1 /*
2  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  */
14 
15 #ifndef __LINUX_W1_H
16 #define __LINUX_W1_H
17 
18 #include <linux/device.h>
19 
20 /**
21  * struct w1_reg_num - broken out slave device id
22  *
23  * @family: identifies the type of device
24  * @id: along with family is the unique device id
25  * @crc: checksum of the other bytes
26  */
27 struct w1_reg_num {
28 #if defined(__LITTLE_ENDIAN_BITFIELD)
29 	__u64	family:8,
30 		id:48,
31 		crc:8;
32 #elif defined(__BIG_ENDIAN_BITFIELD)
33 	__u64	crc:8,
34 		id:48,
35 		family:8;
36 #else
37 #error "Please fix <asm/byteorder.h>"
38 #endif
39 };
40 
41 #ifdef __KERNEL__
42 
43 #define W1_MAXNAMELEN		32
44 
45 #define W1_SEARCH		0xF0
46 #define W1_ALARM_SEARCH		0xEC
47 #define W1_CONVERT_TEMP		0x44
48 #define W1_SKIP_ROM		0xCC
49 #define W1_COPY_SCRATCHPAD	0x48
50 #define W1_WRITE_SCRATCHPAD	0x4E
51 #define W1_READ_SCRATCHPAD	0xBE
52 #define W1_READ_ROM		0x33
53 #define W1_READ_PSUPPLY		0xB4
54 #define W1_MATCH_ROM		0x55
55 #define W1_RESUME_CMD		0xA5
56 
57 /**
58  * struct w1_slave - holds a single slave device on the bus
59  *
60  * @owner: Points to the one wire "wire" kernel module.
61  * @name: Device id is ascii.
62  * @w1_slave_entry: data for the linked list
63  * @reg_num: the slave id in binary
64  * @refcnt: reference count, delete when 0
65  * @flags: bit flags for W1_SLAVE_ACTIVE W1_SLAVE_DETACH
66  * @ttl: decrement per search this slave isn't found, deatch at 0
67  * @master: bus which this slave is on
68  * @family: module for device family type
69  * @family_data: pointer for use by the family module
70  * @dev: kernel device identifier
71  * @hwmon: pointer to hwmon device
72  *
73  */
74 struct w1_slave {
75 	struct module		*owner;
76 	unsigned char		name[W1_MAXNAMELEN];
77 	struct list_head	w1_slave_entry;
78 	struct w1_reg_num	reg_num;
79 	atomic_t		refcnt;
80 	int			ttl;
81 	unsigned long		flags;
82 
83 	struct w1_master	*master;
84 	struct w1_family	*family;
85 	void			*family_data;
86 	struct device		dev;
87 	struct device		*hwmon;
88 };
89 
90 typedef void (*w1_slave_found_callback)(struct w1_master *, u64);
91 
92 /**
93  * struct w1_bus_master - operations available on a bus master
94  *
95  * @data: the first parameter in all the functions below
96  *
97  * @read_bit: Sample the line level @return the level read (0 or 1)
98  *
99  * @write_bit: Sets the line level
100  *
101  * @touch_bit: the lowest-level function for devices that really support the
102  * 1-wire protocol.
103  * touch_bit(0) = write-0 cycle
104  * touch_bit(1) = write-1 / read cycle
105  * @return the bit read (0 or 1)
106  *
107  * @read_byte: Reads a bytes. Same as 8 touch_bit(1) calls.
108  * @return the byte read
109  *
110  * @write_byte: Writes a byte. Same as 8 touch_bit(x) calls.
111  *
112  * @read_block: Same as a series of read_byte() calls
113  * @return the number of bytes read
114  *
115  * @write_block: Same as a series of write_byte() calls
116  *
117  * @triplet: Combines two reads and a smart write for ROM searches
118  * @return bit0=Id bit1=comp_id bit2=dir_taken
119  *
120  * @reset_bus: long write-0 with a read for the presence pulse detection
121  * @return -1=Error, 0=Device present, 1=No device present
122  *
123  * @set_pullup: Put out a strong pull-up pulse of the specified duration.
