diff options
| -rw-r--r-- | Documentation/w1/w1.generic | 18 | ||||
| -rw-r--r-- | drivers/w1/w1.c | 69 | ||||
| -rw-r--r-- | drivers/w1/w1.h | 2 |
3 files changed, 84 insertions, 5 deletions
diff --git a/Documentation/w1/w1.generic b/Documentation/w1/w1.generic index f937fbe..4c6509d 100644 --- a/Documentation/w1/w1.generic +++ b/Documentation/w1/w1.generic @@ -27,8 +27,19 @@ When a w1 master driver registers with the w1 subsystem, the following occurs: When a device is found on the bus, w1 core checks if driver for it's family is loaded. If so, the family driver is attached to the slave. -If there is no driver for the family, a simple sysfs entry is created -for the slave device. +If there is no driver for the family, default one is assigned, which allows to perform +almost any kind of operations. Each logical operation is a transaction +in nature, which can contain several (two or one) low-level operations. +Let's see how one can read EEPROM context: +1. one must write control buffer, i.e. buffer containing command byte +and two byte address. At this step bus is reset and appropriate device +is selected using either W1_SKIP_ROM or W1_MATCH_ROM command. +Then provided control buffer is being written to the wire. +2. reading. This will issue reading eeprom response. + +It is possible that between 1. and 2. w1 master thread will reset bus for searching +and slave device will be even removed, but in this case 0xff will +be read, since no device was selected. W1 device families @@ -89,4 +100,5 @@ driver - (standard) symlink to the w1 driver name - the device name, usually the same as the directory name w1_slave - (optional) a binary file whose meaning depends on the family driver - +rw - (optional) created for slave devices which do not have + appropriate family driver. Allows to read/write binary data. diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c index a698b51..c9486c1 100644 --- a/drivers/w1/w1.c +++ b/drivers/w1/w1.c @@ -139,7 +139,74 @@ static struct bin_attribute w1_slave_attr_bin_id = { }; /* Default family */ -static struct w1_family w1_default_family; + +static ssize_t w1_default_write(struct kobject *kobj, char *buf, loff_t off, size_t count) +{ + struct w1_slave *sl = kobj_to_w1_slave(kobj); + + if (down_interruptible(&sl->master->mutex)) { + count = 0; + goto out; + } + + if (w1_reset_select_slave(sl)) { + count = 0; + goto out_up; + } + + w1_write_block(sl->master, buf, count); + +out_up: + up(&sl->master->mutex); +out: + return count; +} + +static ssize_t w1_default_read(struct kobject *kobj, char *buf, loff_t off, size_t count) +{ + struct w1_slave *sl = kobj_to_w1_slave(kobj); + + if (down_interruptible(&sl->master->mutex)) { + count = 0; + goto out; + } + + w1_read_block(sl->master, buf, count); + + up(&sl->master->mutex); +out: + return count; +} + +static struct bin_attribute w1_default_attr = { + .attr = { + .name = "rw", + .mode = S_IRUGO | S_IWUSR, + .owner = THIS_MODULE, + }, + .size = PAGE_SIZE, + .read = w1_default_read, + .write = w1_default_write, +}; + +static int w1_default_add_slave(struct w1_slave *sl) +{ + return sysfs_create_bin_file(&sl->dev.kobj, &w1_default_attr); +} + +static void w1_default_remove_slave(struct w1_slave *sl) +{ + sysfs_remove_bin_file(&sl->dev.kobj, &w1_default_attr); +} + +static struct w1_family_ops w1_default_fops = { + .add_slave = w1_default_add_slave, + .remove_slave = w1_default_remove_slave, +}; + +static struct w1_family w1_default_family = { + .fops = &w1_default_fops, +}; static int w1_uevent(struct device *dev, char **envp, int num_envp, char *buffer, int buffer_size); diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h index 5698050..02e8cad 100644 --- a/drivers/w1/w1.h +++ b/drivers/w1/w1.h @@ -60,7 +60,7 @@ struct w1_reg_num #define W1_READ_PSUPPLY 0xB4 #define W1_MATCH_ROM 0x55 -#define W1_SLAVE_ACTIVE (1<<0) +#define W1_SLAVE_ACTIVE 0 struct w1_slave { |
