* [PATCH] staging: greybus: introduce pwm_ops::apply
@ 2022-02-10 9:05 Song Chen
2022-02-10 10:03 ` Uwe Kleine-König
0 siblings, 1 reply; 5+ messages in thread
From: Song Chen @ 2022-02-10 9:05 UTC (permalink / raw)
To: johan, elder, gregkh, thierry.reding, u.kleine-koenig, lee.jones,
greybus-dev, linux-staging, linux-kernel, linux-pwm
Cc: Song Chen
Introduce apply in pwm_ops to replace legacy operations,
like enable, disable, config and set_polarity.
Signed-off-by: Song Chen <chensong_2000@189.cn>
---
drivers/staging/greybus/pwm.c | 46 +++++++++++++++--------------------
1 file changed, 19 insertions(+), 27 deletions(-)
diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c
index 891a6a672378..e1889cf979b2 100644
--- a/drivers/staging/greybus/pwm.c
+++ b/drivers/staging/greybus/pwm.c
@@ -204,43 +204,35 @@ static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
gb_pwm_deactivate_operation(pwmc, pwm->hwpwm);
}
-static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
- int duty_ns, int period_ns)
-{
- struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
-
- return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns);
-};
-
-static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
- enum pwm_polarity polarity)
+static int gb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
{
+ int ret;
struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
- return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity);
-};
-
-static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
- struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
+ /* set period and duty cycle*/
+ ret = gb_pwm_config_operation(pwmc, pwm->hwpwm, state->duty_cycle, state->period);
+ if (ret)
+ return ret;
- return gb_pwm_enable_operation(pwmc, pwm->hwpwm);
-};
+ /* set polarity */
+ ret = gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, state->polarity);
+ if (ret)
+ return ret;
-static void gb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
- struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
+ /* enable/disable */
+ if (state->enabled)
+ ret = gb_pwm_enable_operation(pwmc, pwm->hwpwm);
+ else
+ ret = gb_pwm_disable_operation(pwmc, pwm->hwpwm);
- gb_pwm_disable_operation(pwmc, pwm->hwpwm);
-};
+ return ret;
+}
static const struct pwm_ops gb_pwm_ops = {
.request = gb_pwm_request,
.free = gb_pwm_free,
- .config = gb_pwm_config,
- .set_polarity = gb_pwm_set_polarity,
- .enable = gb_pwm_enable,
- .disable = gb_pwm_disable,
+ .apply = gb_pwm_apply,
.owner = THIS_MODULE,
};
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] staging: greybus: introduce pwm_ops::apply
2022-02-10 9:05 [PATCH] staging: greybus: introduce pwm_ops::apply Song Chen
@ 2022-02-10 10:03 ` Uwe Kleine-König
2022-02-11 3:06 ` Song Chen
0 siblings, 1 reply; 5+ messages in thread
From: Uwe Kleine-König @ 2022-02-10 10:03 UTC (permalink / raw)
To: Song Chen
Cc: johan, elder, gregkh, thierry.reding, lee.jones, greybus-dev,
linux-staging, linux-kernel, linux-pwm
[-- Attachment #1: Type: text/plain, Size: 2228 bytes --]
On Thu, Feb 10, 2022 at 05:05:02PM +0800, Song Chen wrote:
> Introduce apply in pwm_ops to replace legacy operations,
> like enable, disable, config and set_polarity.
>
> Signed-off-by: Song Chen <chensong_2000@189.cn>
> ---
> drivers/staging/greybus/pwm.c | 46 +++++++++++++++--------------------
> 1 file changed, 19 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c
> index 891a6a672378..e1889cf979b2 100644
> --- a/drivers/staging/greybus/pwm.c
> +++ b/drivers/staging/greybus/pwm.c
> @@ -204,43 +204,35 @@ static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
> gb_pwm_deactivate_operation(pwmc, pwm->hwpwm);
> }
>
> -static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> - int duty_ns, int period_ns)
> -{
> - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
> -
> - return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns);
> -};
> -
> -static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
> - enum pwm_polarity polarity)
> +static int gb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> + const struct pwm_state *state)
> {
> + int ret;
> struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
>
> - return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity);
> -};
> -
> -static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> -{
> - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
> + /* set period and duty cycle*/
> + ret = gb_pwm_config_operation(pwmc, pwm->hwpwm, state->duty_cycle, state->period);
gb_pwm_config_operation's 3rd parameter is an u32, so you're loosing
bits here as state->duty_cycle is a u64. Ditto for period.
Also it would be nice if you go from
.duty_cycle = A, .period = B, .enabled = 1
to
.duty_cycle = C, .period = D, .enabled = 0
that C/D wasn't visible on the output pin. So please disable earlier
(but keep enable at the end).
