diff options
Diffstat (limited to 'drivers/w1/w1_io.c')
| -rw-r--r-- | drivers/w1/w1_io.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c new file mode 100644 index 00000000000..02796b5a39f --- /dev/null +++ b/drivers/w1/w1_io.c @@ -0,0 +1,195 @@ +/* + * 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 "w1.h" +#include "w1_log.h" +#include "w1_io.h" + +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 +}; + +void w1_delay(unsigned long tm) +{ + udelay(tm * w1_delay_parm); +} + +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 + return w1_read_bit(dev); +} + +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); + } +} + +void w1_write_8(struct w1_master *dev, u8 byte) +{ + int i; + + if (dev->bus_master->write_byte) + dev->bus_master->write_byte(dev->bus_master->data, byte); + else + for (i = 0; i < 8; ++i) + w1_write_bit(dev, (byte >> i) & 0x1); +} + +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; +} + +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_read_bit(dev) << i); + + return res; +} + +void w1_write_block(struct w1_master *dev, u8 *buf, int len) +{ + int i; + + if (dev->bus_master->write_block) + dev->bus_master->write_block(dev->bus_master->data, buf, len); + else + for (i = 0; i < len; ++i) + w1_write_8(dev, buf[i]); +} + +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; +} + +int w1_reset_bus(struct w1_master *dev) +{ + int result = 0; + + 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; +} + +u8 w1_calc_crc8(u8 * data, int len) +{ + u8 crc = 0; + + while (len--) + crc = w1_crc8_table[crc ^ *data++]; + + return crc; +} + +void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb) +{ + dev->attempts++; + if (dev->bus_master->search) + dev->bus_master->search(dev->bus_master->data, cb); + else + w1_search(dev); +} + +EXPORT_SYMBOL(w1_write_bit); +EXPORT_SYMBOL(w1_write_8); +EXPORT_SYMBOL(w1_read_bit); +EXPORT_SYMBOL(w1_read_8); +EXPORT_SYMBOL(w1_reset_bus); +EXPORT_SYMBOL(w1_calc_crc8); +EXPORT_SYMBOL(w1_delay); +EXPORT_SYMBOL(w1_read_block); +EXPORT_SYMBOL(w1_write_block); +EXPORT_SYMBOL(w1_search_devices); |