rtc: rtc-isl12057: fixes and alarm support

Hi,

This series includes six patches for Intersil ISL12057 driver.

- First patch is a fix for masking issues which dates back to driver inclusion. Even if those issues are not critical per se, the patch is a good candidate for stable down to 3.14.

- As suggested by Uwe, second patch adds proper support for century bit provided by the driver. This will allow to use the chip until 2199 if we manage to pass 2038.

- Following another comment by Uwe, third patch corrects the handling of oscillator failure bit.

- fourth patch fixes remaining places where 'isl' is used instead of the expected NASDAQ symbol for Intersil (i.e. isil) after commit 7a6540ca856ae ("ARM: mvebu: Change vendor prefix for Intersil Corporation to isil").

- As suggested by Mark, fifth patch improves failure reports by providing error code in dev_err() code.

- Sixth patch provides alarm support for Intersil ISL12057. This support was not added when the driver was initially pushed in 3.14 kernel due to the inability to check interrupt support. After some soldering, this tests have been performed. More time was also spent on testing.

Comments are welcome,

Cheers,

a+

Changes since v0:

- Kept an "isl,isl12057" compatible string for out-of-tree users w/ a comment this is obsolete as suggested by Mark and Uwe.
- Changed function name from toggle to update for helper as suggested by Uwe and Guenter.
- As suggested by Mark, added a patch to improve error reporting and log the error code
- Driver now handles lack of IRQ correctly by returning -ENOTTY if alarm_irq_enable() handler is called and no IRQ has been provided. Additionally, the device is marked as not supporting UIE when no IRQ is available.
- Following comments from Mark, added a local copy of IRQ (or lack of) in driver's private structure
- Following comments from Mark, removed a useless call to free_irq() (driver makes use of devm_request_threaded_irq() which makes the call pointless)
- Following report from Uwe, added a patch to handle oscillator failure bit properly
- Following suggestions from Uwe, added a patch to handle the century bit the device provides

Arnaud Ebalard (6):
rtc: rtc-isl12057: fix masking of register values
rtc: rtc-isl12057: add support for century bit
rtc: rtc-isl12057: add proper handling of oscillator failure bit
rtc: rtc-isl12057: fix isil vs isl naming for intersil
rtc: rtc-isl12057: report error code upon failure in dev_err() calls
rtc: rtc-isl12057: add alarm support to Intersil ISL12057 RTC driver

 .../devicetree/bindings/i2c/trivial-devices.txt    |   2 +-
 .../devicetree/bindings/vendor-prefixes.txt        |   2 +-
 drivers/rtc/rtc-isl12057.c                         | 408 +++++++++++++++++++--
 3 files changed, 377 insertions(+), 35 deletions(-)

2.1.1