1 // SPDX-License-Identifier: GPL-2.0
10 #define pr_fmt(fmt) "mux-core: " fmt
19 #include <linux/mux/consumer.h>
20 #include <linux/mux/driver.h>
25  * The idle-as-is "state" is not an actual state that may be selected, it
32  * struct mux_state -	Represents a mux controller state specific to a given
34  * @mux:		Pointer to a mux controller.
35  * @state:		State of the mux to be selected.
41 	struct mux_control *mux;  member
46 	.name = "mux",
67 	ida_simple_remove(&mux_ida, mux_chip->id);  in mux_chip_release()
72 	.name = "mux-chip",
77  * mux_chip_alloc() - Allocate a mux-chip.
78  * @dev: The parent device implementing the mux interface.
79  * @controllers: The number of mux controllers to allocate for this chip.
82  * After allocating the mux-chip with the desired number of mux controllers
83  * but before registering the chip, the mux driver is required to configure
84  * the number of valid mux states in the mux_chip->mux[N].states members and
85  * the desired idle state in the returned mux_chip->mux[N].idle_state members.
86  * The default idle state is MUX_IDLE_AS_IS. The mux driver also needs to
87  * provide a pointer to the operations struct in the mux_chip->ops member
88  * before registering the mux-chip with mux_chip_register.
90  * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
99 		return ERR_PTR(-EINVAL);  in mux_chip_alloc()
102 			   controllers * sizeof(*mux_chip->mux) +  in mux_chip_alloc()
105 		return ERR_PTR(-ENOMEM);  in mux_chip_alloc()
107 	mux_chip->mux = (struct mux_control *)(mux_chip + 1);  in mux_chip_alloc()
108 	mux_chip->dev.class = &mux_class;  in mux_chip_alloc()
109 	mux_chip->dev.type = &mux_type;  in mux_chip_alloc()
110 	mux_chip->dev.parent = dev;  in mux_chip_alloc()
111 	mux_chip->dev.of_node = dev->of_node;  in mux_chip_alloc()
112 	dev_set_drvdata(&mux_chip->dev, mux_chip);  in mux_chip_alloc()
114 	mux_chip->id = ida_simple_get(&mux_ida, 0, 0, GFP_KERNEL);  in mux_chip_alloc()
115 	if (mux_chip->id < 0) {  in mux_chip_alloc()
116 		int err = mux_chip->id;  in mux_chip_alloc()
122 	dev_set_name(&mux_chip->dev, "muxchip%d", mux_chip->id);  in mux_chip_alloc()
124 	mux_chip->controllers = controllers;  in mux_chip_alloc()
126 		struct mux_control *mux = &mux_chip->mux[i];  in mux_chip_alloc()  local
128 		mux->chip = mux_chip;  in mux_chip_alloc()
129 		sema_init(&mux->lock, 1);  in mux_chip_alloc()
130 		mux->cached_state = MUX_CACHE_UNKNOWN;  in mux_chip_alloc()
131 		mux->idle_state = MUX_IDLE_AS_IS;  in mux_chip_alloc()
132 		mux->last_change = ktime_get();  in mux_chip_alloc()
135 	device_initialize(&mux_chip->dev);  in mux_chip_alloc()
141 static int mux_control_set(struct mux_control *mux, int state)  in mux_control_set()  argument
143 	int ret = mux->chip->ops->set(mux, state);  in mux_control_set()
145 	mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state;  in mux_control_set()
147 		mux->last_change = ktime_get();  in mux_control_set()
153  * mux_chip_register() - Register a mux-chip, thus readying the controllers
155  * @mux_chip: The mux-chip to register.
157  * Do not retry registration of the same mux-chip on failure. You should
168 	for (i = 0; i < mux_chip->controllers; ++i) {  in mux_chip_register()
169 		struct mux_control *mux = &mux_chip->mux[i];  in mux_chip_register()  local
171 		if (mux->idle_state == mux->cached_state)  in mux_chip_register()
174 		ret = mux_control_set(mux, mux->idle_state);  in mux_chip_register()
176 			dev_err(&mux_chip->dev, "unable to set idle state\n");  in mux_chip_register()
181 	ret = device_add(&mux_chip->dev);  in mux_chip_register()
183 		dev_err(&mux_chip->dev,  in mux_chip_register()
190  * mux_chip_unregister() - Take the mux-chip off-line.
191  * @mux_chip: The mux-chip to unregister.
195  * on a mux-chip that has been registered before.
199 	device_del(&mux_chip->dev);  in mux_chip_unregister()
204  * mux_chip_free() - Free the mux-chip for good.
205  * @mux_chip: The mux-chip to free.
214 	put_device(&mux_chip->dev);  in mux_chip_free()
226  * devm_mux_chip_alloc() - Resource-managed version of mux_chip_alloc().
227  * @dev: The parent device implementing the mux interface.
