* [PATCH v2 0/3] Input: add optional amplifier regulator to pwm-beeper (previously "Input: add optional enable gpio to pwm-beeper")
@ 2017-01-11 20:01 David Lechner
2017-01-11 20:01 ` [PATCH v2 1/3] Input: pwm-beeper: suppress error message on probe defer David Lechner
` (2 more replies)
0 siblings, 3 replies; 11+ messages in thread
From: David Lechner @ 2017-01-11 20:01 UTC (permalink / raw)
To: linux-input, devicetree
Cc: David Lechner, Dmitry Torokhov, Rob Herring, Mark Rutland, linux-kernel
This series adds an optional regulator to the pwm-beeper driver and device tree
bindings. The regulator acts as an amplifier that powers the beeper.
v2 changes:
* Changed from using a gpio to a regulator
* Rebased on the pwm-beeper cleanup series "Input: pwm-beeper - remove calls to
legacy pwm_request API"
David Lechner (3):
Input: pwm-beeper: suppress error message on probe defer
dt-bindings: Input: Add optional amp-supply property to pwm-beeper
Input: pwm-beeper: add optional amplifier regulator
.../devicetree/bindings/input/pwm-beeper.txt | 16 ++++++++++
drivers/input/misc/pwm-beeper.c | 36 +++++++++++++++++++---
2 files changed, 48 insertions(+), 4 deletions(-)
--
2.7.4
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v2 1/3] Input: pwm-beeper: suppress error message on probe defer
2017-01-11 20:01 [PATCH v2 0/3] Input: add optional amplifier regulator to pwm-beeper (previously "Input: add optional enable gpio to pwm-beeper") David Lechner
@ 2017-01-11 20:01 ` David Lechner
2017-01-14 19:17 ` Dmitry Torokhov
2017-01-11 20:02 ` [PATCH v2 2/3] dt-bindings: Input: Add optional amp-supply property to pwm-beeper David Lechner
2017-01-11 20:02 ` [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator David Lechner
2 siblings, 1 reply; 11+ messages in thread
From: David Lechner @ 2017-01-11 20:01 UTC (permalink / raw)
To: linux-input, devicetree
Cc: David Lechner, Dmitry Torokhov, Rob Herring, Mark Rutland, linux-kernel
This suppress printing an error message when pwm_get returns -EPROBE_DEFER.
Otherwise you get a bunch of noise in the kernel log.
Signed-off-by: David Lechner <david@lechnology.com>
---
drivers/input/misc/pwm-beeper.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index ce6eec4..30ac227 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c
@@ -104,9 +104,10 @@ static int pwm_beeper_probe(struct platform_device *pdev)
return -ENOMEM;
beeper->pwm = devm_pwm_get(dev, NULL);
- if (IS_ERR(beeper->pwm)) {
- error = PTR_ERR(beeper->pwm);
- dev_err(dev, "Failed to request pwm device: %d\n", error);
+ error = PTR_ERR_OR_ZERO(beeper->pwm);
+ if (error) {
+ if (error != -EPROBE_DEFER)
+ dev_err(dev, "Failed to request pwm device\n");
return error;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH v2 2/3] dt-bindings: Input: Add optional amp-supply property to pwm-beeper
2017-01-11 20:01 [PATCH v2 0/3] Input: add optional amplifier regulator to pwm-beeper (previously "Input: add optional enable gpio to pwm-beeper") David Lechner
2017-01-11 20:01 ` [PATCH v2 1/3] Input: pwm-beeper: suppress error message on probe defer David Lechner
@ 2017-01-11 20:02 ` David Lechner
2017-01-18 19:58 ` Rob Herring
2017-01-11 20:02 ` [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator David Lechner
2 siblings, 1 reply; 11+ messages in thread
From: David Lechner @ 2017-01-11 20:02 UTC (permalink / raw)
To: linux-input, devicetree
Cc: David Lechner, Dmitry Torokhov, Rob Herring, Mark Rutland, linux-kernel
This adds an optional amp-supply property to pwm-beeper. This is a
regulator that acts as an amplifier for the beeper.
Signed-off-by: David Lechner <david@lechnology.com>
---
Documentation/devicetree/bindings/input/pwm-beeper.txt | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/Documentation/devicetree/bindings/input/pwm-beeper.txt b/Documentation/devicetree/bindings/input/pwm-beeper.txt
index be332ae..529408b 100644
--- a/Documentation/devicetree/bindings/input/pwm-beeper.txt
+++ b/Documentation/devicetree/bindings/input/pwm-beeper.txt
@@ -5,3 +5,19 @@ Registers a PWM device as beeper.
