diff options
Diffstat (limited to 'Documentation/w1')
| -rw-r--r-- | Documentation/w1/00-INDEX | 2 | ||||
| -rw-r--r-- | Documentation/w1/masters/00-INDEX | 4 | ||||
| -rw-r--r-- | Documentation/w1/masters/ds2482 | 10 | ||||
| -rw-r--r-- | Documentation/w1/masters/ds2490 | 50 | ||||
| -rw-r--r-- | Documentation/w1/masters/mxc-w1 | 12 | ||||
| -rw-r--r-- | Documentation/w1/masters/omap-hdq | 46 | ||||
| -rw-r--r-- | Documentation/w1/slaves/00-INDEX | 8 | ||||
| -rw-r--r-- | Documentation/w1/slaves/w1_ds2423 | 47 | ||||
| -rw-r--r-- | Documentation/w1/slaves/w1_ds28e04 | 36 | ||||
| -rw-r--r-- | Documentation/w1/slaves/w1_therm | 50 | ||||
| -rw-r--r-- | Documentation/w1/w1.generic | 17 | ||||
| -rw-r--r-- | Documentation/w1/w1.netlink | 171 |
12 files changed, 404 insertions, 49 deletions
diff --git a/Documentation/w1/00-INDEX b/Documentation/w1/00-INDEX index 5270cf4cb10..cb49802745d 100644 --- a/Documentation/w1/00-INDEX +++ b/Documentation/w1/00-INDEX @@ -1,5 +1,7 @@ 00-INDEX - This file +slaves/ + - Drivers that provide support for specific family codes. masters/ - Individual chips providing 1-wire busses. w1.generic diff --git a/Documentation/w1/masters/00-INDEX b/Documentation/w1/masters/00-INDEX index 7b0ceaaad7a..8330cf9325f 100644 --- a/Documentation/w1/masters/00-INDEX +++ b/Documentation/w1/masters/00-INDEX @@ -4,5 +4,9 @@ ds2482 - The Maxim/Dallas Semiconductor DS2482 provides 1-wire busses. ds2490 - The Maxim/Dallas Semiconductor DS2490 builds USB <-> W1 bridges. +mxc-w1 + - W1 master controller driver found on Freescale MX2/MX3 SoCs +omap-hdq + - HDQ/1-wire module of TI OMAP 2430/3430. w1-gpio - GPIO 1-wire bus master driver. diff --git a/Documentation/w1/masters/ds2482 b/Documentation/w1/masters/ds2482 index 9210d6fa502..56f8edace6a 100644 --- a/Documentation/w1/masters/ds2482 +++ b/Documentation/w1/masters/ds2482 @@ -6,8 +6,8 @@ Supported chips: Prefix: 'ds2482' Addresses scanned: None Datasheets: - http://pdfserv.maxim-ic.com/en/ds/DS2482-100-DS2482S-100.pdf - http://pdfserv.maxim-ic.com/en/ds/DS2482-800-DS2482S-800.pdf + http://datasheets.maxim-ic.com/en/ds/DS2482-100.pdf + http://datasheets.maxim-ic.com/en/ds/DS2482-800.pdf Author: Ben Gardner <bgardner@wabtec.com> @@ -24,8 +24,8 @@ General Remarks Valid addresses are 0x18, 0x19, 0x1a, and 0x1b. However, the device cannot be detected without writing to the i2c bus, so no -detection is done. -You should force the device address. +detection is done. You should instantiate the device explicitly. -$ modprobe ds2482 force=0,0x18 +$ modprobe ds2482 +$ echo ds2482 0x18 > /sys/bus/i2c/devices/i2c-0/new_device diff --git a/Documentation/w1/masters/ds2490 b/Documentation/w1/masters/ds2490 index 239f9ae0184..3e091151dd8 100644 --- a/Documentation/w1/masters/ds2490 +++ b/Documentation/w1/masters/ds2490 @@ -16,3 +16,53 @@ which allows to build USB <-> W1 bridges. DS9490(R) is a USB <-> W1 bus master device which has 0x81 family ID integrated chip and DS2490 low-level operational chip. + +Notes and limitations. +- The weak pullup current is a minimum of 0.9mA and maximum of 6.0mA. +- The 5V strong pullup is supported with a minimum of 5.9mA and a + maximum of 30.4 mA. (From DS2490.pdf) +- The hardware will detect when devices are attached to the bus on the + next bus (reset?) operation, however only a message is printed as + the core w1 code doesn't make use of the information. Connecting + one device tends to give multiple new device notifications. +- The number of USB bus transactions could be reduced if w1_reset_send + was added to the API. The name is just a suggestion. It would take + a write buffer and a read buffer (along with sizes) as arguments. + The ds2490 block I/O command supports reset, write buffer, read + buffer, and strong pullup all in one command, instead of the current + 1 reset bus, 2 write the match rom command and slave rom id, 3 block + write and read data. The write buffer needs to have the match rom + command and slave rom id prepended to the front of the requested + write buffer, both of which are known to the driver. +- The hardware supports normal, flexible, and overdrive bus + communication speeds, but only the normal is supported. +- The registered w1_bus_master functions don't define error + conditions. If a bus search is in progress and the ds2490 is + removed it can produce a good amount of error output before the bus + search finishes. +- The hardware supports detecting some error conditions, such as + short, alarming presence on reset, and no presence on reset, but the + driver