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| author | David Fries <David@Fries.net> | 2014-04-08 22:37:09 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-27 13:56:21 -0700 |
| commit | 8a0427d192e6043834414210dd14cc1289daff18 (patch) | |
| tree | 1e76812e3744b6946a815fb94f877cc31d11b302 /Documentation/w1 | |
| parent | 34470e0bfae223e3f22bd2bd6e0e1dac366c9290 (diff) | |
| download | lwn-8a0427d192e6043834414210dd14cc1289daff18.tar.gz lwn-8a0427d192e6043834414210dd14cc1289daff18.zip | |
w1: optional bundling of netlink kernel replies
Applications can submit a set of commands in one packet to the kernel,
and in some cases it is required such as reading the temperature
sensor results. This adds an option W1_CN_BUNDLE to the flags of
cn_msg to request the kernel to reply in one packet for efficiency.
The cn_msg flags now check for unknown flag values and return an error
if one is seen. See "Proper handling of unknown flags in system
calls" http://lwn.net/Articles/588444/
This corrects the ack values returned as per the protocol standard,
namely the original ack for status messages and seq + 1 for all others
such as the data returned from a read.
Some of the common variable names have been standardized as follows.
struct cn_msg *cn
struct w1_netlink_msg *msg
struct w1_netlink_cmd *cmd
struct w1_master *dev
When an argument and a function scope variable would collide, add req_
to the argument.
Signed-off-by: David Fries <David@Fries.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/w1')
| -rw-r--r-- | Documentation/w1/w1.generic | 2 | ||||
| -rw-r--r-- | Documentation/w1/w1.netlink | 13 |
2 files changed, 9 insertions, 6 deletions
diff --git a/Documentation/w1/w1.generic b/Documentation/w1/w1.generic index a31c5a242973..b2033c64c7da 100644 --- a/Documentation/w1/w1.generic +++ b/Documentation/w1/w1.generic @@ -82,7 +82,7 @@ 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 diff --git a/Documentation/w1/w1.netlink b/Documentation/w1/w1.netlink index 927a52cc0519..ef2727192d69 100644 --- a/Documentation/w1/w1.netlink +++ b/Documentation/w1/w1.netlink @@ -30,7 +30,7 @@ Protocol. W1_SLAVE_CMD userspace command for slave device (read/write/touch) - __u8 res - reserved + __u8 status - error indication from kernel __u16 len - size of data attached to this header data union { __u8 id[8]; - slave unique device id @@ -44,10 +44,14 @@ Protocol. __u8 cmd - command opcode. W1_CMD_READ - read command W1_CMD_WRITE - write command - W1_CMD_TOUCH - touch command - (write and sample data back to userspace) 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 @@ -87,8 +91,7 @@ format: 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, - cn.seq will be increased for each one. + exceeds this, it will be split into several messages. W1 search and alarm search commands. request: |