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] staging: greybus: introduce pwm_ops::apply
2022-02-10 10:03 ` Uwe Kleine-König
@ 2022-02-11 3:06 ` Song Chen
2022-02-11 7:16 ` Uwe Kleine-König
0 siblings, 1 reply; 5+ messages in thread
From: Song Chen @ 2022-02-11 3:06 UTC (permalink / raw)
To: Uwe Kleine-König
Cc: johan, elder, gregkh, thierry.reding, lee.jones, greybus-dev,
linux-staging, linux-kernel, linux-pwm
在 2022/2/10 18:03, Uwe Kleine-König 写道:
> On Thu, Feb 10, 2022 at 05:05:02PM +0800, Song Chen wrote:
>> Introduce apply in pwm_ops to replace legacy operations,
>> like enable, disable, config and set_polarity.
>>
>> Signed-off-by: Song Chen <chensong_2000@189.cn>
>> ---
>> drivers/staging/greybus/pwm.c | 46 +++++++++++++++--------------------
>> 1 file changed, 19 insertions(+), 27 deletions(-)
>>
>> diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c
>> index 891a6a672378..e1889cf979b2 100644
>> --- a/drivers/staging/greybus/pwm.c
>> +++ b/drivers/staging/greybus/pwm.c
>> @@ -204,43 +204,35 @@ static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
>> gb_pwm_deactivate_operation(pwmc, pwm->hwpwm);
>> }
>>
>> -static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>> - int duty_ns, int period_ns)
>> -{
>> - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
>> -
>> - return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns);
>> -};
>> -
>> -static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
>> - enum pwm_polarity polarity)
>> +static int gb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>> + const struct pwm_state *state)
>> {
>> + int ret;
>> struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
>>
>> - return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity);
>> -};
>> -
>> -static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
>> -{
>> - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
>> + /* set period and duty cycle*/
>> + ret = gb_pwm_config_operation(pwmc, pwm->hwpwm, state->duty_cycle, state->period);
>
> gb_pwm_config_operation's 3rd parameter is an u32, so you're loosing
> bits here as state->duty_cycle is a u64. Ditto for period.
originally, pwm_apply_state --> pwm_apply_legacy --> gb_pwm_config -->
gb_pwm_config_operation is also loosing bits, does it mean greybus can
live with that?
Or redefine gb_pwm_config_request, switch duty and period to __le64?
>
> Also it would be nice if you go from
>
> .duty_cycle = A, .period = B, .enabled = 1
>
> to
>
> .duty_cycle = C, .period = D, .enabled = 0
>
> that C/D wasn't visible on the output pin. So please disable earlier
> (but keep enable at the end).
sorry, i don't quite understand this part, but is below code looking
good to you?
static int gb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
int err;
bool enabled = pwm->state.enabled;
struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
/* set polarity */
if (state->polarity != pwm->state.polarity) {
if (enabled) {
gb_pwm_disable_operation(pwmc, pwm->hwpwm);
enabled = false;
}
err = gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, state->polarity);
if (err)
return err;
}
if (!state->enabled) {
if (enabled)
gb_pwm_disable_operation(pwmc, pwm->hwpwm);
return 0;
}
/* set period and duty cycle*/
err = gb_pwm_config_operation(pwmc, pwm->hwpwm, state->duty_cycle,
state->period);
if (err)
return err;
/* enable/disable */
if (!enabled)
return gb_pwm_enable_operation(pwmc, pwm->hwpwm);
return 0;
}
>
> Best regards
> Uwe
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] staging: greybus: introduce pwm_ops::apply
2022-02-11 3:06 ` Song Chen
@ 2022-02-11 7:16 ` Uwe Kleine-König
2022-02-11 7:48 ` Song Chen
0 siblings, 1 reply; 5+ messages in thread
From: Uwe Kleine-König @ 2022-02-11 7:16 UTC (permalink / raw)
To: Song Chen
Cc: johan, elder, gregkh, thierry.reding, lee.jones, greybus-dev,
linux-staging, linux-kernel, linux-pwm
[-- Attachment #1: Type: text/plain, Size: 4646 bytes --]
Hello ,
On Fri, Feb 11, 2022 at 11:06:33AM +0800, Song Chen wrote:
> 在 2022/2/10 18:03, Uwe Kleine-König 写道:
> > On Thu, Feb 10, 2022 at 05:05:02PM +0800, Song Chen wrote:
> > > Introduce apply in pwm_ops to replace legacy operations,
> > > like enable, disable, config and set_polarity.
