[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 2005-06-04 01:30:43 +04:00 committed by Greg Kroah-Hartman
parent be57ce267f
commit 6b72986183
4 changed files with 169 additions and 88 deletions

View file

@ -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) 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; ssize_t count;
if (down_interruptible (&md->mutex)) 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) 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); struct w1_master *md = container_of(dev, struct w1_master, dev);
int c = PAGE_SIZE; int c = PAGE_SIZE;
@ -286,13 +285,13 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
sl->dev.release = &w1_slave_release; sl->dev.release = &w1_slave_release;
snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id), snprintf(&sl->dev.bus_id[0], sizeof(sl->dev.bus_id),
"%02x-%012llx", "%02x-%012llx",
(unsigned int) sl->reg_num.family, (unsigned int) sl->reg_num.family,
(unsigned long long) sl->reg_num.id); (unsigned long long) sl->reg_num.id);
snprintf (&sl->name[0], sizeof(sl->name), snprintf(&sl->name[0], sizeof(sl->name),
"%02x-%012llx", "%02x-%012llx",
(unsigned int) sl->reg_num.family, (unsigned int) sl->reg_num.family,
(unsigned long long) sl->reg_num.id); (unsigned long long) sl->reg_num.id);
dev_dbg(&sl->dev, "%s: registering %s.\n", __func__, dev_dbg(&sl->dev, "%s: registering %s.\n", __func__,
&sl->dev.bus_id[0]); &sl->dev.bus_id[0]);
@ -300,8 +299,8 @@ static int __w1_attach_slave_device(struct w1_slave *sl)
err = device_register(&sl->dev); err = device_register(&sl->dev);
if (err < 0) { if (err < 0) {
dev_err(&sl->dev, dev_err(&sl->dev,
"Device registration [%s] failed. err=%d\n", "Device registration [%s] failed. err=%d\n",
sl->dev.bus_id, err); sl->dev.bus_id, err);
return 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); err = device_create_file(&sl->dev, &sl->attr_name);
if (err < 0) { if (err < 0) {
dev_err(&sl->dev, dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n", "sysfs file creation for [%s] failed. err=%d\n",
sl->dev.bus_id, err); sl->dev.bus_id, err);
device_unregister(&sl->dev); device_unregister(&sl->dev);
return err; 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); err = sysfs_create_bin_file(&sl->dev.kobj, &sl->attr_bin);
if (err < 0) { if (err < 0) {
dev_err(&sl->dev, dev_err(&sl->dev,
"sysfs file creation for [%s] failed. err=%d\n", "sysfs file creation for [%s] failed. err=%d\n",
sl->dev.bus_id, err); sl->dev.bus_id, err);
device_remove_file(&sl->dev, &sl->attr_name); device_remove_file(&sl->dev, &sl->attr_name);
device_unregister(&sl->dev); device_unregister(&sl->dev);
return err; return err;
@ -483,26 +482,39 @@ static void w1_slave_found(unsigned long data, u64 rn)
atomic_dec(&dev->refcnt); 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; u64 last_rn, rn, tmp64;
int i, count = 0; int i, slave_count = 0;
int last_family_desc, last_zero, last_device; int last_zero, last_device;
int search_bit, id_bit, comp_bit, desc_bit; int search_bit, desc_bit;
u8 triplet_ret = 0;
search_bit = id_bit = comp_bit = 0; search_bit = 0;
rn = tmp = last = 0; rn = last_rn = 0;
last_device = last_zero = last_family_desc = 0; last_device = 0;
last_zero = -1;
desc_bit = 64; desc_bit = 64;
while (!(id_bit && comp_bit) && !last_device && while ( !last_device && (slave_count++ < dev->max_slave_count) ) {
count++ < dev->max_slave_count) { last_rn = rn;
last = rn;
rn = 0; rn = 0;
last_family_desc = 0;
/* /*
* Reset bus and all 1-wire device state machines * Reset bus and all 1-wire device state machines
* so they can respond to our requests. * so they can respond to our requests.
@ -514,59 +526,39 @@ void w1_search(struct w1_master *dev)
break; break;
} }
#if 1 /* Start the search */
w1_write_8(dev, W1_SEARCH); w1_write_8(dev, W1_SEARCH);
for (i = 0; i < 64; ++i) { for (i = 0; i < 64; ++i) {
/* /* Determine the direction/search bit */
* Read 2 bits from bus. if (i == desc_bit)
* All who don't sleep must send ID bit and COMPLEMENT ID bit. search_bit = 1; /* took the 0 path last time, so take the 1 path */
* They actually are ANDed between all senders. else if (i > desc_bit)
*/ search_bit = 0; /* take the 0 path on the next branch */
id_bit = w1_touch_bit(dev, 1); else
comp_bit = w1_touch_bit(dev, 1); search_bit = ((last_rn >> i) & 0x1);
if (id_bit && comp_bit) /** Read two bits and write one bit */
triplet_ret = w1_triplet(dev, search_bit);
/* quit if no device responded */
if ( (triplet_ret & 0x03) == 0x03 )
break; break;
if (id_bit == 0 && comp_bit == 0) { /* If both directions were valid, and we took the 0 path... */
if (i == desc_bit) if (triplet_ret == 0)
search_bit = 1; last_zero = i;
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;
}
} else
search_bit = id_bit;
tmp = search_bit;
rn |= (tmp << i);
/*
* 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);
/* extract the direction taken & update the device number */
tmp64 = (triplet_ret >> 2);
rn |= (tmp64 << i);
} }
#endif
if (desc_bit == last_zero) if ( (triplet_ret & 0x03) != 0x03 ) {
last_device = 1; if ( (desc_bit == last_zero) || (last_zero < 0))
last_device = 1;
desc_bit = last_zero; desc_bit = last_zero;
cb(dev->bus_master->data, rn);
w1_slave_found(dev->bus_master->data, rn); }
} }
} }

