Re: [PATCH v2 1/3] spi: add xtfpga SPI controller driver

[Max Filippov]

On Wed, Mar 12, 2014 at 4:49 PM, Mark Brown <broonie@xxxxxxxxxx> wrote:
> On Wed, Mar 12, 2014 at 04:21:03PM +0400, Max Filippov wrote:
>
>> +     case 16:
>> +             /* Bytes that should go out earlier have lower addresses,
>> +              * but the hardware operates with 16 bit words and transmits
>> +              * higher bits first. Thus data in memory is in BE order.
>> +              */
>> +             xspi->data = (xspi->data << 16) | be16_to_cpu(v);
>> +             xspi->data_sz += 2;
>> +             break;
>
> Are you sure you need to do this byte swap?  SPI words are big endian so
> if you are running on a little endian processor if you are transmitting
> 16 bit words you should see the data getting swapped on the bus (this is
> why I say you should never have more than 8 bits per word for regmap).

Looks like this swap is not needed: I've looked at drivers that set
bits_per_word = 16, they submit data in cpu endianness. Will fix in v3.

-- 
Thanks.
-- Max
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