Now that we have a devm variant of rtc_device_register, switch to it.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
The RTC controls the input source of the main 32kHz oscillator in the
system, feeding it to the clock unit too.
By default, this is using an internal, very inaccurate (+/- 30%)
oscillator with a divider to make it roughly around 32kHz. This is however
quite impractical for the RTC, since our time will not be tracked properly.
Since this oscillator is an input of the main clock unit, and since that
clock unit will be probed using CLK_OF_DECLARE, we have to use it as well,
leading to a two stage probe: one to enable the clock, the other one to
enable the RTC.
There is also a slight change in the binding that is required (and should
have been from the beginning), since we'll need a phandle to the external
oscillator used on that board. We support the old binding by not allowing
to switch to the external oscillator and only using the internal one (which
was the previous behaviour) in the case where we're missing that phandle.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
The RTC is clocked from either an internal, imprecise, oscillator or an
external one, which is usually much more accurate.
The difference perceived between the time elapsed and the time reported by
the RTC is in a 10% scale, which prevents the RTC from being useful at all.
Fortunately, the external oscillator is reported to be mandatory in the
Allwinner datasheet, so we can just switch to it.
Cc: stable@vger.kernel.org
Fixes: 9765d2d943 ("rtc: sun6i: Add sun6i RTC driver")
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Some registers have a read-modify-write access pattern that are not atomic.
Add some locking to prevent from concurrent accesses.
Cc: stable@vger.kernel.org
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Since we have to provide the clock very early on, the RTC driver cannot be
built as a module. Make sure that won't happen.
Cc: stable@vger.kernel.org
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This patch introduces the driver for the RTC in the Allwinner A31 and
A23 SoCs.
Unlike the RTC found in A10/A20 SoCs, which was part of the timer, the
RTC in A31/A23 are a separate hardware block, which also contain a few
controls for the RTC block hardware (a regulator and RTC block GPIO pin
latches), while also having separate interrupts for the alarms.
The hardware is different enough to make a different driver for it.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Varka Bhadram <varkabhadram@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Maxime Ripard