Re: [PATCH 4/8] dma: dmamux: Introduce RZN1 DMA router support

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Fri, Feb 18, 2022 at 07:12:22PM +0100, Miquel Raynal wrote:
> The Renesas RZN1 DMA IP is a based on a DW core, with eg. an additional
> dmamux register located in the system control area which can take up to
> 32 requests (16 per DMA controller). Each DMA channel can be wired to
> two different peripherals.
> 
> We need two additional information from the 'dmas' property: the channel
> (bit in the dmamux register) that must be accessed and the value of the
> mux for this channel.

...

> +dw_dmac-y			:= platform.o dmamux.o

We do not need this on other platforms, please make sure we have no dangling
code on, e.g., x86.

...

> +	/* The of_node_put() will be done in the core for the node */
> +	master = map->req_idx < dmamux->dmac_requests ? 0 : 1;

The opposite conditional will be better, no?`

...

> +	dmamux->used_chans |= BIT(map->req_idx);
> +	ret = r9a06g032_syscon_set_dmamux(BIT(map->req_idx),
> +					  val ? BIT(map->req_idx) : 0);


Cleaner to do

	u32 mask = BIT(...);
	...

	dmamux->used_chans |= mask;
	ret = r9a06g032_syscon_set_dmamux(mask, val ? mask : 0);

...

> +static const struct of_device_id rzn1_dmac_match[] __maybe_unused = {
> +	{ .compatible = "renesas,rzn1-dma", },
> +	{},

No comma for terminator entry.

> +};

...

> +	if (!node)
> +		return -ENODEV;

Dup check, why not to simply try for phandle first?

...

> +	if (of_property_read_u32(dmac_node, "dma-requests",
> +				 &dmamux->dmac_requests)) {

One line?

> +		dev_err(&pdev->dev, "Missing DMAC requests information\n");
> +		of_node_put(dmac_node);
> +		return -EINVAL;

First put node, then simply use dev_err_probe().

> +	}

...

> +static const struct of_device_id rzn1_dmamux_match[] = {
> +	{ .compatible = "renesas,rzn1-dmamux", },
> +	{},

No comma.

> +};

-- 
With Best Regards,
Andy Shevchenko