[RFC,2/4] phy: Extend API to support 'status' get and notification

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index 9951efc03eaa..c7b568b99dce 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -551,6 +551,94 @@  int phy_validate(struct phy *phy, enum phy_mode mode, int submode,
 }
 EXPORT_SYMBOL_GPL(phy_validate);
 
+/**
+ * phy_get_status() - Gets the phy status
+ * @phy: the phy returned by phy_get()
+ * @status: the status to retrieve
+ *
+ * Used to get the PHY status. phy_init() must have been called
+ * on the phy. The status will be retrieved from the current phy mode,
+ * that can be changed using phy_set_mode().
+ *
+ * Return: %0 if successful, a negative error code otherwise
+ */
+int phy_get_status(struct phy *phy, union phy_status *status)
+{
+	int ret;
+
+	if (!phy)
+		return -EINVAL;
+
+	if (!phy->ops->get_status)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&phy->mutex);
+	ret = phy->ops->get_status(phy, status);
+	mutex_unlock(&phy->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_get_status);
+
+/**
+ * phy_atomic_notifier_register() - Registers an atomic notifier
+ * @phy: the phy returned by phy_get()
+ * @nb: the notifier block to register
+ *
+ * Used to register a notifier block on PHY events. phy_init() must have
+ * been called on the phy.
+ * The notifier function given in the notifier_block must not sleep.
+ * The available PHY events are present in enum phy_events
+ *
+ * Return: %0 if successful, a negative error code otherwise
+ */
+int phy_atomic_notifier_register(struct phy *phy, struct notifier_block *nb)
+{
+	int ret;
+
+	if (!phy)
+		return -EINVAL;
+
+	if (!phy->ops->atomic_notifier_register ||
+	    !phy->ops->atomic_notifier_unregister)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&phy->mutex);
+	ret = phy->ops->atomic_notifier_register(phy, nb);
+	mutex_unlock(&phy->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_atomic_notifier_register);
+
+/**
+ * phy_atomic_notifier_unregister() - Unregisters an atomic notifier
+ * @phy: the phy returned by phy_get()
+ * @nb: the notifier block to unregister
+ *
+ * Used to unregister a notifier block. phy_init() must have
+ * been called on the phy.
+ *
+ * Return: %0 if successful, a negative error code otherwise
+ */
+int phy_atomic_notifier_unregister(struct phy *phy, struct notifier_block *nb)
+{
+	int ret;
+
+	if (!phy)
+		return -EINVAL;
+
+	if (!phy->ops->atomic_notifier_unregister)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&phy->mutex);
+	ret = phy->ops->atomic_notifier_unregister(phy, nb);
+	mutex_unlock(&phy->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_atomic_notifier_unregister);
+
 /**
  * _of_phy_get() - lookup and obtain a reference to a phy by phandle
  * @np: device_node for which to get the phy
diff --git a/include/linux/phy/phy-basic.h b/include/linux/phy/phy-basic.h
new file mode 100644
index 000000000000..95668c610c78
--- /dev/null
+++ b/include/linux/phy/phy-basic.h
@@ -0,0 +1,27 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2023 CS GROUP France
+ *
+ * Author: Herve Codina <herve.codina@bootlin.com>
+ */
+
+#ifndef __PHY_BASIC_H_
+#define __PHY_BASIC_H_
+
+#include <linux/types.h>
+
+/**
+ * struct phy_status_basic - Basic PHY status
+ *
+ * This structure is used to represent the status of a Basic phy.
+ */
+struct phy_status_basic {
+	/**
+	 * @link_state:
+	 *
+	 * Link state. true, the link is on, false, the link is off.
+	 */
+	bool link_is_on;
+};
+
+#endif /* __PHY_DP_H_ */
diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
index 3a570bc59fc7..40370d41012b 100644
--- a/include/linux/phy/phy.h
+++ b/include/linux/phy/phy.h
@@ -16,6 +16,7 @@ 
 #include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 
+#include <linux/phy/phy-basic.h>
 #include <linux/phy/phy-dp.h>
 #include <linux/phy/phy-lvds.h>
 #include <linux/phy/phy-mipi-dphy.h>
@@ -42,7 +43,8 @@  enum phy_mode {
 	PHY_MODE_MIPI_DPHY,
 	PHY_MODE_SATA,
 	PHY_MODE_LVDS,
-	PHY_MODE_DP
+	PHY_MODE_DP,
+	PHY_MODE_BASIC,
 };
 
 enum phy_media {
@@ -67,6 +69,22 @@  union phy_configure_opts {
 	struct phy_configure_opts_lvds		lvds;
 };
 
