From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752620AbcGAJA5 (ORCPT ); Fri, 1 Jul 2016 05:00:57 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:33042 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752179AbcGAJAx (ORCPT ); Fri, 1 Jul 2016 05:00:53 -0400 Date: Fri, 1 Jul 2016 09:16:36 +0100 From: Mark Brown To: apronin@chromium.org Cc: linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org Message-ID: <20160701081636.GC6247@sirena.org.uk> References: <1467258867-117727-1-git-send-email-apronin@chromium.org> <1467258867-117727-3-git-send-email-apronin@chromium.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="G5yIW5EaChZ5gJdA" Content-Disposition: inline In-Reply-To: <1467258867-117727-3-git-send-email-apronin@chromium.org> X-Cookie: You are always busy. User-Agent: Mutt/1.6.0 (2016-04-01) X-SA-Exim-Connect-IP: 137.158.23.187 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH 3/4] spi: Add option to insert delay between transactions X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --G5yIW5EaChZ5gJdA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jun 29, 2016 at 08:54:26PM -0700, apronin@chromium.org wrote: > Some devices may need CS to be deasserted for some time > between transactions. Added a new capability to guarantee > a delay between SPI transactions for the device. This seems like even more of a per device thing - it's a very rare requirement (I'm guessing for some SPI controller coprocessor) and there's such a wide range of potential patterns that might be needed by different devices. =20 > + if (msg->spi->xfer_delay) > + mdelay(msg->spi->xfer_delay); > + > spi_set_cs(msg->spi, true); This isn't a delay between messages, it's a delay before asserting chip select which will happen every single time we do anything regardless of if there was any activity immediately before or not. --G5yIW5EaChZ5gJdA Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJXdibjAAoJECTWi3JdVIfQZoMH/3DSY6u5/SgZ4LQlWAM86hlf D17E78t1j/bhpUZka7+FOhgly7Ly5HqJ57Gh4R0049KzvUr6pe0+LN6U5bO/OHyW 5JXmodaOA6oSS9Wy9DAKrGP2V+cKC2fP+wl8J4BSGoFKpZ7r+cGtrdx+tBHrFOwz gmTjB1G7QRK6gAg/gco3Nyfv8yW0Ur6Ay8uyTv9hz7T6b8PAGUcBBscQjcZqLtov C7Ise+vXz+ZyQC2UezpCsrYX79p17GDXF6BgntbsH7eP9nUwtfHEcflpbc/G16jI o9ufP81N9qkqW699kvUyb1A2KzS5z9CecY7AGymWU3I/yfRrBi9mvMoveKxDsKA= =r6ig -----END PGP SIGNATURE----- --G5yIW5EaChZ5gJdA--