doesn't query those values. +- The ds2490 specification doesn't cover short bulk in reads in + detail, but my observation is if fewer bytes are requested than are + available, the bulk read will return an error and the hardware will + clear the entire bulk in buffer. It would be possible to read the + maximum buffer size to not run into this error condition, only extra + bytes in the buffer is a logic error in the driver. The code should + should match reads and writes as well as data sizes. Reads and + writes are serialized and the status verifies that the chip is idle + (and data is available) before the read is executed, so it should + not happen. +- Running x86_64 2.6.24 UHCI under qemu 0.9.0 under x86_64 2.6.22-rc6 + with a OHCI controller, ds2490 running in the guest would operate + normally the first time the module was loaded after qemu attached + the ds2490 hardware, but if the module was unloaded, then reloaded + most of the time one of the bulk out or in, and usually the bulk in + would fail. qemu sets a 50ms timeout and the bulk in would timeout + even when the status shows data available. A bulk out write would + show a successful completion, but the ds2490 status register would + show 0 bytes written. Detaching qemu from the ds2490 hardware and + reattaching would clear the problem. usbmon output in the guest and + host did not explain the problem. My guess is a bug in either qemu + or the host OS and more likely the host OS. +-- 03-06-2008 David Fries <David@Fries.net> diff --git a/Documentation/w1/masters/mxc-w1 b/Documentation/w1/masters/mxc-w1 new file mode 100644 index 00000000000..38be1ad6553 --- /dev/null +++ b/Documentation/w1/masters/mxc-w1 @@ -0,0 +1,12 @@ +Kernel driver mxc_w1 +==================== + +Supported chips: + * Freescale MX27, MX31 and probably other i.MX SoCs + Datasheets: + http://www.freescale.com/files/32bit/doc/data_sheet/MCIMX31.pdf?fpsp=1 + http://cache.freescale.com/files/dsp/doc/archive/MCIMX27.pdf?fsrch=1&WT_TYPE= + Data%20Sheets&WT_VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation + +Author: Originally based on Freescale code, prepared for mainline by + Sascha Hauer <s.hauer@pengutronix.de> diff --git a/Documentation/w1/masters/omap-hdq b/Documentation/w1/masters/omap-hdq new file mode 100644 index 00000000000..884dc284b21 --- /dev/null +++ b/Documentation/w1/masters/omap-hdq @@ -0,0 +1,46 @@ +Kernel driver for omap HDQ/1-wire module. +======================================== + +Supported chips: +================ + HDQ/1-wire controller on the TI OMAP 2430/3430 platforms. + +A useful link about HDQ basics: +=============================== +http://focus.ti.com/lit/an/slua408a/slua408a.pdf + +Description: +============ +The HDQ/1-Wire module of TI OMAP2430/3430 platforms implement the hardware +protocol of the master functions of the Benchmark HDQ and the Dallas +Semiconductor 1-Wire protocols. These protocols use a single wire for +communication between the master (HDQ/1-Wire controller) and the slave +(HDQ/1-Wire external compliant device). + +A typical application of the HDQ/1-Wire module is the communication with battery +monitor (gas gauge) integrated circuits. + +The controller supports operation in both HDQ and 1-wire mode. The essential +difference between the HDQ and 1-wire mode is how the slave device responds to +initialization pulse.In HDQ mode, the firmware does not require the host to +create an initialization pulse to the slave.However, the slave can be reset by +using an initialization pulse (also referred to as a break pulse).The slave +does not respond with a presence pulse as it does in the 1-Wire protocol. + +Remarks: +======== +The driver (drivers/w1/masters/omap_hdq.c) supports the HDQ mode of the +controller. In this mode, as we can not read the ID which obeys the W1 +spec(family:id:crc), a module parameter can be passed to the driver which will +be used to calculate the CRC and pass back an appropriate slave ID to the W1 +core. + +By default the master driver and the BQ slave i/f +driver(drivers/w1/slaves/w1_bq27000.c) sets the ID to 1. +Please note to load both the modules with a different ID if required, but note +that the ID used should be same for both master and slave driver loading. + +e.g: +insmod omap_hdq.ko W1_ID=2 +inamod w1_bq27000.ko F_ID=2 + diff --git a/Documentation/w1/slaves/00-INDEX b/Documentation/w1/slaves/00-INDEX new file mode 100644 index 00000000000..6e18c70c347 --- /dev/null +++ b/Documentation/w1/slaves/00-INDEX @@ -0,0 +1,8 @@ +00-INDEX + - This file +w1_therm + - The Maxim/Dallas Semiconductor ds18*20 temperature sensor. +w1_ds2423 + - The Maxim/Dallas Semiconductor ds2423 counter device. +w1_ds28e04 + - The Maxim/Dallas Semiconductor ds28e04 eeprom. diff --git a/Documentation/w1/slaves/w1_ds2423 b/Documentation/w1/slaves/w1_ds2423 new file mode 100644 index 00000000000..3f98b505a0e --- /dev/null +++ b/Documentation/w1/slaves/w1_ds2423 @@ -0,0 +1,47 @@ +Kernel driver w1_ds2423 +======================= + +Supported chips: + * Maxim DS2423 based counter devices. + +supported family codes: + W1_THERM_DS2423 0x1D + +Author: Mika Laitio <lamikr@pilppa.org> + +Description +----------- + +Support is provided through the sysfs w1_slave file. Each opening and +read sequence of w1_slave file initiates the read of counters and ram +available in DS2423 pages 12 - 15. + +Result of each page is provided as an ASCII output where each counter +value and associated ram buffer is outpputed to own line. + +Each lines will contain the values of 42 bytes read from the counter and +memory page along the crc=YES or NO for indicating whether the read operation +was successful and CRC matched. +If the operation was successful, there is also in the end of each line +a counter value expressed as an integer after c= + +Meaning of 42 bytes represented is following: + - 1 byte from ram page + - 4 bytes for the counter value + - 4 zero bytes + - 2 bytes for crc16 which was calculated from the data read since the previous crc bytes + - 31 remaining bytes from the ram page + - crc=YES/NO indicating whether read was ok and crc matched + - c=<int> current counter value + +example from the successful read: +00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2 +00 02 00 00 00 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2 +00 29 c6 5d 18 00 00 00 00 04 37 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=408798761 +00 05 00 00 00 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=YES c=5 + +example from the read with crc errors: +00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2 +00 02 00 00 22 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO +00 e1 61 5d 19 00 00 00 00 df 0b 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO +00 05 00 00 20 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=NO diff --git a/Documentation/w1/slaves/w1_ds28e04 b/Documentation/w1/slaves/w1_ds28e04 new file mode 100644 index 00000000000..7819b65cfa4 --- /dev/null +++ b/Documentation/w1/slaves/w1_ds28e04 @@ -0,0 +1,36 @@ +Kernel driver w1_ds28e04 +======================== + +Supported chips: + * Maxim DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO + +supported family codes: + W1_FAMILY_DS28E04 0x1C + +Author: Markus Franke, <franke.m@sebakmt.com> <franm@hrz.tu-chemnitz.de> + +Description +----------- + +Support is provided through the sysfs files "eeprom" and "pio". CRC checking +during memory accesses can optionally be enabled/disabled via the device +attribute "crccheck". The strong pull-up can optionally be enabled/disabled +via the module parameter "w1_strong_pullup". + +Memory Access + + A read operation on the "eeprom" file reads the given amount of bytes + from the EEPROM of the DS28E04. + + A write operation on the "eeprom" file writes the given byte sequence + to the EEPROM of the DS28E04. If CRC checking mode is enabled only + fully aligned blocks of 32 bytes with valid CRC16 values (in bytes 30 + and 31) are allowed to be written. + +PIO Access + + The 2 PIOs of the DS28E04-100 are accessible via the "pio" sysfs file. + + The current status of the PIO's is returned as an 8 bit value. Bit 0/1 + represent the state of PIO_0/PIO_1. Bits 2..7 do not care. The PIO's are + driven low-active, i.e. the driver delivers/expects low-active values. diff --git a/Documentation/w1/slaves/w1_therm b/Documentation/w1/slaves/w1_therm new file mode 100644 index 00000000000..cc62a95e477 --- /dev/null +++ b/Documentation/w1/slaves/w1_therm @@ -0,0 +1,50 @@ +Kernel driver w1_therm +==================== + +Supported chips: + * Maxim ds18*20 based temperature sensors. + * Maxim ds1825 based temperature sensors. + +Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru> + + +Description +----------- + +w1_therm provides basic temperature conversion for ds18*20 devices. +supported family codes: +W1_THERM_DS18S20 0x10 +W1_THERM_DS1822 0x22 +W1_THERM_DS18B20 0x28 +W1_THERM_DS1825 0x3B + +Support is provided through the sysfs w1_slave file. Each open and +read sequence will initiate a temperature conversion then provide two +lines of ASCII output. The