drivers/reset/core.c

3  * Reset Controller framework
21 #include <linux/reset.h>
22 #include <linux/reset-controller.h>
37  * struct reset_control - a reset control
38  * @rcdev: a pointer to the reset controller device
39  *         this reset control belongs to
40  * @list: list entry for the rcdev's reset controller list
41  * @id: ID of the reset controller in the reset
46  * @array: Is this an array of reset controls (1)?
47  * @deassert_count: Number of times this reset line has been deasserted
48  * @triggered_count: Number of times this reset line has been reset. Currently
65  * struct reset_control_array - an array of reset controls
66  * @base: reset control for compatibility with reset control API functions
67  * @num_rstcs: number of reset controls
68  * @rstc: array of reset controls
77  * struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices
78  * @of_args: phandle to the reset controller with all the args like GPIO number
101  * of_reset_simple_xlate - translate reset_spec to the reset line number
102  * @rcdev: a pointer to the reset controller device
103  * @reset_spec: reset line specifier as found in the device tree
106  * :c:type:`reset_controller_dev` is not set. It is useful for all reset
107  * controllers with 1:1 mapping, where reset lines can be indexed by number
120  * reset_controller_register - register a reset controller device
121  * @rcdev: a pointer to the initialized reset controller device
144  * reset_controller_unregister - unregister a reset controller device
145  * @rcdev: a pointer to the reset controller device
162  * @dev: device that is registering this reset controller
163  * @rcdev: a pointer to the initialized reset controller device
165  * Managed reset_controller_register(). For reset controllers registered by
195  * @lookup: array of reset lookup entries
209 			pr_warn("%s(): reset lookup entry badly specified, skipping\n",  in reset_controller_add_lookup()
341  * reset_control_reset - reset the controlled device
342  * @rstc: reset controller
344  * On a shared reset line the actual reset pulse is only triggered once for the
347  * Consumers must not use reset_control_(de)assert on shared reset lines when
350  * If rstc is NULL it is an optional reset and the function will just
366 	if (!rstc->rcdev->ops->reset)  in reset_control_reset()
380 	ret = rstc->rcdev->ops->reset(rstc->rcdev, rstc->id);  in reset_control_reset()
389  * reset_control_bulk_reset - reset the controlled devices in order
391  * @rstcs: array of struct reset_control_bulk_data with reset controls set
393  * Issue a reset on all provided reset controls, in order.
413  * reset_control_rearm - allow shared reset line to be re-triggered"
414  * @rstc: reset controller
416  * On a shared reset line the actual reset pulse is only triggered once for the
422  * Consumers must not use reset_control_(de)assert on shared reset lines when
453  * reset_control_assert - asserts the reset line
454  * @rstc: reset controller
456  * Calling this on an exclusive reset controller guarantees that the reset
457  * will be asserted. When called on a shared reset controller the line may
460  * For shared reset controls a driver cannot expect the hw's registers and
461  * internal state to be reset, but must be prepared for this to happen.
462  * Consumers must not use reset_control_reset on shared reset lines when
465  * If rstc is NULL it is an optional reset and the function will just
490 		 * Shared reset controls allow the reset line to be in any state  in reset_control_assert()
497 		 * If the reset controller does not implement .assert(), there  in reset_control_assert()
498 		 * is no way to guarantee that the reset line is asserted after  in reset_control_assert()
505 			WARN(1, "reset %s (ID: %u) is not acquired\n",  in reset_control_assert()
516  * reset_control_bulk_assert - asserts the reset lines in order
518  * @rstcs: array of struct reset_control_bulk_data with reset controls set
520  * Assert the reset lines for all provided reset controls, in order.
546  * reset_control_deassert - deasserts the reset line
547  * @rstc: reset controller
549  * After calling this function, the reset is guaranteed to be deasserted.
