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

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
[off-list ref] wrote:

quoted

On 5/14/20 3:07 PM, dillon min wrote:

quoted

Hi Alexandre,

On Thu, May 14, 2020 at 8:53 PM Alexandre Torgue
[off-list ref] wrote:

quoted

On 5/14/20 10:24 AM, Linus Walleij wrote:

quoted

On Tue, May 12, 2020 at 9:04 AM [off-list ref] wrote:

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From: dillon min <redacted>

Enable the ltdc & ili9341 on stm32429-disco board.

Signed-off-by: dillon min <redacted>

This mostly looks good but...

quoted

+&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

quoted

[1]
https://www.phoronix.com/scan.php?page=news_item&px=Linux-DRM-No-2D-Accel-API

quoted

thanks.

quoted

quoted

It is likely the same no matter which device is using spi5.

Yours,
Linus Walleij

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