TWL4030 Real-Time Clock (v2)

Hi,

the following patch adds support for Real-Time Clock device which is an internal subdevice of TWL4030 chip. Issues found by Trilok in previous patch are fixed.

The driver is based on TI's one from 2.6.14 tree. Comparing with TI's driver, this driver misses periodic IRQ functionality (RTC_IRQP_..., RTC_PIE_... ), since TWL4030 RTC hardware supports too large periods (1s/1m/1h/1d) to be set via frequiencies (Hz) except 1s period which is 1Hz and is already supported as update IRQs. To support 1m/1h/1d interrups, probably new ioctls should be added.

Known issue:

The alarm IRQ doesn't work after power reset until RTC time (RTC_SET_TIME) is not set, the issue is also observed with original TI's driver.

Regards,
Dmitry