From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: Re: [PATCH v2 5/5] clk: qcom: ipq4019: Added the cpu clock frequency change notifier Date: Mon, 15 Aug 2016 15:26:14 -0700 Message-ID: <20160815222614.GL361@codeaurora.org> References: <1466516962-18087-1-git-send-email-absahu@codeaurora.org> <1466516962-18087-6-git-send-email-absahu@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1466516962-18087-6-git-send-email-absahu-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Abhishek Sahu Cc: andy.gross-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, david.brown-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, pawel.moll-5wv7dgnIgG8@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org, mturquette-rdvid1DuHRBWk0Htik3J/w@public.gmane.org, galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, pradeepb-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, mmcclint-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, varada-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, architt-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, ntelkar-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-clk-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-arm-msm@vger.kernel.org On 06/21, Abhishek Sahu wrote: > The current driver code gives the crash or gets hang while switching > the CPU frequency some time. The APSS CPU Clock divider is not glitch > free so it the APPS clock need to be switched for stable clock during > the change. > > This patch adds the frequency change notifier for APSS CPU clock. It > changes the parent of this clock to stable PLL FEPLL500 when it gets > for PRE_RATE_CHANGE event. This event will be generated before actual > clock set operations. The clock set operation will again change its > corresponding parent by getting the same from frequency table. > > Signed-off-by: Abhishek Sahu > --- > drivers/clk/qcom/gcc-ipq4019.c | 27 ++++++++++++++++++++++++++- > 1 file changed, 26 insertions(+), 1 deletion(-) > > diff --git a/drivers/clk/qcom/gcc-ipq4019.c b/drivers/clk/qcom/gcc-ipq4019.c > index df159c2..3c014f7 100644 > --- a/drivers/clk/qcom/gcc-ipq4019.c > +++ b/drivers/clk/qcom/gcc-ipq4019.c > @@ -1740,9 +1740,34 @@ static const struct of_device_id gcc_ipq4019_match_table[] = { > }; > MODULE_DEVICE_TABLE(of, gcc_ipq4019_match_table); > > +int cpu_clk_notifier_fn(struct notifier_block *nb, static? Please come up with a better name that is not so generic. > + unsigned long action, void *data) > +{ > + int err = 0; > + > + if (action == PRE_RATE_CHANGE) { > + err = clk_rcg2_ops.set_parent(&apps_clk_src.clkr.hw, > + P_FEPLL500); > + } > + > + return notifier_from_errno(err); > +} > + > +struct notifier_block cpu_clk_notifier = { static? > + .notifier_call = cpu_clk_notifier_fn, > +}; > + > static int gcc_ipq4019_probe(struct platform_device *pdev) > { > - return qcom_cc_probe(pdev, &gcc_ipq4019_desc); > + int err; > + > + err = qcom_cc_probe(pdev, &gcc_ipq4019_desc); > + > + if (!err) > + clk_notifier_register(apps_clk_src.clkr.hw.clk, > + &cpu_clk_notifier); This has to be unregistered on driver remove. > + > + return err; > } -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 15 Aug 2016 15:26:14 -0700 From: Stephen Boyd To: Abhishek Sahu Cc: andy.gross@linaro.org, david.brown@linaro.org, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, mturquette@baylibre.com, galak@codeaurora.org, pradeepb@codeaurora.org, mmcclint@codeaurora.org, varada@codeaurora.org, sricharan@codeaurora.org, architt@codeaurora.org, ntelkar@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH v2 5/5] clk: qcom: ipq4019: Added the cpu clock frequency change notifier Message-ID: <20160815222614.GL361@codeaurora.org> References: <1466516962-18087-1-git-send-email-absahu@codeaurora.org> <1466516962-18087-6-git-send-email-absahu@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1466516962-18087-6-git-send-email-absahu@codeaurora.org> List-ID: On 06/21, Abhishek Sahu wrote: > The current driver code gives the crash or gets hang while switching > the CPU frequency some time. The APSS CPU Clock divider is not glitch > free so it the APPS clock need to be switched for stable clock during > the change. > > This patch adds the frequency change notifier for APSS CPU clock. It > changes the parent of this clock to stable PLL FEPLL500 when it gets > for PRE_RATE_CHANGE event. This event will be generated before actual > clock set operations. The clock set operation will again change its > corresponding parent by getting the same from frequency table. > > Signed-off-by: Abhishek Sahu > --- > drivers/clk/qcom/gcc-ipq4019.c | 27 ++++++++++++++++++++++++++- > 1 file changed, 26 insertions(+), 1 deletion(-) > > diff --git a/drivers/clk/qcom/gcc-ipq4019.c b/drivers/clk/qcom/gcc-ipq4019.c > index df159c2..3c014f7 100644 > --- a/drivers/clk/qcom/gcc-ipq4019.c > +++ b/drivers/clk/qcom/gcc-ipq4019.c > @@ -1740,9 +1740,34 @@ static const struct of_device_id gcc_ipq4019_match_table[] = { > }; > MODULE_DEVICE_TABLE(of, gcc_ipq4019_match_table); > > +int cpu_clk_notifier_fn(struct notifier_block *nb, static? Please come up with a better name that is not so generic. > + unsigned long action, void *data) > +{ > + int err = 0; > + > + if (action == PRE_RATE_CHANGE) { > + err = clk_rcg2_ops.set_parent(&apps_clk_src.clkr.hw, > + P_FEPLL500); > + } > + > + return notifier_from_errno(err); > +} > + > +struct notifier_block cpu_clk_notifier = { static? > + .notifier_call = cpu_clk_notifier_fn, > +}; > + > static int gcc_ipq4019_probe(struct platform_device *pdev) > { > - return qcom_cc_probe(pdev, &gcc_ipq4019_desc); > + int err; > + > + err = qcom_cc_probe(pdev, &gcc_ipq4019_desc); > + > + if (!err) > + clk_notifier_register(apps_clk_src.clkr.hw.clk, > + &cpu_clk_notifier); This has to be unregistered on driver remove. > + > + return err; > } -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project