linux-kernel - Re: [Linux-stm32] [PATCH v3 3/5] ARM: dts: stm32: enable ltdc binding with ili9341 on stm32429-disco board

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Message-ID: <CAL9mu0L6d2V5qypPfOSeMdhc=DdHkcsaF4GysNG-vfDe5npkhw@mail.gmail.com>
Date:   Fri, 15 May 2020 17:24:29 +0800
From:   dillon min <dillon.minfei@...il.com>
To:     Benjamin GAIGNARD <benjamin.gaignard@...com>
Cc:     Alexandre TORGUE <alexandre.torgue@...com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>, Daniel Vetter <daniel@...ll.ch>,
        Dave Airlie <airlied@...ux.ie>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "open list:DRM PANEL DRIVERS" <dri-devel@...ts.freedesktop.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        "thierry.reding@...il.com" <thierry.reding@...il.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Michael Turquette <mturquette@...libre.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [Linux-stm32] [PATCH v3 3/5] ARM: dts: stm32: enable ltdc binding
 with ili9341 on stm32429-disco board

Hi Benjamin,

thanks for reply.

On Fri, May 15, 2020 at 4:31 PM Benjamin GAIGNARD
<benjamin.gaignard@...com> wrote:
>
>
>
> On 5/14/20 3:07 PM, dillon min wrote:
> > Hi Alexandre,
> >
> > On Thu, May 14, 2020 at 8:53 PM Alexandre Torgue
> > <alexandre.torgue@...com> wrote:
> >>
> >>
> >> On 5/14/20 10:24 AM, Linus Walleij wrote:
> >>> On Tue, May 12, 2020 at 9:04 AM <dillon.minfei@...il.com> wrote:
> >>>
> >>>> From: dillon min <dillon.minfei@...il.com>
> >>>>
> >>>> Enable the ltdc & ili9341 on stm32429-disco board.
> >>>>
> >>>> Signed-off-by: dillon min <dillon.minfei@...il.com>
> >>> This mostly looks good but...
> >>>
> >>>> +&spi5 {
> >>>> +       status = "okay";
> >>>> +       pinctrl-0 = <&spi5_pins>;
> >>>> +       pinctrl-names = "default";
> >>>> +       #address-cells = <1>;
> >>>> +       #size-cells = <0>;
> >>>> +       cs-gpios = <&gpioc 2 GPIO_ACTIVE_LOW>;
> >>>> +       dmas = <&dma2 3 2 0x400 0x0>,
> >>>> +              <&dma2 4 2 0x400 0x0>;
> >>>> +       dma-names = "rx", "tx";
> >>> These DMA assignments seem to be SoC things and should
> >>> rather be in the DTS(I) file where &spi5 is defined, right?
> >>> stm32f429.dtsi I suppose?
> >> I agree with Linus, DMA have to be defined in SoC dtsi. And if a board
> >> doesn't want to use it, we use the "delete-property".
> > Yes, will move to Soc dtsi in next submits.
> >
> > i'm working on write a v4l2-m2m driver for dma2d of stm32 to support
> > pixel conversion
> > alpha blending between foreground and background graphics.
> >
> > as you know, some soc's engineer trying to add this function to drm system.
> >
> > do you know st's planning about soc's hardware accelerator driver on stm32mp?
> > such as chrom-art, will add to drm subsystem via ioctl to access, or to v4l2,
> On stm32mp we do not plan to use chrom-art in drm or v4l2 because it
> does fit
> with userland way of working. We use the GPU to do conversion, scaling,
> blending
> and composition in only one go.
> As explain here [1] DRM subsytem it isn't a solution and v4l2-m2m isn't
> used in any
> mainline compositors like Weston or android surfaceflinger.
>
> Benjamin
>

After check stm32mp's datasheets, they don't have chrom-art ip inside. sorry for
didn't check it yet.

for stm32h7 series with chrom-art, jpeg hardware accelerator inside.
does st has plan to
setup a driver to support it ? i prefer v4l2-m2m should be easier to
implement it.
co work with dcmi, fbdev.

thanks.

best regards.

Dillon
> [1]
> https://www.phoronix.com/scan.php?page=news_item&px=Linux-DRM-No-2D-Accel-API
> >
> > thanks.
> >
> >>> It is likely the same no matter which device is using spi5.
> >>>
> >>> Yours,
> >>> Linus Walleij
> >>>
> > _______________________________________________
> > Linux-stm32 mailing list
> > Linux-stm32@...md-mailman.stormreply.com
> > https://st-md-mailman.stormreply.com/mailman/listinfo/linux-stm32

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