Re: [PATCH v4 3/5] phy: qualcomm: qmp-combo: Add preliminary USB4 support

From: Johan Hovold <johan@kernel.org>
To: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Cc: Manivannan Sadhasivam <mani@kernel.org>,
	Konrad Dybcio <konradybcio@kernel.org>,
	Vinod Koul <vkoul@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Bjorn Andersson <andersson@kernel.org>,
	linux-kernel@vger.kernel.org, linux-phy@lists.infradead.org,
	linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
	usb4-upstream@oss.qualcomm.com,
	Raghavendra Thoorpu <rthoorpu@qti.qualcomm.com>,
	Mika Westerberg <westeri@kernel.org>,
	Sven Peter <sven@kernel.org>,
	Abel Vesa <abel.vesa@oss.qualcomm.com>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Subject: Re: [PATCH v4 3/5] phy: qualcomm: qmp-combo: Add preliminary USB4 support
Date: Fri, 4 Sep 2026 10:05:07 +0200	[thread overview]
Message-ID: <app7s9GZySBj7Mzs@hovoldconsulting.com> (raw)
In-Reply-To: <b326edbf-fe34-426b-af19-912edc18ba84@oss.qualcomm.com>

On Fri, Sep 04, 2026 at 09:36:04AM +0200, Konrad Dybcio wrote:
> On 9/1/26 2:44 PM, Manivannan Sadhasivam wrote:
> > On Thu, Aug 20, 2026 at 04:24:12PM +0200, Konrad Dybcio wrote:
> >> From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> >>
> >> Some Combo PHYs (so far only on SC8280XP, X1E80100 and Glymur), come in
> >> a flavor called USB43DP, which as the name implies, features USB4, USB3
> >> and DP signal processing capabilities. In that architecture, USB3 and
> >> USB4 PHYs share the same USB_PLL while featuring separate logic spaces.
> >> The DP part is roughly the same as on the instances without USB4.
> 
> [...]
> 
> >> +	case QMPPHY_MODE_USB4:
> >> +		writel(USB4_MODE, com + QPHY_V3_DP_COM_PHY_MODE_CTRL);
> >> +
> >> +		/* bring both QMP USB and QMP DP PHYs PCS block out of reset */
> >> +		/* TODO: disable DP PLL if there are no active tunnels after router setup */
> > 
> > 100 column width generally applies to code, not comments. Comments should still
> > be wrapped to 80 columns.
> 
> I believe this isn't a real concern.. checkpatch certainly doesn't care:
> 
> # LONG_LINE_COMMENT     a comment starts before but extends beyond $max_line_length
> # LONG_LINE_STRING      a string starts before but extends beyond $max_line_length
> # LONG_LINE             all other lines longer than $max_line_length
> 
> (all take the same value, preset to 100 at the top of the file)

Checkpatch is just a dumb tool. The coding style says the preferred
limit is 80 chars unless breaking it improves readability. And that
exception generally does not apply to comments (e.g. unless it contains
a URL or similar).

Johan

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