Required properties:
- compatible: should be "pwm-beeper"
- pwms: phandle to the physical PWM device
+
+Optional properties:
+- amp-supply: phandle to a regulator that acts as an amplifier for the beeper
+
+Example:
+
+beeper_amp: amplifier {
+ compatible = "fixed-regulator";
+ gpios = <&gpio0 1 GPIO_ACTIVE_HIGH>;
+};
+
+beeper {
+ compatible = "pwm-beeper";
+ pwms = <&pwm0>;
+ amp-supply = <&beeper_amp>;
+};
--
2.7.4
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator
2017-01-11 20:01 [PATCH v2 0/3] Input: add optional amplifier regulator to pwm-beeper (previously "Input: add optional enable gpio to pwm-beeper") David Lechner
2017-01-11 20:01 ` [PATCH v2 1/3] Input: pwm-beeper: suppress error message on probe defer David Lechner
2017-01-11 20:02 ` [PATCH v2 2/3] dt-bindings: Input: Add optional amp-supply property to pwm-beeper David Lechner
@ 2017-01-11 20:02 ` David Lechner
2017-01-14 19:19 ` Dmitry Torokhov
2 siblings, 1 reply; 11+ messages in thread
From: David Lechner @ 2017-01-11 20:02 UTC (permalink / raw)
To: linux-input, devicetree
Cc: David Lechner, Dmitry Torokhov, Rob Herring, Mark Rutland, linux-kernel
This adds an optional regulator to the pwm-beeper device. This regulator
acts as an amplifier. The amplifier is only enabled while beeping in order
to reduce power consumption.
Tested on LEGO MINDSTORMS EV3, which has a speaker connected to PWM through
an amplifier.
Signed-off-by: David Lechner <david@lechnology.com>
---
drivers/input/misc/pwm-beeper.c | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index 30ac227..708e88e 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c
@@ -14,6 +14,7 @@
*/
#include <linux/input.h>
+#include <linux/regulator/consumer.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/of.h>
@@ -25,8 +26,10 @@
struct pwm_beeper {
struct input_dev *input;
struct pwm_device *pwm;
+ struct regulator *reg;
struct work_struct work;
unsigned long period;
+ bool reg_enabled;
};
#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
@@ -38,8 +41,20 @@ static void __pwm_beeper_set(struct pwm_beeper *beeper)
if (period) {
pwm_config(beeper->pwm, period / 2, period);
pwm_enable(beeper->pwm);
- } else
+ if (beeper->reg) {
+ int error;
+
+ error = regulator_enable(beeper->reg);
+ if (!error)
+ beeper->reg_enabled = true;
+ }
+ } else {
+ if (beeper->reg_enabled) {
+ regulator_disable(beeper->reg);
+ beeper->reg_enabled = false;
+ }
pwm_disable(beeper->pwm);
+ }
}
static void pwm_beeper_work(struct work_struct *work)
@@ -82,6 +97,10 @@ static void pwm_beeper_stop(struct pwm_beeper *beeper)
{
cancel_work_sync(&beeper->work);
+ if (beeper->reg_enabled) {
+ regulator_disable(beeper->reg);
+ beeper->reg_enabled = false;
+ }
if (beeper->period)
pwm_disable(beeper->pwm);
}
@@ -111,6 +130,14 @@ static int pwm_beeper_probe(struct platform_device *pdev)
return error;
}
+ beeper->reg = devm_regulator_get_optional(&pdev->dev, "amp");
+ error = PTR_ERR_OR_ZERO(beeper->reg);
+ if (error) {
+ if (error != -EPROBE_DEFER)
+ dev_err(dev, "Failed to get amp regulator\n");
+ return error;
+ }
+
/*
* FIXME: pwm_apply_args() should be removed when switching to
* the atomic PWM API.
--
2.7.4
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH v2 1/3] Input: pwm-beeper: suppress error message on probe defer
2017-01-11 20:01 ` [PATCH v2 1/3] Input: pwm-beeper: suppress error message on probe defer David Lechner
@ 2017-01-14 19:17 ` Dmitry Torokhov
0 siblings, 0 replies; 11+ messages in thread
From: Dmitry Torokhov @ 2017-01-14 19:17 UTC (permalink / raw)
To: David Lechner
Cc: linux-input, devicetree, Rob Herring, Mark Rutland, linux-kernel
On Wed, Jan 11, 2017 at 02:01:59PM -0600, David Lechner wrote:
> This suppress printing an error message when pwm_get returns -EPROBE_DEFER.
