-ID: <df40b4d1-6133-4d49-a7e3-47cbb2b058e9@oss.qualcomm.com> (raw)
In-Reply-To: <20260422-edp_phy-v4-3-c38bef2d027b@oss.qualcomm.com>

On 4/22/26 8:01 AM, Yongxing Mou wrote:
> SC7280 and SC8180X previously shared the same cfg because they did not use
> swing/pre-emphasis tables. Add the corresponding tables for these
> platforms. Since they have different PHY sub-versions, their eDP/DP mode
> tables also differ, so move SC8180X to its own cfg instead of reusing the
> SC7280 one.
> 
> Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
> ---

> +static const struct qcom_edp_swing_pre_emph_cfg edp_phy_swing_pre_emph_cfg_v2 = {
> +	.swing_hbr_rbr = &edp_swing_hbr_rbr,

For eDP / low-Vdiff:

I believe the RBR swing settings for 8180 should
instead be:

0x07 0x0f 0x17 0x1f (matches)
(the rest differs)
0x0d 0x16 0x1e
0x11 0x1b
0x16

The preem RBR almost matches, one byte is off
(arr[0][1] = 0x12 on poipu, 0x11 on kodiak)

The swing and preem settings for HBR3 look OK

For DP / low-Vdiff:

.swing_hbr3_hbr2 OK
.swing_hbr_rbr - I don't know. The docs are unclear whether the same
settings should be used for RBR and HBR3, but maybe? There's a
separate table for mini-DP but I doubt there's any poipu boards with
such a connector (maybe some obscure ones)

.pre_emphasis_hbr3_hbr2 OK
.pre_emphasis_hbr_rbr same as above

Konrad

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