Some PWM regulator has the exponential transition in voltage change as
opposite to fixed slew-rate linear transition on other regulators.
For such PWM regulators, add the property to tell that voltage change
is exponential and having fixed delay for any level of change.
Signed-off-by: Laxman Dewangan <[email protected]>
CC: Douglas Anderson <[email protected]>
CC: Aleksandr Frid <[email protected]>
---
This patch is continuation of discussion on patch
regulator: pwm: Fix regulator ramp delay for continuous mode
https://patchwork.kernel.org/patch/9216857/
where is it discussed to have separate property for PWM which has
exponential voltage transition.
Changes from V1:
- Pass the flag to tell that voltage ramp is exponential instead of
providing delay.
---
.../devicetree/bindings/regulator/pwm-regulator.txt | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
index 3aeba9f..2d9ef3a 100644
--- a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
+++ b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
@@ -54,6 +54,18 @@ Optional properties:
--------------------
- enable-gpios: GPIO to use to enable/disable the regulator
+- voltage-ramp-exponential: Boolean, Some of PWM regulator has the exponential
+ transition in voltage ramp as opposite to fixed
+ slew-rate linear transition on other regulators.
+ For such PWM regulator, presence of this property will
+ tell that value of the regulator ramp delay provided by
+ DT property "regulator-ramp-delay" is exponential and
+ fixed delay for any voltage level change.
+ If PWM regulator supports the fixed linear slew rate
+ then this property should be absent from DT node and
+ property "regulator-ramp-delay" is used as linear slew
+ rate.
+
Any property defined as part of the core regulator binding can also be used.
(See: ../regulator/regulator.txt)
--
2.1.4
Some PWM regulator has the exponential transition in voltage change
as opposite to fixed slew-rate linear transition on other regulators.
For such PWM regulators, add support for handling the exponential
voltage ramp delay.
Signed-off-by: Laxman Dewangan <[email protected]>
CC: Douglas Anderson <[email protected]>
CC: Aleksandr Frid <[email protected]>
---
This patch is continuation of discussion on patch
regulator: pwm: Fix regulator ramp delay for continuous mode
https://patchwork.kernel.org/patch/9216857/
where is it discussed to have separate property for PWM which has
exponential voltage transition.
Changes from V1:
- Use new DT property to finding that voltage ramp is exponential or
not and use flag for having fixed delay for all voltage change.
---
drivers/regulator/pwm-regulator.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
index 1b88e0e1..bcffeee 100644
--- a/drivers/regulator/pwm-regulator.c
+++ b/drivers/regulator/pwm-regulator.c
@@ -233,6 +233,24 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
return 0;
}
+/**
+ * Some of PWM regulators have exponential voltage ramp. On such PWM
+ * regulators, voltage settling time is same regardless of voltage
+ * level change.
+ */
+static int pwm_regulator_set_voltage_time(struct regulator_dev *rdev,
+ int old_uV, int new_uV)
+{
+ return rdev->constraints->ramp_delay;
+}
+
+static int pwm_regulator_set_voltage_time_sel(struct regulator_dev *rdev,
+ unsigned int old_selector,
+ unsigned int new_selector)
+{
+ return rdev->constraints->ramp_delay;
+}
+
static struct regulator_ops pwm_regulator_voltage_table_ops = {
.set_voltage_sel = pwm_regulator_set_voltage_sel,
.get_voltage_sel = pwm_regulator_get_voltage_sel,
@@ -294,17 +312,25 @@ static int pwm_regulator_init_table(struct platform_device *pdev,
drvdata->desc.ops = &drvdata->ops;
drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table);
+ if (of_property_read_bool(np, "voltage-ramp-exponential"))
+ drvdata->ops.set_voltage_time_sel =
+ pwm_regulator_set_voltage_time_sel;
return 0;
}
static int pwm_regulator_init_continuous(struct platform_device *pdev,
struct pwm_regulator_data *drvdata)
{
+ struct device_node *np = pdev->dev.of_node;
u32 dutycycle_range[2] = { 0, 100 };
u32 dutycycle_unit = 100;
memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
sizeof(drvdata->ops));
+
+ if (of_property_read_bool(np, "voltage-ramp-exponential"))
+ drvdata->ops.set_voltage_time = pwm_regulator_set_voltage_time;
+
drvdata->desc.ops = &drvdata->ops;
drvdata->desc.continuous_voltage_range = true;
--
2.1.4
On Fri, Nov 18, 2016 at 08:05:55PM +0530, Laxman Dewangan wrote:
> Some PWM regulator has the exponential transition in voltage change as
> opposite to fixed slew-rate linear transition on other regulators.
