Re: [PATCH v4 06/21] thermal/drivers/db8500: convert to use devm_request*_irq_probe()

[Dmitry Baryshkov]

On 10/07/2023 12:59, Yangtao Li wrote:
> There are more than 700 calls to devm_request_threaded_irq method and
> more than 1000 calls to devm_request_irq method. Most drivers only
> request one interrupt resource, and these error messages are basically
> the same. If error messages are printed everywhere, more than 2000 lines
> of code can be saved by removing the msg in the driver.
>
> And tglx point out that:
>
>    If we actually look at the call sites of
>    devm_request_threaded_irq() then the vast majority of them print more or
>    less lousy error messages. A quick grep/sed/awk/sort/uniq revealed
>
>       519 messages total (there are probably more)
>
>       352 unique messages
>
>       323 unique messages after lower casing
>
>           Those 323 are mostly just variants of the same patterns with
>           slight modifications in formatting and information provided.
>
>       186 of these messages do not deliver any useful information,
>           e.g. "no irq", "
>
>       The most useful one of all is: "could request wakeup irq: %d"
>
>    So there is certainly an argument to be made that this particular
>    function should print a well formatted and informative error message.
>
>    It's not a general allocator like kmalloc(). It's specialized and in the
>    vast majority of cases failing to request the interrupt causes the
>    device probe to fail. So having proper and consistent information why
>    the device cannot be used _is_ useful.
>
> So convert to use devm_request*_irq_probe() API, which ensure that all
> error handling branches print error information.
>
> In this way, when this function fails, the upper-layer functions can
> directly return an error code without missing debugging information.
> Otherwise, the error message will be printed redundantly or missing.
>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> Cc: "Uwe Kleine-König" <u.kleine-koenig@xxxxxxxxxxxxxx>
> Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> Cc: AngeloGioacchino Del Regno  <angelogioacchino.delregno@xxxxxxxxxxxxx>
> Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
> ---
>   drivers/thermal/db8500_thermal.c | 16 ++++++----------
>   drivers/thermal/qcom/lmh.c       |  7 +++----

Please split LMH to a separate driver.

>   2 files changed, 9 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/thermal/db8500_thermal.c b/drivers/thermal/db8500_thermal.c
> index fca5c2c93bf9..0ef8fc2eb4a1 100644
> --- a/drivers/thermal/db8500_thermal.c
> +++ b/drivers/thermal/db8500_thermal.c
> @@ -164,25 +164,21 @@ static int db8500_thermal_probe(struct platform_device *pdev)
>   	if (low_irq < 0)
>   		return low_irq;
>   
> -	ret = devm_request_threaded_irq(dev, low_irq, NULL,
> +	ret = devm_request_threaded_irq_probe(dev, low_irq, NULL,
>   		prcmu_low_irq_handler, IRQF_NO_SUSPEND | IRQF_ONESHOT,
> -		"dbx500_temp_low", th);
> -	if (ret < 0) {
> -		dev_err(dev, "failed to allocate temp low irq\n");
> +		"dbx500_temp_low", th, "temp low");
> +	if (ret < 0)
>   		return ret;
> -	}
>   
>   	high_irq = platform_get_irq_byname(pdev, "IRQ_HOTMON_HIGH");
>   	if (high_irq < 0)
>   		return high_irq;
>   
> -	ret = devm_request_threaded_irq(dev, high_irq, NULL,
> +	ret = devm_request_threaded_irq_probe(dev, high_irq, NULL,
>   		prcmu_high_irq_handler, IRQF_NO_SUSPEND | IRQF_ONESHOT,
> -		"dbx500_temp_high", th);
> -	if (ret < 0) {
> -		dev_err(dev, "failed to allocate temp high irq\n");
> +		"dbx500_temp_high", th, "temp high");
> +	if (ret < 0)
>   		return ret;
> -	}
>   
>   	/* register of thermal sensor and get info from DT */
>   	th->tz = devm_thermal_of_zone_register(dev, 0, th, &thdev_ops);
> diff --git a/drivers/thermal/qcom/lmh.c b/drivers/thermal/qcom/lmh.c
> index f6edb12ec004..48a14d7e8bf5 100644
> --- a/drivers/thermal/qcom/lmh.c
> +++ b/drivers/thermal/qcom/lmh.c
> @@ -207,11 +207,10 @@ static int lmh_probe(struct platform_device *pdev)
>   
>   	/* Disable the irq and let cpufreq enable it when ready to handle the interrupt */
>   	irq_set_status_flags(lmh_data->irq, IRQ_NOAUTOEN);
> -	ret = devm_request_irq(dev, lmh_data->irq, lmh_handle_irq,
> -			       IRQF_ONESHOT | IRQF_NO_SUSPEND,
> -			       "lmh-irq", lmh_data);
> +	ret = devm_request_irq_probe(dev, lmh_data->irq, lmh_handle_irq,
> +				     IRQF_ONESHOT | IRQF_NO_SUSPEND,
> +				     "lmh-irq", lmh_data, NULL);
>   	if (ret) {
> -		dev_err(dev, "Error %d registering irq %x\n", ret, lmh_data->irq);
>   		irq_domain_remove(lmh_data->domain);
>   		return ret;
>   	}

--
With best wishes
Dmitry