1 // SPDX-License-Identifier: GPL-2.0
10 #define pr_fmt(fmt) "mux-core: " fmt
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
37  * This structure is specific to the consumer that acquires it and has
67 	ida_free(&mux_ida, mux_chip->id);  in mux_chip_release()
72 	.name = "mux-chip",
77  * mux_chip_alloc() - Allocate a mux-chip.
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.
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()
105 		return ERR_PTR(-ENOMEM);  in mux_chip_alloc()
107 	mux_chip->dev.class = &mux_class;  in mux_chip_alloc()
108 	mux_chip->dev.type = &mux_type;  in mux_chip_alloc()
109 	mux_chip->dev.parent = dev;  in mux_chip_alloc()
110 	mux_chip->dev.of_node = dev->of_node;  in mux_chip_alloc()
111 	dev_set_drvdata(&mux_chip->dev, mux_chip);  in mux_chip_alloc()
113 	mux_chip->id = ida_alloc(&mux_ida, GFP_KERNEL);  in mux_chip_alloc()
114 	if (mux_chip->id < 0) {  in mux_chip_alloc()
115 		int err = mux_chip->id;  in mux_chip_alloc()
117 		pr_err("muxchipX failed to get a device id\n");  in mux_chip_alloc()
121 	dev_set_name(&mux_chip->dev, "muxchip%d", mux_chip->id);  in mux_chip_alloc()
123 	mux_chip->controllers = controllers;  in mux_chip_alloc()
125 		struct mux_control *mux = &mux_chip->mux[i];  in mux_chip_alloc()
127 		mux->chip = mux_chip;  in mux_chip_alloc()
128 		sema_init(&mux->lock, 1);  in mux_chip_alloc()
129 		mux->cached_state = MUX_CACHE_UNKNOWN;  in mux_chip_alloc()
130 		mux->idle_state = MUX_IDLE_AS_IS;  in mux_chip_alloc()
131 		mux->last_change = ktime_get();  in mux_chip_alloc()
134 	device_initialize(&mux_chip->dev);  in mux_chip_alloc()
142 	int ret = mux->chip->ops->set(mux, state);  in mux_control_set()
144 	mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state;  in mux_control_set()
146 		mux->last_change = ktime_get();  in mux_control_set()
152  * mux_chip_register() - Register a mux-chip, thus readying the controllers
154  * @mux_chip: The mux-chip to register.
156  * Do not retry registration of the same mux-chip on failure. You should
167 	for (i = 0; i < mux_chip->controllers; ++i) {  in mux_chip_register()
168 		struct mux_control *mux = &mux_chip->mux[i];  in mux_chip_register()
170 		if (mux->idle_state == mux->cached_state)  in mux_chip_register()
173 		ret = mux_control_set(mux, mux->idle_state);  in mux_chip_register()
175 			dev_err(&mux_chip->dev, "unable to set idle state\n");  in mux_chip_register()
180 	ret = device_add(&mux_chip->dev);  in mux_chip_register()
182 		dev_err(&mux_chip->dev,  in mux_chip_register()
189  * mux_chip_unregister() - Take the mux-chip off-line.
190  * @mux_chip: The mux-chip to unregister.
194  * on a mux-chip that has been registered before.
198 	device_del(&mux_chip->dev);  in mux_chip_unregister()
203  * mux_chip_free() - Free the mux-chip for good.
204  * @mux_chip: The mux-chip to free.
213 	put_device(&mux_chip->dev);  in mux_chip_free()
225  * devm_mux_chip_alloc() - Resource-managed version of mux_chip_alloc().
227  * @controllers: The number of mux controllers to allocate for this chip.
232  * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
242 		return ERR_PTR(-ENOMEM);  in devm_mux_chip_alloc()
265  * devm_mux_chip_register() - Resource-managed version mux_chip_register().
267  * @mux_chip: The mux-chip to register.
281 		return -ENOMEM;  in devm_mux_chip_register()
297  * mux_control_states() - Query the number of multiplexer states.
298  * @mux: The mux-control to query.
304 	return mux->states;  in mux_control_states()
309  * The mux->lock must be down when calling this function.
315 	if (WARN_ON(state < 0 || state >= mux->states))  in __mux_control_select()
316 		return -EINVAL;  in __mux_control_select()
318 	if (mux->cached_state == state)  in __mux_control_select()
326 	if (mux->idle_state != MUX_IDLE_AS_IS)  in __mux_control_select()
327 		mux_control_set(mux, mux->idle_state);  in __mux_control_select()
340 	delayend = ktime_add_us(mux->last_change, delay_us);  in mux_control_delay()
347  * mux_control_select_delay() - Select the given multiplexer state.
348  * @mux: The mux-control to request a change of state from.
352  * On successfully selecting the mux-control state, it will be locked until
353  * there is a call to mux_control_deselect(). If the mux-control is already
359  * complete and the mux-control is free for others to use, but do not call
362  * Return: 0 when the mux-control state has the requested state or a negative
370 	ret = down_killable(&mux->lock);  in mux_control_select_delay()
379 		up(&mux->lock);  in mux_control_select_delay()
386  * mux_state_select_delay() - Select the given multiplexer state.
387  * @mstate: The mux-state to select.
390  * On successfully selecting the mux-state, its mux-control will be locked
391  * until there is a call to mux_state_deselect(). If the mux-control is already
397  * complete and the mux-control is free for others to use, but do not call
400  * Return: 0 when the mux-state has been selected or a negative
405 	return mux_control_select_delay(mstate->mux, mstate->state, delay_us);  in mux_state_select_delay()
410  * mux_control_try_select_delay() - Try to select the given multiplexer state.
