[v4,1/9] phy: add phy_get_bus_width()/phy_set_bus_width() calls

Message ID 1386847117-21240-2-git-send-email-mporter@linaro.org
State Superseded
Headers show

Commit Message

Matt Porter Dec. 12, 2013, 11:18 a.m.
This adds a pair of APIs that allows the generic PHY subsystem to
provide information on the PHY bus width. The PHY provider driver may
use phy_set_bus_width() to set the bus width that the PHY supports.
The controller driver may then use phy_get_bus_width() to fetch the
PHY bus width in order to properly configure the controller.

Signed-off-by: Matt Porter <mporter@linaro.org>
---
 include/linux/phy/phy.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

Comments

Russell King - ARM Linux Dec. 12, 2013, 11:27 a.m. | #1
On Thu, Dec 12, 2013 at 06:18:29AM -0500, Matt Porter wrote:
>  /**
> + * struct phy_attrs - represents phy attributes
> + * @bus_width: Data path width implemented by PHY
> + */
> +struct phy_attrs {
> +	u32			bus_width;

Why u32?

>  int phy_power_off(struct phy *phy);
> +static inline u32 phy_get_bus_width(struct phy *phy)
> +{
> +	return phy->attrs.bus_width;
...
>  
> +static inline u32 phy_get_bus_width(struct phy *phy)
> +{
> +	return -ENOSYS;

Why u32, especially as you're returning a negative number here.

If the bus width is a small integer (I'm assuming you don't have up to
2^30 bus signals) then what's wrong with it being an 'int' ?
Matt Porter Dec. 12, 2013, 11:50 a.m. | #2
On Thu, Dec 12, 2013 at 11:27:15AM +0000, Russell King wrote:
> On Thu, Dec 12, 2013 at 06:18:29AM -0500, Matt Porter wrote:
> >  /**
> > + * struct phy_attrs - represents phy attributes
> > + * @bus_width: Data path width implemented by PHY
> > + */
> > +struct phy_attrs {
> > +	u32			bus_width;
> 
> Why u32?

Kishon suggested it and I changed it on this rev...forgetting about the
error path below.

> >  int phy_power_off(struct phy *phy);
> > +static inline u32 phy_get_bus_width(struct phy *phy)
> > +{
> > +	return phy->attrs.bus_width;
> ...
> >  
> > +static inline u32 phy_get_bus_width(struct phy *phy)
> > +{
> > +	return -ENOSYS;
> 
> Why u32, especially as you're returning a negative number here.
> 
> If the bus width is a small integer (I'm assuming you don't have up to
> 2^30 bus signals) then what's wrong with it being an 'int' ?

Yes, very correct...it's expected to always be a small positive integer
value or zero (when not populated as it's optional). I agree it should
go back to 'int' especially due to the negative value when GENERIC_PHY
isn't enabled.

-Matt

Patch

diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
index 6d72269..a0dcf2d 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h
@@ -38,6 +38,14 @@  struct phy_ops {
 };
 
 /**
+ * struct phy_attrs - represents phy attributes
+ * @bus_width: Data path width implemented by PHY
+ */
+struct phy_attrs {
+	u32			bus_width;
+};
+
+/**
  * struct phy - represents the phy device
  * @dev: phy device
  * @id: id of the phy device
@@ -46,6 +54,7 @@  struct phy_ops {
  * @mutex: mutex to protect phy_ops
  * @init_count: used to protect when the PHY is used by multiple consumers
  * @power_count: used to protect when the PHY is used by multiple consumers
+ * @phy_attrs: used to specify PHY specific attributes
  */
 struct phy {
 	struct device		dev;
@@ -55,6 +64,7 @@  struct phy {
 	struct mutex		mutex;
 	int			init_count;
 	int			power_count;
+	struct phy_attrs	attrs;
 };
 
 /**
@@ -127,6 +137,14 @@  int phy_init(struct phy *phy);
 int phy_exit(struct phy *phy);
 int phy_power_on(struct phy *phy);
 int phy_power_off(struct phy *phy);
+static inline u32 phy_get_bus_width(struct phy *phy)
+{
+	return phy->attrs.bus_width;
+}
+static inline void phy_set_bus_width(struct phy *phy, u32 bus_width)
+{
+	phy->attrs.bus_width = bus_width;
+}
 struct phy *phy_get(struct device *dev, const char *string);
 struct phy *devm_phy_get(struct device *dev, const char *string);
 void phy_put(struct phy *phy);
@@ -199,6 +217,16 @@  static inline int phy_power_off(struct phy *phy)
 	return -ENOSYS;
 }
 
+static inline u32 phy_get_bus_width(struct phy *phy)
+{
+	return -ENOSYS;
+}
+
+static inline void phy_set_bus_width(struct phy *phy, u32 bus_width)
+{
+	return;
+}
+
 static inline struct phy *phy_get(struct device *dev, const char *string)
 {
 	return ERR_PTR(-ENOSYS);