drivers: phy: add generic PHY framework

The PHY framework provides a set of APIs for the PHY drivers to
create/destroy a PHY and APIs for the PHY users to obtain a reference to the
PHY with or without using phandle. For dt-boot, the PHY drivers should
also register *PHY provider* with the framework.

PHY drivers should create the PHY by passing id and ops like init, exit,
power_on and power_off. This framework is also pm runtime enabled.

The documentation for the generic PHY framework is added in
Documentation/phy.txt and the documentation for dt binding can be found at
Documentation/devicetree/bindings/phy/phy-bindings.txt

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

1 files changed, 344 insertions, 0 deletions

diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
new file mode 100644
index 00000000000..9351a16a9a0
--- /dev/null
+++ b/include/linux/phy/phy.h
@@ -0,0 +1,344 @@
+/*
+ * phy.h -- generic phy header file
+ *
+ * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Author: Kishon Vijay Abraham I <kishon@ti.com>
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __DRIVERS_PHY_H
+#define __DRIVERS_PHY_H
+
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/device.h>
+#include <linux/pm_runtime.h>
+
+struct phy;
+
+/**
+ * struct phy_ops - set of function pointers for performing phy operations
+ * @init: operation to be performed for initializing phy
+ * @exit: operation to be performed while exiting
+ * @power_on: powering on the phy
+ * @power_off: powering off the phy
+ * @owner: the module owner containing the ops
+ */
+struct phy_ops {
+	int	(*init)(struct phy *phy);
+	int	(*exit)(struct phy *phy);
+	int	(*power_on)(struct phy *phy);
+	int	(*power_off)(struct phy *phy);
+	struct module *owner;
+};
+
+/**
+ * struct phy - represents the phy device
+ * @dev: phy device
+ * @id: id of the phy
+ * @ops: function pointers for performing phy operations
+ * @label: label given to the phy
+ * @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
+ */
+struct phy {
+	struct device		dev;
+	int			id;
+	const struct phy_ops	*ops;
+	const char		*label;
+	struct mutex		mutex;
+	int			init_count;
+	int			power_count;
+};
+
+/**
+ * struct phy_provider - represents the phy provider
+ * @dev: phy provider device
+ * @owner: the module owner having of_xlate
+ * @of_xlate: function pointer to obtain phy instance from phy pointer
+ * @list: to maintain a linked list of PHY providers
+ */
+struct phy_provider {
+	struct device		*dev;
+	struct module		*owner;
+	struct list_head	list;
+	struct phy * (*of_xlate)(struct device *dev,
+		struct of_phandle_args *args);
+};
+
+#define	to_phy(dev)	(container_of((dev), struct phy, dev))
+
+#define	of_phy_provider_register(dev, xlate)	\
+	__of_phy_provider_register((dev), THIS_MODULE, (xlate))
+
+#define	devm_of_phy_provider_register(dev, xlate)	\
+	__of_phy_provider_register((dev), THIS_MODULE, (xlate))
+
+static inline void phy_set_drvdata(struct phy *phy, void *data)
+{
+	dev_set_drvdata(&phy->dev, data);
+}
+
+static inline void *phy_get_drvdata(struct phy *phy)
+{
+	return dev_get_drvdata(&phy->dev);
+}
+
+#if IS_ENABLED(CONFIG_GENERIC_PHY)
+extern struct phy *phy_get(struct device *dev, const char *string);
+extern struct phy *devm_phy_get(struct device *dev, const char *string);
+extern void phy_put(struct phy *phy);
+extern void devm_phy_put(struct device *dev, struct phy *phy);
+extern struct phy *of_phy_simple_xlate(struct device *dev,
+	struct of_phandle_args *args);
+extern struct phy *phy_create(struct device *dev, u8 id,
+	const struct phy_ops *ops, const char *label);
+extern struct phy *devm_phy_create(struct device *dev, u8 id,
+	const struct phy_ops *ops, const char *label);
+extern void phy_destroy(struct phy *phy);
+extern void devm_phy_destroy(struct device *dev, struct phy *phy);
+extern struct phy_provider *__of_phy_provider_register(struct device *dev,
+	struct module *owner, struct phy * (*of_xlate)(struct device *dev,
+	struct of_phandle_args *args));
+extern struct phy_provider *__devm_of_phy_provider_register(struct device *dev,
+	struct module *owner, struct phy * (*of_xlate)(struct device *dev,
+	struct of_phandle_args *args));
+extern void of_phy_provider_unregister(struct phy_provider *phy_provider);
+extern void devm_of_phy_provider_unregister(struct device *dev,
+	struct phy_provider *phy_provider);
+#else
+static inline struct phy *phy_get(struct device *dev, const char *string)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline struct phy *devm_phy_get(struct device *dev, const char *string)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline void phy_put(struct phy *phy)