> Otherwise you get a bunch of noise in the kernel log.
>
> Signed-off-by: David Lechner <david@lechnology.com>
> ---
> drivers/input/misc/pwm-beeper.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
> index ce6eec4..30ac227 100644
> --- a/drivers/input/misc/pwm-beeper.c
> +++ b/drivers/input/misc/pwm-beeper.c
> @@ -104,9 +104,10 @@ static int pwm_beeper_probe(struct platform_device *pdev)
> return -ENOMEM;
>
> beeper->pwm = devm_pwm_get(dev, NULL);
> - if (IS_ERR(beeper->pwm)) {
> - error = PTR_ERR(beeper->pwm);
> - dev_err(dev, "Failed to request pwm device: %d\n", error);
> + error = PTR_ERR_OR_ZERO(beeper->pwm);
> + if (error) {
I do not find it in any way clearer than
if (IS_ERR()) {
...
I prefer PTR_ERR_OR_ZERO be used when you need to return value without
acting on it.
I can adjust locally, no need to resubmit.
> + if (error != -EPROBE_DEFER)
> + dev_err(dev, "Failed to request pwm device\n");
> return error;
> }
>
> --
> 2.7.4
>
--
Dmitry
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator
2017-01-11 20:02 ` [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator David Lechner
@ 2017-01-14 19:19 ` Dmitry Torokhov
2017-01-16 0:12 ` David Lechner
0 siblings, 1 reply; 11+ messages in thread
From: Dmitry Torokhov @ 2017-01-14 19:19 UTC (permalink / raw)
To: David Lechner
Cc: linux-input, devicetree, Rob Herring, Mark Rutland, linux-kernel
On Wed, Jan 11, 2017 at 02:02:01PM -0600, David Lechner wrote:
> This adds an optional regulator to the pwm-beeper device. This regulator
> acts as an amplifier. The amplifier is only enabled while beeping in order
> to reduce power consumption.
>
> Tested on LEGO MINDSTORMS EV3, which has a speaker connected to PWM through
> an amplifier.
>
> Signed-off-by: David Lechner <david@lechnology.com>
> ---
> drivers/input/misc/pwm-beeper.c | 29 ++++++++++++++++++++++++++++-
> 1 file changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
> index 30ac227..708e88e 100644
> --- a/drivers/input/misc/pwm-beeper.c
> +++ b/drivers/input/misc/pwm-beeper.c
> @@ -14,6 +14,7 @@
> */
>
> #include <linux/input.h>
> +#include <linux/regulator/consumer.h>
> #include <linux/module.h>
> #include <linux/kernel.h>
> #include <linux/of.h>
> @@ -25,8 +26,10 @@
> struct pwm_beeper {
> struct input_dev *input;
> struct pwm_device *pwm;
> + struct regulator *reg;
> struct work_struct work;
> unsigned long period;
> + bool reg_enabled;
> };
>
> #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
> @@ -38,8 +41,20 @@ static void __pwm_beeper_set(struct pwm_beeper *beeper)
> if (period) {
> pwm_config(beeper->pwm, period / 2, period);
> pwm_enable(beeper->pwm);
> - } else
> + if (beeper->reg) {
> + int error;
> +
> + error = regulator_enable(beeper->reg);
> + if (!error)
> + beeper->reg_enabled = true;
> + }
> + } else {
> + if (beeper->reg_enabled) {
> + regulator_disable(beeper->reg);
> + beeper->reg_enabled = false;
> + }
> pwm_disable(beeper->pwm);
> + }
> }
>
> static void pwm_beeper_work(struct work_struct *work)
> @@ -82,6 +97,10 @@ static void pwm_beeper_stop(struct pwm_beeper *beeper)
> {
> cancel_work_sync(&beeper->work);
>
> + if (beeper->reg_enabled) {
> + regulator_disable(beeper->reg);
> + beeper->reg_enabled = false;
> + }
> if (beeper->period)
> pwm_disable(beeper->pwm);
> }
> @@ -111,6 +130,14 @@ static int pwm_beeper_probe(struct platform_device *pdev)
> return error;
> }
>
> + beeper->reg = devm_regulator_get_optional(&pdev->dev, "amp");
If you do not use optional regulator then you will not have to check if
you have it or not everywhere: regulator core will give you a dummy that
you can toggle to your heart's content.
