10 #define pr_fmt(fmt) "mux-core: " fmt
19 #include <linux/mux/consumer.h>
20 #include <linux/mux/driver.h>
33  * struct mux_state -	Represents a mux controller state specific to a given
35  * @mux:		Pointer to a mux controller.
36  * @state:		State of the mux to be selected.
42 	struct mux_control *mux;  member
47 	.name = "mux",
74 	.name = "mux-chip",
79  * mux_chip_alloc() - Allocate a mux-chip.
80  * @dev: The parent device implementing the mux interface.
81  * @controllers: The number of mux controllers to allocate for this chip.
84  * After allocating the mux-chip with the desired number of mux controllers
85  * but before registering the chip, the mux driver is required to configure
86  * the number of valid mux states in the mux_chip->mux[N].states members and
87  * the desired idle state in the returned mux_chip->mux[N].idle_state members.
88  * The default idle state is MUX_IDLE_AS_IS. The mux driver also needs to
90  * before registering the mux-chip with mux_chip_register.
92  * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
104 			   controllers * sizeof(*mux_chip->mux) +  in mux_chip_alloc()
109 	mux_chip->mux = (struct mux_control *)(mux_chip + 1);  in mux_chip_alloc()
128 		struct mux_control *mux = &mux_chip->mux[i];  in mux_chip_alloc()  local
130 		mux->chip = mux_chip;  in mux_chip_alloc()
131 		sema_init(&mux->lock, 1);  in mux_chip_alloc()
132 		mux->cached_state = MUX_CACHE_UNKNOWN;  in mux_chip_alloc()
133 		mux->idle_state = MUX_IDLE_AS_IS;  in mux_chip_alloc()
134 		mux->last_change = ktime_get();  in mux_chip_alloc()
143 static int mux_control_set(struct mux_control *mux, int state)  in mux_control_set()  argument
145 	int ret = mux->chip->ops->set(mux, state);  in mux_control_set()
147 	mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state;  in mux_control_set()
149 		mux->last_change = ktime_get();  in mux_control_set()
155  * mux_chip_register() - Register a mux-chip, thus readying the controllers
157  * @mux_chip: The mux-chip to register.
159  * Do not retry registration of the same mux-chip on failure. You should
171 		struct mux_control *mux = &mux_chip->mux[i];  in mux_chip_register()  local
173 		if (mux->idle_state == mux->cached_state)  in mux_chip_register()
176 		ret = mux_control_set(mux, mux->idle_state);  in mux_chip_register()
192  * mux_chip_unregister() - Take the mux-chip off-line.
193  * @mux_chip: The mux-chip to unregister.
197  * on a mux-chip that has been registered before.
206  * mux_chip_free() - Free the mux-chip for good.
207  * @mux_chip: The mux-chip to free.
229  * @dev: The parent device implementing the mux interface.
230  * @controllers: The number of mux controllers to allocate for this chip.
235  * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
269  * @dev: The parent device implementing the mux interface.
270  * @mux_chip: The mux-chip to register.
301  * @mux: The mux-control to query.
305 unsigned int mux_control_states(struct mux_control *mux)  in mux_control_states()  argument
307 	return mux->states;  in mux_control_states()
312  * The mux->lock must be down when calling this function.
314 static int __mux_control_select(struct mux_control *mux, int state)  in __mux_control_select()  argument
318 	if (WARN_ON(state < 0 || state >= mux->states))  in __mux_control_select()
321 	if (mux->cached_state == state)  in __mux_control_select()
324 	ret = mux_control_set(mux, state);  in __mux_control_select()
328 	/* The mux update failed, try to revert if appropriate... */  in __mux_control_select()
329 	if (mux->idle_state != MUX_IDLE_AS_IS)  in __mux_control_select()
330 		mux_control_set(mux, mux->idle_state);  in __mux_control_select()
335 static void mux_control_delay(struct mux_control *mux, unsigned int delay_us)  in mux_control_delay()  argument
343 	delayend = ktime_add_us(mux->last_change, delay_us);  in mux_control_delay()
351  * @mux: The mux-control to request a change of state from.
353  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
355  * On successfully selecting the mux-control state, it will be locked until
356  * there is a call to mux_control_deselect(). If the mux-control is already
362  * complete and the mux-control is free for others to use, but do not call
365  * Return: 0 when the mux-control state has the requested state or a negative
368 int mux_control_select_delay(struct mux_control *mux, unsigned int state,  in mux_control_select_delay()  argument
373 	ret = down_killable(&mux->lock);  in mux_control_select_delay()
377 	ret = __mux_control_select(mux, state);  in mux_control_select_delay()
379 		mux_control_delay(mux, delay_us);  in mux_control_select_delay()
382 		up(&mux->lock);  in mux_control_select_delay()
390  * @mstate: The mux-state to select.
391  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
393  * On successfully selecting the mux-state, its mux-control will be locked
394  * until there is a call to mux_state_deselect(). If the mux-control is already
400  * complete and the mux-control is free for others to use, but do not call
403  * Return: 0 when the mux-state has been selected or a negative
408 	return mux_control_select_delay(mstate->mux, mstate->state, delay_us);  in mux_state_select_delay()
414  * @mux: The mux-control to request a change of state from.
