From patchwork Mon Dec 16 10:41:38 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Hogan X-Patchwork-Id: 3353171 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 14BB4C0D4A for ; Mon, 16 Dec 2013 10:42:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id F23842031C for ; Mon, 16 Dec 2013 10:42:24 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B9EBB20304 for ; Mon, 16 Dec 2013 10:42:23 +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 1VsVcx-0004vy-Qz; Mon, 16 Dec 2013 10:42:19 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VsVcv-0007EV-Fx; Mon, 16 Dec 2013 10:42:17 +0000 Received: from multi.imgtec.com ([194.200.65.239]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VsVcs-0007Cw-5A for linux-arm-kernel@lists.infradead.org; Mon, 16 Dec 2013 10:42:15 +0000 From: James Hogan To: Mike Turquette Subject: [PATCH] clk: clk-divider: fix divisor > 255 bug Date: Mon, 16 Dec 2013 10:41:38 +0000 Message-ID: <1387190498-15392-1-git-send-email-james.hogan@imgtec.com> X-Mailer: git-send-email 1.8.1.2 MIME-Version: 1.0 X-Originating-IP: [192.168.154.65] X-SEF-Processed: 7_3_0_01192__2013_12_16_10_41_48 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20131216_054214_274694_135D7CFC X-CRM114-Status: GOOD ( 11.11 ) X-Spam-Score: -2.4 (--) Cc: linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org, James Hogan , linux-kernel@vger.kernel.org, Rajendra Nayak 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 Commit 6d9252bd9a4bb (clk: Add support for power of two type dividers) merged in v3.6 added the _get_val function to convert a divisor value to a register field value depending on the flags. However it used the type u8 for the div field, causing divisors larger than 255 to be masked and the resultant clock rate to be too high. E.g. in my case an 11bit divider was supposed to divide 24.576 MHz down to 32.768KHz. The divisor was correctly calculated as 750 (0x2ee). This was masked to 238 (0xee) resulting in a frequency of 103.26KHz. Signed-off-by: James Hogan Cc: Rajendra Nayak Cc: Mike Turquette Cc: linux-arm-kernel@lists.infradead.org Cc: stable@vger.kernel.org --- Since this bug was introduced in 3.6, it probably should by applied to stable 3.10 and 3.12. --- drivers/clk/clk-divider.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c index 8d3009e44fba..5543b7df8e16 100644 --- a/drivers/clk/clk-divider.c +++ b/drivers/clk/clk-divider.c @@ -87,7 +87,7 @@ static unsigned int _get_table_val(const struct clk_div_table *table, return 0; } -static unsigned int _get_val(struct clk_divider *divider, u8 div) +static unsigned int _get_val(struct clk_divider *divider, unsigned int div) { if (divider->flags & CLK_DIVIDER_ONE_BASED) return div;