| /* |
| * w1_io.c |
| * |
| * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> |
| * |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| |
| #include <asm/io.h> |
| |
| #include <linux/delay.h> |
| #include <linux/moduleparam.h> |
| #include <linux/module.h> |
| |
| #include "w1.h" |
| #include "w1_log.h" |
| |
| static int w1_delay_parm = 1; |
| module_param_named(delay_coef, w1_delay_parm, int, 0); |
| |
| static u8 w1_crc8_table[] = { |
| 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, |
| 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, |
| 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, |
| 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, |
| 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, |
| 219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, |
| 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, |
| 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, |
| 140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205, |
| 17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80, |
| 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238, |
| 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, |
| 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, |
| 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, |
| 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, |
| 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 |
| }; |
| |
| static void w1_delay(unsigned long tm) |
| { |
| udelay(tm * w1_delay_parm); |
| } |
| |
| static void w1_write_bit(struct w1_master *dev, int bit); |
| static u8 w1_read_bit(struct w1_master *dev); |
| |
| /** |
| * Generates a write-0 or write-1 cycle and samples the level. |
| */ |
| static u8 w1_touch_bit(struct w1_master *dev, int bit) |
| { |
| if (dev->bus_master->touch_bit) |
| return dev->bus_master->touch_bit(dev->bus_master->data, bit); |
| else if (bit) |
| return w1_read_bit(dev); |
| else { |
| w1_write_bit(dev, 0); |
| return(0); |
| } |
| } |
| |
| /** |
| * Generates a write-0 or write-1 cycle. |
| * Only call if dev->bus_master->touch_bit is NULL |
| */ |
| static void w1_write_bit(struct w1_master *dev, int bit) |
| { |
| if (bit) { |
| dev->bus_master->write_bit(dev->bus_master->data, 0); |
| w1_delay(6); |
| dev->bus_master->write_bit(dev->bus_master->data, 1); |
| w1_delay(64); |
| } else { |
| dev->bus_master->write_bit(dev->bus_master->data, 0); |
| w1_delay(60); |
| dev->bus_master->write_bit(dev->bus_master->data, 1); |
| w1_delay(10); |
| } |
| } |
| |
| /** |
| * Pre-write operation, currently only supporting strong pullups. |
| * Program the hardware for a strong pullup, if one has been requested and |
| * the hardware supports it. |
| * |
| * @param dev the master device |
| */ |
| static void w1_pre_write(struct w1_master *dev) |
| { |
| if (dev->pullup_duration && |
| dev->enable_pullup && dev->bus_master->set_pullup) { |
| dev->bus_master->set_pullup(dev->bus_master->data, |
| dev->pullup_duration); |
| } |
| } |
| |
| /** |
| * Post-write operation, currently only supporting strong pullups. |
| * If a strong pullup was requested, clear it if the hardware supports |
| * them, or execute the delay otherwise, in either case clear the request. |
| * |
| * @param dev the master device |
| */ |
| static void w1_post_write(struct w1_master *dev) |
| { |
| if (dev->pullup_duration) { |
| if (dev->enable_pullup && dev->bus_master->set_pullup) |
| dev->bus_master->set_pullup(dev->bus_master->data, 0); |
| else |
| msleep(dev->pullup_duration); |
| dev->pullup_duration = 0; |
| } |
| } |
| |
| /** |
| * Writes 8 bits. |
| * |
| * @param dev the master device |
| * @param byte the byte to write |
| */ |
| void w1_write_8(struct w1_master *dev, u8 byte) |
| { |
| int i; |
| |
| if (dev->bus_master->write_byte) { |
| w1_pre_write(dev); |
| dev->bus_master->write_byte(dev->bus_master->data, byte); |
| } |
| else |
| for (i = 0; i < 8; ++i) { |
| if (i == 7) |
| w1_pre_write(dev); |
| w1_touch_bit(dev, (byte >> i) & 0x1); |
| } |
| w1_post_write(dev); |
| } |
| EXPORT_SYMBOL_GPL(w1_write_8); |
| |
| |
| /** |
| * Generates a write-1 cycle and samples the level. |
| * Only call if dev->bus_master->touch_bit is NULL |
| */ |
| static u8 w1_read_bit(struct w1_master *dev) |
| { |
| int result; |
| |
| dev->bus_master->write_bit(dev->bus_master->data, 0); |
| w1_delay(6); |
| dev->bus_master->write_bit(dev->bus_master->data, 1); |
| w1_delay(9); |
| |
| result = dev->bus_master->read_bit(dev->bus_master->data); |
| w1_delay(55); |
| |
| return result & 0x1; |
| } |
| |
| /** |
| * Does a triplet - used for searching ROM addresses. |
| * Return bits: |
| * bit 0 = id_bit |
| * bit 1 = comp_bit |
| * bit 2 = dir_taken |
| * If both bits 0 & 1 are set, the search should be restarted. |
| * |
| * @param dev the master device |
