diff options
Diffstat (limited to 'drivers/w1/w1.c')
-rw-r--r-- | drivers/w1/w1.c | 138 |
1 files changed, 65 insertions, 73 deletions
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index c85d75e..4fa959f 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); + } } } |