[PATCH] reset: add reset_control_status helper function

[PATCH] reset: add reset_control_status helper function

[dinguyen]

From: Dinh Nguyen <dinguyen@opensource.altera.com>

There are cases where a system will want to read a reset status bit before
doing any other toggling. Add a reset_control_status helper function to the
reset controller API.

Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
---
 drivers/reset/core.c             | 13 +++++++++++++
 include/linux/reset-controller.h |  1 +
 include/linux/reset.h            |  7 +++++++
 3 files changed, 21 insertions(+)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index baeaf82..06387a4 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -126,6 +126,19 @@ int reset_control_deassert(struct reset_control *rstc)
 EXPORT_SYMBOL_GPL(reset_control_deassert);
 
 /**
+ * reset_control_status - returns a status of a reset bit
+ * @rstc: reset controller
+ */
+unsigned int reset_control_status(struct reset_control *rstc)
+{
+	if (rstc->rcdev->ops->status)
+		return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
+
+	return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(reset_control_status);
+
+/**
  * of_reset_control_get - Lookup and obtain a reference to a reset controller.
  * @node: device to be reset by the controller
  * @id: reset line name
diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h
index 41a4695..8e659d5 100644
--- a/include/linux/reset-controller.h
+++ b/include/linux/reset-controller.h
@@ -17,6 +17,7 @@ struct reset_control_ops {
 	int (*reset)(struct reset_controller_dev *rcdev, unsigned long id);
 	int (*assert)(struct reset_controller_dev *rcdev, unsigned long id);
 	int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id);
+	unsigned int (*status)(struct reset_controller_dev *rcdev, unsigned long id);
 };
 
 struct module;
diff --git a/include/linux/reset.h b/include/linux/reset.h
index 349f150..09233ee 100644
--- a/include/linux/reset.h
+++ b/include/linux/reset.h
@@ -10,6 +10,7 @@ struct reset_control;
 int reset_control_reset(struct reset_control *rstc);
 int reset_control_assert(struct reset_control *rstc);
 int reset_control_deassert(struct reset_control *rstc);
+unsigned int reset_control_status(struct reset_control *rstc);
 
 struct reset_control *reset_control_get(struct device *dev, const char *id);
 void reset_control_put(struct reset_control *rstc);
@@ -57,6 +58,12 @@ static inline int reset_control_deassert(struct reset_control *rstc)
 	return 0;
 }
 
+static inline unsigned int reset_control_status(struct reset_control *rstc)
+{
+	WARN_ON(1);
+	return 0;
+}
+
 static inline void reset_control_put(struct reset_control *rstc)
 {
 	WARN_ON(1);
-- 
2.0.3

Re: [PATCH] reset: add reset_control_status helper function

[Philipp Zabel]

Hi Dinh,

thank you for the patch. Just two small issues below:

Am Mittwoch, den 08.10.2014, 17:45 -0500 schrieb dinguyen@opensource.altera.com:
[...]
> @@ -126,6 +126,19 @@ int reset_control_deassert(struct reset_control *rstc)
>  EXPORT_SYMBOL_GPL(reset_control_deassert);
>  
>  /**
> + * reset_control_status - returns a status of a reset bit
> + * @rstc: reset controller
> + */
> +unsigned int reset_control_status(struct reset_control *rstc)
> +{
> +	if (rstc->rcdev->ops->status)
> +		return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
> +
> +	return -ENOSYS;
> +}
> +EXPORT_SYMBOL_GPL(reset_control_status);

Since this function can return negative error numbers, please make the
return value of reset_control_status int. That also means that drivers
must not set the MSB when returning status.

> +
> +/**
>   * of_reset_control_get - Lookup and obtain a reference to a reset controller.
>   * @node: device to be reset by the controller
>   * @id: reset line name
> diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h
> index 41a4695..8e659d5 100644
> --- a/include/linux/reset-controller.h
> +++ b/include/linux/reset-controller.h
> @@ -17,6 +17,7 @@ struct reset_control_ops {
>  	int (*reset)(struct reset_controller_dev *rcdev, unsigned long id);
>  	int (*assert)(struct reset_controller_dev *rcdev, unsigned long id);
>  	int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id);
> +	unsigned int (*status)(struct reset_controller_dev *rcdev, unsigned long id);
>  };

Please change the return value of the status callback to int and
describe it in the kerneldoc comment above. It should probably be
mentioned that the returned status value must be >= 0 except in error
cases.
 
regards
Philipp

Re: [PATCH] reset: add reset_control_status helper function

[Dinh Nguyen]

Hi Philipp,

On 10/9/14, 3:44 AM, Philipp Zabel wrote:
> Hi Dinh,
> 
> thank you for the patch. Just two small issues below:
> 
> Am Mittwoch, den 08.10.2014, 17:45 -0500 schrieb dinguyen@opensource.altera.com:
> [...]
>> @@ -126,6 +126,19 @@ int reset_control_deassert(struct reset_control *rstc)
>>  EXPORT_SYMBOL_GPL(reset_control_deassert);
>>  
>>  /**
>> + * reset_control_status - returns a status of a reset bit
>> + * @rstc: reset controller
>> + */
>> +unsigned int reset_control_status(struct reset_control *rstc)
>> +{
>> +	if (rstc->rcdev->ops->status)
>> +		return rstc->rcdev->ops->status(rstc->rcdev, rstc->id);
>> +
>> +	return -ENOSYS;
>> +}
>> +EXPORT_SYMBOL_GPL(reset_control_status);
> 
> Since this function can return negative error numbers, please make the
> return value of reset_control_status int. That also means that drivers
> must not set the MSB when returning status.

Ah yes...Don't why I changed it to unsigned int for the return.

> 
>> +
>> +/**
>>   * of_reset_control_get - Lookup and obtain a reference to a reset controller.
>>   * @node: device to be reset by the controller
>>   * @id: reset line name
>> diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h
>> index 41a4695..8e659d5 100644
>> --- a/include/linux/reset-controller.h
>> +++ b/include/linux/reset-controller.h
>> @@ -17,6 +17,7 @@ struct reset_control_ops {
>>  	int (*reset)(struct reset_controller_dev *rcdev, unsigned long id);
>>  	int (*assert)(struct reset_controller_dev *rcdev, unsigned long id);
>>  	int (*deassert)(struct reset_controller_dev *rcdev, unsigned long id);
>> +	unsigned int (*status)(struct reset_controller_dev *rcdev, unsigned long id);
>>  };
> 
> Please change the return value of the status callback to int and
> describe it in the kerneldoc comment above. It should probably be
> mentioned that the returned status value must be >= 0 except in error
> cases.
>  
Will do for V2...

Dinh