> + error = PTR_ERR_OR_ZERO(beeper->reg);
> + if (error) {
> + if (error != -EPROBE_DEFER)
> + dev_err(dev, "Failed to get amp regulator\n");
> + return error;
> + }
> +
> /*
> * FIXME: pwm_apply_args() should be removed when switching to
> * the atomic PWM API.
> --
> 2.7.4
>
Thanks.
--
Dmitry
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator
2017-01-14 19:19 ` Dmitry Torokhov
@ 2017-01-16 0:12 ` David Lechner
2017-01-16 0:34 ` Dmitry Torokhov
0 siblings, 1 reply; 11+ messages in thread
From: David Lechner @ 2017-01-16 0:12 UTC (permalink / raw)
To: Dmitry Torokhov
Cc: linux-input, devicetree, Rob Herring, Mark Rutland, linux-kernel
On 01/14/2017 01:19 PM, Dmitry Torokhov wrote:
> On Wed, Jan 11, 2017 at 02:02:01PM -0600, David Lechner wrote:
>> This adds an optional regulator to the pwm-beeper device. This regulator
>> acts as an amplifier. The amplifier is only enabled while beeping in order
>> to reduce power consumption.
>>
>> Tested on LEGO MINDSTORMS EV3, which has a speaker connected to PWM through
>> an amplifier.
>>
>> Signed-off-by: David Lechner <david@lechnology.com>
>> ---
>> drivers/input/misc/pwm-beeper.c | 29 ++++++++++++++++++++++++++++-
>> 1 file changed, 28 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
>> index 30ac227..708e88e 100644
>> --- a/drivers/input/misc/pwm-beeper.c
>> +++ b/drivers/input/misc/pwm-beeper.c
>> @@ -14,6 +14,7 @@
>> */
>>
>> #include <linux/input.h>
>> +#include <linux/regulator/consumer.h>
>> #include <linux/module.h>
>> #include <linux/kernel.h>
>> #include <linux/of.h>
>> @@ -25,8 +26,10 @@
>> struct pwm_beeper {
>> struct input_dev *input;
>> struct pwm_device *pwm;
>> + struct regulator *reg;
>> struct work_struct work;
>> unsigned long period;
>> + bool reg_enabled;
>> };
>>
>> #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
>> @@ -38,8 +41,20 @@ static void __pwm_beeper_set(struct pwm_beeper *beeper)
>> if (period) {
>> pwm_config(beeper->pwm, period / 2, period);
>> pwm_enable(beeper->pwm);
>> - } else
>> + if (beeper->reg) {
>> + int error;
>> +
>> + error = regulator_enable(beeper->reg);
>> + if (!error)
>> + beeper->reg_enabled = true;
>> + }
>> + } else {
>> + if (beeper->reg_enabled) {
>> + regulator_disable(beeper->reg);
>> + beeper->reg_enabled = false;
>> + }
>> pwm_disable(beeper->pwm);
>> + }
>> }
>>
>> static void pwm_beeper_work(struct work_struct *work)
>> @@ -82,6 +97,10 @@ static void pwm_beeper_stop(struct pwm_beeper *beeper)
>> {
>> cancel_work_sync(&beeper->work);
>>
>> + if (beeper->reg_enabled) {
>> + regulator_disable(beeper->reg);
>> + beeper->reg_enabled = false;
>> + }
>> if (beeper->period)
>> pwm_disable(beeper->pwm);
>> }
>> @@ -111,6 +130,14 @@ static int pwm_beeper_probe(struct platform_device *pdev)
>> return error;
>> }
>>
>> + beeper->reg = devm_regulator_get_optional(&pdev->dev, "amp");
>
> If you do not use optional regulator then you will not have to check if
> you have it or not everywhere: regulator core will give you a dummy that
> you can toggle to your heart's content.
Some months ago, I learned that if you are not using device tree and you
do not call regulator_has_full_constraints(), then you do not get a
dummy regulator. And here, we are only checking if the regulator exists
in one place. We will still need the checks for beeper->reg_enabled to
keep calls to regulator_enable() and regulator_disable() balanced.
On the other hand, it is recommended that you always call
regulator_has_full_constraints(), so I don't mind changing it if that is
what you think we should do. But, I don't really see much of an
advantage to changing it compared to the current implementation.
