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From: Sowjanya Komatineni <skomatineni@nvidia.com>
To: <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>,
	<skomatineni@nvidia.com>, <linux-tegra@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <mperttunen@nvidia.com>,
	<spatra@nvidia.com>, <robh+dt@kernel.org>, <digetx@gmail.com>,
	<devicetree@vger.kernel.org>, <rjw@rjwysocki.net>,
	<viresh.kumar@linaro.org>, <linux-pm@vger.kernel.org>
Subject: [PATCH v9 12/22] cpufreq: tegra124: Add suspend and resume support
Date: Fri, 16 Aug 2019 12:41:57 -0700
Message-ID: <1565984527-5272-13-git-send-email-skomatineni@nvidia.com> (raw)
In-Reply-To: <1565984527-5272-1-git-send-email-skomatineni@nvidia.com>

This patch adds suspend and resume pm ops for cpufreq driver.

PLLP is the safe clock source for CPU during system suspend and
resume as PLLP rate is below the CPU Fmax at Vmin.

CPUFreq driver suspend switches the CPU clock source to PLLP and
disables the DFLL clock.

During system resume, warmboot code powers up the CPU with PLLP
clock source. So CPUFreq driver resume enabled DFLL clock and
switches CPU back to DFLL clock source.

Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
---
 drivers/cpufreq/tegra124-cpufreq.c | 59 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
index 4f0c637b3b49..7a1ea6fdcab6 100644
--- a/drivers/cpufreq/tegra124-cpufreq.c
+++ b/drivers/cpufreq/tegra124-cpufreq.c
@@ -6,6 +6,7 @@
 #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
 
 #include <linux/clk.h>
+#include <linux/cpufreq.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -128,8 +129,66 @@ static int tegra124_cpufreq_probe(struct platform_device *pdev)
 	return ret;
 }
 
+static int __maybe_unused tegra124_cpufreq_suspend(struct device *dev)
+{
+	struct tegra124_cpufreq_priv *priv = dev_get_drvdata(dev);
+	int err;
+
+	/*
+	 * PLLP rate 408Mhz is below the CPU Fmax at Vmin and is safe to
+	 * use during suspend and resume. So, switch the CPU clock source
+	 * to PLLP and disable DFLL.
+	 */
+	err = clk_set_parent(priv->cpu_clk, priv->pllp_clk);
+	if (err < 0) {
+		dev_err(dev, "failed to reparent to PLLP: %d\n", err);
+		return err;
+	}
+
+	clk_disable_unprepare(priv->dfll_clk);
+
+	return 0;
+}
+
+static int __maybe_unused tegra124_cpufreq_resume(struct device *dev)
+{
+	struct tegra124_cpufreq_priv *priv = dev_get_drvdata(dev);
+	int err;
+
+	/*
+	 * Warmboot code powers up the CPU with PLLP clock source.
+	 * Enable DFLL clock and switch CPU clock source back to DFLL.
+	 */
+	err = clk_prepare_enable(priv->dfll_clk);
+	if (err < 0) {
+		dev_err(dev, "failed to enable DFLL clock for CPU: %d\n", err);
+		goto disable_cpufreq;
+	}
+
+	err = clk_set_parent(priv->cpu_clk, priv->dfll_clk);
+	if (err < 0) {
+		dev_err(dev, "failed to reparent to DFLL clock: %d\n", err);
+		goto disable_dfll;
+	}
+
+	return 0;
+
+disable_dfll:
+	clk_disable_unprepare(priv->dfll_clk);
+disable_cpufreq:
+	disable_cpufreq();
+
+	return err;
+}
+
+static const struct dev_pm_ops tegra124_cpufreq_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(tegra124_cpufreq_suspend,
+				tegra124_cpufreq_resume)
+};
+
 static struct platform_driver tegra124_cpufreq_platdrv = {
 	.driver.name	= "cpufreq-tegra124",
+	.driver.pm	= &tegra124_cpufreq_pm_ops,
 	.probe		= tegra124_cpufreq_probe,
 };
 
-- 
2.7.4


  parent reply index

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16 19:41 [PATCH v9 00/22] SC7 entry and exit support for Tegra210 Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 01/22] pinctrl: tegra: Fix write barrier placement in pmx_writel Sowjanya Komatineni
2019-08-18 22:20   ` Linus Walleij
2019-08-16 19:41 ` [PATCH v9 02/22] pinctrl: tegra: Flush pinctrl writes during resume Sowjanya Komatineni
2019-08-18 22:20   ` Linus Walleij
2019-08-16 19:41 ` [PATCH v9 03/22] clk: tegra: divider: Save and restore divider rate Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 04/22] clk: tegra: pllout: Save and restore pllout context Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 05/22] clk: tegra: pll: Save and restore pll context Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 06/22] clk: tegra: Support for OSC context save and restore Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 07/22] clk: Add API to get index of the clock parent Sowjanya Komatineni
2019-11-06 23:10   ` Stephen Boyd
2019-11-07  0:54     ` Dmitry Osipenko
2019-11-07 15:21       ` Thierry Reding
2019-11-07 19:19         ` Stephen Boyd
2019-11-08 10:11           ` Thierry Reding
2019-11-08 18:12             ` Stephen Boyd
2019-11-08 18:55               ` Thierry Reding
2019-11-08 21:15                 ` Stephen Boyd
2019-08-16 19:41 ` [PATCH v9 08/22] clk: tegra: periph: Add restore_context support Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 09/22] clk: tegra: clk-super: Fix to enable PLLP branches to CPU Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 10/22] clk: tegra: clk-super: Add restore-context support Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 11/22] clk: tegra: clk-dfll: Add suspend and resume support Sowjanya Komatineni
2019-11-08 21:20   ` Stephen Boyd
2019-11-08 23:38     ` Dmitry Osipenko
2019-08-16 19:41 ` Sowjanya Komatineni [this message]
2019-11-02 14:42   ` [PATCH v9 12/22] cpufreq: tegra124: " Thierry Reding
2019-08-16 19:41 ` [PATCH v9 13/22] clk: tegra210: Use fence_udelay during PLLU init Sowjanya Komatineni
2019-08-16 19:41 ` [PATCH v9 14/22] clk: tegra: Share clk and rst register defines with Tegra clock driver Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 15/22] clk: tegra210: Add suspend and resume support Sowjanya Komatineni
2019-08-19 16:47   ` Dmitry Osipenko
2019-08-16 19:42 ` [PATCH v9 16/22] soc/tegra: pmc: Allow to support more tegras wake Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 17/22] soc/tegra: pmc: Add pmc wake support for tegra210 Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 18/22] arm64: tegra: Enable wake from deep sleep on RTC alarm Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 19/22] soc/tegra: pmc: Configure core power request polarity Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 20/22] soc/tegra: pmc: Configure deep sleep control settings Sowjanya Komatineni
2019-08-19 16:48   ` Dmitry Osipenko
2019-08-19 18:20     ` Sowjanya Komatineni
2019-08-19 19:07       ` Sowjanya Komatineni
2019-08-19 19:33         ` Dmitry Osipenko
2019-08-16 19:42 ` [PATCH v9 21/22] arm64: dts: tegra210-p2180: Jetson TX1 SC7 timings Sowjanya Komatineni
2019-08-16 19:42 ` [PATCH v9 22/22] arm64: dts: tegra210-p3450: Jetson Nano " Sowjanya Komatineni

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