> > >
> > > Signed-off-by: Song Chen <chensong_2000@189.cn>
> > > ---
> > > drivers/staging/greybus/pwm.c | 46 +++++++++++++++--------------------
> > > 1 file changed, 19 insertions(+), 27 deletions(-)
> > >
> > > diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c
> > > index 891a6a672378..e1889cf979b2 100644
> > > --- a/drivers/staging/greybus/pwm.c
> > > +++ b/drivers/staging/greybus/pwm.c
> > > @@ -204,43 +204,35 @@ static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
> > > gb_pwm_deactivate_operation(pwmc, pwm->hwpwm);
> > > }
> > > -static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> > > - int duty_ns, int period_ns)
> > > -{
> > > - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
> > > -
> > > - return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns);
> > > -};
> > > -
> > > -static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
> > > - enum pwm_polarity polarity)
> > > +static int gb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> > > + const struct pwm_state *state)
> > > {
> > > + int ret;
> > > struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
> > > - return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity);
> > > -};
> > > -
> > > -static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> > > -{
> > > - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
> > > + /* set period and duty cycle*/
> > > + ret = gb_pwm_config_operation(pwmc, pwm->hwpwm, state->duty_cycle, state->period);
> >
> > gb_pwm_config_operation's 3rd parameter is an u32, so you're loosing
> > bits here as state->duty_cycle is a u64. Ditto for period.
>
> originally, pwm_apply_state --> pwm_apply_legacy --> gb_pwm_config -->
> gb_pwm_config_operation is also loosing bits, does it mean greybus can live
> with that?
This is true, I tried to address that, but Thierry had concerns.
(https://lore.kernel.org/all/20210312212119.1342666-1-u.kleine-koenig@pengutronix.de/
was the patch I suggested.)
> Or redefine gb_pwm_config_request, switch duty and period to __le64?
Don't use __le64, this is only for representing (little endian) register
values. u64 would be the right one.
> > Also it would be nice if you go from
> >
> > .duty_cycle = A, .period = B, .enabled = 1
> >
> > to
> >
> > .duty_cycle = C, .period = D, .enabled = 0
> >
> > that C/D wasn't visible on the output pin. So please disable earlier
> > (but keep enable at the end).
>
> sorry, i don't quite understand this part,
To reexplain: If your hardware is configured for
.duty_cycle = A, .period = B, .enabled = 1
and pwm_apply is called with
.duty_cycle = C, .period = D, .enabled = 0
you configured the registers for .duty_cycle and .period first and only
then disable the PWM. This usually results in glitches because the
hardware shortly runs with
.duty_cycle = C, .period = D, .enabled = 1
. So the idea is, to disable before configuring duty and period if the
eventual goal is a disabled state.
> but is below code looking good to
> you?
>
> static int gb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> const struct pwm_state *state)
> {
> int err;
> bool enabled = pwm->state.enabled;
> struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
>
> /* set polarity */
> if (state->polarity != pwm->state.polarity) {
> if (enabled) {
> gb_pwm_disable_operation(pwmc, pwm->hwpwm);
> enabled = false;
> }
> err = gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, state->polarity);
> if (err)
> return err;
> }
>
> if (!state->enabled) {
> if (enabled)
> gb_pwm_disable_operation(pwmc, pwm->hwpwm);
> return 0;
> }
>
> /* set period and duty cycle*/
> err = gb_pwm_config_operation(pwmc, pwm->hwpwm, state->duty_cycle, state->period);
> if (err)
> return err;
>
> /* enable/disable */
> if (!enabled)
> return gb_pwm_enable_operation(pwmc, pwm->hwpwm);
>
> return 0;
> }
This looks good.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
[-- Attachment #2: signature.asc --]
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] staging: greybus: introduce pwm_ops::apply
2022-02-11 7:16 ` Uwe Kleine-König
@ 2022-02-11 7:48 ` Song Chen
0 siblings, 0 replies; 5+ messages in thread
From: Song Chen @ 2022-02-11 7:48 UTC (permalink / raw)
To: Uwe Kleine-König
Cc: johan, elder, gregkh, thierry.reding, lee.jones, greybus-dev,
linux-staging, linux-kernel, linux-pwm
Hello Uwe,
Thanks for the explain, now i can understand it better.
So, if redefining period and duty as u64 in gb_pwm_config_request is an
acceptable solution, i will send patch v2.
BR
Song
在 2022/2/11 15:16, Uwe Kleine-König 写道:
> Hello ,
>
> On Fri, Feb 11, 2022 at 11:06:33AM +0800, Song Chen wrote:
>> 在 2022/2/10 18:03, Uwe Kleine-König 写道:
>>> On Thu, Feb 10, 2022 at 05:05:02PM +0800, Song Chen wrote:
>>>> Introduce apply in pwm_ops to replace legacy operations,
>>>> like enable, disable, config and set_polarity.
