1 // SPDX-License-Identifier: GPL-2.0
10 #define pr_fmt(fmt) "mux-core: " fmt
18 #include <linux/mux/consumer.h>
19 #include <linux/mux/driver.h>
25  * The idle-as-is "state" is not an actual state that may be selected, it
32 	.name = "mux",
54 	ida_simple_remove(&mux_ida, mux_chip->id);  in mux_chip_release()
59 	.name = "mux-chip",
64  * mux_chip_alloc() - Allocate a mux-chip.
65  * @dev: The parent device implementing the mux interface.
66  * @controllers: The number of mux controllers to allocate for this chip.
69  * After allocating the mux-chip with the desired number of mux controllers
70  * but before registering the chip, the mux driver is required to configure
71  * the number of valid mux states in the mux_chip->mux[N].states members and
72  * the desired idle state in the returned mux_chip->mux[N].idle_state members.
73  * The default idle state is MUX_IDLE_AS_IS. The mux driver also needs to
74  * provide a pointer to the operations struct in the mux_chip->ops member
75  * before registering the mux-chip with mux_chip_register.
77  * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
86 		return ERR_PTR(-EINVAL);  in mux_chip_alloc()
89 			   controllers * sizeof(*mux_chip->mux) +  in mux_chip_alloc()
92 		return ERR_PTR(-ENOMEM);  in mux_chip_alloc()
94 	mux_chip->mux = (struct mux_control *)(mux_chip + 1);  in mux_chip_alloc()
95 	mux_chip->dev.class = &mux_class;  in mux_chip_alloc()
96 	mux_chip->dev.type = &mux_type;  in mux_chip_alloc()
97 	mux_chip->dev.parent = dev;  in mux_chip_alloc()
98 	mux_chip->dev.of_node = dev->of_node;  in mux_chip_alloc()
99 	dev_set_drvdata(&mux_chip->dev, mux_chip);  in mux_chip_alloc()
101 	mux_chip->id = ida_simple_get(&mux_ida, 0, 0, GFP_KERNEL);  in mux_chip_alloc()
102 	if (mux_chip->id < 0) {  in mux_chip_alloc()
103 		int err = mux_chip->id;  in mux_chip_alloc()
109 	dev_set_name(&mux_chip->dev, "muxchip%d", mux_chip->id);  in mux_chip_alloc()
111 	mux_chip->controllers = controllers;  in mux_chip_alloc()
113 		struct mux_control *mux = &mux_chip->mux[i];  in mux_chip_alloc()  local
115 		mux->chip = mux_chip;  in mux_chip_alloc()
116 		sema_init(&mux->lock, 1);  in mux_chip_alloc()
117 		mux->cached_state = MUX_CACHE_UNKNOWN;  in mux_chip_alloc()
118 		mux->idle_state = MUX_IDLE_AS_IS;  in mux_chip_alloc()
121 	device_initialize(&mux_chip->dev);  in mux_chip_alloc()
127 static int mux_control_set(struct mux_control *mux, int state)  in mux_control_set()  argument
129 	int ret = mux->chip->ops->set(mux, state);  in mux_control_set()
131 	mux->cached_state = ret < 0 ? MUX_CACHE_UNKNOWN : state;  in mux_control_set()
137  * mux_chip_register() - Register a mux-chip, thus readying the controllers
139  * @mux_chip: The mux-chip to register.
141  * Do not retry registration of the same mux-chip on failure. You should
152 	for (i = 0; i < mux_chip->controllers; ++i) {  in mux_chip_register()
153 		struct mux_control *mux = &mux_chip->mux[i];  in mux_chip_register()  local
155 		if (mux->idle_state == mux->cached_state)  in mux_chip_register()
158 		ret = mux_control_set(mux, mux->idle_state);  in mux_chip_register()
160 			dev_err(&mux_chip->dev, "unable to set idle state\n");  in mux_chip_register()
165 	ret = device_add(&mux_chip->dev);  in mux_chip_register()
167 		dev_err(&mux_chip->dev,  in mux_chip_register()
174  * mux_chip_unregister() - Take the mux-chip off-line.
175  * @mux_chip: The mux-chip to unregister.
179  * on a mux-chip that has been registered before.
183 	device_del(&mux_chip->dev);  in mux_chip_unregister()
188  * mux_chip_free() - Free the mux-chip for good.
189  * @mux_chip: The mux-chip to free.
198 	put_device(&mux_chip->dev);  in mux_chip_free()
210  * devm_mux_chip_alloc() - Resource-managed version of mux_chip_alloc().
211  * @dev: The parent device implementing the mux interface.
212  * @controllers: The number of mux controllers to allocate for this chip.
217  * Return: A pointer to the new mux-chip, or an ERR_PTR with a negative errno.
227 		return ERR_PTR(-ENOMEM);  in devm_mux_chip_alloc()
250  * devm_mux_chip_register() - Resource-managed version mux_chip_register().
251  * @dev: The parent device implementing the mux interface.
252  * @mux_chip: The mux-chip to register.
266 		return -ENOMEM;  in devm_mux_chip_register()
282  * mux_control_states() - Query the number of multiplexer states.
283  * @mux: The mux-control to query.
287 unsigned int mux_control_states(struct mux_control *mux)  in mux_control_states()  argument
289 	return mux->states;  in mux_control_states()
294  * The mux->lock must be down when calling this function.
