1  /* SPDX-License-Identifier: GPL-2.0-or-later */
2  /*
3   * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
4   */
5  
6  #ifndef __LINUX_W1_H
7  #define __LINUX_W1_H
8  
9  #include <linux/device.h>
10  
11  /**
12   * struct w1_reg_num - broken out slave device id
13   *
14   * @family: identifies the type of device
15   * @id: along with family is the unique device id
16   * @crc: checksum of the other bytes
17   */
18  struct w1_reg_num {
19  #if defined(__LITTLE_ENDIAN_BITFIELD)
20  	__u64	family:8,
21  		id:48,
22  		crc:8;
23  #elif defined(__BIG_ENDIAN_BITFIELD)
24  	__u64	crc:8,
25  		id:48,
26  		family:8;
27  #else
28  #error "Please fix <asm/byteorder.h>"
29  #endif
30  };
31  
32  #ifdef __KERNEL__
33  
34  #define W1_MAXNAMELEN		32
35  
36  #define W1_SEARCH		0xF0
37  #define W1_ALARM_SEARCH		0xEC
38  #define W1_CONVERT_TEMP		0x44
39  #define W1_SKIP_ROM		0xCC
40  #define W1_COPY_SCRATCHPAD	0x48
41  #define W1_WRITE_SCRATCHPAD	0x4E
42  #define W1_READ_SCRATCHPAD	0xBE
43  #define W1_READ_ROM		0x33
44  #define W1_READ_PSUPPLY		0xB4
45  #define W1_MATCH_ROM		0x55
46  #define W1_RESUME_CMD		0xA5
47  
48  /**
49   * struct w1_slave - holds a single slave device on the bus
50   *
51   * @owner: Points to the one wire "wire" kernel module.
52   * @name: Device id is ascii.
53   * @w1_slave_entry: data for the linked list
54   * @reg_num: the slave id in binary
55   * @refcnt: reference count, delete when 0
56   * @flags: bit flags for W1_SLAVE_ACTIVE W1_SLAVE_DETACH
57   * @ttl: decrement per search this slave isn't found, deatch at 0
58   * @master: bus which this slave is on
59   * @family: module for device family type
60   * @family_data: pointer for use by the family module
61   * @dev: kernel device identifier
62   * @hwmon: pointer to hwmon device
63   *
64   */
65  struct w1_slave {
66  	struct module		*owner;
67  	unsigned char		name[W1_MAXNAMELEN];
68  	struct list_head	w1_slave_entry;
69  	struct w1_reg_num	reg_num;
70  	atomic_t		refcnt;
71  	int			ttl;
72  	unsigned long		flags;
73  
74  	struct w1_master	*master;
75  	struct w1_family	*family;
76  	void			*family_data;
77  	struct device		dev;
78  	struct device		*hwmon;
79  };
80  
81  typedef void (*w1_slave_found_callback)(struct w1_master *, u64);
82  
83  /**
84   * struct w1_bus_master - operations available on a bus master
85   *
86   * @data: the first parameter in all the functions below
87   *
88   * @read_bit: Sample the line level
89   * @return the level read (0 or 1)
90   *
91   * @write_bit: Sets the line level
92   *
93   * @touch_bit: the lowest-level function for devices that really support the
94   * 1-wire protocol.
95   * touch_bit(0) = write-0 cycle
96   * touch_bit(1) = write-1 / read cycle
97   * @return the bit read (0 or 1)
98   *
99   * @read_byte: Reads a byte. Same as 8 touch_bit(1) calls.
100   * @return the byte read
101   *
102   * @write_byte: Writes a byte. Same as 8 touch_bit(x) calls.
103   *
104   * @read_block: Same as a series of read_byte() calls
105   * @return the number of bytes read
106   *
107   * @write_block: Same as a series of write_byte() calls
108   *
109   * @triplet: Combines two reads and a smart write for ROM searches
110   * @return bit0=Id bit1=comp_id bit2=dir_taken
111   *
112   * @reset_bus: long write-0 with a read for the presence pulse detection
113   * @return -1=Error, 0=Device present, 1=No device present
114   *
115   * @set_pullup: Put out a strong pull-up pulse of the specified duration.
