linux-kernel - Re: [PATCH 3/8] spi: dw-dma: Configure the DMA channels in dma

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Date:   Fri, 31 Jul 2020 12:16:38 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Serge Semin <Sergey.Semin@...kalelectronics.ru>
Cc:     Mark Brown <broonie@...nel.org>,
        Serge Semin <fancer.lancer@...il.com>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
        Georgy Vlasov <Georgy.Vlasov@...kalelectronics.ru>,
        Ramil Zaripov <Ramil.Zaripov@...kalelectronics.ru>,
        Pavel Parkhomenko <Pavel.Parkhomenko@...kalelectronics.ru>,
        Peter Ujfalusi <peter.ujfalusi@...com>,
        Feng Tang <feng.tang@...el.com>, Vinod Koul <vkoul@...nel.org>,
        linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/8] spi: dw-dma: Configure the DMA channels in dma_setup

On Fri, Jul 31, 2020 at 10:59:48AM +0300, Serge Semin wrote:
> Mainly this is a preparation patch before adding one-by-one DMA SG entries
> transmission. But logically the Tx and Rx DMA channels setup should be
> performed in the dma_setup() callback anyway. So let's move the DMA slave
> channels src/dst burst lengths, address and address width configuration to
> the DMA setup stage. While at it make sure the return value of the
> dmaengine_slave_config() method is checked. It has been unnecessary in
> case if Dw DMAC is utilized as a DMA engine, since its device_config()
> callback always returns zero (though it might change in future). But since
> DW APB SSI driver now supports any DMA back-end we must make sure the
> DMA device configuration has been successful before proceeding with
> further setups.

...

> +	if (!xfer->rx_buf)
> +		return NULL;

...

> +	if (xfer->rx_buf) {

> +	}

This looks like a separate change to drop one of them and not hide in the next patch.

-- 
With Best Regards,
Andy Shevchenko