[v5,1/4] PM / OPP: Support adjusting OPP voltages at runtime
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Message ID 20191016145756.16004-2-s.nawrocki@samsung.com
State New
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Series
  • [v5,1/4] PM / OPP: Support adjusting OPP voltages at runtime
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Commit Message

Sylwester Nawrocki Oct. 16, 2019, 2:57 p.m. UTC
From: Stephen Boyd <sboyd@codeaurora.org>

On some SoCs the Adaptive Voltage Scaling (AVS) technique is
employed to optimize the operating voltage of a device. At a
given frequency, the hardware monitors dynamic factors and either
makes a suggestion for how much to adjust a voltage for the
current frequency, or it automatically adjusts the voltage
without software intervention. Add an API to the OPP library for
the former case, so that AVS type devices can update the voltages
for an OPP when the hardware determines the voltage should
change. The assumption is that drivers like CPUfreq or devfreq
will register for the OPP notifiers and adjust the voltage
according to suggestions that AVS makes.

This patch is derived from [1] submitted by Stephen.
[1] https://lore.kernel.org/patchwork/patch/599279/

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Roger Lu <roger.lu@mediatek.com>
[s.nawrocki@samsung.com: added handling of OPP min/max voltage]
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
---
 drivers/opp/core.c     | 69 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/pm_opp.h | 13 ++++++++
 2 files changed, 82 insertions(+)

--
2.17.1

Comments

Viresh Kumar Oct. 17, 2019, 6:42 a.m. UTC | #1
On 16-10-19, 16:57, Sylwester Nawrocki wrote:
> From: Stephen Boyd <sboyd@codeaurora.org>
> 
> On some SoCs the Adaptive Voltage Scaling (AVS) technique is
> employed to optimize the operating voltage of a device. At a
> given frequency, the hardware monitors dynamic factors and either
> makes a suggestion for how much to adjust a voltage for the
> current frequency, or it automatically adjusts the voltage
> without software intervention. Add an API to the OPP library for
> the former case, so that AVS type devices can update the voltages
> for an OPP when the hardware determines the voltage should
> change. The assumption is that drivers like CPUfreq or devfreq
> will register for the OPP notifiers and adjust the voltage
> according to suggestions that AVS makes.
> 
> This patch is derived from [1] submitted by Stephen.
> [1] https://lore.kernel.org/patchwork/patch/599279/
> 
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> Signed-off-by: Roger Lu <roger.lu@mediatek.com>
> [s.nawrocki@samsung.com: added handling of OPP min/max voltage]
> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> ---
>  drivers/opp/core.c     | 69 ++++++++++++++++++++++++++++++++++++++++++
>  include/linux/pm_opp.h | 13 ++++++++
>  2 files changed, 82 insertions(+)

Applied. Thanks.
Krzysztof Kozlowski Oct. 21, 2019, 11:23 a.m. UTC | #2
On Thu, Oct 17, 2019 at 12:12:58PM +0530, Viresh Kumar wrote:
> On 16-10-19, 16:57, Sylwester Nawrocki wrote:
> > From: Stephen Boyd <sboyd@codeaurora.org>
> > 
> > On some SoCs the Adaptive Voltage Scaling (AVS) technique is
> > employed to optimize the operating voltage of a device. At a
> > given frequency, the hardware monitors dynamic factors and either
> > makes a suggestion for how much to adjust a voltage for the
> > current frequency, or it automatically adjusts the voltage
> > without software intervention. Add an API to the OPP library for
> > the former case, so that AVS type devices can update the voltages
> > for an OPP when the hardware determines the voltage should
> > change. The assumption is that drivers like CPUfreq or devfreq
> > will register for the OPP notifiers and adjust the voltage
> > according to suggestions that AVS makes.
> > 
> > This patch is derived from [1] submitted by Stephen.
> > [1] https://lore.kernel.org/patchwork/patch/599279/
> > 
> > Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> > Signed-off-by: Roger Lu <roger.lu@mediatek.com>
> > [s.nawrocki@samsung.com: added handling of OPP min/max voltage]
> > Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> > ---
> >  drivers/opp/core.c     | 69 ++++++++++++++++++++++++++++++++++++++++++
> >  include/linux/pm_opp.h | 13 ++++++++
> >  2 files changed, 82 insertions(+)
> 
> Applied. Thanks.

