Add I2C driver for MCP3021 that is an ADC chip from Microchip.
The MCP3021 is a successive approximation A/D converter (ADC)
with 10-bit resolution.
The driver export the value of Vin to sysfs, the voltage unit is
mV. Through the sysfs interface, lm-sensors tool can also display
Vin voltage.
Signed-off-by: NMingkai Hu <Mingkai.hu@freescale.com>
Signed-off-by: NXie Xiaobo <X.Xie@freescale.com>
Signed-off-by: NJean Delvare <khali@linux-fr.org>