416  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
418  * On successfully selecting the mux-control state, it will be locked until
422  * complete and the mux-control is free for others to use, but do not call
425  * Return: 0 when the mux-control state has the requested state or a negative
426  * errno on error. Specifically -EBUSY if the mux-control is contended.
428 int mux_control_try_select_delay(struct mux_control *mux, unsigned int state,  in mux_control_try_select_delay()  argument
433 	if (down_trylock(&mux->lock))  in mux_control_try_select_delay()
436 	ret = __mux_control_select(mux, state);  in mux_control_try_select_delay()
438 		mux_control_delay(mux, delay_us);  in mux_control_try_select_delay()
441 		up(&mux->lock);  in mux_control_try_select_delay()
449  * @mstate: The mux-state to select.
450  * @delay_us: The time to delay (in microseconds) if the mux state is changed.
452  * On successfully selecting the mux-state, its mux-control will be locked
456  * complete and the mux-control is free for others to use, but do not call
459  * Return: 0 when the mux-state has been selected or a negative errno on
460  * error. Specifically -EBUSY if the mux-control is contended.
464 	return mux_control_try_select_delay(mstate->mux, mstate->state, delay_us);  in mux_state_try_select_delay()
470  * @mux: The mux-control to deselect.
477  * occur if the mux has an idle state. Note that even if an error occurs, the
478  * mux-control is unlocked and is thus free for the next access.
480 int mux_control_deselect(struct mux_control *mux)  in mux_control_deselect()  argument
484 	if (mux->idle_state != MUX_IDLE_AS_IS &&  in mux_control_deselect()
485 	    mux->idle_state != mux->cached_state)  in mux_control_deselect()
486 		ret = mux_control_set(mux, mux->idle_state);  in mux_control_deselect()
488 	up(&mux->lock);  in mux_control_deselect()
496  * @mstate: The mux-state to deselect.
503  * occur if the mux has an idle state. Note that even if an error occurs, the
504  * mux-control is unlocked and is thus free for the next access.
508 	return mux_control_deselect(mstate->mux);  in mux_state_deselect()
523  * mux_get() - Get the mux-control for a device.
524  * @dev: The device that needs a mux-control.
525  * @mux_name: The name identifying the mux-control.
529  * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
543 			index = of_property_match_string(np, "mux-state-names",  in mux_get()
546 			index = of_property_match_string(np, "mux-control-names",  in mux_get()
549 			dev_err(dev, "mux controller '%s' not found\n",  in mux_get()
557 						 "mux-states", "#mux-state-cells",  in mux_get()
561 						 "mux-controls", "#mux-control-cells",  in mux_get()
564 		dev_err(dev, "%pOF: failed to get mux-%s %s(%i)\n",  in mux_get()
578 			dev_err(dev, "%pOF: wrong #mux-state-cells for %pOF\n",  in mux_get()
594 			dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n",  in mux_get()
605 		dev_err(dev, "%pOF: bad mux controller %u specified in %pOF\n",  in mux_get()
611 	return &mux_chip->mux[controller];  in mux_get()
615  * mux_control_get() - Get the mux-control for a device.
616  * @dev: The device that needs a mux-control.
617  * @mux_name: The name identifying the mux-control.
619  * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
628  * mux_control_put() - Put away the mux-control for good.
629  * @mux: The mux-control to put away.
633 void mux_control_put(struct mux_control *mux)  in mux_control_put()  argument
635 	put_device(&mux->chip->dev);  in mux_control_put()
641 	struct mux_control *mux = *(struct mux_control **)res;  in devm_mux_control_release()  local
643 	mux_control_put(mux);  in devm_mux_control_release()
647  * devm_mux_control_get() - Get the mux-control for a device, with resource
649  * @dev: The device that needs a mux-control.
650  * @mux_name: The name identifying the mux-control.
652  * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno.
657 	struct mux_control **ptr, *mux;  in devm_mux_control_get()  local
663 	mux = mux_control_get(dev, mux_name);  in devm_mux_control_get()
664 	if (IS_ERR(mux)) {  in devm_mux_control_get()
666 		return mux;  in devm_mux_control_get()
669 	*ptr = mux;  in devm_mux_control_get()
672 	return mux;  in devm_mux_control_get()
677  * mux_state_get() - Get the mux-state for a device.
678  * @dev: The device that needs a mux-state.
679  * @mux_name: The name identifying the mux-state.
681  * Return: A pointer to the mux-state, or an ERR_PTR with a negative errno.
691 	mstate->mux = mux_get(dev, mux_name, &mstate->state);  in mux_state_get()
692 	if (IS_ERR(mstate->mux)) {  in mux_state_get()
693 		int err = PTR_ERR(mstate->mux);  in mux_state_get()
703  * mux_state_put() - Put away the mux-state for good.
704  * @mstate: The mux-state to put away.
710 	mux_control_put(mstate->mux);  in mux_state_put()
722  * devm_mux_state_get() - Get the mux-state for a device, with resource
724  * @dev: The device that needs a mux-control.
725  * @mux_name: The name identifying the mux-control.
727  * Return: Pointer to the mux-state, or an ERR_PTR with a negative errno.
753  * the non-modular case - that the subsystem is initialized when mux consumers
754  * and mux controllers start to use it.