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[PATCH] w1: Added the triplet w1 master method and changes w1_search() to use it.
Adds the triplet w1 master method and changes w1_search() to use it. Signed-off-by: Ben Gardner <bgardner@wabtec.com> Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Evgeniy Polyakov
Greg Kroah-Hartman
parent
be57ce267f
commit
6b72986183
4 changed files with 169 additions and 88 deletions
138
drivers/w1/w1.c
138
drivers/w1/w1.c
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@ -135,7 +135,7 @@ struct device w1_device = {
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static ssize_t w1_master_attribute_show_name(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct w1_master *md = container_of (dev, struct w1_master, dev);
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struct w1_master *md = container_of(dev, struct w1_master, dev);
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ssize_t count;
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if (down_interruptible (&md->mutex))
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@ -212,7 +212,6 @@ static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct d
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}
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static ssize_t w1_master_attribute_show_slaves(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct w1_master *md = container_of(dev, struct w1_master, dev);
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int c = PAGE_SIZE;
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@ -286,13 +285,13 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
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sl->dev.release = &w1_slave_release;
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snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
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"%02x-%012llx",
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(unsigned int) sl->reg_num.family,
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(unsigned long long) sl->reg_num.id);
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snprintf (&sl->name[0], sizeof(sl->name),
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"%02x-%012llx",
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(unsigned int) sl->reg_num.family,
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(unsigned long long) sl->reg_num.id);
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"%02x-%012llx",
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(unsigned int) sl->reg_num.family,
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(unsigned long long) sl->reg_num.id);
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snprintf(&sl->name[0], sizeof(sl->name),
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"%02x-%012llx",
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(unsigned int) sl->reg_num.family,
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(unsigned long long) sl->reg_num.id);
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dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
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&sl->dev.bus_id[0]);
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@ -300,8 +299,8 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
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err = device_register(&sl->dev);
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if (err < 0) {
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dev_err(&sl->dev,
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"Device registration [%s] failed. err=%d\n",
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sl->dev.bus_id, err);
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"Device registration [%s] failed. err=%d\n",
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sl->dev.bus_id, err);
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return err;
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}
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@ -314,8 +313,8 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
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err = device_create_file(&sl->dev, &sl->attr_name);
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if (err < 0) {
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dev_err(&sl->dev,
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"sysfs file creation for [%s] failed. err=%d\n",
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sl->dev.bus_id, err);
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"sysfs file creation for [%s] failed. err=%d\n",
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sl->dev.bus_id, err);
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device_unregister(&sl->dev);
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return err;
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}
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@ -323,8 +322,8 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
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err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
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if (err < 0) {
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dev_err(&sl->dev,
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"sysfs file creation for [%s] failed. err=%d\n",
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sl->dev.bus_id, err);
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"sysfs file creation for [%s] failed. err=%d\n",
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sl->dev.bus_id, err);
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device_remove_file(&sl->dev, &sl->attr_name);
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device_unregister(&sl->dev);
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return err;
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@ -483,26 +482,39 @@ static void w1_slave_found(unsigned long data, u64 rn)
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atomic_dec(&dev->refcnt);
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}
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void w1_search(struct w1_master *dev)
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/**
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* Performs a ROM Search & registers any devices found.
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* The 1-wire search is a simple binary tree search.
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* For each bit of the address, we read two bits and write one bit.
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* The bit written will put to sleep all devies that don't match that bit.
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* When the two reads differ, the direction choice is obvious.
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* When both bits are 0, we must choose a path to take.
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* When we can scan all 64 bits without having to choose a path, we are done.
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*
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* See "Application note 187 1-wire search algorithm" at www.maxim-ic.com
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*
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* @dev The master device to search
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* @cb Function to call when a device is found
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*/
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void w1_search(struct w1_master *dev, w1_slave_found_callback cb)
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{
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u64 last, rn, tmp;
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int i, count = 0;
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int last_family_desc, last_zero, last_device;
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int search_bit, id_bit, comp_bit, desc_bit;
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u64 last_rn, rn, tmp64;
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int i, slave_count = 0;
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int last_zero, last_device;
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int search_bit, desc_bit;
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u8 triplet_ret = 0;
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search_bit = id_bit = comp_bit = 0;
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rn = tmp = last = 0;
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last_device = last_zero = last_family_desc = 0;
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search_bit = 0;
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rn = last_rn = 0;
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last_device = 0;
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last_zero = -1;
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desc_bit = 64;
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while (!(id_bit && comp_bit) && !last_device &&
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count++ < dev->max_slave_count) {
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last = rn;
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while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
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last_rn = rn;
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rn = 0;
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last_family_desc = 0;
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/*
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* Reset bus and all 1-wire device state machines
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* so they can respond to our requests.
