xref: /openbmc/u-boot/include/dm/uclass.h (revision 3ade5bc4)
1 /*
2  * Copyright (c) 2013 Google, Inc
3  *
4  * (C) Copyright 2012
5  * Pavel Herrmann <morpheus.ibis@gmail.com>
6  *
7  * SPDX-License-Identifier:	GPL-2.0+
8  */
9 
10 #ifndef _DM_UCLASS_H
11 #define _DM_UCLASS_H
12 
13 #include <dm/uclass-id.h>
14 #include <linker_lists.h>
15 #include <linux/list.h>
16 
17 /**
18  * struct uclass - a U-Boot drive class, collecting together similar drivers
19  *
20  * A uclass provides an interface to a particular function, which is
21  * implemented by one or more drivers. Every driver belongs to a uclass even
22  * if it is the only driver in that uclass. An example uclass is GPIO, which
23  * provides the ability to change read inputs, set and clear outputs, etc.
24  * There may be drivers for on-chip SoC GPIO banks, I2C GPIO expanders and
25  * PMIC IO lines, all made available in a unified way through the uclass.
26  *
27  * @priv: Private data for this uclass
28  * @uc_drv: The driver for the uclass itself, not to be confused with a
29  * 'struct driver'
30  * @dev_head: List of devices in this uclass (devices are attached to their
31  * uclass when their bind method is called)
32  * @sibling_node: Next uclass in the linked list of uclasses
33  */
34 struct uclass {
35 	void *priv;
36 	struct uclass_driver *uc_drv;
37 	struct list_head dev_head;
38 	struct list_head sibling_node;
39 };
40 
41 struct udevice;
42 
43 /* Members of this uclass sequence themselves with aliases */
44 #define DM_UC_FLAG_SEQ_ALIAS			(1 << 0)
45 
46 /**
47  * struct uclass_driver - Driver for the uclass
48  *
49  * A uclass_driver provides a consistent interface to a set of related
50  * drivers.
51  *
52  * @name: Name of uclass driver
53  * @id: ID number of this uclass
54  * @post_bind: Called after a new device is bound to this uclass
55  * @pre_unbind: Called before a device is unbound from this uclass
56  * @pre_probe: Called before a new device is probed
57  * @post_probe: Called after a new device is probed
58  * @pre_remove: Called before a device is removed
59  * @child_post_bind: Called after a child is bound to a device in this uclass
60  * @init: Called to set up the uclass
61  * @destroy: Called to destroy the uclass
62  * @priv_auto_alloc_size: If non-zero this is the size of the private data
63  * to be allocated in the uclass's ->priv pointer. If zero, then the uclass
64  * driver is responsible for allocating any data required.
65  * @per_device_auto_alloc_size: Each device can hold private data owned
66  * by the uclass. If required this will be automatically allocated if this
67  * value is non-zero.
68  * @per_device_platdata_auto_alloc_size: Each device can hold platform data
69  * owned by the uclass as 'dev->uclass_platdata'. If the value is non-zero,
70  * then this will be automatically allocated.
71  * @per_child_auto_alloc_size: Each child device (of a parent in this
72  * uclass) can hold parent data for the device/uclass. This value is only
73  * used as a falback if this member is 0 in the driver.
74  * @per_child_platdata_auto_alloc_size: A bus likes to store information about
75  * its children. If non-zero this is the size of this data, to be allocated
76  * in the child device's parent_platdata pointer. This value is only used as
77  * a falback if this member is 0 in the driver.
78  * @ops: Uclass operations, providing the consistent interface to devices
79  * within the uclass.
80  * @flags: Flags for this uclass (DM_UC_...)
81  */
82 struct uclass_driver {
83 	const char *name;
84 	enum uclass_id id;
85 	int (*post_bind)(struct udevice *dev);
86 	int (*pre_unbind)(struct udevice *dev);
87 	int (*pre_probe)(struct udevice *dev);
88 	int (*post_probe)(struct udevice *dev);
89 	int (*pre_remove)(struct udevice *dev);
90 	int (*child_post_bind)(struct udevice *dev);
91 	int (*child_pre_probe)(struct udevice *dev);
92 	int (*init)(struct uclass *class);
93 	int (*destroy)(struct uclass *class);
94 	int priv_auto_alloc_size;
95 	int per_device_auto_alloc_size;
96 	int per_device_platdata_auto_alloc_size;
97 	int per_child_auto_alloc_size;
98 	int per_child_platdata_auto_alloc_size;
99 	const void *ops;
100 	uint32_t flags;
101 };
102 
103 /* Declare a new uclass_driver */
104 #define UCLASS_DRIVER(__name)						\
105 	ll_entry_declare(struct uclass_driver, __name, uclass)
106 
107 /**
108  * uclass_get() - Get a uclass based on an ID, creating it if needed
109  *
110  * Every uclass is identified by an ID, a number from 0 to n-1 where n is
111  * the number of uclasses. This function allows looking up a uclass by its
112  * ID.
113  *
114  * @key: ID to look up
115  * @ucp: Returns pointer to uclass (there is only one per ID)
116  * @return 0 if OK, -ve on error
117  */
118 int uclass_get(enum uclass_id key, struct uclass **ucp);
119 
120 /**
121  * uclass_get_device() - Get a uclass device based on an ID and index
122  *
123  * The device is probed to activate it ready for use.
