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Subject: Re: [PATCH 5/5] dmaengine: sprd: Add 'device_config' and
 'device_prep_slave_sg' interfaces
To:     Baolin Wang <baolin.wang@linaro.org>, dan.j.williams@intel.com,
        vinod.koul@intel.com
Cc:     eric.long@spreadtrum.com, broonie@kernel.org,
        dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org
References: <abdda9da96185f764d58bbf61db9010d0f72d1b3.1523346135.git.baolin.wang@linaro.org>
 <0a9fa618bd74e74c135ebee2e40b30d361c1d905.1523346135.git.baolin.wang@linaro.org>
From:   Lars-Peter Clausen <lars@metafoo.de>
Message-ID: <5c951129-b167-3ed6-48f4-0a42cd2df28e@metafoo.de>
Date:   Tue, 17 Apr 2018 12:45:20 +0200
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On 04/10/2018 09:46 AM, Baolin Wang wrote:
[...]
> +static int sprd_dma_slave_config(struct dma_chan *chan,
> +				 struct dma_slave_config *config)
> +{
> +	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
> +	struct sprd_dma_config *slave_cfg =
> +		container_of(config, struct sprd_dma_config, config);
> +

Please do not overload standard API with custom semantics. This makes the
driver incompatible to the API and negates the whole idea of having a common
API. E.g. this will crash when somebody passes a normal dma_slave_config
struct to this function.

> +	memcpy(&schan->slave_cfg, slave_cfg, sizeof(*slave_cfg));
> +	return 0;
> +}