diff options
Diffstat (limited to 'drivers/w1')
| -rw-r--r-- | drivers/w1/w1.c | 138 | ||||
| -rw-r--r-- | drivers/w1/w1.h | 87 | ||||
| -rw-r--r-- | drivers/w1/w1_io.c | 43 | ||||
| -rw-r--r-- | drivers/w1/w1_io.h | 1 |
4 files changed, 175 insertions, 94 deletions
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index c85d75ed835a..4fa959f08554 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -135,7 +135,7 @@ struct device w1_device = { static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf) { - struct w1_master *md = container_of (dev, struct w1_master, dev); + struct w1_master *md = container_of(dev, struct w1_master, dev); ssize_t count; if (down_interruptible (&md->mutex)) @@ -212,7 +212,6 @@ static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct d } static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf) - { struct w1_master *md = container_of(dev, struct w1_master, dev); int c = PAGE_SIZE; @@ -286,13 +285,13 @@ static int __w1_attach_slave_device(struct w1_slave *sl) sl->dev.release = &w1_slave_release; snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id), - "%02x-%012llx", - (unsigned int) sl->reg_num.family, - (unsigned long long) sl->reg_num.id); - snprintf (&sl->name[0], sizeof(sl->name), - "%02x-%012llx", - (unsigned int) sl->reg_num.family, - (unsigned long long) sl->reg_num.id); + "%02x-%012llx", + (unsigned int) sl->reg_num.family, + (unsigned long long) sl->reg_num.id); + snprintf(&sl->name[0], sizeof(sl->name), + "%02x-%012llx", + (unsigned int) sl->reg_num.family, + (unsigned long long) sl->reg_num.id); dev_dbg(&sl->dev, "%s: registering %s.\n", __func__, &sl->dev.bus_id[0]); @@ -300,8 +299,8 @@ static int __w1_attach_slave_device(struct w1_slave *sl) err = device_register(&sl->dev); if (err < 0) { dev_err(&sl->dev, - "Device registration [%s] failed. err=%d\n", - sl->dev.bus_id, err); + "Device registration [%s] failed. err=%d\n", + sl->dev.bus_id, err); return err; } @@ -314,8 +313,8 @@ static int __w1_attach_slave_device(struct w1_slave *sl) err = device_create_file(&sl->dev, &sl->attr_name); if (err < 0) { dev_err(&sl->dev, - "sysfs file creation for [%s] failed. err=%d\n", - sl->dev.bus_id, err); + "sysfs file creation for [%s] failed. err=%d\n", + sl->dev.bus_id, err); device_unregister(&sl->dev); return err; } @@ -323,8 +322,8 @@ static int __w1_attach_slave_device(struct w1_slave *sl) err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin); if (err < 0) { dev_err(&sl->dev, - "sysfs file creation for [%s] failed. err=%d\n", - sl->dev.bus_id, err); + "sysfs file creation for [%s] failed. err=%d\n", + sl->dev.bus_id, err); device_remove_file(&sl->dev, &sl->attr_name); device_unregister(&sl->dev); return err; @@ -483,26 +482,39 @@ static void w1_slave_found(unsigned long data, u64 rn) atomic_dec(&dev->refcnt); } -void w1_search(struct w1_master *dev) +/** + * Performs a ROM Search & registers any devices found. + * The 1-wire search is a simple binary tree search. + * For each bit of the address, we read two bits and write one bit. + * The bit written will put to sleep all devies that don't match that bit. + * When the two reads differ, the direction choice is obvious. + * When both bits are 0, we must choose a path to take. + * When we can scan all 64 bits without having to choose a path, we are done. + * + * See "Application note 187 1-wire search algorithm" at www.maxim-ic.com + * + * @dev The master device to search + * @cb Function to call when a device is found + */ +void w1_search(struct w1_master *dev, w1_slave_found_callback cb) { - u64 last, rn, tmp; - int i, count = 0; - int last_family_desc, last_zero, last_device; - int search_bit, id_bit, comp_bit, desc_bit; + u64 last_rn, rn, tmp64; + int i, slave_count = 0; + int last_zero, last_device; + int search_bit, desc_bit; + u8 triplet_ret = 0; - search_bit = id_bit = comp_bit = 0; - rn = tmp = last = 0; - last_device = last_zero = last_family_desc = 0; + search_bit = 0; + rn = last_rn = 0; + last_device = 0; + last_zero = -1; desc_bit = 64; - while (!(id_bit && comp_bit) && !last_device && - count++ < dev->max_slave_count) { - last = rn; + while ( !last_device && (slave_count++ < dev->max_slave_count) ) { + last_rn = rn; rn = 0; - last_family_desc = 0; - /* * Reset bus and all 1-wire device state machines * so they can respond to our requests. @@ -514,59 +526,39 @@ void w1_search(struct w1_master *dev) break; } -#if 1 + /* Start the search */ w1_write_8(dev, W1_SEARCH); for (i = 0; i < 64; ++i) { - /* - * Read 2 bits from bus. - * All who don't sleep must send ID bit and COMPLEMENT ID bit. - * They actually are ANDed between all senders. - */ - id_bit = w1_touch_bit(dev, 1); - comp_bit = w1_touch_bit(dev, 1); - - if (id_bit && comp_bit) - break; - - if (id_bit == 0 && comp_bit == 0) { - if (i == desc_bit) - search_bit = 1; - else if (i > desc_bit) - search_bit = 0; - else - search_bit = ((last >> i) & 0x1); - - if (search_bit == 0) { - last_zero = i; - if (last_zero < 9) - last_family_desc = last_zero; - } + /* Determine