Re: [PATCH v3 1/2] hwmon: pwm-fan: Store tach data separately

[Guenter Roeck <linux@roeck-us.net>]

On Sat, Dec 12, 2020 at 07:50:07PM +0000, Paul Barker wrote:
> The data for the (optional) fan tachometer input is moved to a separate
> structure which is only allocated if an input is actually configured.
> 
> After this change the pulse IRQ handler takes a pointer to the
> tachometer data structure instead of the whole device context.
> 
> Signed-off-by: Paul Barker <pbarker@konsulko.com>

Applied.

Thanks,
Guenter

> ---
>  drivers/hwmon/pwm-fan.c | 52 +++++++++++++++++++++++++----------------
>  1 file changed, 32 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
> index 777439f48c14..4a7f0e87b08f 100644
> --- a/drivers/hwmon/pwm-fan.c
> +++ b/drivers/hwmon/pwm-fan.c
> @@ -21,15 +21,19 @@
>  
>  #define MAX_PWM 255
>  
> +struct pwm_fan_tach {
> +	int irq;
> +	atomic_t pulses;
> +	unsigned int rpm;
> +	u8 pulses_per_revolution;
> +};
> +
>  struct pwm_fan_ctx {
>  	struct mutex lock;
>  	struct pwm_device *pwm;
>  	struct regulator *reg_en;
>  
> -	int irq;
> -	atomic_t pulses;
> -	unsigned int rpm;
> -	u8 pulses_per_revolution;
> +	struct pwm_fan_tach *tach;
>  	ktime_t sample_start;
>  	struct timer_list rpm_timer;
>  
> @@ -65,9 +69,9 @@ static const struct hwmon_channel_info pwm_fan_channel_fan = {
>  /* This handler assumes self resetting edge triggered interrupt. */
>  static irqreturn_t pulse_handler(int irq, void *dev_id)
>  {
> -	struct pwm_fan_ctx *ctx = dev_id;
> +	struct pwm_fan_tach *tach = dev_id;
>  
> -	atomic_inc(&ctx->pulses);
> +	atomic_inc(&tach->pulses);
>  
>  	return IRQ_HANDLED;
>  }
> @@ -75,14 +79,15 @@ static irqreturn_t pulse_handler(int irq, void *dev_id)
>  static void sample_timer(struct timer_list *t)
>  {
>  	struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
> +	struct pwm_fan_tach *tach = ctx->tach;
>  	unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
>  	int pulses;
>  
>  	if (delta) {
> -		pulses = atomic_read(&ctx->pulses);
> -		atomic_sub(pulses, &ctx->pulses);
> -		ctx->rpm = (unsigned int)(pulses * 1000 * 60) /
> -			(ctx->pulses_per_revolution * delta);
> +		pulses = atomic_read(&tach->pulses);
> +		atomic_sub(pulses, &tach->pulses);
> +		tach->rpm = (unsigned int)(pulses * 1000 * 60) /
> +			(tach->pulses_per_revolution * delta);
>  
>  		ctx->sample_start = ktime_get();
>  	}
> @@ -152,7 +157,7 @@ static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
>  		return 0;
>  
>  	case hwmon_fan:
> -		*val = ctx->rpm;
> +		*val = ctx->tach->rpm;
>  		return 0;
>  
>  	default:
> @@ -362,14 +367,21 @@ static int pwm_fan_probe(struct platform_device *pdev)
>  	channels[0] = &pwm_fan_channel_pwm;
>  
>  	if (tach_count > 0) {
> +		struct pwm_fan_tach *tach;
>  		u32 ppr = 2;
>  
> -		ctx->irq = platform_get_irq(pdev, 0);
> -		if (ctx->irq == -EPROBE_DEFER)
> -			return ctx->irq;
> -		if (ctx->irq > 0) {
> -			ret = devm_request_irq(dev, ctx->irq, pulse_handler, 0,
> -					       pdev->name, ctx);
> +		tach = devm_kzalloc(dev, sizeof(struct pwm_fan_tach),
> +					 GFP_KERNEL);
> +		if (!tach)
> +			return -ENOMEM;
> +		ctx->tach = tach;
> +
> +		tach->irq = platform_get_irq(pdev, 0);
> +		if (tach->irq == -EPROBE_DEFER)
> +			return tach->irq;
> +		if (tach->irq > 0) {
> +			ret = devm_request_irq(dev, tach->irq, pulse_handler, 0,
> +					       pdev->name, tach);
>  			if (ret) {
>  				dev_err(dev,
>  					"Failed to request interrupt: %d\n",
> @@ -381,14 +393,14 @@ static int pwm_fan_probe(struct platform_device *pdev)
>  		of_property_read_u32(dev->of_node,
>  				     "pulses-per-revolution",
>  				     &ppr);
> -		ctx->pulses_per_revolution = ppr;
> -		if (!ctx->pulses_per_revolution) {
> +		tach->pulses_per_revolution = ppr;
> +		if (!tach->pulses_per_revolution) {
>  			dev_err(dev, "pulses-per-revolution can't be zero.\n");
>  			return -EINVAL;
>  		}
>  
>  		dev_dbg(dev, "tach: irq=%d, pulses_per_revolution=%d\n",
> -			ctx->irq, ctx->pulses_per_revolution);
> +			tach->irq, tach->pulses_per_revolution);
>  
>  		ctx->sample_start = ktime_get();
>  		mod_timer(&ctx->rpm_timer, jiffies + HZ);