228  * @controllers: The number of mux controllers to allocate for this chip.
233  * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
243 		return ERR_PTR(-ENOMEM);  in devm_mux_chip_alloc()
266  * devm_mux_chip_register() - Resource-managed version mux_chip_register().
267  * @dev: The parent device implementing the mux interface.
268  * @mux_chip: The mux-chip to register.
282 		return -ENOMEM;  in devm_mux_chip_register()
298  * mux_control_states() - Query the number of multiplexer states.
299  * @mux: The mux-control to query.
303 unsigned int mux_control_states(struct mux_control *mux)  in mux_control_states()  argument
305 	return mux->states;  in mux_control_states()
310  * The mux->lock must be down when calling this function.
312 static int __mux_control_select(struct mux_control *mux, int state)  in __mux_control_select()  argument
316 	if (WARN_ON(state < 0 || state >= mux->states))  in __mux_control_select()
317 		return -EINVAL;  in __mux_control_select()
319 	if (mux->cached_state == state)  in __mux_control_select()
322 	ret = mux_control_set(mux, state);  in __mux_control_select()
326 	/* The mux update failed, try to revert if appropriate... */  in __mux_control_select()
327 	if (mux->idle_state != MUX_IDLE_AS_IS)  in __mux_control_select()
328 		mux_control_set(mux, mux->idle_state);  in __mux_control_select()
333 static void mux_control_delay(struct mux_control *mux, unsigned int delay_us)  in mux_control_delay()  argument
341 	delayend = ktime_add_us(mux->last_change, delay_us);  in mux_control_delay()
348  * mux_control_select_delay() - Select the given multiplexer state.
349  * @mux: The mux-control to request a change of state from.
351  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
353  * On successfully selecting the mux-control state, it will be locked until
354  * there is a call to mux_control_deselect(). If the mux-control is already
360  * complete and the mux-control is free for others to use, but do not call
363  * Return: 0 when the mux-control state has the requested state or a negative
366 int mux_control_select_delay(struct mux_control *mux, unsigned int state,  in mux_control_select_delay()  argument
371 	ret = down_killable(&mux->lock);  in mux_control_select_delay()
375 	ret = __mux_control_select(mux, state);  in mux_control_select_delay()
377 		mux_control_delay(mux, delay_us);  in mux_control_select_delay()
380 		up(&mux->lock);  in mux_control_select_delay()
387  * mux_state_select_delay() - Select the given multiplexer state.
388  * @mstate: The mux-state to select.
389  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
391  * On successfully selecting the mux-state, its mux-control will be locked
392  * until there is a call to mux_state_deselect(). If the mux-control is already
398  * complete and the mux-control is free for others to use, but do not call
401  * Return: 0 when the mux-state has been selected or a negative
406 	return mux_control_select_delay(mstate->mux, mstate->state, delay_us);  in mux_state_select_delay()
411  * mux_control_try_select_delay() - Try to select the given multiplexer state.
412  * @mux: The mux-control to request a change of state from.
414  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
416  * On successfully selecting the mux-control state, it will be locked until
420  * complete and the mux-control is free for others to use, but do not call
423  * Return: 0 when the mux-control state has the requested state or a negative
424  * errno on error. Specifically -EBUSY if the mux-control is contended.
426 int mux_control_try_select_delay(struct mux_control *mux, unsigned int state,  in mux_control_try_select_delay()  argument
431 	if (down_trylock(&mux->lock))  in mux_control_try_select_delay()
432 		return -EBUSY;  in mux_control_try_select_delay()
434 	ret = __mux_control_select(mux, state);  in mux_control_try_select_delay()
436 		mux_control_delay(mux, delay_us);  in mux_control_try_select_delay()
439 		up(&mux->lock);  in mux_control_try_select_delay()
446  * mux_state_try_select_delay() - Try to select the given multiplexer state.
447  * @mstate: The mux-state to select.
448  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
450  * On successfully selecting the mux-state, its mux-control will be locked
454  * complete and the mux-control is free for others to use, but do not call
457  * Return: 0 when the mux-state has been selected or a negative errno on
458  * error. Specifically -EBUSY if the mux-control is contended.
462 	return mux_control_try_select_delay(mstate->mux, mstate->state, delay_us);  in mux_state_try_select_delay()
467  * mux_control_deselect() - Deselect the previously selected multiplexer state.
468  * @mux: The mux-control to deselect.
475  * occur if the mux has an idle state. Note that even if an error occurs, the
476  * mux-control is unlocked and is thus free for the next access.
478 int mux_control_deselect(struct mux_control *mux)  in mux_control_deselect()  argument
482 	if (mux->idle_state != MUX_IDLE_AS_IS &&  in mux_control_deselect()
483 	    mux->idle_state != mux->cached_state)  in mux_control_deselect()
484 		ret = mux_control_set(mux, mux->idle_state);  in mux_control_deselect()
486 	up(&mux->lock);  in mux_control_deselect()
493  * mux_state_deselect() - Deselect the previously selected multiplexer state.