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@ -514,59 +526,39 @@ void w1_search(struct w1_master *dev)
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break;
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}
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#if 1
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/* Start the search */
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w1_write_8(dev, W1_SEARCH);
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for (i = 0; i < 64; ++i) {
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/*
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* Read 2 bits from bus.
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* All who don't sleep must send ID bit and COMPLEMENT ID bit.
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* They actually are ANDed between all senders.
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*/
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id_bit = w1_touch_bit(dev, 1);
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comp_bit = w1_touch_bit(dev, 1);
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/* Determine the direction/search bit */
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if (i == desc_bit)
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search_bit = 1; /* took the 0 path last time, so take the 1 path */
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else if (i > desc_bit)
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search_bit = 0; /* take the 0 path on the next branch */
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else
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search_bit = ((last_rn >> i) & 0x1);
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if (id_bit && comp_bit)
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/** Read two bits and write one bit */
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triplet_ret = w1_triplet(dev, search_bit);
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/* quit if no device responded */
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if ( (triplet_ret & 0x03) == 0x03 )
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break;
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if (id_bit == 0 && comp_bit == 0) {
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if (i == desc_bit)
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search_bit = 1;
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else if (i > desc_bit)
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search_bit = 0;
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else
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search_bit = ((last >> i) & 0x1);
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if (search_bit == 0) {
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last_zero = i;
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if (last_zero < 9)
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last_family_desc = last_zero;
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}
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} else
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search_bit = id_bit;
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tmp = search_bit;
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rn |= (tmp << i);
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/*
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* Write 1 bit to bus
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* and make all who don't have "search_bit" in "i"'th position
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* in it's registration number sleep.
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*/
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if (dev->bus_master->touch_bit)
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w1_touch_bit(dev, search_bit);
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else
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w1_write_bit(dev, search_bit);
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/* If both directions were valid, and we took the 0 path... */
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if (triplet_ret == 0)
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last_zero = i;
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/* extract the direction taken & update the device number */
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tmp64 = (triplet_ret >> 2);
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rn |= (tmp64 << i);
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}
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#endif
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if (desc_bit == last_zero)
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last_device = 1;
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desc_bit = last_zero;
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w1_slave_found(dev->bus_master->data, rn);
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if ( (triplet_ret & 0x03) != 0x03 ) {
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if ( (desc_bit == last_zero) || (last_zero < 0))
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last_device = 1;
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desc_bit = last_zero;
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cb(dev->bus_master->data, rn);
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}
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}
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}
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@ -25,9 +25,9 @@
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struct w1_reg_num
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{
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#if defined(__LITTLE_ENDIAN_BITFIELD)
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__u64 family:8,
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id:48,
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crc:8;
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__u64 family:8,
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id:48,
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crc:8;
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#elif defined(__BIG_ENDIAN_BITFIELD)
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__u64 crc:8,
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id:48,
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@ -84,24 +84,71 @@ struct w1_slave
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typedef void (* w1_slave_found_callback)(unsigned long, u64);
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/**
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* Note: read_bit and write_bit are very low level functions and should only
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* be used with hardware that doesn't really support 1-wire operations,
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* like a parallel/serial port.
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* Either define read_bit and write_bit OR define, at minimum, touch_bit and
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* reset_bus.
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*/
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struct w1_bus_master
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{
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unsigned long data;
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/** the first parameter in all the functions below */
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unsigned long data;
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u8 (*read_bit)(unsigned long);
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void (*write_bit)(unsigned long, u8);
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/**
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* Sample the line level
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* @return the level read (0 or 1)
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*/
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u8 (*read_bit)(unsigned long);
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u8 (*read_byte)(unsigned long);
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void (*write_byte)(unsigned long, u8);
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/** Sets the line level */
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void (*write_bit)(unsigned long, u8);
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u8 (*read_block)(unsigned long, u8 *, int);
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void (*write_block)(unsigned long, u8 *, int);
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/**
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* touch_bit is the lowest-level function for devices that really
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* support the 1-wire protocol.