>
>> + error = PTR_ERR_OR_ZERO(beeper->reg);
>> + if (error) {
>> + if (error != -EPROBE_DEFER)
>> + dev_err(dev, "Failed to get amp regulator\n");
>> + return error;
>> + }
>> +
>> /*
>> * FIXME: pwm_apply_args() should be removed when switching to
>> * the atomic PWM API.
>> --
>> 2.7.4
>>
>
> Thanks.
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator
2017-01-16 0:12 ` David Lechner
@ 2017-01-16 0:34 ` Dmitry Torokhov
2017-01-16 1:04 ` David Lechner
0 siblings, 1 reply; 11+ messages in thread
From: Dmitry Torokhov @ 2017-01-16 0:34 UTC (permalink / raw)
To: David Lechner
Cc: linux-input, devicetree, Rob Herring, Mark Rutland, linux-kernel
On Sun, Jan 15, 2017 at 06:12:29PM -0600, David Lechner wrote:
> On 01/14/2017 01:19 PM, Dmitry Torokhov wrote:
> >On Wed, Jan 11, 2017 at 02:02:01PM -0600, David Lechner wrote:
> >>This adds an optional regulator to the pwm-beeper device. This regulator
> >>acts as an amplifier. The amplifier is only enabled while beeping in order
> >>to reduce power consumption.
> >>
> >>Tested on LEGO MINDSTORMS EV3, which has a speaker connected to PWM through
> >>an amplifier.
> >>
> >>Signed-off-by: David Lechner <david@lechnology.com>
> >>---
> >> drivers/input/misc/pwm-beeper.c | 29 ++++++++++++++++++++++++++++-
> >> 1 file changed, 28 insertions(+), 1 deletion(-)
> >>
> >>diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
> >>index 30ac227..708e88e 100644
> >>--- a/drivers/input/misc/pwm-beeper.c
> >>+++ b/drivers/input/misc/pwm-beeper.c
> >>@@ -14,6 +14,7 @@
> >> */
> >>
> >> #include <linux/input.h>
> >>+#include <linux/regulator/consumer.h>
> >> #include <linux/module.h>
> >> #include <linux/kernel.h>
> >> #include <linux/of.h>
> >>@@ -25,8 +26,10 @@
> >> struct pwm_beeper {
> >> struct input_dev *input;
> >> struct pwm_device *pwm;
> >>+ struct regulator *reg;
> >> struct work_struct work;
> >> unsigned long period;
> >>+ bool reg_enabled;
> >> };
> >>
> >> #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
> >>@@ -38,8 +41,20 @@ static void __pwm_beeper_set(struct pwm_beeper *beeper)
> >> if (period) {
> >> pwm_config(beeper->pwm, period / 2, period);
> >> pwm_enable(beeper->pwm);
> >>- } else
> >>+ if (beeper->reg) {
> >>+ int error;
> >>+
> >>+ error = regulator_enable(beeper->reg);
> >>+ if (!error)
> >>+ beeper->reg_enabled = true;
> >>+ }
> >>+ } else {
> >>+ if (beeper->reg_enabled) {
> >>+ regulator_disable(beeper->reg);
> >>+ beeper->reg_enabled = false;
> >>+ }
> >> pwm_disable(beeper->pwm);
> >>+ }
> >> }
> >>
> >> static void pwm_beeper_work(struct work_struct *work)
> >>@@ -82,6 +97,10 @@ static void pwm_beeper_stop(struct pwm_beeper *beeper)
> >> {
> >> cancel_work_sync(&beeper->work);
> >>
> >>+ if (beeper->reg_enabled) {
> >>+ regulator_disable(beeper->reg);
> >>+ beeper->reg_enabled = false;
> >>+ }
> >> if (beeper->period)
> >> pwm_disable(beeper->pwm);
> >> }
> >>@@ -111,6 +130,14 @@ static int pwm_beeper_probe(struct platform_device *pdev)
> >> return error;
> >> }
> >>
> >>+ beeper->reg = devm_regulator_get_optional(&pdev->dev, "amp");
> >
> >If you do not use optional regulator then you will not have to check if
> >you have it or not everywhere: regulator core will give you a dummy that
> >you can toggle to your heart's content.
>
> Some months ago, I learned that if you are not using device tree and
> you do not call regulator_has_full_constraints(), then you do not
> get a dummy regulator. And here, we are only checking if the
> regulator exists in one place. We will still need the checks for
> beeper->reg_enabled to keep calls to regulator_enable() and
> regulator_disable() balanced.
Why? You do not have checks for calls to pwm_enable() and pwm_disable(),
(or rather beeper->period is used as such flag) why regulator would be
any different?
