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From:   dillon min <dillon.minfei@gmail.com>
Date:   Fri, 15 May 2020 18:32:28 +0800
Message-ID: <CAL9mu0J7s589e7weQ7vyi1iFCwPOmmyFHwqhwWfYwWVqJpN+Dw@mail.gmail.com>
Subject: Re: [Linux-stm32] [PATCH v3 3/5] ARM: dts: stm32: enable ltdc binding
 with ili9341 on stm32429-disco board
To:     Benjamin GAIGNARD <benjamin.gaignard@st.com>
Cc:     Alexandre TORGUE <alexandre.torgue@st.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, Daniel Vetter <daniel@ffwll.ch>,
        Dave Airlie <airlied@linux.ie>,
        Linus Walleij <linus.walleij@linaro.org>,
        linux-clk <linux-clk@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "open list:DRM PANEL DRIVERS" <dri-devel@lists.freedesktop.org>,
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        Stephen Boyd <sboyd@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        "thierry.reding@gmail.com" <thierry.reding@gmail.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
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Hi Benjamin,

got it, thanks a lot.

best regards

Dillon

On Fri, May 15, 2020 at 5:34 PM Benjamin GAIGNARD
<benjamin.gaignard@st.com> wrote:
>
>
>
> On 5/15/20 11:24 AM, dillon min wrote:
> > Hi Benjamin,
> >
> > thanks for reply.
> >
> > On Fri, May 15, 2020 at 4:31 PM Benjamin GAIGNARD
> > <benjamin.gaignard@st.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@st.com> wrote:
> >>>>
> >>>> On 5/14/20 10:24 AM, Linus Walleij wrote:
> >>>>> On Tue, May 12, 2020 at 9:04 AM <dillon.minfei@gmail.com> wrote:
> >>>>>
> >>>>>> From: dillon min <dillon.minfei@gmail.com>
> >>>>>>
> >>>>>> Enable the ltdc & ili9341 on stm32429-disco board.
> >>>>>>
> >>>>>> Signed-off-by: dillon min <dillon.minfei@gmail.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.
> ST doesn't plan to create a driver for chrom-art because nothing in
> mainline
> userland could use it.
>
> Benjamin
> >
> > 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@st-md-mailman.stormreply.com
> >>> https://st-md-mailman.stormreply.com/mailman/listinfo/linux-stm32