From patchwork Thu Mar 28 10:59:41 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rajendra Nayak X-Patchwork-Id: 2356021 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id C83C6DF2A1 for ; Thu, 28 Mar 2013 11:00:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753572Ab3C1LAB (ORCPT ); Thu, 28 Mar 2013 07:00:01 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:50832 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753214Ab3C1LAA (ORCPT ); Thu, 28 Mar 2013 07:00:00 -0400 Received: from dbdp20.itg.ti.com ([172.24.170.38]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id r2SAxsBu023788; Thu, 28 Mar 2013 05:59:55 -0500 Received: from DBDE70.ent.ti.com (localhost [127.0.0.1]) by dbdp20.itg.ti.com (8.13.8/8.13.8) with ESMTP id r2SAxqhB001936; Thu, 28 Mar 2013 16:29:53 +0530 (IST) Received: from dbdp33.itg.ti.com (172.24.170.252) by dbde70.ent.ti.com (172.24.170.148) with Microsoft SMTP Server id 14.1.323.3; Thu, 28 Mar 2013 16:29:52 +0530 Received: from ula0131687.apr.dhcp.ti.com (smtpvbd.itg.ti.com [172.24.170.250]) by dbdp33.itg.ti.com (8.13.8/8.13.8) with ESMTP id r2SAxngs025346; Thu, 28 Mar 2013 16:29:50 +0530 From: Rajendra Nayak To: CC: , , , Rajendra Nayak Subject: [PATCH] ARM: OMAP: dpll: enable bypass clock only when attempting dpll bypass Date: Thu, 28 Mar 2013 16:29:41 +0530 Message-ID: <1364468381-10560-1-git-send-email-rnayak@ti.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org omap3_noncore_dpll_set_rate() attempts an enable of bypass clk as well as ref clk for every .set_rate attempt on a noncore DPLL, regardless of whether the .set_rate results in the DPLL being locked or put in bypass. Early at boot, while some of these DPLLs are programmed and locked (using .set_rate for the DPLL), this causes an ordering issue. For instance, on OMAP5, the USB DPLL derives its bypass clk from ABE DPLL. If a .set_rate of USB DPLL which programmes the M,N and locks it is called before the one for ABE, the enable of USB bypass clk (derived from ABE DPLL) then attempts to lock the ABE DPLL and fails as the M,N values for ABE are yet to be programmed. To get rid of this ordering needs, enable bypass clk for a DPLL as part of its .set_rate only when its being put in bypass, and only enable the ref clk when its locked. Reported-by: Roger Quadros Signed-off-by: Rajendra Nayak --- arch/arm/mach-omap2/dpll3xxx.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/arch/arm/mach-omap2/dpll3xxx.c b/arch/arm/mach-omap2/dpll3xxx.c index 3aed4b0..6e9873f 100644 --- a/arch/arm/mach-omap2/dpll3xxx.c +++ b/arch/arm/mach-omap2/dpll3xxx.c @@ -480,20 +480,22 @@ int omap3_noncore_dpll_set_rate(struct clk_hw *hw, unsigned long rate, if (!dd) return -EINVAL; - __clk_prepare(dd->clk_bypass); - clk_enable(dd->clk_bypass); - __clk_prepare(dd->clk_ref); - clk_enable(dd->clk_ref); - if (__clk_get_rate(dd->clk_bypass) == rate && (dd->modes & (1 << DPLL_LOW_POWER_BYPASS))) { pr_debug("%s: %s: set rate: entering bypass.\n", __func__, __clk_get_name(hw->clk)); + __clk_prepare(dd->clk_bypass); + clk_enable(dd->clk_bypass); ret = _omap3_noncore_dpll_bypass(clk); if (!ret) new_parent = dd->clk_bypass; + clk_disable(dd->clk_bypass); + __clk_unprepare(dd->clk_bypass); } else { + __clk_prepare(dd->clk_ref); + clk_enable(dd->clk_ref); + if (dd->last_rounded_rate != rate) rate = __clk_round_rate(hw->clk, rate); @@ -514,6 +516,8 @@ int omap3_noncore_dpll_set_rate(struct clk_hw *hw, unsigned long rate, ret = omap3_noncore_dpll_program(clk, freqsel); if (!ret) new_parent = dd->clk_ref; + clk_disable(dd->clk_ref); + __clk_unprepare(dd->clk_ref); } /* * FIXME - this is all wrong. common code handles reparenting and @@ -525,11 +529,6 @@ int omap3_noncore_dpll_set_rate(struct clk_hw *hw, unsigned long rate, if (!ret) __clk_reparent(hw->clk, new_parent); - clk_disable(dd->clk_ref); - __clk_unprepare(dd->clk_ref); - clk_disable(dd->clk_bypass); - __clk_unprepare(dd->clk_bypass); - return 0; }