From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [PATCH v8 11/21] clk: tegra: clk-dfll: Add suspend and resume support Date: Fri, 9 Aug 2019 15:23:50 +0300 Message-ID: References: <1565308020-31952-1-git-send-email-skomatineni@nvidia.com> <1565308020-31952-12-git-send-email-skomatineni@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <1565308020-31952-12-git-send-email-skomatineni@nvidia.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Sowjanya Komatineni , thierry.reding@gmail.com, jonathanh@nvidia.com, tglx@linutronix.de, jason@lakedaemon.net, marc.zyngier@arm.com, linus.walleij@linaro.org, stefan@agner.ch, mark.rutland@arm.com Cc: pdeschrijver@nvidia.com, pgaikwad@nvidia.com, sboyd@kernel.org, linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org, jckuo@nvidia.com, josephl@nvidia.com, talho@nvidia.com, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, mperttunen@nvidia.com, spatra@nvidia.com, robh+dt@kernel.org, devicetree@vger.kernel.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, linux-pm@vger.kernel.org List-Id: devicetree@vger.kernel.org 09.08.2019 2:46, Sowjanya Komatineni пишет: > This patch implements DFLL suspend and resume operation. > > During system suspend entry, CPU clock will switch CPU to safe > clock source of PLLP and disables DFLL clock output. > > DFLL driver suspend confirms DFLL disable state and errors out on > being active. > > DFLL is re-initialized during the DFLL driver resume as it goes > through complete reset during suspend entry. > > Signed-off-by: Sowjanya Komatineni > --- > drivers/clk/tegra/clk-dfll.c | 56 ++++++++++++++++++++++++++++++ > drivers/clk/tegra/clk-dfll.h | 2 ++ > drivers/clk/tegra/clk-tegra124-dfll-fcpu.c | 1 + > 3 files changed, 59 insertions(+) > > diff --git a/drivers/clk/tegra/clk-dfll.c b/drivers/clk/tegra/clk-dfll.c > index f8688c2ddf1a..eb298a5d7be9 100644 > --- a/drivers/clk/tegra/clk-dfll.c > +++ b/drivers/clk/tegra/clk-dfll.c > @@ -1487,6 +1487,7 @@ static int dfll_init(struct tegra_dfll *td) > td->last_unrounded_rate = 0; > > pm_runtime_enable(td->dev); > + pm_runtime_irq_safe(td->dev); > pm_runtime_get_sync(td->dev); > > dfll_set_mode(td, DFLL_DISABLED); > @@ -1513,6 +1514,61 @@ static int dfll_init(struct tegra_dfll *td) > return ret; > } > > +/** > + * tegra_dfll_suspend - check DFLL is disabled > + * @dev: DFLL device * > + * > + * DFLL clock should be disabled by the CPUFreq driver. So, make > + * sure it is disabled and disable all clocks needed by the DFLL. > + */ > +int tegra_dfll_suspend(struct device *dev) > +{ > + struct tegra_dfll *td = dev_get_drvdata(dev); > + > + if (dfll_is_running(td)) { > + dev_err(td->dev, "dfll is enabled while shouldn't be\n"); > + return -EBUSY; > + } > + > + reset_control_assert(td->dvco_rst); > + > + return 0; > +} > +EXPORT_SYMBOL(tegra_dfll_suspend); > + > +/** > + * tegra_dfll_resume - reinitialize DFLL on resume > + * @dev: DFLL instance > + * > + * DFLL is disabled and reset during suspend and resume. > + * So, reinitialize the DFLL IP block back for use. > + * DFLL clock is enabled later in closed loop mode by CPUFreq > + * driver before switching its clock source to DFLL output. > + */ > +int tegra_dfll_resume(struct device *dev) > +{ > + struct tegra_dfll *td = dev_get_drvdata(dev); > + > + reset_control_deassert(td->dvco_rst); This doesn't look right because I assume that DFLL resetting is synchronous and thus clk should be enabled in order for reset to propagate inside hardware. > + pm_runtime_get_sync(td->dev); Hence it will be better to remove the above reset_control_deassert() and add here: reset_control_reset(td->dvco_rst); > + dfll_set_mode(td, DFLL_DISABLED); > + dfll_set_default_params(td); > + > + if (td->soc->init_clock_trimmers) > + td->soc->init_clock_trimmers(); > + > + dfll_set_open_loop_config(td); > + > + dfll_init_out_if(td); > + > + pm_runtime_put_sync(td->dev); > + > + return 0; > +} > +EXPORT_SYMBOL(tegra_dfll_resume); > + > /* > * DT data fetch > */ > diff --git a/drivers/clk/tegra/clk-dfll.h b/drivers/clk/tegra/clk-dfll.h > index 1b14ebe7268b..fb209eb5f365 100644 > --- a/drivers/clk/tegra/clk-dfll.h > +++ b/drivers/clk/tegra/clk-dfll.h > @@ -42,5 +42,7 @@ int tegra_dfll_register(struct platform_device *pdev, > struct tegra_dfll_soc_data *tegra_dfll_unregister(struct platform_device *pdev); > int tegra_dfll_runtime_suspend(struct device *dev); > int tegra_dfll_runtime_resume(struct device *dev); > +int tegra_dfll_suspend(struct device *dev); > +int tegra_dfll_resume(struct device *dev); > > #endif /* __DRIVERS_CLK_TEGRA_CLK_DFLL_H */ > diff --git a/drivers/clk/tegra/clk-tegra124-dfll-fcpu.c b/drivers/clk/tegra/clk-tegra124-dfll-fcpu.c > index e84b6d52cbbd..2ac2679d696d 100644 > --- a/drivers/clk/tegra/clk-tegra124-dfll-fcpu.c > +++ b/drivers/clk/tegra/clk-tegra124-dfll-fcpu.c > @@ -631,6 +631,7 @@ static int tegra124_dfll_fcpu_remove(struct platform_device *pdev) > static const struct dev_pm_ops tegra124_dfll_pm_ops = { > SET_RUNTIME_PM_OPS(tegra_dfll_runtime_suspend, > tegra_dfll_runtime_resume, NULL) > + SET_SYSTEM_SLEEP_PM_OPS(tegra_dfll_suspend, tegra_dfll_resume) > }; > > static struct platform_driver tegra124_dfll_fcpu_driver = { >