2014-10-09 20:48:46

by Dinh Nguyen

Subject: [PATCHv2] reset: add reset_control_status helper function

From: Dinh Nguyen <[email protected]>

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 <[email protected]>
---
v2: reset_control_status should be returning an int, and add a comment about
status in reset-controller.h
---
drivers/reset/core.c | 13 +++++++++++++
include/linux/reset-controller.h | 2 ++
include/linux/reset.h | 7 +++++++
3 files changed, 22 insertions(+)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index baeaf82..1e7ff06 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
+ */
+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..ce6b962 100644
--- a/include/linux/reset-controller.h
+++ b/include/linux/reset-controller.h
@@ -12,11 +12,13 @@ struct reset_controller_dev;
* things to reset the device
* @assert: manually assert the reset line, if supported
* @deassert: manually deassert the reset line, if supported
+ * @status: return the status of the reset line, if supported
*/
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);
+ 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..f7c76f2 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 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

2014-10-10 08:14:35

by Philipp Zabel

Subject: Re: [PATCHv2] reset: add reset_control_status helper function

Hi Dinh,

you forgot one s/^+unsigned int/+int/ below.

Am Donnerstag, den 09.10.2014, 15:44 -0500 schrieb [email protected]:
[...]
> @@ -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

+ *
+ * Returns a negative errno if not supported, a positive value if the reset
+ * line is asserted, or zero if the reset line is not asserted.

Maybe add something like this?

[...]
> diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h
> index 41a4695..ce6b962 100644
> --- a/include/linux/reset-controller.h
> +++ b/include/linux/reset-controller.h
> @@ -12,11 +12,13 @@ struct reset_controller_dev;
> * things to reset the device
> * @assert: manually assert the reset line, if supported
> * @deassert: manually deassert the reset line, if supported
> + * @status: return the status of the reset line, if supported
> */
> 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);
> + 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..f7c76f2 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);

int

> struct reset_control *reset_control_get(struct device *dev, const char *id);
> void reset_control_put(struct reset_control *rstc);
[...]

regards
Philipp