| * @param bdir the bit to write if both id_bit and comp_bit are 0 |
| * @return bit fields - see above |
| */ |
| u8 w1_triplet(struct w1_master *dev, int bdir) |
| { |
| if ( dev->bus_master->triplet ) |
| return(dev->bus_master->triplet(dev->bus_master->data, bdir)); |
| else { |
| u8 id_bit = w1_touch_bit(dev, 1); |
| u8 comp_bit = w1_touch_bit(dev, 1); |
| u8 retval; |
| |
| if ( id_bit && comp_bit ) |
| return(0x03); /* error */ |
| |
| if ( !id_bit && !comp_bit ) { |
| /* Both bits are valid, take the direction given */ |
| retval = bdir ? 0x04 : 0; |
| } else { |
| /* Only one bit is valid, take that direction */ |
| bdir = id_bit; |
| retval = id_bit ? 0x05 : 0x02; |
| } |
| |
| if ( dev->bus_master->touch_bit ) |
| w1_touch_bit(dev, bdir); |
| else |
| w1_write_bit(dev, bdir); |
| return(retval); |
| } |
| } |
| |
| /** |
| * Reads 8 bits. |
| * |
| * @param dev the master device |
| * @return the byte read |
| */ |
| static u8 w1_read_8(struct w1_master * dev) |
| { |
| int i; |
| u8 res = 0; |
| |
| if (dev->bus_master->read_byte) |
| res = dev->bus_master->read_byte(dev->bus_master->data); |
| else |
| for (i = 0; i < 8; ++i) |
| res |= (w1_touch_bit(dev,1) << i); |
| |
| return res; |
| } |
| |
| /** |
| * Writes a series of bytes. |
| * |
| * @param dev the master device |
| * @param buf pointer to the data to write |
| * @param len the number of bytes to write |
| * @return the byte read |
| */ |
| void w1_write_block(struct w1_master *dev, const u8 *buf, int len) |
| { |
| int i; |
| |
| if (dev->bus_master->write_block) { |
| w1_pre_write(dev); |
| dev->bus_master->write_block(dev->bus_master->data, buf, len); |
| } |
| else |
| for (i = 0; i < len; ++i) |
| w1_write_8(dev, buf[i]); /* calls w1_pre_write */ |
| w1_post_write(dev); |
| } |
| EXPORT_SYMBOL_GPL(w1_write_block); |
| |
| /** |
| * Reads a series of bytes. |
| * |
| * @param dev the master device |
| * @param buf pointer to the buffer to fill |
| * @param len the number of bytes to read |
| * @return the number of bytes read |
| */ |
| u8 w1_read_block(struct w1_master *dev, u8 *buf, int len) |
| { |
| int i; |
| u8 ret; |
| |
| if (dev->bus_master->read_block) |
| ret = dev->bus_master->read_block(dev->bus_master->data, buf, len); |
| else { |
| for (i = 0; i < len; ++i) |
| buf[i] = w1_read_8(dev); |
| ret = len; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(w1_read_block); |
| |
| /** |
| * Issues a reset bus sequence. |
| * |
| * @param dev The bus master pointer |
| * @return 0=Device present, 1=No device present or error |
| */ |
| int w1_reset_bus(struct w1_master *dev) |
| { |
| int result; |
| |
| if (dev->bus_master->reset_bus) |
| result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1; |
| else { |
| dev->bus_master->write_bit(dev->bus_master->data, 0); |
| w1_delay(480); |
| dev->bus_master->write_bit(dev->bus_master->data, 1); |
| w1_delay(70); |
| |
| result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1; |
| w1_delay(410); |
| } |
| |
| return result; |
| } |
| EXPORT_SYMBOL_GPL(w1_reset_bus); |
| |
| u8 w1_calc_crc8(u8 * data, int len) |
| { |
| u8 crc = 0; |
| |
| while (len--) |
| crc = w1_crc8_table[crc ^ *data++]; |
| |
| return crc; |
| } |
| EXPORT_SYMBOL_GPL(w1_calc_crc8); |
| |
| void w1_search_devices(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) |
| { |
| dev->attempts++; |
| if (dev->bus_master->search) |
| dev->bus_master->search(dev->bus_master->data, dev, |
| search_type, cb); |
| else |
| w1_search(dev, search_type, cb); |
| } |
| |
| /** |
| * Resets the bus and then selects the slave by sending either a skip rom |
| * or a rom match. |
| * The w1 master lock must be held. |
| * |
| * @param sl the slave to select |
| * @return 0=success, anything else=error |
| */ |
| int w1_reset_select_slave(struct w1_slave *sl) |
| { |
| if (w1_reset_bus(sl->master)) |
| return -1; |
| |
| if (sl->master->slave_count == 1) |
| w1_write_8(sl->master, W1_SKIP_ROM); |
| else { |
| u8 match[9] = {W1_MATCH_ROM, }; |
| memcpy(&match[1], (u8 *)&sl->reg_num, 8); |
| w1_write_block(sl->master, match, 9); |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(w1_reset_select_slave); |
| |
| /** |
| * Put out a strong pull-up of the specified duration after the next write |
| * operation. Not all hardware supports strong pullups. Hardware that |
| * doesn't support strong pullups will sleep for the given time after the |
| * write operation without a strong pullup. This is a one shot request for |
| * the next write, specifying zero will clear a previous request. |
| * The w1 master lock must be held. |
| * |
| * @param delay time in milliseconds |
| * @return 0=success, anything else=error |
| */ |
| void w1_next_pullup(struct w1_master *dev, int delay) |
| { |
| dev->pullup_duration = delay; |
| } |
| EXPORT_SYMBOL_GPL(w1_next_pullup); |