From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x233.google.com (mail-pf0-x233.google.com [IPv6:2607:f8b0:400e:c00::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3qtwGS3lK5zDq62 for ; Tue, 26 Apr 2016 04:48:16 +1000 (AEST) Received: by mail-pf0-x233.google.com with SMTP id n1so72029489pfn.2 for ; Mon, 25 Apr 2016 11:48:16 -0700 (PDT) From: Caleb Crome To: Timur Tabi , Nicolin Chen , Xiubo Li , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Cc: Caleb Crome Subject: [PATCH v2 1/1] ASoC: fsl_ssi: add CCSR_SSI_SOR to volatile register list Date: Mon, 25 Apr 2016 11:36:18 -0700 Message-Id: <1461609378-467-1-git-send-email-caleb@crome.org> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The CCSR_SSI_SOR is a register that clears the TX and/or the RX fifo on the i.MX SSI port. The fsl_ssi_trigger writes this register in order to clear the fifo at trigger time. However, since the CCSR_SSI_SOR register is not in the volatile list, the caching mechanism prevented the register write in the trigger function. This caused the fifo to not be cleared (because the value was unchanged from the last time the register was written), and thus causes the channels in both TDM or simple I2S mode to slip and be in the wrong time slots on SSI restart. This has gone unnoticed for so long because with simple stereo mode, the consequence is that left and right are swapped, which isn't that noticeable. However, it's catestrophic in some systems that require the channels to be in the right slots. Signed-off-by: Caleb Crome Suggested-by: Arnaud Mouiche --- sound/soc/fsl/fsl_ssi.c | 1 + 1 file changed, 1 insertion(+) diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c index 216e3cb..2f3bf9c 100644 --- a/sound/soc/fsl/fsl_ssi.c +++ b/sound/soc/fsl/fsl_ssi.c @@ -151,6 +151,7 @@ static bool fsl_ssi_volatile_reg(struct device *dev, unsigned int reg) case CCSR_SSI_SACDAT: case CCSR_SSI_SATAG: case CCSR_SSI_SACCST: + case CCSR_SSI_SOR: return true; default: return false; -- 1.9.1