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: 0x74 - 0x77 Datasheet: http://www.semiconductors.philips.com/acrobat/datasheets/PCA9539_2.pdf Author: Ben Gardner 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. 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