From patchwork Fri Nov 14 15:32:09 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Hogan X-Patchwork-Id: 5307711 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 4318CC11AC for ; Fri, 14 Nov 2014 15:41:13 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 23AEA20136 for ; Fri, 14 Nov 2014 15:41:11 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (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 096C520123 for ; Fri, 14 Nov 2014 15:41:10 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XpIws-0007uE-AL; Fri, 14 Nov 2014 15:38:10 +0000 Received: from mailapp01.imgtec.com ([195.59.15.196]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XpIre-0001CJ-Tl; Fri, 14 Nov 2014 15:32:48 +0000 Received: from KLMAIL01.kl.imgtec.org (unknown [192.168.5.35]) by Websense Email Security Gateway with ESMTPS id C5CB2B8449FBE; Fri, 14 Nov 2014 15:32:20 +0000 (GMT) Received: from KLMAIL02.kl.imgtec.org (10.40.60.222) by KLMAIL01.kl.imgtec.org (192.168.5.35) with Microsoft SMTP Server (TLS) id 14.3.195.1; Fri, 14 Nov 2014 15:32:23 +0000 Received: from LEMAIL01.le.imgtec.org (192.168.152.62) by klmail02.kl.imgtec.org (10.40.60.222) with Microsoft SMTP Server (TLS) id 14.3.195.1; Fri, 14 Nov 2014 15:32:23 +0000 Received: from jhogan-linux.le.imgtec.org (192.168.154.101) by LEMAIL01.le.imgtec.org (192.168.152.62) with Microsoft SMTP Server (TLS) id 14.3.210.2; Fri, 14 Nov 2014 15:32:22 +0000 From: James Hogan To: , Mike Turquette Subject: [PATCH] clk-divider: Fix READ_ONLY when divider > 1 Date: Fri, 14 Nov 2014 15:32:09 +0000 Message-ID: <1415979129-21325-1-git-send-email-james.hogan@imgtec.com> X-Mailer: git-send-email 2.0.4 MIME-Version: 1.0 X-Originating-IP: [192.168.154.101] X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141114_073247_256383_344D4B04 X-CRM114-Status: GOOD ( 12.71 ) X-Spam-Score: -0.0 (/) Cc: James Hogan , Heiko Stuebner , Tomasz Figa , Max Schwarz , stable@vger.kernel.org, linux-rockchip@lists.infradead.org, Thomas Abraham , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 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=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_LOW, T_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 79c6ab509558 (clk: divider: add CLK_DIVIDER_READ_ONLY flag) in v3.16 introduced the CLK_DIVIDER_READ_ONLY flag which caused the recalc_rate() and round_rate() clock callbacks to be omitted. However using this flag has the unfortunate side effect of causing the clock recalculation code when a clock rate change is attempted to always treat it as a pass-through clock, i.e. with a fixed divide of 1, which may not be the case. Child clock rates are then recalculated using the wrong parent rate. Therefore instead of dropping the recalc_rate() and round_rate() callbacks, alter clk_divider_bestdiv() to always report the current divider as the best divider so that it is never altered. For me the read only clock was the system clock, which divided the PLL rate by 2, from which both the UART and the SPI clocks were divided. Initial setting of the UART rate set it correctly, but when the SPI clock was set, the other child clocks were miscalculated. The UART clock was recalculated using the PLL rate as the parent rate, resulting in a UART new_rate of double what it should be, and a UART which spewed forth garbage when the rate changes were propagated. Signed-off-by: James Hogan Cc: Mike Turquette Cc: Heiko Stuebner Cc: Thomas Abraham Cc: Tomasz Figa Cc: Max Schwarz Cc: # v3.16+ Reviewed-by: Heiko Stuebner --- drivers/clk/clk-divider.c | 18 +++++++++--------- drivers/clk/rockchip/clk.c | 4 +--- include/linux/clk-provider.h | 1 - 3 files changed, 10 insertions(+), 13 deletions(-) diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c index 18a9de29df0e..c0a842b335c5 100644 --- a/drivers/clk/clk-divider.c +++ b/drivers/clk/clk-divider.c @@ -263,6 +263,14 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, if (!rate) rate = 1; + /* if read only, just return current value */ + if (divider->flags & CLK_DIVIDER_READ_ONLY) { + bestdiv = readl(divider->reg) >> divider->shift; + bestdiv &= div_mask(divider); + bestdiv = _get_div(divider, bestdiv); + return bestdiv; + } + maxdiv = _get_maxdiv(divider); if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) { @@ -361,11 +369,6 @@ const struct clk_ops clk_divider_ops = { }; EXPORT_SYMBOL_GPL(clk_divider_ops); -const struct clk_ops clk_divider_ro_ops = { - .recalc_rate = clk_divider_recalc_rate, -}; -EXPORT_SYMBOL_GPL(clk_divider_ro_ops); - static struct clk *_register_divider(struct device *dev, const char *name, const char *parent_name, unsigned long flags, void __iomem *reg, u8 shift, u8 width, @@ -391,10 +394,7 @@ static struct clk *_register_divider(struct device *dev, const char *name, } init.name = name; - if (clk_divider_flags & CLK_DIVIDER_READ_ONLY) - init.ops = &clk_divider_ro_ops; - else - init.ops = &clk_divider_ops; + init.ops = &clk_divider_ops; init.flags = flags | CLK_IS_BASIC; init.parent_names = (parent_name ? &parent_name: NULL); init.num_parents = (parent_name ? 1 : 0); diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c index 1e68bff481b8..880a266f0143 100644 --- a/drivers/clk/rockchip/clk.c +++ b/drivers/clk/rockchip/clk.c @@ -90,9 +90,7 @@ static struct clk *rockchip_clk_register_branch(const char *name, div->width = div_width; div->lock = lock; div->table = div_table; - div_ops = (div_flags & CLK_DIVIDER_READ_ONLY) - ? &clk_divider_ro_ops - : &clk_divider_ops; + div_ops = &clk_divider_ops; } clk = clk_register_composite(NULL, name, parent_names, num_parents, diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index be21af149f11..2839c639f092 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -352,7 +352,6 @@ struct clk_divider { #define CLK_DIVIDER_READ_ONLY BIT(5) extern const struct clk_ops clk_divider_ops; -extern const struct clk_ops clk_divider_ro_ops; struct clk *clk_register_divider(struct device *dev, const char *name, const char *parent_name, unsigned long flags, void __iomem *reg, u8 shift, u8 width,