124  * @return -1=Error, 0=completed
125  *
126  * @search: Really nice hardware can handles the different types of ROM search
127  * w1_master* is passed to the slave found callback.
128  * u8 is search_type, W1_SEARCH or W1_ALARM_SEARCH
129  *
130  * Note: read_bit and write_bit are very low level functions and should only
131  * be used with hardware that doesn't really support 1-wire operations,
132  * like a parallel/serial port.
133  * Either define read_bit and write_bit OR define, at minimum, touch_bit and
134  * reset_bus.
135  *
136  */
137 struct w1_bus_master {
138 	void		*data;
139 
140 	u8		(*read_bit)(void *);
141 
142 	void		(*write_bit)(void *, u8);
143 
144 	u8		(*touch_bit)(void *, u8);
145 
146 	u8		(*read_byte)(void *);
147 
148 	void		(*write_byte)(void *, u8);
149 
150 	u8		(*read_block)(void *, u8 *, int);
151 
152 	void		(*write_block)(void *, const u8 *, int);
153 
154 	u8		(*triplet)(void *, u8);
155 
156 	u8		(*reset_bus)(void *);
157 
158 	u8		(*set_pullup)(void *, int);
159 
160 	void		(*search)(void *, struct w1_master *,
161 		u8, w1_slave_found_callback);
162 };
163 
164 /**
165  * enum w1_master_flags - bitfields used in w1_master.flags
166  * @W1_ABORT_SEARCH: abort searching early on shutdown
167  * @W1_WARN_MAX_COUNT: limit warning when the maximum count is reached
168  */
169 enum w1_master_flags {
170 	W1_ABORT_SEARCH = 0,
171 	W1_WARN_MAX_COUNT = 1,
172 };
173 
174 /**
175  * struct w1_master - one per bus master
176  * @w1_master_entry:	master linked list
177  * @owner:		module owner
178  * @name:		dynamically allocate bus name
179  * @list_mutex:		protect slist and async_list
180  * @slist:		linked list of slaves
181  * @async_list:		linked list of netlink commands to execute
182  * @max_slave_count:	maximum number of slaves to search for at a time
183  * @slave_count:	current number of slaves known
184  * @attempts:		number of searches ran
185  * @slave_ttl:		number of searches before a slave is timed out
186  * @initialized:	prevent init/removal race conditions
187  * @id:			w1 bus number
188  * @search_count:	number of automatic searches to run, -1 unlimited
189  * @search_id:		allows continuing a search
190  * @refcnt:		reference count
191  * @priv:		private data storage
192  * @enable_pullup:	allows a strong pullup
193  * @pullup_duration:	time for the next strong pullup
194  * @flags:		one of w1_master_flags
195  * @thread:		thread for bus search and netlink commands
196  * @mutex:		protect most of w1_master
197  * @bus_mutex:		pretect concurrent bus access
198  * @driver:		sysfs driver
199  * @dev:		sysfs device
200  * @bus_master:		io operations available
201  * @seq:		sequence number used for netlink broadcasts
202  */
203 struct w1_master {
204 	struct list_head	w1_master_entry;
205 	struct module		*owner;
206 	unsigned char		name[W1_MAXNAMELEN];
207 	/* list_mutex protects just slist and async_list so slaves can be
208 	 * searched for and async commands added while the master has
209 	 * w1_master.mutex locked and is operating on the bus.