>
> On the other hand, it is recommended that you always call
> regulator_has_full_constraints(), so I don't mind changing it if
> that is what you think we should do. But, I don't really see much of
> an advantage to changing it compared to the current implementation.
It greatly simplifies control flow in the driver (since I believe you
can get rid of the flags you introduced).
As far as arch not having full constraints - I am not sure if this makes
sense anymore. I am not quite sure what the original intent here was, we
should probably ask Mark Brown. But a lot of drivers do expect the dummy
substitution to imply work.
Thanks.
--
Dmitry
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator
2017-01-16 0:34 ` Dmitry Torokhov
@ 2017-01-16 1:04 ` David Lechner
2017-01-19 22:34 ` Dmitry Torokhov
0 siblings, 1 reply; 11+ messages in thread
From: David Lechner @ 2017-01-16 1:04 UTC (permalink / raw)
To: Dmitry Torokhov
Cc: linux-input, devicetree, Rob Herring, Mark Rutland, linux-kernel
On 01/15/2017 06:34 PM, Dmitry Torokhov wrote:
> On Sun, Jan 15, 2017 at 06:12:29PM -0600, David Lechner wrote:
>> On 01/14/2017 01:19 PM, Dmitry Torokhov wrote:
>>> On Wed, Jan 11, 2017 at 02:02:01PM -0600, David Lechner wrote:
>>>> This adds an optional regulator to the pwm-beeper device. This regulator
>>>> acts as an amplifier. The amplifier is only enabled while beeping in order
>>>> to reduce power consumption.
>>>>
>>>> Tested on LEGO MINDSTORMS EV3, which has a speaker connected to PWM through
>>>> an amplifier.
>>>>
>>>> Signed-off-by: David Lechner <david@lechnology.com>
>>>> ---
>>>> drivers/input/misc/pwm-beeper.c | 29 ++++++++++++++++++++++++++++-
>>>> 1 file changed, 28 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
>>>> index 30ac227..708e88e 100644
>>>> --- a/drivers/input/misc/pwm-beeper.c
>>>> +++ b/drivers/input/misc/pwm-beeper.c
>>>> @@ -14,6 +14,7 @@
>>>> */
>>>>
>>>> #include <linux/input.h>
>>>> +#include <linux/regulator/consumer.h>
>>>> #include <linux/module.h>
>>>> #include <linux/kernel.h>
>>>> #include <linux/of.h>
>>>> @@ -25,8 +26,10 @@
>>>> struct pwm_beeper {
>>>> struct input_dev *input;
>>>> struct pwm_device *pwm;
>>>> + struct regulator *reg;
>>>> struct work_struct work;
>>>> unsigned long period;
>>>> + bool reg_enabled;
>>>> };
>>>>
>>>> #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
>>>> @@ -38,8 +41,20 @@ static void __pwm_beeper_set(struct pwm_beeper *beeper)
>>>> if (period) {
>>>> pwm_config(beeper->pwm, period / 2, period);
>>>> pwm_enable(beeper->pwm);
>>>> - } else
>>>> + if (beeper->reg) {
>>>> + int error;
>>>> +
>>>> + error = regulator_enable(beeper->reg);
>>>> + if (!error)
>>>> + beeper->reg_enabled = true;
>>>> + }
>>>> + } else {
>>>> + if (beeper->reg_enabled) {
>>>> + regulator_disable(beeper->reg);
>>>> + beeper->reg_enabled = false;
>>>> + }
>>>> pwm_disable(beeper->pwm);
>>>> + }
>>>> }
>>>>
>>>> static void pwm_beeper_work(struct work_struct *work)
>>>> @@ -82,6 +97,10 @@ static void pwm_beeper_stop(struct pwm_beeper *beeper)
>>>> {
>>>> cancel_work_sync(&beeper->work);
>>>>
>>>> + if (beeper->reg_enabled) {
>>>> + regulator_disable(beeper->reg);
>>>> + beeper->reg_enabled = false;
>>>> + }
>>>> if (beeper->period)
>>>> pwm_disable(beeper->pwm);
>>>> }
>>>> @@ -111,6 +130,14 @@ static int pwm_beeper_probe(struct platform_device *pdev)
>>>> return error;
>>>> }
>>>>
>>>> + beeper->reg = devm_regulator_get_optional(&pdev->dev, "amp");
>>>
>>> If you do not use optional regulator then you will not have to check if
>>> you have it or not everywhere: regulator core will give you a dummy that
>>> you can toggle to your heart's content.
