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authorWolfram Sang <w.sang@pengutronix.de>2009-09-18 22:45:48 +0200
committerJean Delvare <khali@linux-fr.org>2009-09-18 22:45:48 +0200
commit8f67eeb0b44cde19216955975ffef8513a87c0c0 (patch)
treec848851a7494b72038f24beca93362755567e8cc /Documentation
parent4ba2ccb83e03077bb94f8848ee573f1e27cea969 (diff)
downloadop-kernel-dev-8f67eeb0b44cde19216955975ffef8513a87c0c0.zip
op-kernel-dev-8f67eeb0b44cde19216955975ffef8513a87c0c0.tar.gz
i2c/chips: Remove deprecated pcf8575 driver
The pcf8575 driver in drivers/i2c/chips which just exports its register to sysfs is superseded by drivers/gpio/pcf857x.c which properly uses the gpiolib. As this driver has been deprecated for more than a year, finally remove it. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Cc: Bart Van Assche <bart.vanassche@gmail.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/i2c/chips/pcf857569
1 files changed, 0 insertions, 69 deletions
diff --git a/Documentation/i2c/chips/pcf8575 b/Documentation/i2c/chips/pcf8575
deleted file mode 100644
index 40b268e..0000000
--- 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.
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