Hi Claudiu,
On Thu, 23 Feb 2017 12:25:58 +0200
m18063 <Claudiu.Beznea@xxxxxxxxxxxxx> wrote:
> Hi,
>
>
> On 23.02.2017 11:21, Alexandre Belloni wrote:
> > On 23/02/2017 at 10:38:40 +0200, Claudiu Beznea wrote:
> >> sama5d2 supports changing of pwm parameters like period and
> >> duty factor without first to disable pwm. Since pwm code
> >> is supported by more than one SoC add allow_runtime_cfg
> >> parameter to atmel_pwm_chip data structure. This will be
> >> filled statically for every SoC, saved in pwm specific
> >> structure at probing time and checked while configuring
> >> the device. Based on this, pwm clock will not be
> >> enabled/disabled while configuring if it still enabled.
> >>
> >> Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
> >> ---
> >> drivers/pwm/pwm-atmel.c | 24 ++++++++++++++++++------
> >> 1 file changed, 18 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
> >> index 4406639..9e1dece 100644
> >> --- a/drivers/pwm/pwm-atmel.c
> >> +++ b/drivers/pwm/pwm-atmel.c
> >> @@ -68,6 +68,8 @@ struct atmel_pwm_chip {
> >>
> >> void (*config)(struct pwm_chip *chip, struct pwm_device *pwm,
> >> unsigned long dty, unsigned long prd);
> >> +
> >> + bool allow_runtime_cfg;
> >> };
> >>
> >> static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct pwm_chip *chip)
> >> @@ -114,7 +116,8 @@ static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> >> u32 val;
> >> int ret;
> >>
> >> - if (pwm_is_enabled(pwm) && (period_ns != pwm_get_period(pwm))) {
> >> + if (!atmel_pwm->allow_runtime_cfg &&
> >> + pwm_is_enabled(pwm) && (period_ns != pwm_get_period(pwm))) {
> >> dev_err(chip->dev, "cannot change PWM period while enabled\n");
> >> return -EBUSY;
> >> }
> >> @@ -139,10 +142,12 @@ static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> >> do_div(div, period_ns);
> >> dty = prd - div;
> >>
> >> - ret = clk_enable(atmel_pwm->clk);
> >> - if (ret) {
> >> - dev_err(chip->dev, "failed to enable PWM clock\n");
> >> - return ret;
> >> + if (!pwm_is_enabled(pwm)) {
> >> + ret = clk_enable(atmel_pwm->clk);
> >> + if (ret) {
> >> + dev_err(chip->dev, "failed to enable PWM clock\n");
> >> + return ret;
> >> + }
> >> }
> >>
> > It is probably worth switching to atomic PWM instead of changing this
> > function. This would simplify the whole driver.
> I was thinking to switch to atomic PWM in a future patch.
Actually, I think it's better to do it before adding support for the
new IP (even before patch 1), but maybe I'm the only one to think
so :-).
Note that switching to the atomic API is not a big (actually, it should
even simplify the code).
Regards,
Boris
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