>>
>> Some months ago, I learned that if you are not using device tree and
>> you do not call regulator_has_full_constraints(), then you do not
>> get a dummy regulator. And here, we are only checking if the
>> regulator exists in one place. We will still need the checks for
>> beeper->reg_enabled to keep calls to regulator_enable() and
>> regulator_disable() balanced.
>
> Why? You do not have checks for calls to pwm_enable() and pwm_disable(),
> (or rather beeper->period is used as such flag) why regulator would be
> any different?
regulator_enable() has a __must_check attribute on it, so we get
compiler warnings if we do not check the return value. Also, if enabling
the regulator fails and returns an error, then calling
regulator_disable() later would cause an imbalance.
pwm_enable() and pwm_disable() work differently because they don't count
how many times they have been called. regulator_enable() and
regulator_disable(), on the other hand, work like reference counting.
>
>>
>> On the other hand, it is recommended that you always call
>> regulator_has_full_constraints(), so I don't mind changing it if
>> that is what you think we should do. But, I don't really see much of
>> an advantage to changing it compared to the current implementation.
>
> It greatly simplifies control flow in the driver (since I believe you
> can get rid of the flags you introduced).
>
> As far as arch not having full constraints - I am not sure if this makes
> sense anymore. I am not quite sure what the original intent here was, we
> should probably ask Mark Brown. But a lot of drivers do expect the dummy
> substitution to imply work.
I am OK with using the dummy regulator, but I don't see how I can get
rid of the beeper->reg_enabled flag.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2 2/3] dt-bindings: Input: Add optional amp-supply property to pwm-beeper
2017-01-11 20:02 ` [PATCH v2 2/3] dt-bindings: Input: Add optional amp-supply property to pwm-beeper David Lechner
@ 2017-01-18 19:58 ` Rob Herring
0 siblings, 0 replies; 11+ messages in thread
From: Rob Herring @ 2017-01-18 19:58 UTC (permalink / raw)
To: David Lechner
Cc: linux-input, devicetree, Dmitry Torokhov, Mark Rutland, linux-kernel
On Wed, Jan 11, 2017 at 02:02:00PM -0600, David Lechner wrote:
> This adds an optional amp-supply property to pwm-beeper. This is a
> regulator that acts as an amplifier for the beeper.
>
> Signed-off-by: David Lechner <david@lechnology.com>
> ---
> Documentation/devicetree/bindings/input/pwm-beeper.txt | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
Acked-by: Rob Herring <robh@kernel.org>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator
2017-01-16 1:04 ` David Lechner
@ 2017-01-19 22:34 ` Dmitry Torokhov
0 siblings, 0 replies; 11+ messages in thread
From: Dmitry Torokhov @ 2017-01-19 22:34 UTC (permalink / raw)
To: David Lechner
Cc: linux-input, devicetree, Rob Herring, Mark Rutland, linux-kernel
On Sun, Jan 15, 2017 at 07:04:09PM -0600, David Lechner wrote:
> On 01/15/2017 06:34 PM, Dmitry Torokhov wrote:
> >On Sun, Jan 15, 2017 at 06:12:29PM -0600, David Lechner wrote:
> >>On 01/14/2017 01:19 PM, Dmitry Torokhov wrote:
> >>>On Wed, Jan 11, 2017 at 02:02:01PM -0600, David Lechner wrote:
> >>>>This adds an optional regulator to the pwm-beeper device. This regulator
> >>>>acts as an amplifier. The amplifier is only enabled while beeping in order
> >>>>to reduce power consumption.
> >>>>
> >>>>Tested on LEGO MINDSTORMS EV3, which has a speaker connected to PWM through
> >>>>an amplifier.