124  *
125  * @id: ID to look up
126  * @index: Device number within that uclass (0=first)
127  * @devp: Returns pointer to device (there is only one per for each ID)
128  * @return 0 if OK, -ve on error
129  */
130 int uclass_get_device(enum uclass_id id, int index, struct udevice **devp);
131 
132 /**
133  * uclass_get_device_by_name() - Get a uclass device by its name
134  *
135  * This searches the devices in the uclass for one with the exactly given name.
136  *
137  * The device is probed to activate it ready for use.
138  *
139  * @id: ID to look up
140  * @name: name of a device to get
141  * @devp: Returns pointer to device (the first one with the name)
142  * @return 0 if OK, -ve on error
143  */
144 int uclass_get_device_by_name(enum uclass_id id, const char *name,
145 			      struct udevice **devp);
146 
147 /**
148  * uclass_get_device_by_seq() - Get a uclass device based on an ID and sequence
149  *
150  * If an active device has this sequence it will be returned. If there is no
151  * such device then this will check for a device that is requesting this
152  * sequence.
153  *
154  * The device is probed to activate it ready for use.
155  *
156  * @id: ID to look up
157  * @seq: Sequence number to find (0=first)
158  * @devp: Returns pointer to device (there is only one for each seq)
159  * @return 0 if OK, -ve on error
160  */
161 int uclass_get_device_by_seq(enum uclass_id id, int seq, struct udevice **devp);
162 
163 /**
164  * uclass_get_device_by_of_offset() - Get a uclass device by device tree node
165  *
166  * This searches the devices in the uclass for one attached to the given
167  * device tree node.
168  *
169  * The device is probed to activate it ready for use.
170  *
171  * @id: ID to look up
172  * @node: Device tree offset to search for (if -ve then -ENODEV is returned)
173  * @devp: Returns pointer to device (there is only one for each node)
174  * @return 0 if OK, -ve on error
175  */
176 int uclass_get_device_by_of_offset(enum uclass_id id, int node,
177 				   struct udevice **devp);
178 
179 /**
180  * uclass_get_device_by_phandle() - Get a uclass device by phandle
181  *
182  * This searches the devices in the uclass for one with the given phandle.
183  *
184  * The device is probed to activate it ready for use.
185  *
186  * @id: uclass ID to look up
187  * @parent: Parent device containing the phandle pointer
188  * @name: Name of property in the parent device node
189  * @devp: Returns pointer to device (there is only one for each node)
190  * @return 0 if OK, -ENOENT if there is no @name present in the node, other
191  *	-ve on error
192  */
193 int uclass_get_device_by_phandle(enum uclass_id id, struct udevice *parent,
194 				 const char *name, struct udevice **devp);
195 
196 /**
197  * uclass_first_device() - Get the first device in a uclass
198  *
199  * The device returned is probed if necessary, and ready for use
200  *
201  * @id: Uclass ID to look up
202  * @devp: Returns pointer to the first device in that uclass, or NULL if none
203  * @return 0 if OK (found or not found), -1 on error
204  */
205 int uclass_first_device(enum uclass_id id, struct udevice **devp);
206 
207 /**
208  * uclass_next_device() - Get the next device in a uclass
209  *
210  * The device returned is probed if necessary, and ready for use
211  *
212  * @devp: On entry, pointer to device to lookup. On exit, returns pointer
213  * to the next device in the same uclass, or NULL if none
214  * @return 0 if OK (found or not found), -1 on error
215  */
216 int uclass_next_device(struct udevice **devp);
217 
218 /**
219  * uclass_resolve_seq() - Resolve a device's sequence number
220  *
221  * On entry dev->seq is -1, and dev->req_seq may be -1 (to allocate a
222  * sequence number automatically, or >= 0 to select a particular number.
223  * If the requested sequence number is in use, then this device will
224  * be allocated another one.
225  *
226  * Note that the device's seq value is not changed by this function.
227  *
228  * @dev: Device for which to allocate sequence number
229  * @return sequence number allocated, or -ve on error
230  */
231 int uclass_resolve_seq(struct udevice *dev);
232 
233 /**
234  * uclass_foreach_dev() - Helper function to iteration through devices
235  *
236  * This creates a for() loop which works through the available devices in
237  * a uclass in order from start to end.
238  *
239  * @pos: struct udevice * to hold the current device. Set to NULL when there
240  * are no more devices.
241  * @uc: uclass to scan
242  */
243 #define uclass_foreach_dev(pos, uc)	\
244 	list_for_each_entry(pos, &uc->dev_head, uclass_node)
245 
246 /**
247  * uclass_foreach_dev_safe() - Helper function to safely iteration through devs
248  *
249  * This creates a for() loop which works through the available devices in
250  * a uclass in order from start to end. Inside the loop, it is safe to remove
251  * @pos if required.
252  *
253  * @pos: struct udevice * to hold the current device. Set to NULL when there
254  * are no more devices.
255  * @next: struct udevice * to hold the next next
256  * @uc: uclass to scan
257  */
258 #define uclass_foreach_dev_safe(pos, next, uc)	\
259 	list_for_each_entry_safe(pos, next, &uc->dev_head, uclass_node)
260 
261 #endif
262