Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751968AbdHCCEa (ORCPT ); Wed, 2 Aug 2017 22:04:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:34690 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751188AbdHCCE2 (ORCPT ); Wed, 2 Aug 2017 22:04:28 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0ACA22BE3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=shawnguo@kernel.org Date: Thu, 3 Aug 2017 10:03:22 +0800 From: Shawn Guo To: =?iso-8859-1?Q?S=E9bastien?= Szymanski , Anson Huang , Leonard Crestez Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Viresh Kumar , "Rafael J. Wysocki" , Julien Boibessot , Fabio Estevam , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/1] cpufreq: imx6q: imx6ull: use PLL1 for frequency higher than 528MHz Message-ID: <20170803020320.GG31819@dragon> References: <1501230993-15812-1-git-send-email-sebastien.szymanski@armadeus.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1501230993-15812-1-git-send-email-sebastien.szymanski@armadeus.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3118 Lines: 88 On Fri, Jul 28, 2017 at 10:36:33AM +0200, S?bastien Szymanski wrote: > Setting the frequency higher than 528Mhz actually sets the ARM > clock to 528MHz. That's because PLL2 is used as the root clock when the > frequency is higher than 396MHz. > > cpupower frequency-set -f 792000 > > arm_clk_root on the CCM_CLKO2 signal is 528MHz instead of 792MHz. > > [ 61.606383] cpu cpu0: 396 MHz, 1025 mV --> 792 MHz, 1225 mV > > pll2 1 1 528000000 0 0 > pll2_bypass 1 1 528000000 0 0 > pll2_bus 3 3 528000000 0 0 > ca7_secondary_sel 1 1 528000000 0 0 > step 1 1 528000000 0 0 > pll1_sw 1 1 528000000 0 0 > arm 1 1 528000000 0 0 > > Fixes this by using the PLL1 as the root clock when the frequency is > higher than 528MHz. > > cpupower frequency-set -f 792000 > > arm_clk_root on the CCM_CLKO2 signal is now 792MHz as expected. > > [ 69.717987] cpu cpu0: 198 MHz, 950 mV --> 792 MHz, 1225 mV > > pll1 1 1 792000000 0 0 > pll1_bypass 1 1 792000000 0 0 > pll1_sys 1 1 792000000 0 0 > pll1_sw 1 1 792000000 0 0 > arm 1 1 792000000 0 0 > > Signed-off-by: S?bastien Szymanski Can you please specify on which SoCs you are seeing this problem? And I would like invite Anson and Leonard to review it. Shawn > --- > drivers/cpufreq/imx6q-cpufreq.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c > index b6edd3c..e5fba50 100644 > --- a/drivers/cpufreq/imx6q-cpufreq.c > +++ b/drivers/cpufreq/imx6q-cpufreq.c > @@ -18,6 +18,7 @@ > > #define PU_SOC_VOLTAGE_NORMAL 1250000 > #define PU_SOC_VOLTAGE_HIGH 1275000 > +#define FREQ_528_MHZ 528000000 > #define FREQ_1P2_GHZ 1200000000 > > static struct regulator *arm_reg; > @@ -110,14 +111,20 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index) > * voltage of 528MHz, so lower the CPU frequency to one > * half before changing CPU frequency. > */ > - clk_set_rate(arm_clk, (old_freq >> 1) * 1000); > - clk_set_parent(pll1_sw_clk, pll1_sys_clk); > + if ((old_freq * 1000) <= FREQ_528_MHZ) { > + clk_set_rate(arm_clk, (old_freq >> 1) * 1000); > + clk_set_parent(pll1_sw_clk, pll1_sys_clk); > + } > if (freq_hz > clk_get_rate(pll2_pfd2_396m_clk)) > clk_set_parent(secondary_sel_clk, pll2_bus_clk); > else > clk_set_parent(secondary_sel_clk, pll2_pfd2_396m_clk); > clk_set_parent(step_clk, secondary_sel_clk); > clk_set_parent(pll1_sw_clk, step_clk); > + if (freq_hz > FREQ_528_MHZ) { > + clk_set_rate(pll1_sys_clk, freq_hz); > + clk_set_parent(pll1_sw_clk, pll1_sys_clk); > + } > } else { > clk_set_parent(step_clk, pll2_pfd2_396m_clk); > clk_set_parent(pll1_sw_clk, step_clk); > -- > 2.7.3 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel