Re: [PATCH v6 1/7] thermal/drivers/loongson2: Correct thermal sensor registration loop

[Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>]

On 9/28/26 06:44, Binbin Zhou wrote:
> The registration loop in loongson2_thermal_probe() incorrectly uses
> dev_err_probe() when the sensor is not present (-ENODEV). In that case,
> the driver should continue to the next sensor index rather than treating
> it as a fatal error.
> 
> Fix this by correctly handling -ENODEV and only returning on other
> errors. Also add a final check to ensure at least one thermal zone was
> registered.
> 
> Cc: stable@vger.kernel.org
> Reported-by: Sashiko <sashiko-bot@kernel.org>
> Closes: https://sashiko.dev/#/patchset/cover.1783670011.git.zhoubinbin@loongson.cn?part=2
> Fixes: e7e3a7c35791 ("thermal/drivers/loongson-2: Add thermal management support")
> Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> ---
>   drivers/thermal/loongson2_thermal.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/thermal/loongson2_thermal.c b/drivers/thermal/loongson2_thermal.c
> index 4d40fc706a53..99b7392fc68f 100644
> --- a/drivers/thermal/loongson2_thermal.c
> +++ b/drivers/thermal/loongson2_thermal.c
> @@ -160,16 +160,18 @@ static int loongson2_thermal_probe(struct platform_device *pdev)
>   
>   	for (i = 0; i <= LOONGSON2_MAX_SENSOR_SEL_NUM; i++) {
>   		tzd = devm_thermal_of_zone_register(dev, i, data, thermal_ops);
> -
>   		if (!IS_ERR(tzd))
>   			break;
>   
> -		if (PTR_ERR(tzd) != -ENODEV)
> +		if (PTR_ERR(tzd) == -ENODEV)
>   			continue;
>   
> -		return dev_err_probe(dev, PTR_ERR(tzd), "failed to register");
> +		return dev_err_probe(dev, PTR_ERR(tzd), "failed to register sensor %d\n", i);


>   	}
>   
> +	if (IS_ERR(tzd))
> +		return dev_err_probe(dev, -ENODEV, "No thermal sensor registered\n");
> +
>   	ret = devm_request_threaded_irq(dev, irq, NULL, loongson2_thermal_irq_thread,
>   					IRQF_ONESHOT, "loongson2_thermal", tzd);
>   	if (ret < 0)


The [no]error paths are confusing and prone to error, eg: 'if there is 
no error then check if there is an error', 'when exiting the loop 
without registering any sensor, then we assume tzd is -ENODEV'.

Please make a less cumbersome and implicit checks here. For example 
count the number of sensors and then do the check against.