411  * @mux: The mux-control to request a change of state from.
415  * On successfully selecting the mux-control state, it will be locked until
419  * complete and the mux-control is free for others to use, but do not call
422  * Return: 0 when the mux-control state has the requested state or a negative
423  * errno on error. Specifically -EBUSY if the mux-control is contended.
430 	if (down_trylock(&mux->lock))  in mux_control_try_select_delay()
431 		return -EBUSY;  in mux_control_try_select_delay()
438 		up(&mux->lock);  in mux_control_try_select_delay()
445  * mux_state_try_select_delay() - Try to select the given multiplexer state.
446  * @mstate: The mux-state to select.
449  * On successfully selecting the mux-state, its mux-control will be locked
453  * complete and the mux-control is free for others to use, but do not call
456  * Return: 0 when the mux-state has been selected or a negative errno on
457  * error. Specifically -EBUSY if the mux-control is contended.
461 	return mux_control_try_select_delay(mstate->mux, mstate->state, delay_us);  in mux_state_try_select_delay()
466  * mux_control_deselect() - Deselect the previously selected multiplexer state.
467  * @mux: The mux-control to deselect.
474  * occur if the mux has an idle state. Note that even if an error occurs, the
475  * mux-control is unlocked and is thus free for the next access.
481 	if (mux->idle_state != MUX_IDLE_AS_IS &&  in mux_control_deselect()
482 	    mux->idle_state != mux->cached_state)  in mux_control_deselect()
483 		ret = mux_control_set(mux, mux->idle_state);  in mux_control_deselect()
485 	up(&mux->lock);  in mux_control_deselect()
492  * mux_state_deselect() - Deselect the previously selected multiplexer state.
493  * @mstate: The mux-state to deselect.
500  * occur if the mux has an idle state. Note that even if an error occurs, the
501  * mux-control is unlocked and is thus free for the next access.
505 	return mux_control_deselect(mstate->mux);  in mux_state_deselect()
520  * mux_get() - Get the mux-control for a device.
521  * @dev: The device that needs a mux-control.
522  * @mux_name: The name identifying the mux-control.
526  * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
531 	struct device_node *np = dev->of_node;  in mux_get()
540 			index = of_property_match_string(np, "mux-state-names",  in mux_get()
543 			index = of_property_match_string(np, "mux-control-names",  in mux_get()
554 						 "mux-states", "#mux-state-cells",  in mux_get()
558 						 "mux-controls", "#mux-control-cells",  in mux_get()
561 		dev_err(dev, "%pOF: failed to get mux-%s %s(%i)\n",  in mux_get()
569 		return ERR_PTR(-EPROBE_DEFER);  in mux_get()
574 		    (args.args_count < 2 && mux_chip->controllers > 1)) {  in mux_get()
575 			dev_err(dev, "%pOF: wrong #mux-state-cells for %pOF\n",  in mux_get()
577 			put_device(&mux_chip->dev);  in mux_get()
578 			return ERR_PTR(-EINVAL);  in mux_get()
590 		    (!args.args_count && mux_chip->controllers > 1)) {  in mux_get()
591 			dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n",  in mux_get()
593 			put_device(&mux_chip->dev);  in mux_get()
594 			return ERR_PTR(-EINVAL);  in mux_get()
601 	if (controller >= mux_chip->controllers) {  in mux_get()
604 		put_device(&mux_chip->dev);  in mux_get()
605 		return ERR_PTR(-EINVAL);  in mux_get()
608 	return &mux_chip->mux[controller];  in mux_get()
612  * mux_control_get() - Get the mux-control for a device.
613  * @dev: The device that needs a mux-control.
614  * @mux_name: The name identifying the mux-control.
616  * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
625  * mux_control_put() - Put away the mux-control for good.
626  * @mux: The mux-control to put away.
632 	put_device(&mux->chip->dev);  in mux_control_put()
644  * devm_mux_control_get() - Get the mux-control for a device, with resource
646  * @dev: The device that needs a mux-control.
647  * @mux_name: The name identifying the mux-control.
649  * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno.
658 		return ERR_PTR(-ENOMEM);  in devm_mux_control_get()
674  * mux_state_get() - Get the mux-state for a device.
675  * @dev: The device that needs a mux-state.
676  * @mux_name: The name identifying the mux-state.
678  * Return: A pointer to the mux-state, or an ERR_PTR with a negative errno.
686 		return ERR_PTR(-ENOMEM);  in mux_state_get()
688 	mstate->mux = mux_get(dev, mux_name, &mstate->state);  in mux_state_get()
689 	if (IS_ERR(mstate->mux)) {  in mux_state_get()
690 		int err = PTR_ERR(mstate->mux);  in mux_state_get()
700  * mux_state_put() - Put away the mux-state for good.
701  * @mstate: The mux-state to put away.
707 	mux_control_put(mstate->mux);  in mux_state_put()
719  * devm_mux_state_get() - Get the mux-state for a device, with resource
721  * @dev: The device that needs a mux-control.
722  * @mux_name: The name identifying the mux-control.
724  * Return: Pointer to the mux-state, or an ERR_PTR with a negative errno.
733 		return ERR_PTR(-ENOMEM);  in devm_mux_state_get()
749  * Using subsys_initcall instead of module_init here to try to ensure - for
750  * the non-modular case - that the subsystem is initialized when mux consumers