net: add framework to support Ethernet PSE and PDs devices

This framework was create with intention to provide support for Ethernet PSE
(Power Sourcing Equipment) and PDs (Powered Device).

At current step this patch implements generic PSE support for PoDL (Power over
Data Lines 802.3bu) specification with reserving name space for PD devices as
well.

This framework can be extended to support 802.3af and 802.3at "Power via the
Media Dependent Interface" (or PoE/Power over Ethernet)

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 67 insertions, 0 deletions

diff --git a/include/linux/pse-pd/pse.h b/include/linux/pse-pd/pse.h
new file mode 100644
index 000000000000..3ba787a48b15
--- /dev/null
+++ b/include/linux/pse-pd/pse.h
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+// Copyright (c) 2022 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
+ */
+#ifndef _LINUX_PSE_CONTROLLER_H
+#define _LINUX_PSE_CONTROLLER_H
+
+#include <linux/ethtool.h>
+#include <linux/list.h>
+#include <uapi/linux/ethtool.h>
+
+struct module;
+struct device_node;
+struct of_phandle_args;
+struct pse_control;
+
+/**
+ * struct pse_controller_dev - PSE controller entity that might
+ *                             provide multiple PSE controls
+ * @ops: a pointer to device specific struct pse_controller_ops
+ * @owner: kernel module of the PSE controller driver
+ * @list: internal list of PSE controller devices
+ * @pse_control_head: head of internal list of requested PSE controls
+ * @dev: corresponding driver model device struct
+ * @of_pse_n_cells: number of cells in PSE line specifiers
+ * @of_xlate: translation function to translate from specifier as found in the
+ *            device tree to id as given to the PSE control ops
+ * @nr_lines: number of PSE controls in this controller device
+ * @lock: Mutex for serialization access to the PSE controller
+ */
+struct pse_controller_dev {
+	const struct pse_controller_ops *ops;
+	struct module *owner;
+	struct list_head list;
+	struct list_head pse_control_head;
+	struct device *dev;
+	int of_pse_n_cells;
+	int (*of_xlate)(struct pse_controller_dev *pcdev,
+			const struct of_phandle_args *pse_spec);
+	unsigned int nr_lines;
+	struct mutex lock;
+};
+
+#if IS_ENABLED(CONFIG_PSE_CONTROLLER)
+int pse_controller_register(struct pse_controller_dev *pcdev);
+void pse_controller_unregister(struct pse_controller_dev *pcdev);
+struct device;
+int devm_pse_controller_register(struct device *dev,
+				 struct pse_controller_dev *pcdev);
+
+struct pse_control *of_pse_control_get(struct device_node *node);
+void pse_control_put(struct pse_control *psec);
+
+#else
+
+static inline struct pse_control *of_pse_control_get(struct device_node *node)
+{
+	return ERR_PTR(-ENOENT);
+}
+
+static inline void pse_control_put(struct pse_control *psec)
+{
+}
+
+#endif
+
+#endif