| Message ID | 1484164921-30587-4-git-send-email-david@lechnology.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
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.
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. > -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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.
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. -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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.
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.
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(-)