Re: [PATCH v2 1/2] hwmon: pwm-fan: Refactor pwm_fan_probe

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

On Sat, Nov 28, 2020 at 05:49:08PM +0000, Paul Barker wrote:
> Use platform_irq_count to determine the number of fan tachometer inputs
> configured in the device tree. At this stage we support either 0 or 1
> inputs.
> 
> Once we have this information we only need to read the
> pulses-per-revolution value if a fan tachometer is actually configured
> via an IRQ value.
> 
> Also add a debug print of the IRQ number and the pulses-per-revolution
> value to aid in investigating issues.
> 
> Signed-off-by: Paul Barker <pbarker@konsulko.com>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>

Applied.

Thanks,
Guenter

> ---
>  drivers/hwmon/pwm-fan.c | 50 +++++++++++++++++++++++++++--------------
>  1 file changed, 33 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
> index 1f63807c0399..efe2764f42d3 100644
> --- a/drivers/hwmon/pwm-fan.c
> +++ b/drivers/hwmon/pwm-fan.c
> @@ -286,7 +286,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
>  	struct device *hwmon;
>  	int ret;
>  	struct pwm_state state = { };
> -	u32 ppr = 2;
> +	int tach_count;
>  
>  	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
>  	if (!ctx)
> @@ -300,10 +300,6 @@ static int pwm_fan_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, ctx);
>  
> -	ctx->irq = platform_get_irq_optional(pdev, 0);
> -	if (ctx->irq == -EPROBE_DEFER)
> -		return ctx->irq;
> -
>  	ctx->reg_en = devm_regulator_get_optional(dev, "fan");
>  	if (IS_ERR(ctx->reg_en)) {
>  		if (PTR_ERR(ctx->reg_en) != -ENODEV)
> @@ -339,20 +335,40 @@ static int pwm_fan_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> -	of_property_read_u32(dev->of_node, "pulses-per-revolution", &ppr);
> -	ctx->pulses_per_revolution = ppr;
> -	if (!ctx->pulses_per_revolution) {
> -		dev_err(dev, "pulses-per-revolution can't be zero.\n");
> -		return -EINVAL;
> -	}
> +	tach_count = platform_irq_count(pdev);
> +	if (tach_count < 0)
> +		return dev_err_probe(dev, tach_count,
> +				     "Could not get number of fan tachometer inputs\n");
> +
> +	if (tach_count > 0) {
> +		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);
> +			if (ret) {
> +				dev_err(dev,
> +					"Failed to request interrupt: %d\n",
> +					ret);
> +				return ret;
> +			}
> +		}
>  
> -	if (ctx->irq > 0) {
> -		ret = devm_request_irq(dev, ctx->irq, pulse_handler, 0,
> -				       pdev->name, ctx);
> -		if (ret) {
> -			dev_err(dev, "Failed to request interrupt: %d\n", ret);
> -			return ret;
> +		of_property_read_u32(dev->of_node,
> +				     "pulses-per-revolution",
> +				     &ppr);
> +		ctx->pulses_per_revolution = ppr;
> +		if (!ctx->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);
> +
>  		ctx->sample_start = ktime_get();
>  		mod_timer(&ctx->rpm_timer, jiffies + HZ);
>  	}
> -- 
> 2.26.2
>