Re: [PATCH v2 3/7] bus: add bus driver for accessing Allwinner A64 DE2

[Maxime Ripard <maxime.ripard-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org>]

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On Fri, Jun 22, 2018 at 08:45:36PM +0800, Icenowy Zheng wrote:
> The "Display Engine 2.0" (usually called DE2) on the Allwinner A64 SoC
> is different from the ones on other Allwinner SoCs. It requires a SRAM
> region to be claimed, otherwise all DE2 subblocks won't be accessible.
> 
> Add a bus driver for the Allwinner A64 DE2 part which claims the SRAM
> region when probing.
> 
> Signed-off-by: Icenowy Zheng <icenowy-h8G6r0blFSE@public.gmane.org>
> ---
> No changes since v1.
> 
>  drivers/bus/Kconfig      | 10 ++++++++
>  drivers/bus/Makefile     |  1 +
>  drivers/bus/sun50i-de2.c | 49 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 60 insertions(+)
>  create mode 100644 drivers/bus/sun50i-de2.c
> 
> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
> index d1c0b60e9326..1851112ccc29 100644
> --- a/drivers/bus/Kconfig
> +++ b/drivers/bus/Kconfig
> @@ -103,6 +103,16 @@ config SIMPLE_PM_BUS
>  	  Controller (BSC, sometimes called "LBSC within Bus Bridge", or
>  	  "External Bus Interface") as found on several Renesas ARM SoCs.
>  
> +config SUN50I_DE2_BUS
> +	bool "Allwinner A64 DE2 Bus Driver"
> +	  default ARM64
> +	  depends on ARCH_SUNXI
> +	  select SUNXI_SRAM
> +	  help

The alignment here should be one tab.

> +static int sun50i_de2_bus_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	int ret;
> +
> +	ret = sunxi_sram_claim(&pdev->dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Error couldn't map SRAM to device\n");
> +		return ret;
> +	}
> +
> +	if (np)
> +		of_platform_populate(np, NULL, NULL, &pdev->dev);

Why do you need to test np here?

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com