View file

@ -25,9 +25,9 @@
struct w1_reg_num struct w1_reg_num
{ {
#if defined(__LITTLE_ENDIAN_BITFIELD) #if defined(__LITTLE_ENDIAN_BITFIELD)
__u64 family:8, __u64 family:8,
id:48, id:48,
crc:8; crc:8;
#elif defined(__BIG_ENDIAN_BITFIELD) #elif defined(__BIG_ENDIAN_BITFIELD)
__u64 crc:8, __u64 crc:8,
id:48, id:48,
@ -84,24 +84,71 @@ struct w1_slave
typedef void (* w1_slave_found_callback)(unsigned long, u64); 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 struct w1_bus_master
{ {
unsigned long data; /** the first parameter in all the functions below */
unsigned long data;
u8 (*read_bit)(unsigned long); /**
void (*write_bit)(unsigned long, u8); * Sample the line level
* @return the level read (0 or 1)
*/
u8 (*read_bit)(unsigned long);
u8 (*read_byte)(unsigned long); /** Sets the line level */
void (*write_byte)(unsigned long, u8); void (*write_bit)(unsigned long, u8);
u8 (*read_block)(unsigned long, u8 *, int); /**
void (*write_block)(unsigned long, u8 *, int); * 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);
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);
u8 (*reset_bus)(unsigned long); /**
* Writes a byte. Same as 8 touch_bit(x) calls.
*/
void (*write_byte)(unsigned long, u8);
void (*search)(unsigned long, w1_slave_found_callback); /**
* 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 struct w1_master
@ -137,7 +184,7 @@ struct w1_master
}; };
int w1_create_master_attributes(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__ */ #endif /* __KERNEL__ */

View file

@ -129,6 +129,47 @@ static u8 w1_read_bit(struct w1_master *dev)
return result & 0x1; 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. * Reads 8 bits.
* *
@ -233,7 +274,7 @@ void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb)
if (dev->bus_master->search) if (dev->bus_master->search)
dev->bus_master->search(dev->bus_master->data, cb); dev->bus_master->search(dev->bus_master->data, cb);
else else
w1_search(dev); w1_search(dev, cb);
} }
EXPORT_SYMBOL(w1_touch_bit); EXPORT_SYMBOL(w1_touch_bit);

View file

@ -26,6 +26,7 @@
void w1_delay(unsigned long); void w1_delay(unsigned long);
u8 w1_touch_bit(struct w1_master *, int); 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); void w1_write_8(struct w1_master *, u8);
u8 w1_read_8(struct w1_master *); u8 w1_read_8(struct w1_master *);
int w1_reset_bus(struct w1_master *); int w1_reset_bus(struct w1_master *);