>>>>
>>>> Signed-off-by: Song Chen <chensong_2000@189.cn>
>>>> ---
>>>> drivers/staging/greybus/pwm.c | 46 +++++++++++++++--------------------
>>>> 1 file changed, 19 insertions(+), 27 deletions(-)
>>>>
>>>> diff --git a/drivers/staging/greybus/pwm.c b/drivers/staging/greybus/pwm.c
>>>> index 891a6a672378..e1889cf979b2 100644
>>>> --- a/drivers/staging/greybus/pwm.c
>>>> +++ b/drivers/staging/greybus/pwm.c
>>>> @@ -204,43 +204,35 @@ static void gb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
>>>> gb_pwm_deactivate_operation(pwmc, pwm->hwpwm);
>>>> }
>>>> -static int gb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>>>> - int duty_ns, int period_ns)
>>>> -{
>>>> - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
>>>> -
>>>> - return gb_pwm_config_operation(pwmc, pwm->hwpwm, duty_ns, period_ns);
>>>> -};
>>>> -
>>>> -static int gb_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
>>>> - enum pwm_polarity polarity)
>>>> +static int gb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>>>> + const struct pwm_state *state)
>>>> {
>>>> + int ret;
>>>> struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
>>>> - return gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, polarity);
>>>> -};
>>>> -
>>>> -static int gb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
>>>> -{
>>>> - struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
>>>> + /* set period and duty cycle*/
>>>> + ret = gb_pwm_config_operation(pwmc, pwm->hwpwm, state->duty_cycle, state->period);
>>>
>>> gb_pwm_config_operation's 3rd parameter is an u32, so you're loosing
>>> bits here as state->duty_cycle is a u64. Ditto for period.
>>
>> originally, pwm_apply_state --> pwm_apply_legacy --> gb_pwm_config -->
>> gb_pwm_config_operation is also loosing bits, does it mean greybus can live
>> with that?
>
> This is true, I tried to address that, but Thierry had concerns.
> (https://lore.kernel.org/all/20210312212119.1342666-1-u.kleine-koenig@pengutronix.de/
> was the patch I suggested.)
>
>> Or redefine gb_pwm_config_request, switch duty and period to __le64?
>
> Don't use __le64, this is only for representing (little endian) register
> values. u64 would be the right one.
>
>>> Also it would be nice if you go from
>>>
>>> .duty_cycle = A, .period = B, .enabled = 1
>>>
>>> to
>>>
>>> .duty_cycle = C, .period = D, .enabled = 0
>>>
>>> that C/D wasn't visible on the output pin. So please disable earlier
>>> (but keep enable at the end).
>>
>> sorry, i don't quite understand this part,
>
> To reexplain: If your hardware is configured for
>
> .duty_cycle = A, .period = B, .enabled = 1
>
> and pwm_apply is called with
>
> .duty_cycle = C, .period = D, .enabled = 0
>
> you configured the registers for .duty_cycle and .period first and only
> then disable the PWM. This usually results in glitches because the
> hardware shortly runs with
>
> .duty_cycle = C, .period = D, .enabled = 1
>
> . So the idea is, to disable before configuring duty and period if the
> eventual goal is a disabled state.
understood, thanks.
>
>> but is below code looking good to
>> you?
>>
>> static int gb_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>> const struct pwm_state *state)
>> {
>> int err;
>> bool enabled = pwm->state.enabled;
>> struct gb_pwm_chip *pwmc = pwm_chip_to_gb_pwm_chip(chip);
>>
>> /* set polarity */
>> if (state->polarity != pwm->state.polarity) {
>> if (enabled) {
>> gb_pwm_disable_operation(pwmc, pwm->hwpwm);
>> enabled = false;
>> }
>> err = gb_pwm_set_polarity_operation(pwmc, pwm->hwpwm, state->polarity);
>> if (err)
>> return err;
>> }
>>
>> if (!state->enabled) {
>> if (enabled)
>> gb_pwm_disable_operation(pwmc, pwm->hwpwm);
>> return 0;
>> }
>>
>> /* set period and duty cycle*/
>> err = gb_pwm_config_operation(pwmc, pwm->hwpwm, state->duty_cycle, state->period);
>> if (err)
>> return err;
>>
>> /* enable/disable */
>> if (!enabled)
>> return gb_pwm_enable_operation(pwmc, pwm->hwpwm);
>>
>> return 0;
>> }
>
> This looks good.
>
> Best regards
> Uwe
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-02-11 7:49 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2022-02-10 9:05 [PATCH] staging: greybus: introduce pwm_ops::apply Song Chen
2022-02-10 10:03 ` Uwe Kleine-König
2022-02-11 3:06 ` Song Chen
2022-02-11 7:16 ` Uwe Kleine-König
2022-02-11 7:48 ` Song Chen
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