Subject: Re: [PATCH] genirq/irqdesc: Add state node to show if IRQ is enabled
To:     tglx@linutronix.de
Cc:     linux-kernel@vger.kernel.org
References: <20211116123447.23902-1-srinivas.kandagatla@linaro.org>
From:   Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Message-ID: <ffef6293-da93-2d22-f1eb-8e74a6035303@linaro.org>
Date:   Tue, 16 Nov 2021 12:47:24 +0000
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On 16/11/2021 12:34, Srinivas Kandagatla wrote:
> While debugging some issues with SoundWire WakeUp interrupt,
> I did not find a way to figure out if the interrupt is really enabled
> or disabled.
> 
> So I have added an new state entry in the sysfs to dump the current
> interrupt state.
> 
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> ---
> 
> While debugging I found this patch very useful, specially in SoundWire Wakeup
> usecase where we dynamically enable Low Power Wakeup interrupt.
> 
> Sending this out, hoping that it will be useful for others as well.
> 
> --srini


Please ignore this patch! It will not work for every case.

--srini


> 
> 
>   Documentation/ABI/testing/sysfs-kernel-irq |  7 +++++++
>   kernel/irq/irqdesc.c                       | 16 ++++++++++++++++
>   2 files changed, 23 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-kernel-irq b/Documentation/ABI/testing/sysfs-kernel-irq
> index 8910d0c4bcd8..d858ed133ba2 100644
> --- a/Documentation/ABI/testing/sysfs-kernel-irq
> +++ b/Documentation/ABI/testing/sysfs-kernel-irq
> @@ -58,3 +58,10 @@ KernelVersion:	4.17
>   Contact:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>   Description:	The wakeup state of the interrupt. Either the string
>   		'enabled' or 'disabled'.
> +
> +What:		/sys/kernel/irq/<irq>/state
> +Date:		November 2021
> +KernelVersion:	5.16
> +Contact:	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> +Description:	The state of the interrupt. Either the string
> +		'enabled' or 'disabled'.
> diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
> index 2267e6527db3..60c69978ea45 100644
> --- a/kernel/irq/irqdesc.c
> +++ b/kernel/irq/irqdesc.c
> @@ -265,6 +265,21 @@ static ssize_t actions_show(struct kobject *kobj,
>   }
>   IRQ_ATTR_RO(actions);
>   
> +static ssize_t state_show(struct kobject *kobj,
> +			  struct kobj_attribute *attr, char *buf)
> +{
> +	struct irq_desc *desc = container_of(kobj, struct irq_desc, kobj);
> +	ssize_t ret;
> +
> +	raw_spin_lock_irq(&desc->lock);
> +	ret = sprintf(buf, "%s\n",
> +		      irqd_irq_disabled(&desc->irq_data) ? "disabled" : "enabled");
> +	raw_spin_unlock_irq(&desc->lock);
> +
> +	return ret;
> +}
> +IRQ_ATTR_RO(state);
> +
>   static struct attribute *irq_attrs[] = {
>   	&per_cpu_count_attr.attr,
>   	&chip_name_attr.attr,
> @@ -273,6 +288,7 @@ static struct attribute *irq_attrs[] = {
>   	&wakeup_attr.attr,
>   	&name_attr.attr,
>   	&actions_attr.attr,
> +	&state_attr.attr,
>   	NULL
>   };
>   ATTRIBUTE_GROUPS(irq);
>