Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755875Ab3IYNz5 (ORCPT ); Wed, 25 Sep 2013 09:55:57 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:33346 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755690Ab3IYNz4 (ORCPT ); Wed, 25 Sep 2013 09:55:56 -0400 MIME-Version: 1.0 In-Reply-To: <1380108138-30402-2-git-send-email-l.majewski@samsung.com> References: <1380108138-30402-1-git-send-email-l.majewski@samsung.com> <1380108138-30402-2-git-send-email-l.majewski@samsung.com> Date: Wed, 25 Sep 2013 19:25:54 +0530 Message-ID: Subject: Re: [PATCH 1/2] cpufreq: exynos4x12: Use the common clock framework to set APLL clock rate From: Yadwinder Singh Brar To: Lukasz Majewski Cc: "Rafael J. Wysocki" , Viresh Kumar , Linux PM list , Lukasz Majewski , linux-kernel , Bartlomiej Zolnierkiewicz , Tomasz Figa , Myungjoo Ham , Kukjin Kim , Kukjin Kim , linux-samsung-soc Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3339 Lines: 89 Hi Lukasz, On Wed, Sep 25, 2013 at 4:52 PM, Lukasz Majewski wrote: > In the exynos4x12_set_apll() function, the APLL frequency is set with > direct register manipulation. > > Such approach is not allowed in the common clock framework. The frequency > is changed, but the corresponding clock value is not updated. This causes > wrong frequency read from cpufreq's cpuinfo_cur_freq sysfs attribute. > This patch looks incomplete, leaving the driver in untidy state, perhaps its doesn't fix the above stated problem completely. what about if (!exynos4x12_pms_change(old_index, new_index)) becomes true? IMHO, this driver needs lot more work in addition to this patch to cleanly and completely move the cpufreq driver to common clock framework. For fixing this issue urgently, setting CLK_GET_RATE_NOCACHE for apll in clk driver can also be quicker fix. Regards, Yadwinder > Tested at: > - Exynos4412 - Trats2 board (linux 3.12-rc1) > > Signed-off-by: Lukasz Majewski > Reviewed-by: Bartlomiej Zolnierkiewicz > Reviewed-by: Tomasz Figa > --- > drivers/cpufreq/exynos4x12-cpufreq.c | 23 ++++------------------- > 1 file changed, 4 insertions(+), 19 deletions(-) > > diff --git a/drivers/cpufreq/exynos4x12-cpufreq.c b/drivers/cpufreq/exynos4x12-cpufreq.c > index 08b7477..b2f51c9 100644 > --- a/drivers/cpufreq/exynos4x12-cpufreq.c > +++ b/drivers/cpufreq/exynos4x12-cpufreq.c > @@ -128,9 +128,9 @@ static void exynos4x12_set_clkdiv(unsigned int div_index) > > static void exynos4x12_set_apll(unsigned int index) > { > - unsigned int tmp, pdiv; > + unsigned int tmp, freq = apll_freq_4x12[index].freq; > > - /* 1. MUX_CORE_SEL = MPLL, ARMCLK uses MPLL for lock time */ > + /* MUX_CORE_SEL = MPLL, ARMCLK uses MPLL for lock time */ > clk_set_parent(moutcore, mout_mpll); > > do { > @@ -140,24 +140,9 @@ static void exynos4x12_set_apll(unsigned int index) > tmp &= 0x7; > } while (tmp != 0x2); > > - /* 2. Set APLL Lock time */ > - pdiv = ((apll_freq_4x12[index].mps >> 8) & 0x3f); > + clk_set_rate(mout_apll, freq * 1000); > > - __raw_writel((pdiv * 250), EXYNOS4_APLL_LOCK); > - > - /* 3. Change PLL PMS values */ > - tmp = __raw_readl(EXYNOS4_APLL_CON0); > - tmp &= ~((0x3ff << 16) | (0x3f << 8) | (0x7 << 0)); > - tmp |= apll_freq_4x12[index].mps; > - __raw_writel(tmp, EXYNOS4_APLL_CON0); > - > - /* 4. wait_lock_time */ > - do { > - cpu_relax(); > - tmp = __raw_readl(EXYNOS4_APLL_CON0); > - } while (!(tmp & (0x1 << EXYNOS4_APLLCON0_LOCKED_SHIFT))); > - > - /* 5. MUX_CORE_SEL = APLL */ > + /* MUX_CORE_SEL = APLL */ > clk_set_parent(moutcore, mout_apll); > > do { > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/