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.
Signed-off-by: Sowjanya Komatineni <[email protected]>
---
drivers/cpufreq/tegra124-cpufreq.c | 60 ++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
index 4f0c637b3b49..e979a3370988 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 +129,67 @@ 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;
+ }
+
+ /* disable DFLL clock */
+ 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
On 31-07-19, 14:10, Sowjanya Komatineni wrote:
> 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.
>
> Signed-off-by: Sowjanya Komatineni <[email protected]>
> ---
> drivers/cpufreq/tegra124-cpufreq.c | 60 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 60 insertions(+)
Is there any hard dependency of this patch on the rest of the patches?
Can I apply it alone to cpufreq tree ?
--
viresh
On 7/31/19 10:40 PM, Viresh Kumar wrote:
> On 31-07-19, 14:10, Sowjanya Komatineni wrote:
>> 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.
>>
>> Signed-off-by: Sowjanya Komatineni <[email protected]>
>> ---
>> drivers/cpufreq/tegra124-cpufreq.c | 60 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 60 insertions(+)
> Is there any hard dependency of this patch on the rest of the patches?
> Can I apply it alone to cpufreq tree ?
>
This patch cannot be applied alone as it has dependency on dfll clock
suspend and resume sequence.
On 31-07-19, 14:10, Sowjanya Komatineni wrote:
> 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.
>
> Signed-off-by: Sowjanya Komatineni <[email protected]>
> ---
> drivers/cpufreq/tegra124-cpufreq.c | 60 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 60 insertions(+)
Acked-by: Viresh Kumar <[email protected]>
--
viresh