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Date:   Mon, 15 May 2023 22:00:56 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Kelvin.Cao@microchip.com
Cc:     hch@infradead.org, dmaengine@vger.kernel.org, vkoul@kernel.org,
        George.Ge@microchip.com, linux-kernel@vger.kernel.org,
        logang@deltatee.com, tglx@linutronix.de,
        christophe.jaillet@wanadoo.fr
Subject: Re: [PATCH v4 1/1] dmaengine: switchtec-dma: Introduce Switchtec DMA
 engine PCI driver
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References: <20230423213717.318655-1-kelvin.cao@microchip.com>
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 <50e111a3cfecd0f232508d1b03e02d1e25d9d4a9.camel@microchip.com>
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On Mon, May 15, 2023 at 06:18:07PM +0000, Kelvin.Cao@microchip.com wrote:
> > I find this rather confusing, especially as some code literally
> > switches on the op to fill in either set.
> 
> It's a hardware interface, and not possible to change it at the point.
> I guess I can make it look slightly better by grouping the related
> names together:
> 
> union {
>         struct {
>                 __le32 saddr_lo;
>                 __le32 saddr_hi;
>         };
>         struct {
>                 __le32 widata_lo;
>                 __le32 widata_hi;
>         };
> };

The hardware interface is simply:

	__le32 field_lo;
	__le32 field_hi;

hardware documentation might decide to give those fields two different
names just to confuse you :)

I think everyone else would be served better by:
	
	__le32 addr_lo; /* SADDR_LO/WIADDR_LO */
	__le32 addr_hi; /* SADDR_HI/WIADDR_HI */