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* touch_bit(0) = write-0 cycle
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* touch_bit(1) = write-1 / read cycle
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* @return the bit read (0 or 1)
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*/
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u8 (*touch_bit)(unsigned long, u8);
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u8 (*touch_bit)(unsigned long, u8);
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/**
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* Reads a bytes. Same as 8 touch_bit(1) calls.
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* @return the byte read
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*/
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u8 (*read_byte)(unsigned long);
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u8 (*reset_bus)(unsigned long);
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/**
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* Writes a byte. Same as 8 touch_bit(x) calls.
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*/
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void (*write_byte)(unsigned long, u8);
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void (*search)(unsigned long, w1_slave_found_callback);
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/**
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* Same as a series of read_byte() calls
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* @return the number of bytes read
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*/
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u8 (*read_block)(unsigned long, u8 *, int);
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/** Same as a series of write_byte() calls */
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void (*write_block)(unsigned long, const u8 *, int);
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/**
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* Combines two reads and a smart write for ROM searches
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* @return bit0=Id bit1=comp_id bit2=dir_taken
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*/
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u8 (*triplet)(unsigned long, u8);
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/**
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* long write-0 with a read for the presence pulse detection
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* @return -1=Error, 0=Device present, 1=No device present
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*/
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u8 (*reset_bus)(unsigned long);
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/** Really nice hardware can handles the ROM searches */
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void (*search)(unsigned long, w1_slave_found_callback);
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};
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struct w1_master
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@ -137,7 +184,7 @@ struct w1_master
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};
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int w1_create_master_attributes(struct w1_master *);
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void w1_search(struct w1_master *dev);
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void w1_search(struct w1_master *dev, w1_slave_found_callback cb);
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#endif /* __KERNEL__ */
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@ -129,6 +129,47 @@ static u8 w1_read_bit(struct w1_master *dev)
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return result & 0x1;
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}
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/**
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* Does a triplet - used for searching ROM addresses.
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* Return bits:
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* bit 0 = id_bit
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* bit 1 = comp_bit
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* bit 2 = dir_taken
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* If both bits 0 & 1 are set, the search should be restarted.
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*
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* @param dev the master device
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* @param bdir the bit to write if both id_bit and comp_bit are 0
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* @return bit fields - see above
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*/
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u8 w1_triplet(struct w1_master *dev, int bdir)
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{
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if ( dev->bus_master->triplet )
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return(dev->bus_master->triplet(dev->bus_master->data, bdir));
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else {
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u8 id_bit = w1_touch_bit(dev, 1);
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u8 comp_bit = w1_touch_bit(dev, 1);
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u8 retval;
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if ( id_bit && comp_bit )
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return(0x03); /* error */
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if ( !id_bit && !comp_bit ) {
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/* Both bits are valid, take the direction given */
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retval = bdir ? 0x04 : 0;
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} else {
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/* Only one bit is valid, take that direction */
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bdir = id_bit;
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retval = id_bit ? 0x05 : 0x02;
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}
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if ( dev->bus_master->touch_bit )
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w1_touch_bit(dev, bdir);
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else
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w1_write_bit(dev, bdir);
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return(retval);
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}
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}
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/**
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* Reads 8 bits.
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*
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@ -233,7 +274,7 @@ void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb)
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if (dev->bus_master->search)
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dev->bus_master->search(dev->bus_master->data, cb);
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else
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w1_search(dev);
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w1_search(dev, cb);
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}
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EXPORT_SYMBOL(w1_touch_bit);
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@ -26,6 +26,7 @@
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void w1_delay(unsigned long);
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u8 w1_touch_bit(struct w1_master *, int);
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u8 w1_triplet(struct w1_master *dev, int bdir);
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void w1_write_8(struct w1_master *, u8);
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u8 w1_read_8(struct w1_master *);
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int w1_reset_bus(struct w1_master *);
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