[RFC PATCH 4/5] ARM: dts: stm32: support display on stm32f469-disco board

[Patrice CHOTARD]

On 9/3/23 22:57, Dario Binacchi wrote:
> Add support to Orise Tech OTM8009A display on stm32f469-disco board.
> 
> It was necessary to retrieve the framebuffer address from the device tree
> because the address returned by the video-uclass driver pointed to a memory
> area that was not usable.
> 
> Furthermore, unlike Linux, the DSI driver requires the LTDC clock to be
> properly probed. Hence, the changes made to the DSI node in
> stm32f469-disco-u-boot.dtsi.
> 
> Signed-off-by: Dario Binacchi <dario.binacchi at amarulasolutions.com>
> ---
> 
>  arch/arm/dts/stm32f469-disco-u-boot.dtsi |  4 +++
>  configs/stm32f469-discovery_defconfig    | 13 +++++++++
>  drivers/video/stm32/stm32_ltdc.c         | 37 +++++++++++++++++++++++-
>  3 files changed, 53 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/dts/stm32f469-disco-u-boot.dtsi b/arch/arm/dts/stm32f469-disco-u-boot.dtsi
> index 8e781c5a7b23..47ba9fa4a783 100644
> --- a/arch/arm/dts/stm32f469-disco-u-boot.dtsi
> +++ b/arch/arm/dts/stm32f469-disco-u-boot.dtsi
> @@ -92,7 +92,9 @@
>  
>  &dsi {
>  	clocks = <&rcc 0 STM32F4_APB2_CLOCK(DSI)>,
> +		 <&rcc 0 STM32F4_APB2_CLOCK(LTDC)>,
>  		 <&clk_hse>;
> +	clock-names = "pclk", "px_clk", "ref";
>  };
>  
>  &gpioa {
> @@ -140,6 +142,8 @@
>  };
>  
>  &ltdc {
> +	bootph-all;
> +
>  	clocks = <&rcc 0 STM32F4_APB2_CLOCK(LTDC)>;
>  };
>  
> diff --git a/configs/stm32f469-discovery_defconfig b/configs/stm32f469-discovery_defconfig
> index 35d18d58be6f..9796b8f2d9a5 100644
> --- a/configs/stm32f469-discovery_defconfig
> +++ b/configs/stm32f469-discovery_defconfig
> @@ -21,6 +21,7 @@ CONFIG_CMD_GPT=y
>  # CONFIG_RANDOM_UUID is not set
>  CONFIG_CMD_MMC=y
>  # CONFIG_CMD_SETEXPR is not set
> +CONFIG_CMD_BMP=y
>  CONFIG_CMD_CACHE=y
>  CONFIG_CMD_TIMER=y
>  # CONFIG_ISO_PARTITION is not set
> @@ -40,3 +41,15 @@ CONFIG_SPI_FLASH_STMICRO=y
>  CONFIG_SPI=y
>  CONFIG_DM_SPI=y
>  CONFIG_STM32_QSPI=y
> +CONFIG_VIDEO=y
> +CONFIG_BACKLIGHT_GPIO=y
> +CONFIG_VIDEO_LCD_ORISETECH_OTM8009A=y
> +CONFIG_VIDEO_STM32=y
> +CONFIG_VIDEO_STM32_DSI=y
> +CONFIG_VIDEO_STM32_MAX_XRES=480
> +CONFIG_VIDEO_STM32_MAX_YRES=800
> +CONFIG_BMP_16BPP=y
> +CONFIG_BMP_24BPP=y
> +CONFIG_BMP_32BPP=y
> +CONFIG_DM_REGULATOR=y
> +CONFIG_DM_REGULATOR_FIXED=y
> diff --git a/drivers/video/stm32/stm32_ltdc.c b/drivers/video/stm32/stm32_ltdc.c
> index f48badc517a8..428b0addc43c 100644
> --- a/drivers/video/stm32/stm32_ltdc.c
> +++ b/drivers/video/stm32/stm32_ltdc.c
> @@ -494,6 +494,34 @@ static void stm32_ltdc_set_layer1(struct stm32_ltdc_priv *priv, ulong fb_addr)
>  	setbits_le32(priv->regs + LTDC_L1CR, LXCR_LEN);
>  }
>  
> +#if IS_ENABLED(CONFIG_TARGET_STM32F469_DISCOVERY)

We want to avoid this kind of #define specific to a particular target

> +static int stm32_ltdc_get_fb_addr(struct udevice *dev, ulong *base, uint size,
> +				  uint align)
> +{
> +	phys_addr_t cpu;
> +	dma_addr_t bus;
> +	u64 dma_size;
> +	int ret;
> +
> +	ret = dev_get_dma_range(dev, &cpu, &bus, &dma_size);
> +	if (ret) {
> +		dev_err(dev, "failed to get dma address\n");
> +		return ret;
> +	}
> +
> +	*base = bus + 0x1000000 - ALIGN(size, align);

Why adding 0x1000000 ? avoid to insert const whithout any description and use a #define instead.

> +	return 0;
> +}
> +#else
> +static int stm32_ltdc_get_fb_addr(struct udevice *dev, ulong *base, uint size,
> +				  uint align)
> +{
> +	/* Delegate framebuffer allocation to video-uclass */
> +	*base = 0;
> +	return 0;
> +}
> +#endif
> +
>  static int stm32_ltdc_probe(struct udevice *dev)
>  {
>  	struct video_uc_plat *uc_plat = dev_get_uclass_plat(dev);
> @@ -504,7 +532,7 @@ static int stm32_ltdc_probe(struct udevice *dev)
>  	struct display_timing timings;
>  	struct clk pclk;
>  	struct reset_ctl rst;
> -	ulong rate;
> +	ulong rate, fb_base;
>  	int ret;
>  
>  	priv->regs = dev_read_addr_ptr(dev);
> @@ -604,6 +632,13 @@ static int stm32_ltdc_probe(struct udevice *dev)
>  	priv->crop_h = timings.vactive.typ;
>  	priv->alpha = 0xFF;
>  
> +	ret = stm32_ltdc_get_fb_addr(dev, &fb_base, uc_plat->size,
> +				     uc_plat->align);
> +	if (ret)
> +		return ret;
> +
> +	uc_plat->base = fb_base;
> +

It breaks display on stm32f746-disco and also on stm32f769-disco.

Thanks
Patrice

>  	dev_dbg(dev, "%dx%d %dbpp frame buffer at 0x%lx\n",
>  		timings.hactive.typ, timings.vactive.typ,
>  		VNBITS(priv->l2bpp), uc_plat->base);