Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933602AbbDII5e (ORCPT ); Thu, 9 Apr 2015 04:57:34 -0400 Received: from mail.kernel.org ([198.145.29.136]:43455 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932697AbbDII5Z (ORCPT ); Thu, 9 Apr 2015 04:57:25 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Eric Nelson , Mark Brown , Zefan Li Subject: [PATCH 3.4 148/176] ASoC: sgtl5000: add delay before first I2C access Date: Thu, 9 Apr 2015 16:46:36 +0800 Message-Id: <1428569224-23820-148-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1428569028-23762-1-git-send-email-lizf@kernel.org> References: <1428569028-23762-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1550 Lines: 47 From: Eric Nelson 3.4.107-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit 58cc9c9a175885bbf6bae3acf18233d0a8229a84 upstream. To quote from section 1.3.1 of the data sheet: The SGTL5000 has an internal reset that is deasserted 8 SYS_MCLK cycles after all power rails have been brought up. After this time, communication can start ... 1.0us represents 8 SYS_MCLK cycles at the minimum 8.0 MHz SYS_MCLK. Signed-off-by: Eric Nelson Reviewed-by: Fabio Estevam Signed-off-by: Mark Brown Signed-off-by: Zefan Li --- sound/soc/codecs/sgtl5000.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c index c40b7ca..87cbf14 100644 --- a/sound/soc/codecs/sgtl5000.c +++ b/sound/soc/codecs/sgtl5000.c @@ -1238,6 +1238,9 @@ static int sgtl5000_enable_regulators(struct snd_soc_codec *codec) /* wait for all power rails bring up */ udelay(10); + /* Need 8 clocks before I2C accesses */ + udelay(1); + /* read chip information */ reg = snd_soc_read(codec, SGTL5000_CHIP_ID); if (((reg & SGTL5000_PARTID_MASK) >> SGTL5000_PARTID_SHIFT) != -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/