linux-kernel - Re: [PATCH v1 6/6] drm/mediatek: Add support for MT8195 Digital Parallel Interface

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Message-ID: <fd48c582e99d6c07be4b66919fb6c309379ad752.camel@mediatek.com>
Date: Tue, 26 Nov 2024 03:07:11 +0000
From: CK Hu (胡俊光) <ck.hu@...iatek.com>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	"chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"tzimmermann@...e.de" <tzimmermann@...e.de>, "kernel@...labora.com"
	<kernel@...labora.com>, Jitao Shi (石记涛)
	<jitao.shi@...iatek.com>, "mripard@...nel.org" <mripard@...nel.org>,
	"simona@...ll.ch" <simona@...ll.ch>, "p.zabel@...gutronix.de"
	<p.zabel@...gutronix.de>, "maarten.lankhorst@...ux.intel.com"
	<maarten.lankhorst@...ux.intel.com>, "conor+dt@...nel.org"
	<conor+dt@...nel.org>, "robh@...nel.org" <robh@...nel.org>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"airlied@...il.com" <airlied@...il.com>,
	"linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "matthias.bgg@...il.com"
	<matthias.bgg@...il.com>, "krzk+dt@...nel.org" <krzk+dt@...nel.org>
Subject: Re: [PATCH v1 6/6] drm/mediatek: Add support for MT8195 Digital
 Parallel Interface

On Mon, 2024-11-25 at 17:55 +0100, AngeloGioacchino Del Regno wrote:
> External email : Please do not click links or open attachments until you have verified the sender or the content.
> 
> 
> Il 22/11/24 08:23, CK Hu (胡俊光) ha scritto:
> > Hi, Angelo:
> > 
> > On Wed, 2024-11-20 at 13:44 +0100, AngeloGioacchino Del Regno wrote:
> > > External email : Please do not click links or open attachments until you have verified the sender or the content.
> > > 
> > > 
> > > Add support for the DPI block found in the MT8195 and MT8188 SoCs.
> > > Inside of the SoC, this block is directly connected to the HDMI IP.
> > 
> > In MT8173, DPI0 is directly connected to HDMI.
> > The first version of this driver is just for MT8173 DPI0.
> > Does MT8173 DPI0 need this modification?
> > Or this modification is just for MT8188 and MT8195, then the description should be more than 'directly connected'.
> > 
> 
> This is only for MT8188 and MT8195, and MT8173 does *not* need any modification.
> 
> Please, what would you like to see in the description of this commit?

This patch does four jobs.

1. Enable/disable tvd_clk for MT8195/MT8188 DPI.
2. Do not set pixel clock for MT8195/MT8188 DPI.
3. New DPI_INPUT_XXX and DPI_OUTPUT_XXX control for MT8195/MT8188 DPI.
4. Do not power on/off for MT8195/MT8188 DPI.

Maybe you should break into 4 patches and each one has different reason.

For #1 and #2, I've not reviewed the HDMI driver. Is the clock control influenced by new HDMI driver.
If it is software reason, maybe we can modify the new HDMI driver and make DPI driver consistent with MT8173.
If it is hardware reason. just describe the hardware reason.

For #4, I don't know why DPI do not control power by its self?
Even though other driver may control the same power, power manager has reference count,
so each driver could control the same power by its self.

Regards,
CK


> 
> Cheers,
> Angelo
> 
> > Regards,
> > CK
> > 
> > > 
> > > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> > > ---
> 
>