494  * @mstate: The mux-state to deselect.
501  * occur if the mux has an idle state. Note that even if an error occurs, the
502  * mux-control is unlocked and is thus free for the next access.
506 	return mux_control_deselect(mstate->mux);  in mux_state_deselect()
521  * mux_get() - Get the mux-control for a device.
522  * @dev: The device that needs a mux-control.
523  * @mux_name: The name identifying the mux-control.
527  * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
532 	struct device_node *np = dev->of_node;  in mux_get()
541 			index = of_property_match_string(np, "mux-state-names",  in mux_get()
544 			index = of_property_match_string(np, "mux-control-names",  in mux_get()
547 			dev_err(dev, "mux controller '%s' not found\n",  in mux_get()
555 						 "mux-states", "#mux-state-cells",  in mux_get()
559 						 "mux-controls", "#mux-control-cells",  in mux_get()
562 		dev_err(dev, "%pOF: failed to get mux-%s %s(%i)\n",  in mux_get()
563 			np, state ? "state" : "control", mux_name ?: "", index);  in mux_get()
570 		return ERR_PTR(-EPROBE_DEFER);  in mux_get()
575 		    (args.args_count < 2 && mux_chip->controllers > 1)) {  in mux_get()
576 			dev_err(dev, "%pOF: wrong #mux-state-cells for %pOF\n",  in mux_get()
578 			put_device(&mux_chip->dev);  in mux_get()
579 			return ERR_PTR(-EINVAL);  in mux_get()
591 		    (!args.args_count && mux_chip->controllers > 1)) {  in mux_get()
592 			dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n",  in mux_get()
594 			put_device(&mux_chip->dev);  in mux_get()
595 			return ERR_PTR(-EINVAL);  in mux_get()
602 	if (controller >= mux_chip->controllers) {  in mux_get()
603 		dev_err(dev, "%pOF: bad mux controller %u specified in %pOF\n",  in mux_get()
605 		put_device(&mux_chip->dev);  in mux_get()
606 		return ERR_PTR(-EINVAL);  in mux_get()
609 	return &mux_chip->mux[controller];  in mux_get()
613  * mux_control_get() - Get the mux-control for a device.
614  * @dev: The device that needs a mux-control.
615  * @mux_name: The name identifying the mux-control.
617  * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
626  * mux_control_put() - Put away the mux-control for good.
627  * @mux: The mux-control to put away.
631 void mux_control_put(struct mux_control *mux)  in mux_control_put()  argument
633 	put_device(&mux->chip->dev);  in mux_control_put()
639 	struct mux_control *mux = *(struct mux_control **)res;  in devm_mux_control_release()  local
641 	mux_control_put(mux);  in devm_mux_control_release()
645  * devm_mux_control_get() - Get the mux-control for a device, with resource
647  * @dev: The device that needs a mux-control.
648  * @mux_name: The name identifying the mux-control.
650  * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno.
655 	struct mux_control **ptr, *mux;  in devm_mux_control_get()  local
659 		return ERR_PTR(-ENOMEM);  in devm_mux_control_get()
661 	mux = mux_control_get(dev, mux_name);  in devm_mux_control_get()
662 	if (IS_ERR(mux)) {  in devm_mux_control_get()
664 		return mux;  in devm_mux_control_get()
667 	*ptr = mux;  in devm_mux_control_get()
670 	return mux;  in devm_mux_control_get()
675  * mux_state_get() - Get the mux-state for a device.
676  * @dev: The device that needs a mux-state.
677  * @mux_name: The name identifying the mux-state.
679  * Return: A pointer to the mux-state, or an ERR_PTR with a negative errno.
687 		return ERR_PTR(-ENOMEM);  in mux_state_get()
689 	mstate->mux = mux_get(dev, mux_name, &mstate->state);  in mux_state_get()
690 	if (IS_ERR(mstate->mux)) {  in mux_state_get()
691 		int err = PTR_ERR(mstate->mux);  in mux_state_get()
701  * mux_state_put() - Put away the mux-state for good.
702  * @mstate: The mux-state to put away.
708 	mux_control_put(mstate->mux);  in mux_state_put()
720  * devm_mux_state_get() - Get the mux-state for a device, with resource
722  * @dev: The device that needs a mux-control.
723  * @mux_name: The name identifying the mux-control.
725  * Return: Pointer to the mux-state, or an ERR_PTR with a negative errno.
734 		return ERR_PTR(-ENOMEM);  in devm_mux_state_get()
750  * Using subsys_initcall instead of module_init here to try to ensure - for
751  * the non-modular case - that the subsystem is initialized when mux consumers
752  * and mux controllers start to use it.