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@@ -0,0 +1,312 @@
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+// SPDX-License-Identifier: GPL-2.0
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+/*
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+ * Multiplexer subsystem
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+ *
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+ * Based on the linux multiplexer framework
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+ *
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+ * Copyright (C) 2017 Axentia Technologies AB
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+ * Author: Peter Rosin <peda@axentia.se>
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+ *
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+ * Copyright (C) 2017-2018 Texas Instruments Incorporated - http://www.ti.com/
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+ * Jean-Jacques Hiblot <jjhiblot@ti.com>
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+ */
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+
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+#include <common.h>
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+#include <dm.h>
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+#include <mux-internal.h>
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+#include <dm/device-internal.h>
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+#include <dm/device_compat.h>
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+#include <dm/devres.h>
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+#include <dt-bindings/mux/mux.h>
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+#include <linux/bug.h>
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+
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+/*
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+ * The idle-as-is "state" is not an actual state that may be selected, it
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+ * only implies that the state should not be changed. So, use that state
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+ * as indication that the cached state of the multiplexer is unknown.
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+ */
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+#define MUX_CACHE_UNKNOWN MUX_IDLE_AS_IS
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+
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+/**
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+ * mux_control_ops() - Get the mux_control ops.
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+ * @dev: The client device.
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+ *
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+ * Return: A pointer to the 'mux_control_ops' of the device.
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+ */
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+static inline const struct mux_control_ops *mux_dev_ops(struct udevice *dev)
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+{
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+ return (const struct mux_control_ops *)dev->driver->ops;
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+}
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+
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+/**
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+ * mux_control_set() - Set the state of the given mux controller.
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+ * @mux: A multiplexer control
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+ * @state: The new requested state.
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+ *
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+ * Return: 0 if OK, or a negative error code.
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+ */
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+static int mux_control_set(struct mux_control *mux, int state)
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+{
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+ int ret = mux_dev_ops(mux->dev)->set(mux, state);
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+
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+ mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state;
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+
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+ return ret;
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+}
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+
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+unsigned int mux_control_states(struct mux_control *mux)
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+{
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+ return mux->states;
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+}
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+
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+/**
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+ * __mux_control_select() - Select the given multiplexer state.
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+ * @mux: The mux-control to request a change of state from.
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+ * @state: The new requested state.
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+ *
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+ * Try to set the mux to the requested state. If not, try to revert if
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+ * appropriate.
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+ */
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+static int __mux_control_select(struct mux_control *mux, int state)
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+{
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+ int ret;
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+
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+ if (WARN_ON(state < 0 || state >= mux->states))
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+ return -EINVAL;
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+
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+ if (mux->cached_state == state)
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+ return 0;
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+
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+ ret = mux_control_set(mux, state);
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+ if (ret >= 0)
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+ return 0;
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+
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+ /* The mux update failed, try to revert if appropriate... */
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+ if (mux->idle_state != MUX_IDLE_AS_IS)
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+ mux_control_set(mux, mux->idle_state);
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+
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+ return ret;
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+}
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+
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+int mux_control_select(struct mux_control *mux, unsigned int state)
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+{
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+ int ret;
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+
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+ if (mux->in_use)
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+ return -EBUSY;
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+
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+ ret = __mux_control_select(mux, state);
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+
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+ if (ret < 0)
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+ return ret;
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+
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+ mux->in_use = true;
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+
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+ return 0;
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+}
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+
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+int mux_control_deselect(struct mux_control *mux)
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+{
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+ int ret = 0;
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+
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+ if (mux->idle_state != MUX_IDLE_AS_IS &&
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+ mux->idle_state != mux->cached_state)
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+ ret = mux_control_set(mux, mux->idle_state);
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+
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+ mux->in_use = false;
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+
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+ return ret;
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+}
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+
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+static int mux_of_xlate_default(struct mux_chip *mux_chip,
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+ struct ofnode_phandle_args *args,
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+ struct mux_control **muxp)
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+{
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+ struct mux_control *mux;
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+ int id;
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+
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+ log_debug("%s(muxp=%p)\n", __func__, muxp);
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+
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+ if (args->args_count > 1) {
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+ debug("Invaild args_count: %d\n", args->args_count);
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+ return -EINVAL;
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+ }
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+
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+ if (args->args_count)
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+ id = args->args[0];
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+ else
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+ id = 0;
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+
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+ if (id >= mux_chip->controllers) {
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+ pr_err("bad mux controller %u specified in %s\n",
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+ id, ofnode_get_name(args->node));
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+ return -ERANGE;
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+ }
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+
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+ mux = &mux_chip->mux[id];
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+ mux->id = id;
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+ *muxp = mux;
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+ return 0;
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+}
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+
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+/**
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+ * mux_get_by_indexed_prop() - Get a mux control by integer index
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+ * @dev: The client device.
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+ * @prop_name: Name of the device tree property.
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+ * @index: The index of the mux to get
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+ * @mux: A pointer to the 'mux_control' struct to initialize.
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+ *
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+ * Return: 0 of OK, -errno otherwise.