first line contains the nine hex bytes +read along with a calculated crc value and YES or NO if it matched. +If the crc matched the returned values are retained. The second line +displays the retained values along with a temperature in millidegrees +Centigrade after t=. + +Parasite powered devices are limited to one slave performing a +temperature conversion at a time. If none of the devices are parasite +powered it would be possible to convert all the devices at the same +time and then go back to read individual sensors. That isn't +currently supported. The driver also doesn't support reduced +precision (which would also reduce the conversion time). + +The module parameter strong_pullup can be set to 0 to disable the +strong pullup, 1 to enable autodetection or 2 to force strong pullup. +In case of autodetection, the driver will use the "READ POWER SUPPLY" +command to check if there are pariste powered devices on the bus. +If so, it will activate the master's strong pullup. +In case the detection of parasite devices using this command fails +(seems to be the case with some DS18S20) the strong pullup can +be force-enabled. +If the strong pullup is enabled, the master's strong pullup will be +driven when the conversion is taking place, provided the master driver +does support the strong pullup (or it falls back to a pullup +resistor). The DS18b20 temperature sensor specification lists a +maximum current draw of 1.5mA and that a 5k pullup resistor is not +sufficient. The strong pullup is designed to provide the additional +current required. diff --git a/Documentation/w1/w1.generic b/Documentation/w1/w1.generic index 4c6509dd478..b2033c64c7d 100644 --- a/Documentation/w1/w1.generic +++ b/Documentation/w1/w1.generic @@ -25,8 +25,8 @@ When a w1 master driver registers with the w1 subsystem, the following occurs: - sysfs entries for that w1 master are created - the w1 bus is periodically searched for new slave devices -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. +When a device is found on the bus, w1 core tries to load the driver for its family +and check if it is loaded. If so, the family driver is attached to the slave. 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. @@ -79,10 +79,13 @@ w1 master sysfs interface <xx-xxxxxxxxxxxxx> - a directory for a found device. The format is family-serial bus - (standard) symlink to the w1 bus driver - (standard) symlink to the w1 driver +w1_master_add - Manually register a slave device w1_master_attempts - the number of times a search was attempted w1_master_max_slave_count - - the maximum slaves that may be attached to a master + - maximum number of slaves to search for at a time w1_master_name - the name of the device (w1_bus_masterX) +w1_master_pullup - 5V strong pullup 0 enabled, 1 disabled +w1_master_remove - Manually remove a slave device w1_master_search - the number of searches left to do, -1=continual (default) w1_master_slave_count - the number of slaves found @@ -90,7 +93,13 @@ w1_master_slaves - the names of the slaves, one per line w1_master_timeout - the delay in seconds between searches If you have a w1 bus that never changes (you don't add or remove devices), -you can set w1_master_search to a positive value to disable searches. +you can set the module parameter search_count to a small positive number +for an initially small number of bus searches. Alternatively it could be +set to zero, then manually add the slave device serial numbers by +w1_master_add device file. The w1_master_add and w1_master_remove files +generally only make sense when searching is disabled, as a search will +redetect manually removed devices that are present and timeout manually +added devices that aren't on the bus. w1 slave sysfs interface diff --git a/Documentation/w1/w1.netlink b/Documentation/w1/w1.netlink index 3640c7c87d4..ef2727192d6 100644 --- a/Documentation/w1/w1.netlink +++ b/Documentation/w1/w1.netlink @@ -5,74 +5,165 @@ Message types. ============= There are three types of messages between w1 core and userspace: -1. Events. They are generated each time new master or slave device found - either due to automatic or requested search. -2. Userspace commands. Includes read/write and search/alarm search comamnds. +1. Events. They are generated each time a new master or slave device + is found either due to automatic or requested search. +2. Userspace commands. 