drivers: Add a new framework for multiplexer devices

Add a new subsystem that handles multiplexer controllers. The API is the
same as in Linux.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
[trini: Update some error calls to use different functions or pass
        correct arguments]
Signed-off-by: Tom Rini <trini@konsulko.com>

1 files changed, 109 insertions, 0 deletions

diff --git a/include/mux-internal.h b/include/mux-internal.h
new file mode 100644
index 0000000000..93e3a5cdd7
--- /dev/null
+++ b/include/mux-internal.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Based on the linux multiplexer framework
+ *
+ * Copyright (C) 2017 Axentia Technologies AB
+ * Author: Peter Rosin <peda@axentia.se>
+ *
+ * Copyright (C) 2017-2018 Texas Instruments Incorporated - http://www.ti.com/
+ * Jean-Jacques Hiblot <jjhiblot@ti.com>
+ */
+
+#ifndef _MUX_INTERNAL_H
+#define _MUX_INTERNAL_H
+
+/* See mux.h for background documentation. */
+
+struct ofnode_phandle_args;
+
+/**
+ * struct mux_chip -	Represents a chip holding mux controllers.
+ * @controllers:	Number of mux controllers handled by the chip.
+ * @mux:		Array of mux controllers that are handled.
+ *
+ * This a per-device uclass-private data.
+ */
+struct mux_chip {
+	unsigned int controllers;
+	struct mux_control *mux;
+};
+
+/**
+ * struct mux_control_ops -	Mux controller operations for a mux chip.
+ * @set:			Set the state of the given mux controller.
+ */
+struct mux_control_ops {
+	/**
+	 * set - Apply a state to a multiplexer control
+	 *
+	 * @mux:	A multiplexer control
+	 * @return 0 if OK, or a negative error code.
+	 */
+	int (*set)(struct mux_control *mux, int state);
+
+	/**
+	 * of_xlate - Translate a client's device-tree (OF) multiplexer
+	 * specifier.
+	 *
+	 * If this function pointer is set to NULL, the multiplexer core will
+	 * use a default implementation, which assumes #mux-control-cells = <1>
+	 * and that the DT cell contains a simple integer channel ID.
+	 *
+	 * @dev_mux:	The multiplexer device. A single device may handle
+	 *              several multiplexer controls.
+	 * @args:	The multiplexer specifier values from device tree.
+	 * @muxp:	(out) A multiplexer control
+	 * @return 0 if OK, or a negative error code.
+	 */
+	int (*of_xlate)(struct mux_chip *dev_mux,
+			struct ofnode_phandle_args *args,
+			struct mux_control **muxp);
+};
+
+/**
+ * struct mux_control -	Represents a mux controller.
+ * @in_use:		Whether the mux controller is in use or not.
+ * @dev:		The client device.
+ * @cached_state:	The current mux controller state, or -1 if none.
+ * @states:		The number of mux controller states.
+ * @idle_state:		The mux controller state to use when inactive, or one
+ *			of MUX_IDLE_AS_IS and MUX_IDLE_DISCONNECT.
+ * @id:			The index of the mux controller within the mux chip
+ *			it is a part of.
+ *
+ * Mux drivers may only change @states and @idle_state, and may only do so
+ * between allocation and registration of the mux controller. Specifically,
+ * @cached_state is internal to the mux core and should never be written by
+ * mux drivers.
+ */
+struct mux_control {
+	bool	in_use;
+	struct udevice *dev;
+	int cached_state;
+	unsigned int states;
+	int idle_state;
+	int id;
+};
+
+/**
+ * mux_control_get_index() - Get the index of the given mux controller
+ * @mux:		The mux-control to get the index for.
+ *
+ * Return: The index of the mux controller within the mux chip the mux
+ * controller is a part of.
+ */
+static inline unsigned int mux_control_get_index(struct mux_control *mux)
+{
+	return mux->id;
+}
+
+/**
+ * mux_alloc_controllers() - Allocate the given number of mux controllers.
+ * @dev:		The client device.
+ * controllers:		Number of controllers to allocate.
+ *
+ * Return: 0 of OK, -errno otherwise.
+ */
+int mux_alloc_controllers(struct udevice *dev, unsigned int controllers);
+
+#endif