diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 09:30:48 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 09:30:48 -0700 |
commit | 40aba218969914d1b225e742617adb921cf94eae (patch) | |
tree | 663ec9cdadbedec5f8eab754cbc590298c1d40be /Documentation/i2c/chips/pcf8575 | |
parent | b64ada6b23d4a305fb3ca59b79dd38707fc53b69 (diff) | |
parent | cfd550ed3d3bd509b475c7a9d425fc63bf843a7c (diff) |
Merge branch 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging
* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
i2c: Clearly mark ACPI drivers as such
i2c: Add driver for SMBus Control Method Interface
i2c-pnx: Correct use of request_region/request_mem_region
MAINTAINERS: Add maintainer for AT24 and PCA9564/PCA9665
i2c-piix4: Add AMD SB900 SMBus device ID
i2c/chips: Remove deprecated pcf8574 driver
i2c/chips: Remove deprecated pca9539 driver
i2c/chips: Remove deprecated pcf8575 driver
gpio/pcf857x: Copy i2c_device_id from old pcf8574 driver
i2c/scx200_acb: Provide more information on bus errors
i2c: Provide compatibility links for i2c adapters
i2c: Convert i2c adapters to bus devices
i2c: Convert i2c clients to a device type
i2c/tsl2550: Use combined SMBus transactions
i2c-taos-evm: Switch echo off to improve performance
i2c: Drop unused i2c_driver.id field
Diffstat (limited to 'Documentation/i2c/chips/pcf8575')
-rw-r--r-- | Documentation/i2c/chips/pcf8575 | 69 |
1 files changed, 0 insertions, 69 deletions
diff --git a/Documentation/i2c/chips/pcf8575 b/Documentation/i2c/chips/pcf8575 deleted file mode 100644 index 40b268eb276f..000000000000 --- a/Documentation/i2c/chips/pcf8575 +++ /dev/null @@ -1,69 +0,0 @@ -About the PCF8575 chip and the pcf8575 kernel driver -==================================================== - -The PCF8575 chip is produced by the following manufacturers: - - * Philips NXP - http://www.nxp.com/#/pip/cb=[type=product,path=50807/41735/41850,final=PCF8575_3]|pip=[pip=PCF8575_3][0] - - * Texas Instruments - http://focus.ti.com/docs/prod/folders/print/pcf8575.html - - -Some vendors sell small PCB's with the PCF8575 mounted on it. You can connect -such a board to a Linux host via e.g. an USB to I2C interface. Examples of -PCB boards with a PCF8575: - - * SFE Breakout Board for PCF8575 I2C Expander by RobotShop - http://www.robotshop.ca/home/products/robot-parts/electronics/adapters-converters/sfe-pcf8575-i2c-expander-board.html - - * Breakout Board for PCF8575 I2C Expander by Spark Fun Electronics - http://www.sparkfun.com/commerce/product_info.php?products_id=8130 - - -Description ------------ -The PCF8575 chip is a 16-bit I/O expander for the I2C bus. Up to eight of -these chips can be connected to the same I2C bus. You can find this -chip on some custom designed hardware, but you won't find it on PC -motherboards. - -The PCF8575 chip consists of a 16-bit quasi-bidirectional port and an I2C-bus -interface. Each of the sixteen I/O's can be independently used as an input or -an output. To set up an I/O pin as an input, you have to write a 1 to the -corresponding output. - -For more information please see the datasheet. - - -Detection ---------- - -There is no method known to detect whether a chip on a given I2C address is -a PCF8575 or whether it is any other I2C device, so you have to pass the I2C -bus and address of the installed PCF8575 devices explicitly to the driver at -load time via the force=... parameter. - -/sys interface --------------- - -For each address on which a PCF8575 chip was found or forced the following -files will be created under /sys: -* /sys/bus/i2c/devices/<bus>-<address>/read -* /sys/bus/i2c/devices/<bus>-<address>/write -where bus is the I2C bus number (0, 1, ...) and address is the four-digit -hexadecimal representation of the 7-bit I2C address of the PCF8575 -(0020 .. 0027). - -The read file is read-only. Reading it will trigger an I2C read and will hence -report the current input state for the pins configured as inputs, and the -current output value for the pins configured as outputs. - -The write file is read-write. Writing a value to it will configure all pins -as output for which the corresponding bit is zero. Reading the write file will -return the value last written, or -EAGAIN if no value has yet been written to -the write file. - -On module initialization the configuration of the chip is not changed -- the -chip is left in the state it was already configured in through either power-up -or through previous I2C write actions. |