3. Replies to userspace commands. Protocol. ======== -[struct cn_msg] - connector header. It's length field is equal to size of the attached data. +[struct cn_msg] - connector header. + Its length field is equal to size of the attached data [struct w1_netlink_msg] - w1 netlink header. __u8 type - message type. - W1_SLAVE_ADD/W1_SLAVE_REMOVE - slave add/remove events. - W1_MASTER_ADD/W1_MASTER_REMOVE - master add/remove events. - W1_MASTER_CMD - userspace command for bus master device (search/alarm search). - W1_SLAVE_CMD - userspace command for slave device (read/write/ search/alarm search - for bus master device where given slave device found). - __u8 res - reserved - __u16 len - size of attached to this header data. + W1_LIST_MASTERS + list current bus masters + W1_SLAVE_ADD/W1_SLAVE_REMOVE + slave add/remove events + W1_MASTER_ADD/W1_MASTER_REMOVE + master add/remove events + W1_MASTER_CMD + userspace command for bus master + device (search/alarm search) + W1_SLAVE_CMD + userspace command for slave device + (read/write/touch) + __u8 status - error indication from kernel + __u16 len - size of data attached to this header data union { - __u8 id; - slave unique device id + __u8 id[8]; - slave unique device id struct w1_mst { - __u32 id; - master's id. + __u32 id; - master's id __u32 res; - reserved } mst; } id; -[strucrt w1_netlink_cmd] - command for gived master or slave device. +[struct w1_netlink_cmd] - command for given master or slave device. __u8 cmd - command opcode. - W1_CMD_READ - read command. - W1_CMD_WRITE - write command. - W1_CMD_SEARCH - search command. - W1_CMD_ALARM_SEARCH - alarm search command. + W1_CMD_READ - read command + W1_CMD_WRITE - write command + W1_CMD_SEARCH - search command + W1_CMD_ALARM_SEARCH - alarm search command + W1_CMD_TOUCH - touch command + (write and sample data back to userspace) + W1_CMD_RESET - send bus reset + W1_CMD_SLAVE_ADD - add slave to kernel list + W1_CMD_SLAVE_REMOVE - remove slave from kernel list + W1_CMD_LIST_SLAVES - get slaves list from kernel __u8 res - reserved - __u16 len - length of data for this command. - For read command data must be allocated like for write command. - __u8 data[0] - data for this command. + __u16 len - length of data for this command + For read command data must be allocated like for write command + __u8 data[0] - data for this command + +Each connector message can include one or more w1_netlink_msg with +zero or more attached w1_netlink_cmd messages. -Each connector message can include one or more w1_netlink_msg with zero of more attached w1_netlink_cmd messages. +For event messages there are no w1_netlink_cmd embedded structures, +only connector header and w1_netlink_msg strucutre with "len" field +being zero and filled type (one of event types) and id: +either 8 bytes of slave unique id in host order, +or master's id, which is assigned to bus master device +when it is added to w1 core. -For event messages there are no w1_netlink_cmd embedded structures, only connector header -and w1_netlink_msg strucutre with "len" field being zero and filled type (one of event types) -and id - either 8 bytes of slave unique id in host order, or master's id, which is assigned -to bus master device when it is added to w1 core. +Currently replies to userspace commands are only generated for read +command request. One reply is generated exactly for one w1_netlink_cmd +read request. Replies are not combined when sent - i.e. typical reply +messages looks like the following: -Currently replies to userspace commands are only generated for read command request. -One reply is generated exactly for one w1_netlink_cmd read request. -Replies are not combined when sent - i.e. typical reply messages looks like the following: [cn_msg][w1_netlink_msg][w1_netlink_cmd] -cn_msg.len = sizeof(struct w1_netlink_msg) + sizeof(struct w1_netlink_cmd) + cmd->len; +cn_msg.len = sizeof(struct w1_netlink_msg) + + sizeof(struct w1_netlink_cmd) + + cmd->len; w1_netlink_msg.len = sizeof(struct w1_netlink_cmd) + cmd->len; w1_netlink_cmd.len = cmd->len; +Replies to W1_LIST_MASTERS should send a message back to the userspace +which will contain list of all registered master ids in the following +format: + + cn_msg (CN_W1_IDX.CN_W1_VAL as id, len is equal to sizeof(struct + w1_netlink_msg) plus number of masters multiplied by 4) + w1_netlink_msg (type: W1_LIST_MASTERS, len is equal to + number of masters multiplied by 4 (u32 size)) + id0 ... idN + + Each message is at most 4k in size, so if number of master devices + exceeds this, it will be split into several messages. + +W1 search and alarm search commands. +request: +[cn_msg] + [w1_netlink_msg type = W1_MASTER_CMD + id is equal to the bus master id to use for searching] + [w1_netlink_cmd cmd = W1_CMD_SEARCH or W1_CMD_ALARM_SEARCH] + +reply: + [cn_msg, ack = 1 and increasing, 0 means the last message, + seq is equal to the request seq] + [w1_netlink_msg type = W1_MASTER_CMD] + [w1_netlink_cmd cmd = W1_CMD_SEARCH or W1_CMD_ALARM_SEARCH + len is equal to number of IDs multiplied by 8] + [64bit-id0 ... 