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+ */
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+static int mux_get_by_indexed_prop(struct udevice *dev, const char *prop_name,
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+ int index, struct mux_control **mux)
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+{
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+ int ret;
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+ struct ofnode_phandle_args args;
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+ struct udevice *dev_mux;
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+ const struct mux_control_ops *ops;
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+ struct mux_chip *mux_chip;
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+
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+ log_debug("%s(dev=%p, index=%d, mux=%p)\n", __func__, dev, index, mux);
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+
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+ ret = dev_read_phandle_with_args(dev, prop_name, "#mux-control-cells",
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+ 0, index, &args);
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+ if (ret) {
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+ debug("%s: fdtdec_parse_phandle_with_args failed: err=%d\n",
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+ __func__, ret);
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+ return ret;
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+ }
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+
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+ ret = uclass_get_device_by_ofnode(UCLASS_MUX, args.node, &dev_mux);
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+ if (ret) {
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+ debug("%s: uclass_get_device_by_ofnode failed: err=%d\n",
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+ __func__, ret);
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+ return ret;
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+ }
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+
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+ mux_chip = dev_get_uclass_priv(dev_mux);
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+
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+ ops = mux_dev_ops(dev_mux);
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+ if (ops->of_xlate)
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+ ret = ops->of_xlate(mux_chip, &args, mux);
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+ else
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+ ret = mux_of_xlate_default(mux_chip, &args, mux);
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+ if (ret) {
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+ debug("of_xlate() failed: %d\n", ret);
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+ return ret;
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+ }
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+ (*mux)->dev = dev_mux;
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+
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+ return 0;
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+}
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+
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+int mux_get_by_index(struct udevice *dev, int index, struct mux_control **mux)
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+{
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+ return mux_get_by_indexed_prop(dev, "mux-controls", index, mux);
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+}
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+
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+int mux_control_get(struct udevice *dev, const char *name,
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+ struct mux_control **mux)
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+{
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+ int index;
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+
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+ debug("%s(dev=%p, name=%s, mux=%p)\n", __func__, dev, name, mux);
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+
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+ index = dev_read_stringlist_search(dev, "mux-control-names", name);
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+ if (index < 0) {
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+ debug("fdt_stringlist_search() failed: %d\n", index);
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+ return index;
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+ }
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+
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+ return mux_get_by_index(dev, index, mux);
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+}
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+
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+void mux_control_put(struct mux_control *mux)
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+{
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+ mux_control_deselect(mux);
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+}
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+
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+/**
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+ * devm_mux_control_release() - Release the given managed mux.
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+ * @dev: The client device.
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+ * @res: Pointer to the mux to be released.
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+ *
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+ * This function is called by devres to release the mux. It reverses the
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+ * effects of mux_control_get().
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+ */
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+static void devm_mux_control_release(struct udevice *dev, void *res)
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+{
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+ mux_control_put(*(struct mux_control **)res);
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+}
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+
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+struct mux_control *devm_mux_control_get(struct udevice *dev, const char *id)
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+{
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+ int rc;
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+ struct mux_control **mux;
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+
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+ mux = devres_alloc(devm_mux_control_release,
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+ sizeof(struct mux_control *), __GFP_ZERO);
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+ if (unlikely(!mux))
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+ return ERR_PTR(-ENOMEM);
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+
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+ rc = mux_control_get(dev, id, mux);
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+ if (rc)
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+ return ERR_PTR(rc);
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+
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+ devres_add(dev, mux);
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+ return *mux;
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+}
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+
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+int mux_alloc_controllers(struct udevice *dev, unsigned int controllers)
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+{
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+ int i;
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+ struct mux_chip *mux_chip = dev_get_uclass_priv(dev);
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+
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+ mux_chip->mux = devm_kmalloc(dev,
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+ sizeof(struct mux_control) * controllers,
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+ __GFP_ZERO);
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+ if (!mux_chip->mux)
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+ return -ENOMEM;
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+
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+ mux_chip->controllers = controllers;
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+
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+ for (i = 0; i < mux_chip->controllers; ++i) {
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+ struct mux_control *mux = &mux_chip->mux[i];
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+
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+ mux->dev = dev;
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+ mux->cached_state = MUX_CACHE_UNKNOWN;
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+ mux->idle_state = MUX_IDLE_AS_IS;
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+ mux->in_use = false;
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+ mux->id = i;
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+ }
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+
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+ return 0;
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+}
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+
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+static int mux_uclass_post_probe(struct udevice *dev)
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+{
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+ int i, ret;
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+ struct mux_chip *mux_chip = dev_get_uclass_priv(dev);
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+
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+ /* Set all mux controllers to their idle state. */
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+ for (i = 0; i < mux_chip->controllers; ++i) {
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+ struct mux_control *mux = &mux_chip->mux[i];
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+
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+ if (mux->idle_state == mux->cached_state)
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+ continue;
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+
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+ ret = mux_control_set(mux, mux->idle_state);
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+ if (ret < 0) {
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+ dev_err(dev, "unable to set idle state\n");
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+ return ret;
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+ }
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+ }
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+ return 0;
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+}
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+
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+UCLASS_DRIVER(mux) = {
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+ .id = UCLASS_MUX,
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+ .name = "mux",
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+ .post_probe = mux_uclass_post_probe,
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+ .per_device_auto_alloc_size = sizeof(struct mux_chip),
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+};
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