550  * Consumers must not use reset_control_reset on shared reset lines when
553  * If rstc is NULL it is an optional reset and the function will just
575 			WARN(1, "reset %s (ID: %u) is not acquired\n",  in reset_control_deassert()
582 	 * If the reset controller does not implement .deassert(), we assume  in reset_control_deassert()
583 	 * that it handles self-deasserting reset lines via .reset(). In that  in reset_control_deassert()
584 	 * case, the reset lines are deasserted by default. If that is not the  in reset_control_deassert()
585 	 * case, the reset controller driver should implement .deassert() and  in reset_control_deassert()
596  * reset_control_bulk_deassert - deasserts the reset lines in reverse order
598  * @rstcs: array of struct reset_control_bulk_data with reset controls set
600  * Deassert the reset lines for all provided reset controls, in reverse order.
627  * positive value if the reset line is asserted, or zero if the reset
628  * line is not asserted or if the desc is NULL (optional reset).
629  * @rstc: reset controller
647  * reset_control_acquire() - acquires a reset control for exclusive use
648  * @rstc: reset control
650  * This is used to explicitly acquire a reset control for exclusive use. Note
652  * second consumer to be able to control the reset, the first consumer has to
654  * reset_control_get_exclusive_released() to obtain an instance of the reset
655  * control. Such reset controls are not acquired by default.
657  * Consumers implementing shared access to an exclusive reset need to follow
659  * a reset they must acquire exclusive access using reset_control_acquire().
660  * After they are done operating the reset, they must release exclusive access
662  * access to the reset as long as another consumer hasn't released a reset.
703  * reset_control_bulk_acquire - acquires reset controls for exclusive use
705  * @rstcs: array of struct reset_control_bulk_data with reset controls set
707  * This is used to explicitly acquire reset controls requested with
733  * reset_control_release() - releases exclusive access to a reset control
734  * @rstc: reset control
736  * Releases exclusive access right to a reset control previously obtained by a
755  * reset_control_bulk_release() - releases exclusive access to reset controls
757  * @rstcs: array of struct reset_control_bulk_data with reset controls set
759  * Releases exclusive access right to reset controls previously obtained by a
787 			 * controlled reset line.  in __reset_control_get_internal()
858 		pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n",  in __reset_add_reset_gpio_lookup()
881 	lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id);  in __reset_add_reset_gpio_lookup()
887 	lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset",  in __reset_add_reset_gpio_lookup()
915 	 * Registering reset-gpio device might cause immediate  in __reset_add_reset_gpio_device()
916 	 * bind, resulting in its probe() registering new reset controller thus  in __reset_add_reset_gpio_device()
953 	pdev = platform_device_register_data(NULL, "reset-gpio", id,  in __reset_add_reset_gpio_device()
1011 						 "reset-names", id);  in __of_reset_control_get()
1018 	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",  in __of_reset_control_get()
1027 		 * There can be only one reset-gpio for regular devices, so  in __of_reset_control_get()
1028 		 * don't bother with the "reset-gpios" phandle index.  in __of_reset_control_get()
1030 		ret = of_parse_phandle_with_args(node, "reset-gpios", "#gpio-cells",  in __of_reset_control_get()
1115 				/* Reset provider may not be ready yet. */  in __reset_control_get_from_lookup()
1189  * reset_control_put - free the reset controller
1190  * @rstc: reset controller
1209  * reset_control_bulk_put - free the reset controllers
1211  * @rstcs: array of struct reset_control_bulk_data with reset controls set
1290  * __device_reset - find reset controller associated with the device
1291  *                  and perform reset
1292  * @dev: device to be reset by the controller
1293  * @optional: whether it is optional to reset the device
1296  * This is useful for the common case of devices with single, dedicated reset
1329  * APIs to manage an array of reset controls.
1337  * Returns positive reset count on success, or error number on failure and
1347 	count = of_count_phandle_with_args(node, "resets", "#reset-cells");  in of_reset_control_get_count()
1355  * of_reset_control_array_get - Get a list of reset controls using
1358  * @np: device node for the device that requests the reset controls array
1359  * @shared: whether reset controls are shared or not
1360  * @optional: whether it is optional to get the reset controls
1361  * @acquired: only one reset control may be acquired for a given controller
1407  * devm_reset_control_array_get - Resource managed reset control array get
1409  * @dev: device that requests the list of reset controls
1410  * @shared: whether reset controls are shared or not
1411  * @optional: whether it is optional to get the reset controls
1413  * The reset control array APIs are intended for a list of resets
1472  * Returns positive reset count on success, or error number on failure and