1 // SPDX-License-Identifier: GPL-2.0-or-later
8 #include <linux/delay.h>
48  * w1_touch_bit() - Generates a write-0 or write-1 cycle and samples the level.
50  * @bit:	0 - write a 0, 1 - write a 0 read the level
54 	if (dev->bus_master->touch_bit)  in w1_touch_bit()
55 		return dev->bus_master->touch_bit(dev->bus_master->data, bit);  in w1_touch_bit()
66  * w1_write_bit() - Generates a write-0 or write-1 cycle.
70  * Only call if dev->bus_master->touch_bit is NULL
79 		dev->bus_master->write_bit(dev->bus_master->data, 0);  in w1_write_bit()
81 		dev->bus_master->write_bit(dev->bus_master->data, 1);  in w1_write_bit()
84 		dev->bus_master->write_bit(dev->bus_master->data, 0);  in w1_write_bit()
86 		dev->bus_master->write_bit(dev->bus_master->data, 1);  in w1_write_bit()
94  * w1_pre_write() - pre-write operations
97  * Pre-write operation, currently only supporting strong pullups.
103 	if (dev->pullup_duration &&  in w1_pre_write()
104 		dev->enable_pullup && dev->bus_master->set_pullup) {  in w1_pre_write()
105 		dev->bus_master->set_pullup(dev->bus_master->data,  in w1_pre_write()
106 			dev->pullup_duration);  in w1_pre_write()
111  * w1_post_write() - post-write options
114  * Post-write operation, currently only supporting strong pullups.
116  * them, or execute the delay otherwise, in either case clear the request.
120 	if (dev->pullup_duration) {  in w1_post_write()
121 		if (dev->enable_pullup && dev->bus_master->set_pullup)  in w1_post_write()
122 			dev->bus_master->set_pullup(dev->bus_master->data, 0);  in w1_post_write()
124 			msleep(dev->pullup_duration);  in w1_post_write()
125 		dev->pullup_duration = 0;  in w1_post_write()
130  * w1_write_8() - Writes 8 bits.
138 	if (dev->bus_master->write_byte) {  in w1_write_8()
140 		dev->bus_master->write_byte(dev->bus_master->data, byte);  in w1_write_8()
154  * w1_read_bit() - Generates a write-1 cycle and samples the level.
157  * Only call if dev->bus_master->touch_bit is NULL
166 	dev->bus_master->write_bit(dev->bus_master->data, 0);  in w1_read_bit()
168 	dev->bus_master->write_bit(dev->bus_master->data, 1);  in w1_read_bit()
171 	result = dev->bus_master->read_bit(dev->bus_master->data);  in w1_read_bit()
180  * w1_triplet() - * Does a triplet - used for searching ROM addresses.
191  * Return:        bit fields - see above
195 	if (dev->bus_master->triplet)  in w1_triplet()
196 		return dev->bus_master->triplet(dev->bus_master->data, bdir);  in w1_triplet()
214 		if (dev->bus_master->touch_bit)  in w1_triplet()
224  * w1_read_8() - Reads 8 bits.
234 	if (dev->bus_master->read_byte)  in w1_read_8()
235 		res = dev->bus_master->read_byte(dev->bus_master->data);  in w1_read_8()
245  * w1_write_block() - Writes a series of bytes.
254 	if (dev->bus_master->write_block) {  in w1_write_block()
256 		dev->bus_master->write_block(dev->bus_master->data, buf, len);  in w1_write_block()
266  * w1_touch_block() - Touches a series of bytes.
290  * w1_read_block() - Reads a series of bytes.
301 	if (dev->bus_master->read_block)  in w1_read_block()
302 		ret = dev->bus_master->read_block(dev->bus_master->data, buf, len);  in w1_read_block()
314  * w1_reset_bus() - Issues a reset bus sequence.
325 	if (dev->bus_master->reset_bus)  in w1_reset_bus()
326 		result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;  in w1_reset_bus()
328 		dev->bus_master->write_bit(dev->bus_master->data, 0);  in w1_reset_bus()
329 		/* minimum 480, max ? us  in w1_reset_bus()
330 		 * be nice and sleep, except 18b20 spec lists 960us maximum,  in w1_reset_bus()
337 		dev->bus_master->write_bit(dev->bus_master->data, 1);  in w1_reset_bus()
340 		result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;  in w1_reset_bus()
341 		/* minimum 70 (above) + 430 = 500 us  in w1_reset_bus()
342 		 * There aren't any timing requirements between a reset and  in w1_reset_bus()
359 	while (len--)  in w1_calc_crc8()
368 	dev->attempts++;  in w1_search_devices()
369 	if (dev->bus_master->search)  in w1_search_devices()
370 		dev->bus_master->search(dev->bus_master->data, dev,  in w1_search_devices()
377  * w1_reset_select_slave() - reset and select a slave
389 	if (w1_reset_bus(sl->master))  in w1_reset_select_slave()
390 		return -1;  in w1_reset_select_slave()
392 	if (sl->master->slave_count == 1)  in w1_reset_select_slave()
393 		w1_write_8(sl->master, W1_SKIP_ROM);  in w1_reset_select_slave()
396 		u64 rn = le64_to_cpu(*((u64*)&sl->reg_num));  in w1_reset_select_slave()
399 		w1_write_block(sl->master, match, 9);  in w1_reset_select_slave()
406  * w1_reset_resume_command() - resume instead of another match ROM
410  * successive commands a reset between each, this function is similar
411  * to doing a reset then a match ROM for the last matched ROM. The
416  * and a "SKIP ROM" is done for efficiency. On multi-slave busses, this
424 		return -1;  in w1_reset_resume_command()
426 	w1_write_8(dev, dev->slave_count > 1 ? W1_RESUME_CMD : W1_SKIP_ROM);  in w1_reset_resume_command()
432  * w1_next_pullup() - register for a strong pullup
434  * @delay:	time in milliseconds
436  * Put out a strong pull-up of the specified duration after the next write
445 void w1_next_pullup(struct w1_master *dev, int delay)  in w1_next_pullup()  argument
447 	dev->pullup_duration = delay;  in w1_next_pullup()