[PATCH 5/6] spi: bcm2835: add polling mode for transfers below 30us

[Stephen Warren]

On 03/31/2015 12:00 AM, Martin Sperl wrote:
>
>> On 31.03.2015, at 05:28, Stephen Warren <swarren at wwwdotorg.org> wrote:
>>> +	/* check if we shall run in polling mode */
>>> +	xfer_time_us = tfr->len * 9 * 1000000 / spi_used_hz;
>>
>> Why 9 not 8; presumably thats bits per byte, and IIRC SPI doesn't have
>> anything like I2C's ack bit per byte?
>
> Well - the bcm2835 make a 1 cycle wait after each byte transferred.
> Hence 9 bit actual length we need to account for.

How odd. A comment to that effect might be useful for future readers.