+{
+}
+
+static inline void devm_phy_put(struct device *dev, struct phy *phy)
+{
+}
+
+static inline struct phy *of_phy_simple_xlate(struct device *dev,
+	struct of_phandle_args *args)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline struct phy *phy_create(struct device *dev, u8 id,
+	const struct phy_ops *ops, const char *label)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline struct phy *devm_phy_create(struct device *dev, u8 id,
+	const struct phy_ops *ops, const char *label)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline void phy_destroy(struct phy *phy)
+{
+}
+
+static inline void devm_phy_destroy(struct device *dev, struct phy *phy)
+{
+}
+
+static inline struct phy_provider *__of_phy_provider_register(
+	struct device *dev, struct module *owner, struct phy * (*of_xlate)(
+	struct device *dev, struct of_phandle_args *args))
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline struct phy_provider *__devm_of_phy_provider_register(struct device
+	*dev, struct module *owner, struct phy * (*of_xlate)(struct device *dev,
+	struct of_phandle_args *args))
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline void of_phy_provider_unregister(struct phy_provider *phy_provider)
+{
+}
+
+static inline void devm_of_phy_provider_unregister(struct device *dev,
+	struct phy_provider *phy_provider)
+{
+}
+#endif
+
+static inline int phy_pm_runtime_get(struct phy *phy)
+{
+	if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
+		return -EINVAL;
+
+	if (!pm_runtime_enabled(&phy->dev))
+		return -ENOTSUPP;
+
+	return pm_runtime_get(&phy->dev);
+}
+
+static inline int phy_pm_runtime_get_sync(struct phy *phy)
+{
+	if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
+		return -EINVAL;
+
+	if (!pm_runtime_enabled(&phy->dev))
+		return -ENOTSUPP;
+
+	return pm_runtime_get_sync(&phy->dev);
+}
+
+static inline int phy_pm_runtime_put(struct phy *phy)
+{
+	if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
+		return -EINVAL;
+
+	if (!pm_runtime_enabled(&phy->dev))
+		return -ENOTSUPP;
+
+	return pm_runtime_put(&phy->dev);
+}
+
+static inline int phy_pm_runtime_put_sync(struct phy *phy)
+{
+	if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
+		return -EINVAL;
+
+	if (!pm_runtime_enabled(&phy->dev))
+		return -ENOTSUPP;
+
+	return pm_runtime_put_sync(&phy->dev);
+}
+
+static inline void phy_pm_runtime_allow(struct phy *phy)
+{
+	if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
+		return;
+
+	if (!pm_runtime_enabled(&phy->dev))
+		return;
+
+	pm_runtime_allow(&phy->dev);
+}
+
+static inline void phy_pm_runtime_forbid(struct phy *phy)
+{
+	if (WARN(IS_ERR(phy), "Invalid PHY reference\n"))
+		return;
+
+	if (!pm_runtime_enabled(&phy->dev))
+		return;
+
+	pm_runtime_forbid(&phy->dev);
+}
+
+static inline int phy_init(struct phy *phy)
+{
+	int ret;
+
+	ret = phy_pm_runtime_get_sync(phy);
+	if (ret < 0 && ret != -ENOTSUPP)
+		return ret;
+
+	mutex_lock(&phy->mutex);
+	if (phy->init_count++ == 0 && phy->ops->init) {
+		ret = phy->ops->init(phy);
+		if (ret < 0) {
+			dev_err(&phy->dev, "phy init failed --> %d\n", ret);
+			goto out;
+		}
+	}
+
+out:
+	mutex_unlock(&phy->mutex);
+	phy_pm_runtime_put(phy);
+	return ret;
+}
+
+static inline int phy_exit(struct phy *phy)
+{
+	int ret;
+
+	ret = phy_pm_runtime_get_sync(phy);
+	if (ret < 0 && ret != -ENOTSUPP)
+		return ret;
+
+	mutex_lock(&phy->mutex);
+	if (--phy->init_count == 0 && phy->ops->exit) {
+		ret = phy->ops->exit(phy);
+		if (ret < 0) {
+			dev_err(&phy->dev, "phy exit failed --> %d\n", ret);
+			goto out;
+		}
+	}
+
+out:
+	mutex_unlock(&phy->mutex);
+	phy_pm_runtime_put(phy);
+	return ret;
+}
+
+static inline int phy_power_on(struct phy *phy)
+{
+	int ret = -ENOTSUPP;
+
+	ret = phy_pm_runtime_get_sync(phy);
+	if (ret < 0 && ret != -ENOTSUPP)
+		return ret;
+
+	mutex_lock(&phy->mutex);
+	if (phy->power_count++ == 0 && phy->ops->power_on) {
+		ret = phy->ops->power_on(phy);
+		if (ret < 0) {
+			dev_err(&phy->dev, "phy poweron failed --> %d\n", ret);
+			goto out;
+		}
+	}
+
+out:
+	mutex_unlock(&phy->mutex);
+
+	return ret;
+}
+
+static inline int phy_power_off(struct phy *phy)
+{
+	int ret = -ENOTSUPP;
+
+	mutex_lock(&phy->mutex);
+	if (--phy->power_count == 0 && phy->ops->power_off) {
+		ret =  phy->ops->power_off(phy);
+		if (ret < 0) {
+			dev_err(&phy->dev, "phy poweroff failed --> %d\n", ret);
+			goto out;
+		}
+	}
+
+out:
+	mutex_unlock(&phy->mutex);
+	phy_pm_runtime_put(phy);
+
+	return ret;
+}
+
+#endif /* __DRIVERS_PHY_H */