> >>>>
> >>>>Signed-off-by: David Lechner <david@lechnology.com>
> >>>>---
> >>>>drivers/input/misc/pwm-beeper.c | 29 ++++++++++++++++++++++++++++-
> >>>>1 file changed, 28 insertions(+), 1 deletion(-)
> >>>>
> >>>>diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
> >>>>index 30ac227..708e88e 100644
> >>>>--- a/drivers/input/misc/pwm-beeper.c
> >>>>+++ b/drivers/input/misc/pwm-beeper.c
> >>>>@@ -14,6 +14,7 @@
> >>>> */
> >>>>
> >>>>#include <linux/input.h>
> >>>>+#include <linux/regulator/consumer.h>
> >>>>#include <linux/module.h>
> >>>>#include <linux/kernel.h>
> >>>>#include <linux/of.h>
> >>>>@@ -25,8 +26,10 @@
> >>>>struct pwm_beeper {
> >>>> struct input_dev *input;
> >>>> struct pwm_device *pwm;
> >>>>+ struct regulator *reg;
> >>>> struct work_struct work;
> >>>> unsigned long period;
> >>>>+ bool reg_enabled;
> >>>>};
> >>>>
> >>>>#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
> >>>>@@ -38,8 +41,20 @@ static void __pwm_beeper_set(struct pwm_beeper *beeper)
> >>>> if (period) {
> >>>> pwm_config(beeper->pwm, period / 2, period);
> >>>> pwm_enable(beeper->pwm);
> >>>>- } else
> >>>>+ if (beeper->reg) {
> >>>>+ int error;
> >>>>+
> >>>>+ error = regulator_enable(beeper->reg);
> >>>>+ if (!error)
> >>>>+ beeper->reg_enabled = true;
> >>>>+ }
> >>>>+ } else {
> >>>>+ if (beeper->reg_enabled) {
> >>>>+ regulator_disable(beeper->reg);
> >>>>+ beeper->reg_enabled = false;
> >>>>+ }
> >>>> pwm_disable(beeper->pwm);
> >>>>+ }
> >>>>}
> >>>>
> >>>>static void pwm_beeper_work(struct work_struct *work)
> >>>>@@ -82,6 +97,10 @@ static void pwm_beeper_stop(struct pwm_beeper *beeper)
> >>>>{
> >>>> cancel_work_sync(&beeper->work);
> >>>>
> >>>>+ if (beeper->reg_enabled) {
> >>>>+ regulator_disable(beeper->reg);
> >>>>+ beeper->reg_enabled = false;
> >>>>+ }
> >>>> if (beeper->period)
> >>>> pwm_disable(beeper->pwm);
> >>>>}
> >>>>@@ -111,6 +130,14 @@ static int pwm_beeper_probe(struct platform_device *pdev)
> >>>> return error;
> >>>> }
> >>>>
> >>>>+ beeper->reg = devm_regulator_get_optional(&pdev->dev, "amp");
> >>>
> >>>If you do not use optional regulator then you will not have to check if
> >>>you have it or not everywhere: regulator core will give you a dummy that
> >>>you can toggle to your heart's content.
> >>
> >>Some months ago, I learned that if you are not using device tree and
> >>you do not call regulator_has_full_constraints(), then you do not
> >>get a dummy regulator. And here, we are only checking if the
> >>regulator exists in one place. We will still need the checks for
> >>beeper->reg_enabled to keep calls to regulator_enable() and
> >>regulator_disable() balanced.
> >
> >Why? You do not have checks for calls to pwm_enable() and pwm_disable(),
> >(or rather beeper->period is used as such flag) why regulator would be
> >any different?
>
> regulator_enable() has a __must_check attribute on it, so we get
> compiler warnings if we do not check the return value. Also, if
> enabling the regulator fails and returns an error, then calling
> regulator_disable() later would cause an imbalance.
>
> pwm_enable() and pwm_disable() work differently because they don't
> count how many times they have been called. regulator_enable() and
> regulator_disable(), on the other hand, work like reference
> counting.
Ah, you are right, but it is more than that. It is possible to receive
multiple SND_BELL/SND_TONE events with non-0 value. You need to check if
regulator is already enabled before trying to enable it second time, or
your counting will be off.
Thanks.
--
Dmitry
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2017-01-19 22:34 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-01-11 20:01 [PATCH v2 0/3] Input: add optional amplifier regulator to pwm-beeper (previously "Input: add optional enable gpio to pwm-beeper") David Lechner
2017-01-11 20:01 ` [PATCH v2 1/3] Input: pwm-beeper: suppress error message on probe defer David Lechner
2017-01-14 19:17 ` Dmitry Torokhov
2017-01-11 20:02 ` [PATCH v2 2/3] dt-bindings: Input: Add optional amp-supply property to pwm-beeper David Lechner
2017-01-18 19:58 ` Rob Herring
2017-01-11 20:02 ` [PATCH v2 3/3] Input: pwm-beeper: add optional amplifier regulator David Lechner
2017-01-14 19:19 ` Dmitry Torokhov
2017-01-16 0:12 ` David Lechner
2017-01-16 0:34 ` Dmitry Torokhov
2017-01-16 1:04 ` David Lechner
2017-01-19 22:34 ` Dmitry Torokhov
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).