Hi Viresh,

Can you provide a stable tag with this patch so I can take soc/samsung
driver?

Best regards,
Krzysztof
Viresh Kumar Oct. 22, 2019, 2:23 a.m. UTC | #3
On 21-10-19, 13:23, Krzysztof Kozlowski wrote:
> On Thu, Oct 17, 2019 at 12:12:58PM +0530, Viresh Kumar wrote:
> > On 16-10-19, 16:57, Sylwester Nawrocki wrote:
> > > From: Stephen Boyd <sboyd@codeaurora.org>
> > > 
> > > On some SoCs the Adaptive Voltage Scaling (AVS) technique is
> > > employed to optimize the operating voltage of a device. At a
> > > given frequency, the hardware monitors dynamic factors and either
> > > makes a suggestion for how much to adjust a voltage for the
> > > current frequency, or it automatically adjusts the voltage
> > > without software intervention. Add an API to the OPP library for
> > > the former case, so that AVS type devices can update the voltages
> > > for an OPP when the hardware determines the voltage should
> > > change. The assumption is that drivers like CPUfreq or devfreq
> > > will register for the OPP notifiers and adjust the voltage
> > > according to suggestions that AVS makes.
> > > 
> > > This patch is derived from [1] submitted by Stephen.
> > > [1] https://lore.kernel.org/patchwork/patch/599279/
> > > 
> > > Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> > > Signed-off-by: Roger Lu <roger.lu@mediatek.com>
> > > [s.nawrocki@samsung.com: added handling of OPP min/max voltage]
> > > Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> > > ---
> > >  drivers/opp/core.c     | 69 ++++++++++++++++++++++++++++++++++++++++++
> > >  include/linux/pm_opp.h | 13 ++++++++
> > >  2 files changed, 82 insertions(+)
> > 
> > Applied. Thanks.
> 
> Hi Viresh,
> 
> Can you provide a stable tag with this patch so I can take soc/samsung
> driver?

opp-5.4-support-adjust-voltages
Krzysztof Kozlowski Oct. 22, 2019, 6:43 p.m. UTC | #4
On Tue, Oct 22, 2019 at 07:53:41AM +0530, Viresh Kumar wrote:
> On 21-10-19, 13:23, Krzysztof Kozlowski wrote:
> > On Thu, Oct 17, 2019 at 12:12:58PM +0530, Viresh Kumar wrote:
> > > On 16-10-19, 16:57, Sylwester Nawrocki wrote:
> > > > From: Stephen Boyd <sboyd@codeaurora.org>
> > > > 
> > > > On some SoCs the Adaptive Voltage Scaling (AVS) technique is
> > > > employed to optimize the operating voltage of a device. At a
> > > > given frequency, the hardware monitors dynamic factors and either
> > > > makes a suggestion for how much to adjust a voltage for the
> > > > current frequency, or it automatically adjusts the voltage
> > > > without software intervention. Add an API to the OPP library for
> > > > the former case, so that AVS type devices can update the voltages
> > > > for an OPP when the hardware determines the voltage should
> > > > change. The assumption is that drivers like CPUfreq or devfreq
> > > > will register for the OPP notifiers and adjust the voltage
> > > > according to suggestions that AVS makes.
> > > > 
> > > > This patch is derived from [1] submitted by Stephen.
> > > > [1] https://lore.kernel.org/patchwork/patch/599279/
> > > > 
> > > > Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> > > > Signed-off-by: Roger Lu <roger.lu@mediatek.com>
> > > > [s.nawrocki@samsung.com: added handling of OPP min/max voltage]
> > > > Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
> > > > ---
> > > >  drivers/opp/core.c     | 69 ++++++++++++++++++++++++++++++++++++++++++
> > > >  include/linux/pm_opp.h | 13 ++++++++
> > > >  2 files changed, 82 insertions(+)
> > > 
> > > Applied. Thanks.
> > 
> > Hi Viresh,
> > 
> > Can you provide a stable tag with this patch so I can take soc/samsung
> > driver?
> 
> opp-5.4-support-adjust-voltages

Thanks, merged.