116   * @return -1=Error, 0=completed
117   *
118   * @search: Really nice hardware can handle the different types of ROM search
119   * w1_master* is passed to the slave found callback.
120   * u8 is search_type, W1_SEARCH or W1_ALARM_SEARCH
121   *
122   * @dev_id: Optional device id string, which w1 slaves could use for
123   * creating names, which then give a connection to the w1 master
124   *
125   * Note: read_bit and write_bit are very low level functions and should only
126   * be used with hardware that doesn't really support 1-wire operations,
127   * like a parallel/serial port.
128   * Either define read_bit and write_bit OR define, at minimum, touch_bit and
129   * reset_bus.
130   *
131   */
132  struct w1_bus_master {
133  	void		*data;
134  
135  	u8		(*read_bit)(void *);
136  
137  	void		(*write_bit)(void *, u8);
138  
139  	u8		(*touch_bit)(void *, u8);
140  
141  	u8		(*read_byte)(void *);
142  
143  	void		(*write_byte)(void *, u8);
144  
145  	u8		(*read_block)(void *, u8 *, int);
146  
147  	void		(*write_block)(void *, const u8 *, int);
148  
149  	u8		(*triplet)(void *, u8);
150  
151  	u8		(*reset_bus)(void *);
152  
153  	u8		(*set_pullup)(void *, int);
154  
155  	void		(*search)(void *, struct w1_master *,
156  		u8, w1_slave_found_callback);
157  
158  	char		*dev_id;
159  };
160  
161  /**
162   * enum w1_master_flags - bitfields used in w1_master.flags
163   * @W1_ABORT_SEARCH: abort searching early on shutdown
164   * @W1_WARN_MAX_COUNT: limit warning when the maximum count is reached
165   */
166  enum w1_master_flags {
167  	W1_ABORT_SEARCH = 0,
168  	W1_WARN_MAX_COUNT = 1,
169  };
170  
171  /**
172   * struct w1_master - one per bus master
173   * @w1_master_entry:	master linked list
174   * @owner:		module owner
175   * @name:		dynamically allocate bus name
176   * @list_mutex:		protect slist and async_list
177   * @slist:		linked list of slaves
178   * @async_list:		linked list of netlink commands to execute
179   * @max_slave_count:	maximum number of slaves to search for at a time
180   * @slave_count:	current number of slaves known
181   * @attempts:		number of searches ran
182   * @slave_ttl:		number of searches before a slave is timed out
183   * @initialized:	prevent init/removal race conditions
184   * @id:			w1 bus number
185   * @search_count:	number of automatic searches to run, -1 unlimited
186   * @search_id:		allows continuing a search
187   * @refcnt:		reference count
188   * @priv:		private data storage
189   * @enable_pullup:	allows a strong pullup
190   * @pullup_duration:	time for the next strong pullup
191   * @flags:		one of w1_master_flags
192   * @thread:		thread for bus search and netlink commands
193   * @mutex:		protect most of w1_master
194   * @bus_mutex:		pretect concurrent bus access
195   * @driver:		sysfs driver
196   * @dev:		sysfs device
197   * @bus_master:		io operations available
198   * @seq:		sequence number used for netlink broadcasts
199   */
200  struct w1_master {
201  	struct list_head	w1_master_entry;
202  	struct module		*owner;
203  	unsigned char		name[W1_MAXNAMELEN];
204  	/* list_mutex protects just slist and async_list so slaves can be
205  	 * searched for and async commands added while the master has
206  	 * w1_master.mutex locked and is operating on the bus.
