path: root/Documentation/w1
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authorDavid Fries <David@Fries.net>2014-04-08 22:37:09 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-27 13:56:21 -0700
commit8a0427d192e6043834414210dd14cc1289daff18 (patch)
tree1e76812e3744b6946a815fb94f877cc31d11b302 /Documentation/w1
parent34470e0bfae223e3f22bd2bd6e0e1dac366c9290 (diff)
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')
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
- - 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.
userspace command for slave device
- __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.

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