From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754908AbaFKXnJ (ORCPT ); Wed, 11 Jun 2014 19:43:09 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:37671 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753694AbaFKXnG (ORCPT ); Wed, 11 Jun 2014 19:43:06 -0400 Date: Thu, 12 Jun 2014 00:42:12 +0100 From: Mark Brown To: Chew Chiau Ee Cc: Eric Miao , Russell King , Haojian Zhuang , Mika Westerberg , LKML , linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org Message-ID: <20140611234212.GR5099@sirena.org.uk> References: <1402502222-19520-1-git-send-email-chiau.ee.chew@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="kwyOAufsvjrbDa1R" Content-Disposition: inline In-Reply-To: <1402502222-19520-1-git-send-email-chiau.ee.chew@intel.com> X-Cookie: Ditat Deus. User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: 94.175.94.161 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH] spi/pxa2xx: fix incorrect SW mode chipselect setting for BayTrail LPSS SPI 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 --kwyOAufsvjrbDa1R Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Jun 11, 2014 at 11:57:02PM +0800, Chew Chiau Ee wrote: > It was observed that after module removal followed by insertion, > the SW mode chipselect is not properly set. Thus causing transfer > failure due to incorrect CS toggling. > - value &= ~SPI_CS_CONTROL_SW_MODE; > + orig = value &= ~SPI_CS_CONTROL_SW_MODE; > writel(value, drv_data->ioaddr + offset + SPI_CS_CONTROL); > value = readl(drv_data->ioaddr + offset + SPI_CS_CONTROL); > if (value != orig) { This is a *really* non-obvious fix, I'd have expected the original value to be re-read from the hardware here rather than just tweaked, or at least some comment explaining what's going on. Possibly also saving to a differently named temporary variable would do it but whatever I had to go look at the context to figure out what was happening and even there I was unclear. --kwyOAufsvjrbDa1R Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJTmOlQAAoJELSic+t+oim9Wv8P/1Gz0KrR669OKT2VF81LbZY9 E4bFy442ARqHkro+hmUCOb+M2W5rah01S6e7GAzWlbWTnDoOQthFe3ei7t/yrhO3 hGTqvyx6Sca5vreAy7hAQ6YUFJAhI1XxydsrlzdjMXHnwGwvp36D/uRMrG0JUQ+e TXiRfFZgRe2ezIsUa/R7rjaFGlCm0UBv3N5izVr2aifz5kvC1bqusx+XcmZDBuYu ODpSKNvxerzcqVio+vtMgPoQlszmRbh5f2pupqlgcYTsU66zWRfz9SIrgJGEzUcN Z1SKJAfQDb3LZUxO9YGlWYC0v6782Ol/FAnh2V3/9N0DxM0pgKb+ZhdTyCvF2/Fe 1KLyLLtk063149XJqATk5lt2Vbi2gvrPxDBq/gHZGdOcFqfL0zYbIyPZRzFmLLwc Lnc0RR6hwzUZNdgXLkAQdcz6bY8zGOkVOgCJ436QSG14lJhtV4YZ/XkCogBBB9k6 XZjYp0WQKyCBGDe3NISSgbudvGrjfTg+bF4Bohx/69nWfFtU0v/dXLy/iSiESCdO k4wUCKCJV1wqxoF6SXhzWdL8IYWcidArS9xKEYUh8ZbHqFCqzt09piNkccYaaKSy a+OQJEl4hm7AgBGf1vcT9GCiDZzfOujAm3jamRqHUuEVYEpmTp8m7jBRS/1DrSAD g4AoojhZtsg5mf0uaEuQ =tqR6 -----END PGP SIGNATURE----- --kwyOAufsvjrbDa1R--