210 	 * lock order w1_mlock, w1_master.mutex, w1_master.list_mutex
211 	 */
212 	struct mutex		list_mutex;
213 	struct list_head	slist;
214 	struct list_head	async_list;
215 	int			max_slave_count, slave_count;
216 	unsigned long		attempts;
217 	int			slave_ttl;
218 	int			initialized;
219 	u32			id;
220 	int			search_count;
221 	/* id to start searching on, to continue a search or 0 to restart */
222 	u64			search_id;
223 
224 	atomic_t		refcnt;
225 
226 	void			*priv;
227 
228 	/** 5V strong pullup enabled flag, 1 enabled, zero disabled. */
229 	int			enable_pullup;
230 	/** 5V strong pullup duration in milliseconds, zero disabled. */
231 	int			pullup_duration;
232 
233 	long			flags;
234 
235 	struct task_struct	*thread;
236 	struct mutex		mutex;
237 	struct mutex		bus_mutex;
238 
239 	struct device_driver	*driver;
240 	struct device		dev;
241 
242 	struct w1_bus_master	*bus_master;
243 
244 	u32			seq;
245 };
246 
247 int w1_add_master_device(struct w1_bus_master *master);
248 void w1_remove_master_device(struct w1_bus_master *master);
249 
250 /**
251  * struct w1_family_ops - operations for a family type
252  * @add_slave: add_slave
253  * @remove_slave: remove_slave
254  * @groups: sysfs group
255  * @chip_info: pointer to struct hwmon_chip_info
256  */
257 struct w1_family_ops {
258 	int  (*add_slave)(struct w1_slave *sl);
259 	void (*remove_slave)(struct w1_slave *sl);
260 	const struct attribute_group **groups;
261 	const struct hwmon_chip_info *chip_info;
262 };
263 
264 /**
265  * struct w1_family - reference counted family structure.
266  * @family_entry:	family linked list
267  * @fid:		8 bit family identifier
268  * @fops:		operations for this family
269  * @refcnt:		reference counter
270  */
271 struct w1_family {
272 	struct list_head	family_entry;
273 	u8			fid;
274 
275 	struct w1_family_ops	*fops;
276 
277 	const struct of_device_id *of_match_table;
278 
279 	atomic_t		refcnt;
280 };
281 
282 int w1_register_family(struct w1_family *family);
283 void w1_unregister_family(struct w1_family *family);
284 
285 /**
286  * module_w1_driver() - Helper macro for registering a 1-Wire families
287  * @__w1_family: w1_family struct
288  *
289  * Helper macro for 1-Wire families which do not do anything special in module
290  * init/exit. This eliminates a lot of boilerplate. Each module may only
291  * use this macro once, and calling it replaces module_init() and module_exit()
292  */
293 #define module_w1_family(__w1_family) \
294 	module_driver(__w1_family, w1_register_family, \
295 			w1_unregister_family)
296 
297 u8 w1_triplet(struct w1_master *dev, int bdir);
298 u8 w1_touch_bit(struct w1_master *dev, int bit);
299 void w1_write_8(struct w1_master *, u8);
300 u8 w1_read_8(struct w1_master *);
301 int w1_reset_bus(struct w1_master *);
302 u8 w1_calc_crc8(u8 *, int);
303 void w1_write_block(struct w1_master *, const u8 *, int);
304 void w1_touch_block(struct w1_master *, u8 *, int);
305 u8 w1_read_block(struct w1_master *, u8 *, int);
306 int w1_reset_select_slave(struct w1_slave *sl);
307 int w1_reset_resume_command(struct w1_master *);
308 void w1_next_pullup(struct w1_master *, int);
309 
dev_to_w1_slave(struct device * dev)310 static inline struct w1_slave* dev_to_w1_slave(struct device *dev)
311 {
312 	return container_of(dev, struct w1_slave, dev);
313 }
314 
kobj_to_w1_slave(struct kobject * kobj)315 static inline struct w1_slave* kobj_to_w1_slave(struct kobject *kobj)
316 {
317 	return dev_to_w1_slave(container_of(kobj, struct device, kobj));
318 }
319 
dev_to_w1_master(struct device * dev)320 static inline struct w1_master* dev_to_w1_master(struct device *dev)
321 {
322 	return container_of(dev, struct w1_master, dev);
323 }
324 
325 #endif /* __KERNEL__ */
326 
327 #endif /* __LINUX_W1_H */
328