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Subject: Re: [PATCH v5 08/10] spi: expose master transfer size limitation.
From: Martin Sperl <martin@sperl.org>
In-Reply-To: <20151201231233.GA1929@sirena.org.uk>
Date: Fri, 4 Dec 2015 15:30:50 +0100
Cc: Michal Suchanek <hramrach@gmail.com>,
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References: <cover.1448988089.git.hramrach@gmail.com> <8c34c7790244489c2ce0072c72bd9bc7c4cdb965.1448988089.git.hramrach@gmail.com> <20151201231233.GA1929@sirena.org.uk>
To: Mark Brown <broonie@kernel.org>
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> On 02.12.2015, at 00:12, Mark Brown <broonie@kernel.org> wrote:
> 
> On Tue, Dec 01, 2015 at 04:51:06PM -0000, Michal Suchanek wrote:
> 
>> +static inline size_t
>> +spi_max_transfer_size(struct spi_device *spi)
>> +{
>> +	struct spi_master *master = spi->master;
>> +	if (!master->max_transfer_size)
>> +		return 0;
>> +	return master->max_transfer_size(spi);
>> +}
> 
> Can we change this to return SIZE_MAX instead (ie, the maximum value for
> a size_t)?  That way callers don't need to worry if there is a limit, if
> they want to handle it they can just unconditionally assume that a limit
> will be provided.

As I just came across: spi_master.max_dma_len, so I wonder how this 
value would differ from the proposed spi_master.max_transfer_size
on specific HW?

For all practical purposes I would assume both are identical.

Martin