diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/DocBook/uio-howto.tmpl | 7 | ||||
| -rw-r--r-- | Documentation/i2c/ten-bit-addresses | 36 | ||||
| -rw-r--r-- | Documentation/serial/serial-rs485.txt | 14 |
3 files changed, 36 insertions, 21 deletions
diff --git a/Documentation/DocBook/uio-howto.tmpl b/Documentation/DocBook/uio-howto.tmpl index 54883de5d5f..ac3d0018140 100644 --- a/Documentation/DocBook/uio-howto.tmpl +++ b/Documentation/DocBook/uio-howto.tmpl @@ -521,6 +521,11 @@ Here's a description of the fields of <varname>struct uio_mem</varname>: <itemizedlist> <listitem><para> +<varname>const char *name</varname>: Optional. Set this to help identify +the memory region, it will show up in the corresponding sysfs node. +</para></listitem> + +<listitem><para> <varname>int memtype</varname>: Required if the mapping is used. Set this to <varname>UIO_MEM_PHYS</varname> if you you have physical memory on your card to be mapped. Use <varname>UIO_MEM_LOGICAL</varname> for logical @@ -553,7 +558,7 @@ instead to remember such an address. </itemizedlist> <para> -Please do not touch the <varname>kobj</varname> element of +Please do not touch the <varname>map</varname> element of <varname>struct uio_mem</varname>! It is used by the UIO framework to set up sysfs files for this mapping. Simply leave it alone. </para> diff --git a/Documentation/i2c/ten-bit-addresses b/Documentation/i2c/ten-bit-addresses index e9890709c50..cdfe13901b9 100644 --- a/Documentation/i2c/ten-bit-addresses +++ b/Documentation/i2c/ten-bit-addresses @@ -1,22 +1,24 @@ The I2C protocol knows about two kinds of device addresses: normal 7 bit addresses, and an extended set of 10 bit addresses. The sets of addresses do not intersect: the 7 bit address 0x10 is not the same as the 10 bit -address 0x10 (though a single device could respond to both of them). You -select a 10 bit address by adding an extra byte after the address -byte: - S Addr7 Rd/Wr .... -becomes - S 11110 Addr10 Rd/Wr -S is the start bit, Rd/Wr the read/write bit, and if you count the number -of bits, you will see the there are 8 after the S bit for 7 bit addresses, -and 16 after the S bit for 10 bit addresses. +address 0x10 (though a single device could respond to both of them). -WARNING! The current 10 bit address support is EXPERIMENTAL. There are -several places in the code that will cause SEVERE PROBLEMS with 10 bit -addresses, even though there is some basic handling and hooks. Also, -almost no supported adapter handles the 10 bit addresses correctly. +I2C messages to and from 10-bit address devices have a different format. +See the I2C specification for the details. -As soon as a real 10 bit address device is spotted 'in the wild', we -can and will add proper support. Right now, 10 bit address devices -are defined by the I2C protocol, but we have never seen a single device -which supports them. +The current 10 bit address support is minimal. It should work, however +you can expect some problems along the way: +* Not all bus drivers support 10-bit addresses. Some don't because the + hardware doesn't support them (SMBus doesn't require 10-bit address + support for example), some don't because nobody bothered adding the + code (or it's there but not working properly.) Software implementation + (i2c-algo-bit) is known to work. +* Some optional features do not support 10-bit addresses. This is the + case of automatic detection and instantiation of devices by their, + drivers, for example. +* Many user-space packages (for example i2c-tools) lack support for + 10-bit addresses. + +Note that 10-bit address devices are still pretty rare, so the limitations +listed above could stay for a long time, maybe even forever if nobody +needs them to be fixed. diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt index 079cb3df62c..41c8378c0b2 100644 --- a/Documentation/serial/serial-rs485.txt +++ b/Documentation/serial/serial-rs485.txt @@ -97,15 +97,23 @@ struct serial_rs485 rs485conf; - /* Set RS485 mode: */ + /* Enable RS485 mode: */ rs485conf.flags |= SER_RS485_ENABLED; + /* Set logical level for RTS pin equal to 1 when sending: */ + rs485conf.flags |= SER_RS485_RTS_ON_SEND; + /* or, set logical level for RTS pin equal to 0 when sending: */ + rs485conf.flags &= ~(SER_RS485_RTS_ON_SEND); + + /* Set logical level for RTS pin equal to 1 after sending: */ + rs485conf.flags |= SER_RS485_RTS_AFTER_SEND; + /* or, set logical level for RTS pin equal to 0 after sending: */ + rs485conf.flags &= ~(SER_RS485_RTS_AFTER_SEND); + /* Set rts delay before send, if needed: */ - rs485conf.flags |= SER_RS485_RTS_BEFORE_SEND; rs485conf.delay_rts_before_send = ...; /* Set rts delay after send, if needed: */ - rs485conf.flags |= SER_RS485_RTS_AFTER_SEND; rs485conf.delay_rts_after_send = ...; /* Set this flag if you want to receive data even whilst sending data */ |