64bit-idN] +Length in each header corresponds to the size of the data behind it, so +w1_netlink_cmd->len = N * 8; where N is number of IDs in this message. + Can be zero. +w1_netlink_msg->len = sizeof(struct w1_netlink_cmd) + N * 8; +cn_msg->len = sizeof(struct w1_netlink_msg) + + sizeof(struct w1_netlink_cmd) + + N*8; + +W1 reset command. +[cn_msg] + [w1_netlink_msg type = W1_MASTER_CMD + id is equal to the bus master id to use for searching] + [w1_netlink_cmd cmd = W1_CMD_RESET] + + +Command status replies. +====================== + +Each command (either root, master or slave with or without w1_netlink_cmd +structure) will be 'acked' by the w1 core. Format of the reply is the same +as request message except that length parameters do not account for data +requested by the user, i.e. read/write/touch IO requests will not contain +data, so w1_netlink_cmd.len will be 0, w1_netlink_msg.len will be size +of the w1_netlink_cmd structure and cn_msg.len will be equal to the sum +of the sizeof(struct w1_netlink_msg) and sizeof(struct w1_netlink_cmd). +If reply is generated for master or root command (which do not have +w1_netlink_cmd attached), reply will contain only cn_msg and w1_netlink_msg +structures. + +w1_netlink_msg.status field will carry positive error value +(EINVAL for example) or zero in case of success. + +All other fields in every structure will mirror the same parameters in the +request message (except lengths as described above). + +Status reply is generated for every w1_netlink_cmd embedded in the +w1_netlink_msg, if there are no w1_netlink_cmd structures, +reply will be generated for the w1_netlink_msg. + +All w1_netlink_cmd command structures are handled in every w1_netlink_msg, +even if there were errors, only length mismatch interrupts message processing. + Operation steps in w1 core when new command is received. ======================================================= -When new message (w1_netlink_msg) is received w1 core detects if it is master of slave request, -according to w1_netlink_msg.type field. +When new message (w1_netlink_msg) is received w1 core detects if it is +master or slave request, according to w1_netlink_msg.type field. Then master or slave device is searched for. -When found, master device (requested or those one on where slave device is found) is locked. -If slave command is requested, then reset/select procedure is started to select given device. +When found, master device (requested or those one on where slave device +is found) is locked. If slave command is requested, then reset/select +procedure is started to select given device. Then all requested in w1_netlink_msg operations are performed one by one. If command requires reply (like read command) it is sent on command completion. -When all commands (w1_netlink_cmd) are processed muster device is unlocked +When all commands (w1_netlink_cmd) are processed master device is unlocked and next w1_netlink_msg header processing started. @@ -82,8 +173,8 @@ Connector [1] specific documentation. Each connector message includes two u32 fields as "address". w1 uses CN_W1_IDX and CN_W1_VAL defined in include/linux/connector.h header. Each message also includes sequence and acknowledge numbers. -Sequence number for event messages is appropriate bus master sequence number increased with -each event message sent "through" this master. +Sequence number for event messages is appropriate bus master sequence number +increased with each event message sent "through" this master. Sequence number for userspace requests is set by userspace application. Sequence number for reply is the same as was in request, and acknowledge number is set to seq+1. @@ -93,6 +184,6 @@ Additional documantion, source code examples. ============================================ 1. Documentation/connector -2. http://tservice.net.ru/~s0mbre/archive/w1 -This archive includes userspace application w1d.c which -uses read/write/search commands for all master/slave devices found on the bus. +2. http://www.ioremap.net/archive/w1 +This archive includes userspace application w1d.c which uses +read/write/search commands for all master/slave devices found on the bus. |