207  	 * lock order w1_mlock, w1_master.mutex, w1_master.list_mutex
208  	 */
209  	struct mutex		list_mutex;
210  	struct list_head	slist;
211  	struct list_head	async_list;
212  	int			max_slave_count, slave_count;
213  	unsigned long		attempts;
214  	int			slave_ttl;
215  	int			initialized;
216  	u32			id;
217  	int			search_count;
218  	/* id to start searching on, to continue a search or 0 to restart */
219  	u64			search_id;
220  
221  	atomic_t		refcnt;
222  
223  	void			*priv;
224  
225  	/** 5V strong pullup enabled flag, 1 enabled, zero disabled. */
226  	int			enable_pullup;
227  	/** 5V strong pullup duration in milliseconds, zero disabled. */
228  	int			pullup_duration;
229  
230  	long			flags;
231  
232  	struct task_struct	*thread;
233  	struct mutex		mutex;
234  	struct mutex		bus_mutex;
235  
236  	struct device_driver	*driver;
237  	struct device		dev;
238  
239  	struct w1_bus_master	*bus_master;
240  
241  	u32			seq;
242  };
243  
244  int w1_add_master_device(struct w1_bus_master *master);
245  void w1_remove_master_device(struct w1_bus_master *master);
246  
247  /**
248   * struct w1_family_ops - operations for a family type
249   * @add_slave: add_slave
250   * @remove_slave: remove_slave
251   * @groups: sysfs group
252   * @chip_info: pointer to struct hwmon_chip_info
253   */
254  struct w1_family_ops {
255  	int  (*add_slave)(struct w1_slave *sl);
256  	void (*remove_slave)(struct w1_slave *sl);
257  	const struct attribute_group **groups;
258  	const struct hwmon_chip_info *chip_info;
259  };
260  
261  /**
262   * struct w1_family - reference counted family structure.
263   * @family_entry:	family linked list
264   * @fid:		8 bit family identifier
265   * @fops:		operations for this family
266   * @of_match_table: open firmware match table
267   * @refcnt:		reference counter
268   */
269  struct w1_family {
270  	struct list_head	family_entry;
271  	u8			fid;
272  
273  	const struct w1_family_ops *fops;
274  
275  	const struct of_device_id *of_match_table;
276  
277  	atomic_t		refcnt;
278  };
279  
280  int w1_register_family(struct w1_family *family);
281  void w1_unregister_family(struct w1_family *family);
282  
283  /**
284   * module_w1_family() - Helper macro for registering a 1-Wire families
285   * @__w1_family: w1_family struct
286   *
287   * Helper macro for 1-Wire families which do not do anything special in module
288   * init/exit. This eliminates a lot of boilerplate. Each module may only
289   * use this macro once, and calling it replaces module_init() and module_exit()
290   */
291  #define module_w1_family(__w1_family) \
292  	module_driver(__w1_family, w1_register_family, \
293  			w1_unregister_family)
294  
295  u8 w1_triplet(struct w1_master *dev, int bdir);
296  u8 w1_touch_bit(struct w1_master *dev, int bit);
297  void w1_write_8(struct w1_master *, u8);
298  u8 w1_read_8(struct w1_master *);
299  int w1_reset_bus(struct w1_master *);
300  u8 w1_calc_crc8(u8 *, int);
301  void w1_write_block(struct w1_master *, const u8 *, int);
302  void w1_touch_block(struct w1_master *, u8 *, int);
303  u8 w1_read_block(struct w1_master *, u8 *, int);
304  int w1_reset_select_slave(struct w1_slave *sl);
305  int w1_reset_resume_command(struct w1_master *);
306  void w1_next_pullup(struct w1_master *, int);
307  
dev_to_w1_slave(struct device * dev)308  static inline struct w1_slave* dev_to_w1_slave(struct device *dev)
309  {
310  	return container_of(dev, struct w1_slave, dev);
311  }
312  
kobj_to_w1_slave(struct kobject * kobj)313  static inline struct w1_slave* kobj_to_w1_slave(struct kobject *kobj)
314  {
315  	return dev_to_w1_slave(container_of(kobj, struct device, kobj));
316  }
317  
dev_to_w1_master(struct device * dev)318  static inline struct w1_master* dev_to_w1_master(struct device *dev)
319  {
320  	return container_of(dev, struct w1_master, dev);
321  }
322  
323  #endif /* __KERNEL__ */
324  
325  #endif /* __LINUX_W1_H */
326