+/**
+ * union phy_status - Opaque generic phy status
+ *
+ * @basic:	Status availbale phys supporting the Basic phy mode.
+ */
+union phy_status {
+	struct phy_status_basic		basic;
+};
+
+/**
+ * phy_event - event available for notification
+ */
+enum phy_event {
+	PHY_EVENT_STATUS,	/* Event notified on phy_status changes */
+};
+
 /**
  * struct phy_ops - set of function pointers for performing phy operations
  * @init: operation to be performed for initializing phy
@@ -120,6 +138,45 @@  struct phy_ops {
 	 */
 	int	(*validate)(struct phy *phy, enum phy_mode mode, int submode,
 			    union phy_configure_opts *opts);
+
+	/**
+	 * @get_status:
+	 *
+	 * Optional.
+	 *
+	 * Used to get the PHY status. phy_init() must have
+	 * been called on the phy.
+	 *
+	 * Returns: 0 if successful, an negative error code otherwise
+	 */
+	int	(*get_status)(struct phy *phy, union phy_status *status);
+
+	/**
+	 * @atomic_notifier_register:
+	 *
+	 * Optional.
+	 *
+	 * Used to register a notifier block on PHY events. phy_init() must have
+	 * been called on the phy.
+	 * The notifier function given in the notifier_block must not sleep.
+	 * The available PHY events are present in enum phy_events
+	 *
+	 * Returns: 0 if successful, an negative error code otherwise
+	 */
+	int	(*atomic_notifier_register)(struct phy *phy, struct notifier_block *nb);
+
+	/**
+	 * @atomic_notifier_unregister:
+	 *
+	 * Mandatoty if @atomic_notifier_register is set.
+	 *
+	 * Used to unregister a notifier block on PHY events. phy_init() must have
+	 * been called on the phy.
+	 *
+	 * Returns: 0 if successful, an negative error code otherwise
+	 */
+	int	(*atomic_notifier_unregister)(struct phy *phy, struct notifier_block *nb);
+
 	int	(*reset)(struct phy *phy);
 	int	(*calibrate)(struct phy *phy);
 	void	(*release)(struct phy *phy);
@@ -234,6 +291,10 @@  int phy_set_speed(struct phy *phy, int speed);
 int phy_configure(struct phy *phy, union phy_configure_opts *opts);
 int phy_validate(struct phy *phy, enum phy_mode mode, int submode,
 		 union phy_configure_opts *opts);
+int phy_get_status(struct phy *phy, union phy_status *status);
+int phy_atomic_notifier_register(struct phy *phy, struct notifier_block *nb);
+int phy_atomic_notifier_unregister(struct phy *phy, struct notifier_block *nb);
+
 
 static inline enum phy_mode phy_get_mode(struct phy *phy)
 {
@@ -412,6 +473,32 @@  static inline int phy_validate(struct phy *phy, enum phy_mode mode, int submode,
 	return -ENOSYS;
 }
 
+static inline int phy_get_status(struct phy *phy, union phy_status *status)
+{
+	if (!phy)
+		return 0;
+
+	return -ENOSYS;
+}
+
+static inline int phy_atomic_notifier_register(struct phy *phy,
+					       struct notifier_block *nb)
+{
+	if (!phy)
+		return 0;
+
+	return -ENOSYS;
+}
+
+static inline int phy_atomic_notifier_unregister(struct phy *phy,
+						 struct notifier_block *nb)
+{
+	if (!phy)
+		return 0;
+
+	return -ENOSYS;
+}
+
 static inline int phy_get_bus_width(struct phy *phy)
 {
 	return -ENOSYS;