> For such PWM regulators, add the property to tell that voltage change
> is exponential and having fixed delay for any level of change.
>
> Signed-off-by: Laxman Dewangan <[email protected]>
> CC: Douglas Anderson <[email protected]>
> CC: Aleksandr Frid <[email protected]>
>
> ---
> This patch is continuation of discussion on patch
> regulator: pwm: Fix regulator ramp delay for continuous mode
> https://patchwork.kernel.org/patch/9216857/
> where is it discussed to have separate property for PWM which has
> exponential voltage transition.
>
> Changes from V1:
> - Pass the flag to tell that voltage ramp is exponential instead of
> providing delay.
> ---
> .../devicetree/bindings/regulator/pwm-regulator.txt | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
> index 3aeba9f..2d9ef3a 100644
> --- a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
> +++ b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
> @@ -54,6 +54,18 @@ Optional properties:
> --------------------
> - enable-gpios: GPIO to use to enable/disable the regulator
>
> +- voltage-ramp-exponential: Boolean, Some of PWM regulator has the exponential
> + transition in voltage ramp as opposite to fixed
> + slew-rate linear transition on other regulators.
> + For such PWM regulator, presence of this property will
> + tell that value of the regulator ramp delay provided by
> + DT property "regulator-ramp-delay" is exponential and
> + fixed delay for any voltage level change.
> + If PWM regulator supports the fixed linear slew rate
> + then this property should be absent from DT node and
> + property "regulator-ramp-delay" is used as linear slew
> + rate.
Sorry, but on further thought, I don't think we should mix different
units for the same property. Also, the fact that the ramp is exponential
is irrelevant. You just want an absolute delay time rather than a rate,
right? So instead, how about just "regulator-ramp-time-us". Roughly what
you had in v1, but not PWM specific.
Rob
On Monday 21 November 2016 09:47 PM, Rob Herring wrote:
> On Fri, Nov 18, 2016 at 08:05:55PM +0530, Laxman Dewangan wrote:
>> Some PWM regulator has the exponential transition in voltage change as
>> opposite to fixed slew-rate linear transition on other regulators.
>> For such PWM regulators, add the property to tell that voltage change
>> is exponential and having fixed delay for any level of change.
>>
>> Signed-off-by: Laxman Dewangan <[email protected]>
>> CC: Douglas Anderson <[email protected]>
>> CC: Aleksandr Frid <[email protected]>
>>
>> ---
>> This patch is continuation of discussion on patch
>> regulator: pwm: Fix regulator ramp delay for continuous mode
>> https://patchwork.kernel.org/patch/9216857/
>> where is it discussed to have separate property for PWM which has
>> exponential voltage transition.
>>
>> Changes from V1:
>> - Pass the flag to tell that voltage ramp is exponential instead of
>> providing delay.
>> ---
>> .../devicetree/bindings/regulator/pwm-regulator.txt | 12 ++++++++++++
>> 1 file changed, 12 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
>> index 3aeba9f..2d9ef3a 100644
>> --- a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
>> +++ b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
>> @@ -54,6 +54,18 @@ Optional properties:
>> --------------------
>> - enable-gpios: GPIO to use to enable/disable the regulator
>>
>> +- voltage-ramp-exponential: Boolean, Some of PWM regulator has the exponential
>> + transition in voltage ramp as opposite to fixed
>> + slew-rate linear transition on other regulators.
