w1.h

  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 */
 18struct 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 */
 65struct 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
 81typedef 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 */
132struct 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 */
166enum 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 */
200struct 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
244int w1_add_master_device(struct w1_bus_master *master);
245void 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 */
254struct 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 */
269struct 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
280int w1_register_family(struct w1_family *family);
281void 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
295u8 w1_triplet(struct w1_master *dev, int bdir);
296u8 w1_touch_bit(struct w1_master *dev, int bit);
297void w1_write_8(struct w1_master *, u8);
298u8 w1_read_8(struct w1_master *);
299int w1_reset_bus(struct w1_master *);
300u8 w1_calc_crc8(u8 *, int);
301void w1_write_block(struct w1_master *, const u8 *, int);
302void w1_touch_block(struct w1_master *, u8 *, int);
303u8 w1_read_block(struct w1_master *, u8 *, int);
304int w1_reset_select_slave(struct w1_slave *sl);
305int w1_reset_resume_command(struct w1_master *);
306void w1_next_pullup(struct w1_master *, int);
307
308static inline struct w1_slave* dev_to_w1_slave(struct device *dev)
309{
310	return container_of(dev, struct w1_slave, dev);
311}
312
313static 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
318static 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 */