driver proposal

[Krassimir Slavchev]

Hi,

 From the datasheet:
The PCF8563 is a CMOS real time clock/calendar optimized for low power
consumption. A programmable clock output, interrupt output and 
voltage-low detector
are also provided. All address and data are transferred serially via a 
two-line
bidirectional I2C-bus. Maximum bus speed is 400 kbit/s. The built-in 
word address
register is incremented automatically after each written or read data byte.

There is the driver:
http://mnemonic.bulinfo.net/~krassi/pcf8563.c

The chip uses only 0xa2 as a slave address but on my arm board the TWI 
controller rewrites it to 0x51, so device hints can be used:

hint.pcf8563.0.at="iicbus0"
hint.pcf8563.0.addr=0x51

I will be very happy if anyone commit this driver.

Best Regards