Re: [PATCH v3] spi: core: Validate length of the transfers in message

From: Mark Brown
Date: Tue Feb 25 2014 - 19:32:50 EST


On Tue, Feb 25, 2014 at 10:55:28PM +0900, Atsushi Nemoto wrote:

> Is xfer->len == 0 invalid?
> Long time ago I have fixed atmel spi driver to support zero length
> transfer (commit 06719814 atmel_spi: support zero length transfer).

> According to Documentation/spi/spi-summary, zeto length transfer seems
> valid.

> + optionally defining short delays after transfers ... using
> the spi_transfer.delay_usecs setting (this delay can be the
> only protocol effect, if the buffer length is zero);

*sigh* I guess it is valid, though frankly I'm concerned that this
isn't a good idea - it's certainly not going to work reliably given the
need for every driver to open code this, most of them get the delay
stuff wrong.

Attachment: signature.asc
Description: Digital signature