diff options
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/DocBook/kernel-api.tmpl | 55 | ||||
-rw-r--r-- | Documentation/feature-removal-schedule.txt | 7 | ||||
-rw-r--r-- | Documentation/i2c/busses/i2c-i801 | 4 | ||||
-rw-r--r-- | Documentation/i2c/busses/i2c-piix4 | 2 | ||||
-rw-r--r-- | Documentation/i2c/busses/i2c-taos-evm | 46 | ||||
-rw-r--r-- | Documentation/i2c/chips/max6875 | 2 | ||||
-rw-r--r-- | Documentation/i2c/chips/x1205 | 38 | ||||
-rw-r--r-- | Documentation/i2c/summary | 2 | ||||
-rw-r--r-- | Documentation/i2c/writing-clients | 2 |
9 files changed, 113 insertions, 45 deletions
diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl index 8c5698a..46bcff2 100644 --- a/Documentation/DocBook/kernel-api.tmpl +++ b/Documentation/DocBook/kernel-api.tmpl @@ -643,6 +643,60 @@ X!Idrivers/video/console/fonts.c !Edrivers/spi/spi.c </chapter> + <chapter id="i2c"> + <title>I<superscript>2</superscript>C and SMBus Subsystem</title> + + <para> + I<superscript>2</superscript>C (or without fancy typography, "I2C") + is an acronym for the "Inter-IC" bus, a simple bus protocol which is + widely used where low data rate communications suffice. + Since it's also a licensed trademark, some vendors use another + name (such as "Two-Wire Interface", TWI) for the same bus. + I2C only needs two signals (SCL for clock, SDA for data), conserving + board real estate and minimizing signal quality issues. + Most I2C devices use seven bit addresses, and bus speeds of up + to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet + found wide use. + I2C is a multi-master bus; open drain signaling is used to + arbitrate between masters, as well as to handshake and to + synchronize clocks from slower clients. + </para> + + <para> + The Linux I2C programming interfaces support only the master + side of bus interactions, not the slave side. + The programming interface is structured around two kinds of driver, + and two kinds of device. + An I2C "Adapter Driver" abstracts the controller hardware; it binds + to a physical device (perhaps a PCI device or platform_device) and + exposes a <structname>struct i2c_adapter</structname> representing + each I2C bus segment it manages. + On each I2C bus segment will be I2C devices represented by a + <structname>struct i2c_client</structname>. Those devices will + be bound to a <structname>struct i2c_driver</structname>, + which should follow the standard Linux driver model. + (At this writing, a legacy model is more widely used.) + There are functions to perform various I2C protocol operations; at + this writing all such functions are usable only from task context. + </para> + + <para> + The System Management Bus (SMBus) is a sibling protocol. Most SMBus + systems are also I2C conformant. The electrical constraints are + tighter for SMBus, and it standardizes particular protocol messages + and idioms. Controllers that support I2C can also support most + SMBus operations, but SMBus controllers don't support all the protocol + options that an I2C controller will. + There are functions to perform various SMBus protocol operations, + either using I2C primitives or by issuing SMBus commands to + i2c_adapter devices which don't support those I2C operations. + </para> + +!Iinclude/linux/i2c.h +!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info +!Edrivers/i2c/i2c-core.c + </chapter> + <chapter id="splice"> <title>splice API</title> <para>) @@ -654,4 +708,5 @@ X!Idrivers/video/console/fonts.c !Ffs/splice.c </chapter> + </book> diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 3a159da..281458b 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -330,3 +330,10 @@ Who: Tejun Heo <htejun@gmail.com> --------------------------- +What: Legacy RTC drivers (under drivers/i2c/chips) +When: November 2007 +Why: Obsolete. We have a RTC subsystem with better drivers. +Who: Jean Delvare <khali@linux-fr.org> + +--------------------------- + diff --git a/Documentation/i2c/busses/i2c-i801 b/Documentation/i2c/busses/i2c-i801 index c34f0db..fe6406f 100644 --- a/Documentation/i2c/busses/i2c-i801 +++ b/Documentation/i2c/busses/i2c-i801 @@ -5,8 +5,8 @@ Supported adapters: '810' and '810E' chipsets) * Intel 82801BA (ICH2 - part of the '815E' chipset) * Intel 82801CA/CAM (ICH3) - * Intel 82801DB (ICH4) (HW PEC supported, 32 byte buffer not supported) - * Intel 82801EB/ER (ICH5) (HW PEC supported, 32 byte buffer not supported) + * Intel 82801DB (ICH4) (HW PEC supported) + * Intel 82801EB/ER (ICH5) (HW PEC supported) * Intel 6300ESB * Intel 82801FB/FR/FW/FRW (ICH6) * Intel 82801G (ICH7) diff --git a/Documentation/i2c/busses/i2c-piix4 b/Documentation/i2c/busses/i2c-piix4 index 7cbe43f..fa0c786 100644 --- a/Documentation/i2c/busses/i2c-piix4 +++ b/Documentation/i2c/busses/i2c-piix4 @@ -6,7 +6,7 @@ Supported adapters: Datasheet: Publicly available at the Intel website * ServerWorks OSB4, CSB5, CSB6 and HT-1000 southbridges Datasheet: Only available via NDA from ServerWorks - * ATI IXP200, IXP300, IXP400 and SB600 southbridges + * ATI IXP200, IXP300, IXP400, SB600 and SB700 southbridges Datasheet: Not publicly available * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge Datasheet: Publicly available at the SMSC website http://www.smsc.com diff --git a/Documentation/i2c/busses/i2c-taos-evm b/Documentation/i2c/busses/i2c-taos-evm new file mode 100644 index 0000000..9146e33 --- /dev/null +++ b/Documentation/i2c/busses/i2c-taos-evm @@ -0,0 +1,46 @@ +Kernel driver i2c-taos-evm + +Author: Jean Delvare <khali@linux-fr.org> + +This is a driver for the evaluation modules for TAOS I2C/SMBus chips. +The modules include an SMBus master with limited capabilities, which can +be controlled over the serial port. Virtually all evaluation modules +are supported, but a few lines of code need to be added for each new +module to instantiate the right I2C chip on the bus. Obviously, a driver +for the chip in question is also needed. + +Currently supported devices are: + +* TAOS TSL2550 EVM + +For addtional information on TAOS products, please see + http://www.taosinc.com/ + + +Using this driver +----------------- + +In order to use this driver, you'll need the serport driver, and the +inputattach tool, which is part of the input-utils package. The following +commands will tell the kernel that you have a TAOS EVM on the first +serial port: + +# modprobe serport +# inputattach --taos-evm /dev/ttyS0 + + +Technical details +----------------- + +Only 4 SMBus transaction types are supported by the TAOS evaluation +modules: +* Receive Byte +* Send Byte +* Read Byte +* Write Byte + +The communication protocol is text-based and pretty simple. It is +described in a PDF document on the CD which comes with the evaluation +module. The communication is rather slow, because the serial port has +to operate at 1200 bps. However, I don't think this is a big concern in +practice, as these modules are meant for evaluation and testing only. diff --git a/Documentation/i2c/chips/max6875 b/Documentation/i2c/chips/max6875 index 96fec56..a0cd8af 100644 --- a/Documentation/i2c/chips/max6875 +++ b/Documentation/i2c/chips/max6875 @@ -99,7 +99,7 @@ And then read the data or - count = i2c_smbus_read_i2c_block_data(fd, 0x84, buffer); + count = i2c_smbus_read_i2c_block_data(fd, 0x84, 16, buffer); The block read should read 16 bytes. 0x84 is the block read command. diff --git a/Documentation/i2c/chips/x1205 b/Documentation/i2c/chips/x1205 deleted file mode 100644 index 09407c9..0000000 --- a/Documentation/i2c/chips/x1205 +++ /dev/null @@ -1,38 +0,0 @@ -Kernel driver x1205 -=================== - -Supported chips: - * Xicor X1205 RTC - Prefix: 'x1205' - Addresses scanned: none - Datasheet: http://www.intersil.com/cda/deviceinfo/0,1477,X1205,00.html - -Authors: - Karen Spearel <kas11@tampabay.rr.com>, - Alessandro Zummo <a.zummo@towertech.it> - -Description ------------ - -This module aims to provide complete access to the Xicor X1205 RTC. -Recently Xicor has merged with Intersil, but the chip is -still sold under the Xicor brand. - -This chip is located at address 0x6f and uses a 2-byte register addressing. -Two bytes need to be written to read a single register, while most -other chips just require one and take the second one as the data -to be written. To prevent corrupting unknown chips, the user must -explicitely set the probe parameter. - -example: - -modprobe x1205 probe=0,0x6f - -The module supports one more option, hctosys, which is used to set the -software clock from the x1205. On systems where the x1205 is the -only hardware rtc, this parameter could be used to achieve a correct -date/time earlier in the system boot sequence. - -example: - -modprobe x1205 probe=0,0x6f hctosys=1 diff --git a/Documentation/i2c/summary b/Documentation/i2c/summary index aea60bf..003c731 100644 --- a/Documentation/i2c/summary +++ b/Documentation/i2c/summary @@ -67,7 +67,6 @@ i2c-proc: The /proc/sys/dev/sensors interface for device (client) drivers Algorithm drivers ----------------- -i2c-algo-8xx: An algorithm for CPM's I2C device in Motorola 8xx processors (NOT BUILT BY DEFAULT) i2c-algo-bit: A bit-banging algorithm i2c-algo-pcf: A PCF 8584 style algorithm i2c-algo-ibm_ocp: An algorithm for the I2C device in IBM 4xx processors (NOT BUILT BY DEFAULT) @@ -81,6 +80,5 @@ i2c-pcf-epp: PCF8584 on a EPP parallel port (uses i2c-algo-pcf) (NOT mkpatch i2c-philips-par: Philips style parallel port adapter (uses i2c-algo-bit) i2c-adap-ibm_ocp: IBM 4xx processor I2C device (uses i2c-algo-ibm_ocp) (NOT BUILT BY DEFAULT) i2c-pport: Primitive parallel port adapter (uses i2c-algo-bit) -i2c-rpx: RPX board Motorola 8xx I2C device (uses i2c-algo-8xx) (NOT BUILT BY DEFAULT) i2c-velleman: Velleman K8000 parallel port adapter (uses i2c-algo-bit) diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index 3d8d36b..2c17003 100644 --- a/Documentation/i2c/writing-clients +++ b/Documentation/i2c/writing-clients @@ -571,7 +571,7 @@ SMBus communication u8 command, u8 length, u8 *values); extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client * client, - u8 command, u8 *values); + u8 command, u8 length, u8 *values); These ones were removed in Linux 2.6.10 because they had no users, but could be added back later if needed: |