>> + For such PWM regulator, presence of this property will
>> + tell that value of the regulator ramp delay provided by
>> + DT property "regulator-ramp-delay" is exponential and
>> + fixed delay for any voltage level change.
>> + If PWM regulator supports the fixed linear slew rate
>> + then this property should be absent from DT node and
>> + property "regulator-ramp-delay" is used as linear slew
>> + rate.
> Sorry, but on further thought, I don't think we should mix different
> units for the same property. Also, the fact that the ramp is exponential
> is irrelevant. You just want an absolute delay time rather than a rate,
> right? So instead, how about just "regulator-ramp-time-us". Roughly what
> you had in v1, but not PWM specific.
Can we say "regulator-settling-time-us" and make it generic i.e. part of
the regulator core instead of PWM regulator specific?
So no change for "regulator-ramp-delay".
new property "regulator-settling-time-us" for fixed settling time in any
voltage level change.
On Tue, Nov 22, 2016 at 2:50 AM, Laxman Dewangan <[email protected]> wrote:
>
> On Monday 21 November 2016 09:47 PM, Rob Herring wrote:
>>
>> On Fri, Nov 18, 2016 at 08:05:55PM +0530, Laxman Dewangan wrote:
>>>
>>> Some PWM regulator has the exponential transition in voltage change as
>>> opposite to fixed slew-rate linear transition on other regulators.
>>> For such PWM regulators, add the property to tell that voltage change
>>> is exponential and having fixed delay for any level of change.
>>>
>>> Signed-off-by: Laxman Dewangan <[email protected]>
>>> CC: Douglas Anderson <[email protected]>
>>> CC: Aleksandr Frid <[email protected]>
>>>
>>> ---
>>> This patch is continuation of discussion on patch
>>> regulator: pwm: Fix regulator ramp delay for continuous mode
>>> https://patchwork.kernel.org/patch/9216857/
>>> where is it discussed to have separate property for PWM which has
>>> exponential voltage transition.
>>>
>>> Changes from V1:
>>> - Pass the flag to tell that voltage ramp is exponential instead of
>>> providing delay.
>>> ---
>>> .../devicetree/bindings/regulator/pwm-regulator.txt | 12
>>> ++++++++++++
>>> 1 file changed, 12 insertions(+)
>>>
>>> diff --git
>>> a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
>>> b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
>>> index 3aeba9f..2d9ef3a 100644
>>> --- a/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
>>> +++ b/Documentation/devicetree/bindings/regulator/pwm-regulator.txt
>>> @@ -54,6 +54,18 @@ Optional properties:
>>> --------------------
>>> - enable-gpios: GPIO to use to enable/disable the
>>> regulator
>>> +- voltage-ramp-exponential: Boolean, Some of PWM regulator has the
>>> exponential
>>> + transition in voltage ramp as opposite to fixed
>>> + slew-rate linear transition on other regulators.
>>> + For such PWM regulator, presence of this property
>>> will
>>> + tell that value of the regulator ramp delay
>>> provided by
>>> + DT property "regulator-ramp-delay" is exponential
>>> and
>>> + fixed delay for any voltage level change.
>>> + If PWM regulator supports the fixed linear slew
>>> rate
>>> + then this property should be absent from DT node
>>> and
>>> + property "regulator-ramp-delay" is used as linear
>>> slew
>>> + rate.
>>
>> Sorry, but on further thought, I don't think we should mix different
>> units for the same property. Also, the fact that the ramp is exponential
>> is irrelevant. You just want an absolute delay time rather than a rate,
>> right? So instead, how about just "regulator-ramp-time-us". Roughly what
>> you had in v1, but not PWM specific.
>
>
> Can we say "regulator-settling-time-us" and make it generic i.e. part of the
> regulator core instead of PWM regulator specific?
Sure.
Rob