296 static int __mux_control_select(struct mux_control *mux, int state)  in __mux_control_select()  argument
300 	if (WARN_ON(state < 0 || state >= mux->states))  in __mux_control_select()
301 		return -EINVAL;  in __mux_control_select()
303 	if (mux->cached_state == state)  in __mux_control_select()
306 	ret = mux_control_set(mux, state);  in __mux_control_select()
310 	/* The mux update failed, try to revert if appropriate... */  in __mux_control_select()
311 	if (mux->idle_state != MUX_IDLE_AS_IS)  in __mux_control_select()
312 		mux_control_set(mux, mux->idle_state);  in __mux_control_select()
318  * mux_control_select() - Select the given multiplexer state.
319  * @mux: The mux-control to request a change of state from.
322  * On successfully selecting the mux-control state, it will be locked until
323  * there is a call to mux_control_deselect(). If the mux-control is already
328  * complete and the mux-control is free for others to use, but do not call
331  * Return: 0 when the mux-control state has the requested state or a negative
334 int mux_control_select(struct mux_control *mux, unsigned int state)  in mux_control_select()  argument
338 	ret = down_killable(&mux->lock);  in mux_control_select()
342 	ret = __mux_control_select(mux, state);  in mux_control_select()
345 		up(&mux->lock);  in mux_control_select()
352  * mux_control_try_select() - Try to select the given multiplexer state.
353  * @mux: The mux-control to request a change of state from.
356  * On successfully selecting the mux-control state, it will be locked until
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
364  * errno on error. Specifically -EBUSY if the mux-control is contended.
366 int mux_control_try_select(struct mux_control *mux, unsigned int state)  in mux_control_try_select()  argument
370 	if (down_trylock(&mux->lock))  in mux_control_try_select()
371 		return -EBUSY;  in mux_control_try_select()
373 	ret = __mux_control_select(mux, state);  in mux_control_try_select()
376 		up(&mux->lock);  in mux_control_try_select()
383  * mux_control_deselect() - Deselect the previously selected multiplexer state.
384  * @mux: The mux-control to deselect.
391  * occur if the mux has an idle state. Note that even if an error occurs, the
392  * mux-control is unlocked and is thus free for the next access.
394 int mux_control_deselect(struct mux_control *mux)  in mux_control_deselect()  argument
398 	if (mux->idle_state != MUX_IDLE_AS_IS &&  in mux_control_deselect()
399 	    mux->idle_state != mux->cached_state)  in mux_control_deselect()
400 		ret = mux_control_set(mux, mux->idle_state);  in mux_control_deselect()
402 	up(&mux->lock);  in mux_control_deselect()
419  * mux_control_get() - Get the mux-control for a device.
420  * @dev: The device that needs a mux-control.
421  * @mux_name: The name identifying the mux-control.
423  * Return: A pointer to the mux-control, or an ERR_PTR with a negative errno.
427 	struct device_node *np = dev->of_node;  in mux_control_get()
435 		index = of_property_match_string(np, "mux-control-names",  in mux_control_get()
438 			dev_err(dev, "mux controller '%s' not found\n",  in mux_control_get()
445 					 "mux-controls", "#mux-control-cells",  in mux_control_get()
448 		dev_err(dev, "%pOF: failed to get mux-control %s(%i)\n",  in mux_control_get()
456 		return ERR_PTR(-EPROBE_DEFER);  in mux_control_get()
459 	    (!args.args_count && (mux_chip->controllers > 1))) {  in mux_control_get()
460 		dev_err(dev, "%pOF: wrong #mux-control-cells for %pOF\n",  in mux_control_get()
462 		put_device(&mux_chip->dev);  in mux_control_get()
463 		return ERR_PTR(-EINVAL);  in mux_control_get()
470 	if (controller >= mux_chip->controllers) {  in mux_control_get()
471 		dev_err(dev, "%pOF: bad mux controller %u specified in %pOF\n",  in mux_control_get()
473 		put_device(&mux_chip->dev);  in mux_control_get()
474 		return ERR_PTR(-EINVAL);  in mux_control_get()
477 	return &mux_chip->mux[controller];  in mux_control_get()
482  * mux_control_put() - Put away the mux-control for good.
483  * @mux: The mux-control to put away.
487 void mux_control_put(struct mux_control *mux)  in mux_control_put()  argument
489 	put_device(&mux->chip->dev);  in mux_control_put()
495 	struct mux_control *mux = *(struct mux_control **)res;  in devm_mux_control_release()  local
497 	mux_control_put(mux);  in devm_mux_control_release()
501  * devm_mux_control_get() - Get the mux-control for a device, with resource
503  * @dev: The device that needs a mux-control.
504  * @mux_name: The name identifying the mux-control.
506  * Return: Pointer to the mux-control, or an ERR_PTR with a negative errno.
511 	struct mux_control **ptr, *mux;  in devm_mux_control_get()  local
515 		return ERR_PTR(-ENOMEM);  in devm_mux_control_get()
517 	mux = mux_control_get(dev, mux_name);  in devm_mux_control_get()
518 	if (IS_ERR(mux)) {  in devm_mux_control_get()
520 		return mux;  in devm_mux_control_get()
523 	*ptr = mux;  in devm_mux_control_get()
526 	return mux;  in devm_mux_control_get()
531  * Using subsys_initcall instead of module_init here to try to ensure - for
532  * the non-modular case - that the subsystem is initialized when mux consumers
533  * and mux controllers start to use it.