diff mbox

[v9,3/5] rtc: max77686: Fail to probe if no RTC regmap irqchip is set

Message ID 1408350877-15921-4-git-send-email-javier.martinez@collabora.co.uk
State Superseded
Headers show

Commit Message

Javier Martinez Canillas Aug. 18, 2014, 8:34 a.m. UTC
The max77686 mfd driver adds a regmap IRQ chip which creates an
IRQ domain that is used to map the virtual RTC alarm1 interrupt.

The RTC driver assumes that this will always be true since the
PMIC IRQ is a required property according to the max77686 DT
binding doc. If an "interrupts" property is not defined for a
max77686 PMIC, then the mfd probe function will fail and the
RTC platform driver will never be probed. But even when it is
not possible to probe the rtc-max77686 driver without a regmap
IRQ chip, it's better to explicitly check if the IRQ chip data
is not NULL and gracefully fail instead of getting an OOPS.

Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
---

Fixes the issue reported by Krzystof in: https://lkml.org/lkml/2014/8/8/121
---
 drivers/rtc/rtc-max77686.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Krzysztof Kozlowski Aug. 28, 2014, 9:21 a.m. UTC | #1
On pon, 2014-08-18 at 10:34 +0200, Javier Martinez Canillas wrote:
> The max77686 mfd driver adds a regmap IRQ chip which creates an
> IRQ domain that is used to map the virtual RTC alarm1 interrupt.
> 
> The RTC driver assumes that this will always be true since the
> PMIC IRQ is a required property according to the max77686 DT
> binding doc. If an "interrupts" property is not defined for a
> max77686 PMIC, then the mfd probe function will fail and the
> RTC platform driver will never be probed. But even when it is
> not possible to probe the rtc-max77686 driver without a regmap
> IRQ chip, it's better to explicitly check if the IRQ chip data
> is not NULL and gracefully fail instead of getting an OOPS.

The OOPS was possible only with Bartlomiej's patch because he changed
the MFD driver probe function to skip IRQ setup on lack of interrupts.
In current state the OOPS should not happen so mentioning OOPS in commit
message may be misleading. Maybe just don't put the OOPS here?

Anyway the patch looks good and a check for non-null
regmap_irq_chip_data is still a valid precaution so:

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

Best regards,
Krzysztof


> 
> Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
> ---
> 
> Fixes the issue reported by Krzystof in: https://lkml.org/lkml/2014/8/8/121
> ---
>  drivers/rtc/rtc-max77686.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
> index 7bb5433..55396bb 100644
> --- a/drivers/rtc/rtc-max77686.c
> +++ b/drivers/rtc/rtc-max77686.c
> @@ -466,6 +466,12 @@ static int max77686_rtc_probe(struct platform_device *pdev)
>  		goto err_rtc;
>  	}
>  
> +	if (!max77686->rtc_irq_data) {
> +		ret = -EINVAL;
> +		dev_err(&pdev->dev, "%s: no RTC regmap IRQ chip\n", __func__);
> +		goto err_rtc;
> +	}
> +
>  	info->virq = regmap_irq_get_virq(max77686->rtc_irq_data,
>  					 MAX77686_RTCIRQ_RTCA1);
>  	if (!info->virq) {
Javier Martinez Canillas Sept. 8, 2014, 6:50 a.m. UTC | #2
Hello Krzysztof,

Sorry for the late response, I was on holidays and slowly catching up on email.

On 08/28/2014 11:21 AM, Krzysztof Kozlowski wrote:
> On pon, 2014-08-18 at 10:34 +0200, Javier Martinez Canillas wrote:
>> The max77686 mfd driver adds a regmap IRQ chip which creates an
>> IRQ domain that is used to map the virtual RTC alarm1 interrupt.
>> 
>> The RTC driver assumes that this will always be true since the
>> PMIC IRQ is a required property according to the max77686 DT
>> binding doc. If an "interrupts" property is not defined for a
>> max77686 PMIC, then the mfd probe function will fail and the
>> RTC platform driver will never be probed. But even when it is
>> not possible to probe the rtc-max77686 driver without a regmap
>> IRQ chip, it's better to explicitly check if the IRQ chip data
>> is not NULL and gracefully fail instead of getting an OOPS.
> 
> The OOPS was possible only with Bartlomiej's patch because he changed
> the MFD driver probe function to skip IRQ setup on lack of interrupts.
> In current state the OOPS should not happen so mentioning OOPS in commit
> message may be misleading. Maybe just don't put the OOPS here?
> 
> Anyway the patch looks good and a check for non-null
> regmap_irq_chip_data is still a valid precaution so:
>

Yes I know but as you said the check for non-null is still a valid precaution
(albeit maybe paranoid) just in case someone find that not having the IRQ
hooked makes sense in a design and changes the mfd driver in the future.

> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> 
> Best regards,
> Krzysztof
> 
> 

Best regards,
Javier
diff mbox

Patch

diff --git a/drivers/rtc/rtc-max77686.c b/drivers/rtc/rtc-max77686.c
index 7bb5433..55396bb 100644
--- a/drivers/rtc/rtc-max77686.c
+++ b/drivers/rtc/rtc-max77686.c
@@ -466,6 +466,12 @@  static int max77686_rtc_probe(struct platform_device *pdev)
 		goto err_rtc;
 	}
 
+	if (!max77686->rtc_irq_data) {
+		ret = -EINVAL;
+		dev_err(&pdev->dev, "%s: no RTC regmap IRQ chip\n", __func__);
+		goto err_rtc;
+	}
+
 	info->virq = regmap_irq_get_virq(max77686->rtc_irq_data,
 					 MAX77686_RTCIRQ_RTCA1);
 	if (!info->virq) {