From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: How to handle SPI components requiring heading/leading clock cycles with CS off Date: Wed, 24 Aug 2016 12:27:02 +0100 Message-ID: <20160824112701.GE22076@sirena.org.uk> References: <79679118-c092-1f9c-1972-0bb81bc59411@c-s.fr> <20160824094456.GB22076@sirena.org.uk> <8c6cbd99-7dd8-bbbf-89ee-a33752ab3063@c-s.fr> <20160824105640.GC22076@sirena.org.uk> <15444613-2f3d-9417-7d81-e545058afdf0@c-s.fr> <20160824111206.GD22076@sirena.org.uk> <9e854e9d-146c-61ea-da6e-a46b316b56c5@c-s.fr> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="kUmo4NyTJbuJZ752" Cc: linux-spi To: Christophe Leroy Return-path: Content-Disposition: inline In-Reply-To: <9e854e9d-146c-61ea-da6e-a46b316b56c5-GgN8y9CXRhA@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: --kUmo4NyTJbuJZ752 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Aug 24, 2016 at 01:19:50PM +0200, Christophe Leroy wrote: > No I can't see any special reason for this. But I can confirm that without > the two additional clock cycles with CS\ high, the commands are not taken > into account. Right, I just looked at the datasheet and it says in the serial control interface section that it needs a three clock cycle idle state. Clearly the designers weren't having a very good day when they did the digital here but based on that you probably only need to send an extra byte with chip select deasserted at the end of the transfer to satisfy it rather than padding at both start and end. Like I say it'll need a new core feature though. --kUmo4NyTJbuJZ752 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJXvYSEAAoJECTWi3JdVIfQq1oH+wWjrLPyOoIX+6dPHcMtV9zT p50kPHxBIR9XS6c5KVFZ/F/AZV4FVdjqLaSGAxLrAIwTO363DARpAwXW9XWlYGZB Ne/Be6kMsoki4nR6S1ea8wVYb994/ZeVg8V+l5pgZVVMjOX7KbbadbHUoivzKouo Wkfln9rDsai5xOvwP286w+ZzFFhqBRry7T30lGQoKq/MfarAKXtT5qXrJ8yYBZN0 esy7wcWi9EnAy5P+XS3hwwCdXYQ006TV9DzYjFdWkXZLavbqx/lwZbDtDOl7lguQ TQLDmOCCkGBxp3g+UGBALwXfjXOdO6mhMP3FhkwYgVJt7LY85/BpmynjYeyfSCY= =jIRs -----END PGP SIGNATURE----- --kUmo4NyTJbuJZ752-- -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html