linux-kernel - Re: [PATCH v14 7/7] phy: freescale: Add HDMI PHY driver for i.MX8MQ

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Message-ID: <1880037.tdWV9SEqCh@steina-w>
Date: Wed, 21 Feb 2024 15:32:01 +0100
From: Alexander Stein <alexander.stein@...tq-group.com>
To: "dmitry.baryshkov@...aro.org" <dmitry.baryshkov@...aro.org>,
	"andrzej.hajda@...el.com" <andrzej.hajda@...el.com>,
	"neil.armstrong@...aro.org" <neil.armstrong@...aro.org>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	"jonas@...boo.se" <jonas@...boo.se>,
	"jernej.skrabec@...il.com" <jernej.skrabec@...il.com>,
	"airlied@...il.com" <airlied@...il.com>,
	"daniel@...ll.ch" <daniel@...ll.ch>,
	"robh+dt@...nel.org" <robh+dt@...nel.org>,
	"krzysztof.kozlowski+dt@...aro.org" <krzysztof.kozlowski+dt@...aro.org>,
	"shawnguo@...nel.org" <shawnguo@...nel.org>,
	"s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
	"festevam@...il.com" <festevam@...il.com>,
	"vkoul@...nel.org" <vkoul@...nel.org>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-phy@...ts.infradead.org" <"li nux-phy"@lists.infradead.org>,
	Sandor Yu <sandor.yu@....com>
Cc: "kernel@...gutronix.de" <kernel@...gutronix.de>, dl-linux-imx <linux-imx@....com>, Oliver Brown <oliver.brown@....com>, "sam@...nborg.org" <sam@...nborg.org>
Subject: Re: [PATCH v14 7/7] phy: freescale: Add HDMI PHY driver for i.MX8MQ

Hi Sandor,

Am Mittwoch, 21. Februar 2024, 08:47:52 CET schrieb Sandor Yu:
> Hi Alexander,
> 
> Thanks for your comments,
> 
> >
> > Hi,
> >
> > thanks for the update.
> >
> > Am Dienstag, 20. Februar 2024, 04:23:55 CET schrieb Sandor Yu:
> > > Add Cadence HDP-TX HDMI PHY driver for i.MX8MQ.
> > >
> > > Cadence HDP-TX PHY could be put in either DP mode or HDMI mode base
> > on
> > > the configuration chosen.
> > > HDMI PHY mode is configurated in the driver.
> > >
> > > Signed-off-by: Sandor Yu <Sandor.yu@....com>
> > > Tested-by: Alexander Stein <alexander.stein@...tq-group.com>
> >
> > This still works as before. I noticed there is a lot of code duplication with
> > patch 6. IMHO these PHY drivers should be merged into a single one where
> > the mode is configured using phy_set_mode() from cdns-mhdp8501-core.c.
> > This nicely matches my concerns regarding patch 5.
> >
> Yes, there are some registers offset are same and the clock management function could be reused for DP and HDMI PHY driver.
> But because of HDMI and DP PHY totally different work mode, the functions in struct phy_ops,
> Such as ->init, ->power_on/off and ->configure could not combine into a single one,
> So separate DP and HDMI PHY driver should be a better resolution.

Despite some output type (DP/HDMI) specific settings, the similarities
are quite huge actually. Even though apparently DP has it's own ->init setup,
this can be delayed until ->set_mode or even ->configure.
The distinction between each mode can be done by checking phy->attrs.mode.
For a prove of concept I've hacked both drivers into a single one. I can't
test DP, but HDMI still works. Feel free to contact me in private.

Best regards,
Alexander

> B.R
> Sandor
> 
> 
> > Best regards,
> > Alexander
> >
> > > ---
> > > v13->v14:
> > >  *No change.
> > >
> > > v12->v13:
> > > - Fix build warning
> > >
> > > v11->v12:
> > > - Adjust clk disable order.
> > > - Return error code to replace -1 for function wait_for_ack().
> > > - Use bool for variable pclk_in.
> > > - Add year 2024 to copyright.
> > >
> > >  drivers/phy/freescale/Kconfig               |  10 +
> > >  drivers/phy/freescale/Makefile              |   1 +
> > >  drivers/phy/freescale/phy-fsl-imx8mq-hdmi.c | 960
> > > ++++++++++++++++++++
> > >  3 files changed, 971 insertions(+)
> > >  create mode 100644 drivers/phy/freescale/phy-fsl-imx8mq-hdmi.c
> > >
> > > diff --git a/drivers/phy/freescale/Kconfig
> > > b/drivers/phy/freescale/Kconfig index c39709fd700ac..14f47b7cc77ab
> > > 100644
> > > --- a/drivers/phy/freescale/Kconfig
> > > +++ b/drivers/phy/freescale/Kconfig

> [snip]

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