Best regards,
Krzysztof

Patch
diff mbox series

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 3b7ffd0234e9..f38b3be85072 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -2112,6 +2112,75 @@  static int _opp_set_availability(struct device *dev, unsigned long freq,
 	return r;
 }

+/**
+ * dev_pm_opp_adjust_voltage() - helper to change the voltage of an OPP
+ * @dev:		device for which we do this operation
+ * @freq:		OPP frequency to adjust voltage of
+ * @u_volt:		new OPP target voltage
+ * @u_volt_min:		new OPP min voltage
+ * @u_volt_max:		new OPP max voltage
+ *
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * copy operation, returns 0 if no modifcation was done OR modification was
+ * successful.
+ */
+int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
+			      unsigned long u_volt, unsigned long u_volt_min,
+			      unsigned long u_volt_max)
+
+{
+	struct opp_table *opp_table;
+	struct dev_pm_opp *tmp_opp, *opp = ERR_PTR(-ENODEV);
+	int r = 0;
+
+	/* Find the opp_table */
+	opp_table = _find_opp_table(dev);
+	if (IS_ERR(opp_table)) {
+		r = PTR_ERR(opp_table);
+		dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
+		return r;
+	}
+
+	mutex_lock(&opp_table->lock);
+
+	/* Do we have the frequency? */
+	list_for_each_entry(tmp_opp, &opp_table->opp_list, node) {
+		if (tmp_opp->rate == freq) {
+			opp = tmp_opp;
+			break;
+		}
+	}
+
+	if (IS_ERR(opp)) {
+		r = PTR_ERR(opp);
+		goto adjust_unlock;
+	}
+
+	/* Is update really needed? */
+	if (opp->supplies->u_volt == u_volt)
+		goto adjust_unlock;
+
+	opp->supplies->u_volt = u_volt;
+	opp->supplies->u_volt_min = u_volt_min;
+	opp->supplies->u_volt_max = u_volt_max;
+
+	dev_pm_opp_get(opp);
+	mutex_unlock(&opp_table->lock);
+
+	/* Notify the voltage change of the OPP */
+	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADJUST_VOLTAGE,
+				     opp);
+
+	dev_pm_opp_put(opp);
+	goto adjust_put_table;
+
+adjust_unlock:
+	mutex_unlock(&opp_table->lock);
+adjust_put_table:
+	dev_pm_opp_put_opp_table(opp_table);
+	return r;
+}
+
 /**
  * dev_pm_opp_enable() - Enable a specific OPP
  * @dev:	device for which we do this operation
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index b8197ab014f2..747861816f4f 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -22,6 +22,7 @@  struct opp_table;

 enum dev_pm_opp_event {
 	OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
+	OPP_EVENT_ADJUST_VOLTAGE,
 };

 /**
@@ -113,6 +114,10 @@  int dev_pm_opp_add(struct device *dev, unsigned long freq,
 void dev_pm_opp_remove(struct device *dev, unsigned long freq);
 void dev_pm_opp_remove_all_dynamic(struct device *dev);

+int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
+			      unsigned long u_volt, unsigned long u_volt_min,
+			      unsigned long u_volt_max);
+
 int dev_pm_opp_enable(struct device *dev, unsigned long freq);

 int dev_pm_opp_disable(struct device *dev, unsigned long freq);
@@ -242,6 +247,14 @@  static inline void dev_pm_opp_remove_all_dynamic(struct device *dev)
 {
 }

+static inline int
+dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
+			  unsigned long u_volt, unsigned long u_volt_min,
+			  unsigned long u_volt_max)
+{
+	return 0;
+}
+
 static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq)
 {
 	return 0;