[PATCH net-next 4/5] net: phy: phylink: Allow setting a custom link state callback

[Florian Fainelli <f.fainelli@gmail.com>]

phylink_get_fixed_state() currently consults an optional "link_gpio"
GPIO descriptor, expand this mechanism to allow specifying a custom
callback. This is necessary to support out of band link notifcation
(e.g: from an interrupt within a MMIO register).

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/phy/phylink.c | 26 ++++++++++++++++++++++++--
 include/linux/phylink.h   |  3 +++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index a41f0a224512..0a8fd9aa1a19 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -50,6 +50,8 @@ struct phylink {
 	/* The link configuration settings */
 	struct phylink_link_state link_config;
 	struct gpio_desc *link_gpio;
+	void (*get_fixed_state)(struct net_device *dev,
+				struct phylink_link_state *s);
 
 	struct mutex state_mutex;
 	struct phylink_link_state phy_state;
@@ -339,12 +341,14 @@ static int phylink_get_mac_state(struct phylink *pl, struct phylink_link_state *
 }
 
 /* The fixed state is... fixed except for the link state,
- * which may be determined by a GPIO.
+ * which may be determined by a GPIO or a callback.
  */
 static void phylink_get_fixed_state(struct phylink *pl, struct phylink_link_state *state)
 {
 	*state = pl->link_config;
-	if (pl->link_gpio)
+	if (pl->get_fixed_state)
+		pl->get_fixed_state(pl->netdev, state);
+	else if (pl->link_gpio)
 		state->link = !!gpiod_get_value(pl->link_gpio);
 }
 
@@ -737,6 +741,24 @@ void phylink_disconnect_phy(struct phylink *pl)
 }
 EXPORT_SYMBOL_GPL(phylink_disconnect_phy);
 
+int phylink_fixed_state_cb(struct phylink *pl,
+			   void (*cb)(struct net_device *dev,
+				      struct phylink_link_state *state))
+{
+	/* It does not make sense to let the link be overriden unless we use
+	 * MLO_AN_FIXED
+	 */
+	if (pl->link_an_mode != MLO_AN_FIXED)
+		return -EINVAL;
+
+	mutex_lock(&pl->state_mutex);
+	pl->get_fixed_state = cb;
+	mutex_unlock(&pl->state_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(phylink_fixed_state_cb);
+
 void phylink_mac_change(struct phylink *pl, bool up)
 {
 	if (!up)
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 875717a4e873..d505ea321eb5 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -107,6 +107,9 @@ void phylink_destroy(struct phylink *);
 int phylink_connect_phy(struct phylink *, struct phy_device *);
 int phylink_of_phy_connect(struct phylink *, struct device_node *, u32 flags);
 void phylink_disconnect_phy(struct phylink *);
+int phylink_fixed_state_cb(struct phylink *,
+			   void (*cb)(struct net_device *dev,
+				      struct phylink_link_state *));
 
 void phylink_mac_change(struct phylink *, bool up);
 
-- 
2.14.3