linux-kernel - RE: [PATCH] pwm: sti: Maintain a bitmap of configured devices

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Message-ID: <7C5AEAE2DCC6B24D92612A29E172F04A59034539BD@EAPEX1MAIL2.st.com>
Date:	Wed, 3 Dec 2014 17:18:42 +0800
From:	Ajit Pal SINGH <ajitpal.singh@...com>
To:	"thierry.reding@...il.com" <thierry.reding@...il.com>,
	"linux-pwm@...r.kernel.org" <linux-pwm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Maxime COQUELIN <maxime.coquelin@...com>
Subject: RE: [PATCH] pwm: sti: Maintain a bitmap of configured devices

Hi Thierry,

Can you please have a look at this patch.

Regards
Ajitpal Singh

> -----Original Message-----
> From: Ajit Pal SINGH
> Sent: Tuesday, November 11, 2014 4:08 PM
> To: thierry.reding@...il.com; linux-pwm@...r.kernel.org; linux-
> kernel@...r.kernel.org; Maxime COQUELIN
> Cc: Ajit Pal SINGH
> Subject: [PATCH] pwm: sti: Maintain a bitmap of configured devices
> 
> This patch introduces a bitmap which is used to keep track of the pwm channels
> which have been configured in a pwm chip.
> 
> The method used earlier to find the number of configured channels, was to count
> the pwmdevices with PWMF_REQUESTED field set and period value configured.
> This was not correct and failed when of_pwm_get()/pwm_get() and then
> pwm_config() was used.
> 
> Signed-off-by: Ajit Pal Singh <ajitpal.singh@...com>
> ---
>  drivers/pwm/pwm-sti.c |   30 +++++++++++-------------------
>  1 files changed, 11 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c index
> b95115c..92abbd5 100644
> --- a/drivers/pwm/pwm-sti.c
> +++ b/drivers/pwm/pwm-sti.c
> @@ -57,6 +57,7 @@ struct sti_pwm_chip {
>  	struct regmap_field *pwm_int_en;
>  	struct pwm_chip chip;
>  	struct pwm_device *cur;
> +	unsigned long configured;
>  	unsigned int en_count;
>  	struct mutex sti_pwm_lock; /* To sync between enable/disable calls */
>  	void __iomem *mmio;
> @@ -102,24 +103,6 @@ static int sti_pwm_get_prescale(struct sti_pwm_chip *pc,
> unsigned long period,
>  	return 0;
>  }
> 
> -/* Calculate the number of PWM devices configured with a period. */ -static
> unsigned int sti_pwm_count_configured(struct pwm_chip *chip) -{
> -	struct pwm_device *pwm;
> -	unsigned int ncfg = 0;
> -	unsigned int i;
> -
> -	for (i = 0; i < chip->npwm; i++) {
> -		pwm = &chip->pwms[i];
> -		if (test_bit(PWMF_REQUESTED, &pwm->flags)) {
> -			if (pwm_get_period(pwm))
> -				ncfg++;
> -		}
> -	}
> -
> -	return ncfg;
> -}
> -
>  /*
>   * For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles.
>   * The only way to change the period (apart from changing the PWM input clock)
> @@ -141,7 +124,7 @@ static int sti_pwm_config(struct pwm_chip *chip, struct
> pwm_device *pwm,
>  	unsigned int ncfg;
>  	bool period_same = false;
> 
> -	ncfg = sti_pwm_count_configured(chip);
> +	ncfg = hweight_long(pc->configured);
>  	if (ncfg)
>  		period_same = (period_ns == pwm_get_period(cur));
> 
> @@ -197,6 +180,7 @@ static int sti_pwm_config(struct pwm_chip *chip, struct
> pwm_device *pwm,
> 
>  		ret = regmap_field_write(pc->pwm_int_en, 0);
> 
> +		set_bit(pwm->hwpwm, &pc->configured);
>  		pc->cur = pwm;
> 
>  		dev_dbg(dev, "prescale:%u, period:%i, duty:%i, pwmvalx:%u\n",
> @@ -254,10 +238,18 @@ static void sti_pwm_disable(struct pwm_chip *chip, struct
> pwm_device *pwm)
>  	mutex_unlock(&pc->sti_pwm_lock);
>  }
> 
> +static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> +	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
> +
> +	clear_bit(pwm->hwpwm, &pc->configured); }
> +
>  static const struct pwm_ops sti_pwm_ops = {
>  	.config = sti_pwm_config,
>  	.enable = sti_pwm_enable,
>  	.disable = sti_pwm_disable,
> +	.free = sti_pwm_free,
>  	.owner = THIS_MODULE,
>  };
> 
> --
> 1.7.5.4

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