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Diffstat (limited to 'Documentation/i2c/chips')
-rw-r--r-- | Documentation/i2c/chips/pca9539 | 58 | ||||
-rw-r--r-- | Documentation/i2c/chips/pcf8574 | 65 | ||||
-rw-r--r-- | Documentation/i2c/chips/pcf8575 | 69 |
3 files changed, 0 insertions, 192 deletions
diff --git a/Documentation/i2c/chips/pca9539 b/Documentation/i2c/chips/pca9539 deleted file mode 100644 index 6aff890088b..00000000000 --- a/Documentation/i2c/chips/pca9539 +++ /dev/null @@ -1,58 +0,0 @@ -Kernel driver pca9539 -===================== - -NOTE: this driver is deprecated and will be dropped soon, use -drivers/gpio/pca9539.c instead. - -Supported chips: - * Philips PCA9539 - Prefix: 'pca9539' - Addresses scanned: none - Datasheet: - http://www.semiconductors.philips.com/acrobat/datasheets/PCA9539_2.pdf - -Author: Ben Gardner <bgardner@wabtec.com> - - -Description ------------ - -The Philips PCA9539 is a 16 bit low power I/O device. -All 16 lines can be individually configured as an input or output. -The input sense can also be inverted. -The 16 lines are split between two bytes. - - -Detection ---------- - -The PCA9539 is difficult to detect and not commonly found in PC machines, -so you have to pass the I2C bus and address of the installed PCA9539 -devices explicitly to the driver at load time via the force=... parameter. - - -Sysfs entries -------------- - -Each is a byte that maps to the 8 I/O bits. -A '0' suffix is for bits 0-7, while '1' is for bits 8-15. - -input[01] - read the current value -output[01] - sets the output value -direction[01] - direction of each bit: 1=input, 0=output -invert[01] - toggle the input bit sense - -input reads the actual state of the line and is always available. -The direction defaults to input for all channels. - - -General Remarks ---------------- - -Note that each output, direction, and invert entry controls 8 lines. -You should use the read, modify, write sequence. -For example. to set output bit 0 of 1. - val=$(cat output0) - val=$(( $val | 1 )) - echo $val > output0 - diff --git a/Documentation/i2c/chips/pcf8574 b/Documentation/i2c/chips/pcf8574 deleted file mode 100644 index 235815c075f..00000000000 --- a/Documentation/i2c/chips/pcf8574 +++ /dev/null @@ -1,65 +0,0 @@ -Kernel driver pcf8574 -===================== - -Supported chips: - * Philips PCF8574 - Prefix: 'pcf8574' - Addresses scanned: none - Datasheet: Publicly available at the Philips Semiconductors website - http://www.semiconductors.philips.com/pip/PCF8574P.html - - * Philips PCF8574A - Prefix: 'pcf8574a' - Addresses scanned: none - Datasheet: Publicly available at the Philips Semiconductors website - http://www.semiconductors.philips.com/pip/PCF8574P.html - -Authors: - Frodo Looijaard <frodol@dds.nl>, - Philip Edelbrock <phil@netroedge.com>, - Dan Eaton <dan.eaton@rocketlogix.com>, - Aurelien Jarno <aurelien@aurel32.net>, - Jean Delvare <khali@linux-fr.org>, - - -Description ------------ -The PCF8574(A) is an 8-bit I/O expander for the I2C bus produced by Philips -Semiconductors. It is designed to provide a byte I2C interface to up to 16 -separate devices (8 x PCF8574 and 8 x PCF8574A). - -This device consists of a quasi-bidirectional port. Each of the eight I/Os -can be independently used as an input or output. To setup an I/O as an -input, you have to write a 1 to the corresponding output. - -For more informations see the datasheet. - - -Accessing PCF8574(A) via /sys interface -------------------------------------- - -The PCF8574(A) is plainly impossible to detect ! Stupid chip. -So, you have to pass the I2C bus and address of the installed PCF857A -and PCF8574A devices explicitly to the driver at load time via the -force=... parameter. - -On detection (i.e. insmod, modprobe et al.), directories are being -created for each detected PCF8574(A): - -/sys/bus/i2c/devices/<0>-<1>/ -where <0> is the bus the chip was detected on (e. g. i2c-0) -and <1> the chip address ([20..27] or [38..3f]): - -(example: /sys/bus/i2c/devices/1-0020/) - -Inside these directories, there are two files each: -read and write (and one file with chip name). - -The read file is read-only. Reading gives you the current I/O input -if the corresponding output is set as 1, otherwise the current output -value, that is to say 0. - -The write file is read/write. Writing a value outputs it on the I/O -port. Reading returns the last written value. As it is not possible -to read this value from the chip, you need to write at least once to -this file before you can read back from it. diff --git a/Documentation/i2c/chips/pcf8575 b/Documentation/i2c/chips/pcf8575 deleted file mode 100644 index 40b268eb276..00000000000 --- 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. |