the direction/search bit */ + if (i == desc_bit) + search_bit = 1; /* took the 0 path last time, so take the 1 path */ + else if (i > desc_bit) + search_bit = 0; /* take the 0 path on the next branch */ + else + search_bit = ((last_rn >> i) & 0x1); - } else - search_bit = id_bit; + /** Read two bits and write one bit */ + triplet_ret = w1_triplet(dev, search_bit); - tmp = search_bit; - rn |= (tmp << i); + /* quit if no device responded */ + if ( (triplet_ret & 0x03) == 0x03 ) + break; - /* - * Write 1 bit to bus - * and make all who don't have "search_bit" in "i"'th position - * in it's registration number sleep. - */ - if (dev->bus_master->touch_bit) - w1_touch_bit(dev, search_bit); - else - w1_write_bit(dev, search_bit); + /* If both directions were valid, and we took the 0 path... */ + if (triplet_ret == 0) + last_zero = i; + /* extract the direction taken & update the device number */ + tmp64 = (triplet_ret >> 2); + rn |= (tmp64 << i); } -#endif - - if (desc_bit == last_zero) - last_device = 1; - desc_bit = last_zero; - - w1_slave_found(dev->bus_master->data, rn); + if ( (triplet_ret & 0x03) != 0x03 ) { + if ( (desc_bit == last_zero) || (last_zero < 0)) + last_device = 1; + desc_bit = last_zero; + cb(dev->bus_master->data, rn); + } } } diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h index 44dfb92e55cd..3cfdd08d32fc 100644 --- a/drivers/w1/w1.h +++ b/drivers/w1/w1.h @@ -25,9 +25,9 @@ struct w1_reg_num { #if defined(__LITTLE_ENDIAN_BITFIELD) - __u64 family:8, - id:48, - crc:8; + __u64 family:8, + id:48, + crc:8; #elif defined(__BIG_ENDIAN_BITFIELD) __u64 crc:8, id:48, @@ -84,24 +84,71 @@ struct w1_slave typedef void (* w1_slave_found_callback)(unsigned long, u64); + +/** + * Note: read_bit and write_bit are very low level functions and should only + * be used with hardware that doesn't really support 1-wire operations, + * like a parallel/serial port. + * Either define read_bit and write_bit OR define, at minimum, touch_bit and + * reset_bus. + */ struct w1_bus_master { - unsigned long data; - - u8 (*read_bit)(unsigned long); - void (*write_bit)(unsigned long, u8); - - u8 (*read_byte)(unsigned long); - void (*write_byte)(unsigned long, u8); - - u8 (*read_block)(unsigned long, u8 *, int); - void (*write_block)(unsigned long, u8 *, int); - - u8 (*touch_bit)(unsigned long, u8); - - u8 (*reset_bus)(unsigned long); - - void (*search)(unsigned long, w1_slave_found_callback); + /** the first parameter in all the functions below */ + unsigned long data; + + /** + * Sample the line level + * @return the level read (0 or 1) + */ + u8 (*read_bit)(unsigned long); + + /** Sets the line level */ + void (*write_bit)(unsigned long, u8); + + /** + * touch_bit is the lowest-level function for devices that really + * support the 1-wire protocol. + * touch_bit(0) = write-0 cycle + * touch_bit(1) = write-1 / read cycle + * @return the bit read (0 or 1) + */ + u8 (*touch_bit)(unsigned long, u8); + + /** + * Reads a bytes. Same as 8 touch_bit(1) calls. + * @return the byte read + */ + u8 (*read_byte)(unsigned long); + + /** + * Writes a byte. Same as 8 touch_bit(x) calls. + */ + void (*write_byte)(unsigned long, u8); + + /** + * Same as a series of read_byte() calls + * @return the number of bytes read + */ + u8 (*read_block)(unsigned long, u8 *, int); + + /** Same as a series of write_byte() calls */ + void (*write_block)(unsigned long, const u8 *, int); + + /** + * Combines two reads and a smart write for ROM searches + * @return bit0=Id bit1=comp_id bit2=dir_taken + */ + u8 (*triplet)(unsigned long, u8); + + /** + * long write-0 with a read for the presence pulse detection + * @return -1=Error, 0=Device present, 1=No device present + */ + u8 (*reset_bus)(unsigned long); + + /** Really nice hardware can handles the ROM searches */ + void (*search)(unsigned long, w1_slave_found_callback); }; struct w1_master @@ -137,7 +184,7 @@ struct w1_master }; int w1_create_master_attributes(struct w1_master *); -void w1_search(struct w1_master *dev); +void w1_search(struct w1_master *dev, w1_slave_found_callback cb); #endif /* __KERNEL__ */ diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c index 2173336b60a7..00f032220173 100644 --- a/drivers/w1/w1_io.c +++ b/drivers/w1/w1_io.c @@ -130,6 +130,47 @@ static u8 w1_read_bit(struct w1_master *dev) } /** + * 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 @@ -233,7 +274,7 @@ void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb) if (dev->bus_master->search) dev->bus_master->search(dev->bus_master->data, cb); else - w1_search(dev); + w1_search(dev, cb); } EXPORT_SYMBOL(w1_touch_bit); diff --git a/drivers/w1/w1_io.h b/drivers/w1/w1_io.h index d6daa3189c61..af5829778aaa 100644 --- a/drivers/w1/w1_io.h +++ b/drivers/w1/w1_io.h @@ -26,6 +26,7 @@ void w1_delay(unsigned long); u8 w1_touch_bit(struct w1_master *, int); +u8 w1_triplet(struct w1_master *dev, int bdir); void w1_write_8(struct w1_master *, u8); u8 w1_read_8(struct w1_master *); int w1_reset_bus(struct w1_master *); |
