From patchwork Fri Nov 22 16:08:43 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ludovic Desroches X-Patchwork-Id: 3223071 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id A855CC045B for ; Fri, 22 Nov 2013 16:09:35 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7AF2B207A1 for ; Fri, 22 Nov 2013 16:09:31 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DAA3E20502 for ; Fri, 22 Nov 2013 16:09:26 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VjtIC-0003SU-By; Fri, 22 Nov 2013 16:09:16 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VjtIA-0002Ur-0Q; Fri, 22 Nov 2013 16:09:14 +0000 Received: from eusmtp01.atmel.com ([212.144.249.242]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VjtI7-0002TQ-Fl for linux-arm-kernel@lists.infradead.org; Fri, 22 Nov 2013 16:09:11 +0000 Received: from ibiza.corp.atmel.com (10.161.101.13) by eusmtp01.atmel.com (10.161.101.30) with Microsoft SMTP Server id 14.2.347.0; Fri, 22 Nov 2013 17:08:42 +0100 From: To: Subject: [PATCH v2] ARM: at91: sama5d3: reduce TWI internal clock frequency Date: Fri, 22 Nov 2013 17:08:43 +0100 Message-ID: <1385136523-11962-1-git-send-email-ludovic.desroches@atmel.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20131122_110911_624568_312C2C0D X-CRM114-Status: UNSURE ( 9.25 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.4 (--) Cc: plagnioj@jcrosoft.com, Ludovic Desroches , nicolas.ferre@atmel.com, linux-i2c@vger.kernel.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.7 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Ludovic Desroches With some devices, transfer hangs during I2C frame transmission. This issue disappears when reducing the internal frequency of the TWI IP. Even if it is indicated that internal clock max frequency is 66MHz, it seems we have oversampling on I2C signals making TWI believe that a transfer in progress is done. This fix has no impact on the I2C bus frequency. Cc: #3.10+ Acked-by: Nicolas Ferre Signed-off-by: Ludovic Desroches Acked-by: Wolfram Sang Acked-by: Jean-Christophe PLAGNIOL-VILLARD --- v2: update commit message arch/arm/mach-at91/sama5d3.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm/mach-at91/sama5d3.c b/arch/arm/mach-at91/sama5d3.c index 4012797..4ee0de5 100644 --- a/arch/arm/mach-at91/sama5d3.c +++ b/arch/arm/mach-at91/sama5d3.c @@ -95,19 +95,19 @@ static struct clk twi0_clk = { .name = "twi0_clk", .pid = SAMA5D3_ID_TWI0, .type = CLK_TYPE_PERIPHERAL, - .div = AT91_PMC_PCR_DIV2, + .div = AT91_PMC_PCR_DIV8, }; static struct clk twi1_clk = { .name = "twi1_clk", .pid = SAMA5D3_ID_TWI1, .type = CLK_TYPE_PERIPHERAL, - .div = AT91_PMC_PCR_DIV2, + .div = AT91_PMC_PCR_DIV8, }; static struct clk twi2_clk = { .name = "twi2_clk", .pid = SAMA5D3_ID_TWI2, .type = CLK_TYPE_PERIPHERAL, - .div = AT91_PMC_PCR_DIV2, + .div = AT91_PMC_PCR_DIV8, }; static struct clk mmc0_clk = { .name = "mci0_clk",