The CPU cluster PLLs on the A80 are NP clocks that are atypical in two ways:
- The P factor is 1 bit wide, and translates to a /1 or /4 divider.
- The P factor should only be used for output frequencies lower than
288 MHz. The N factor has a lower limit of 12, which likely contributed
to this extra divider.
According to the user manual, the clocks can only go as low as 200 MHz.
The vendor BSP kernel does not even define operating points below 360
MHz for these clocks. The lower end for cpufreq in the vendor kernel is
even higher. The mainline Linux kernel doesn't support cpufreq for the
A80 at the moment. This means the lower frequencies are untested, and
will likely remain unused.
The new sunxi-ng style clocks don't support the quirks listed above.
Instead of trying to work the quirks in for something of little usage,
we re-model the clocks into N-type multipler clocks, with P fixed at 1.
At probe time we check if P is set to 4, and fix it up if needed. This
is highly unlikely though.
Fixes: b8eb71dcdd ("clk: sunxi-ng: Add A80 CCU")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Add support for the main clock unit found in the A80. Some clocks were
not documented in the released user manual, but were found in the
official kernel from Allwinner. These include controls for the I2S,
SPDIF, SATA, and eDP blocks.
Note that on the A80, some subsystems have separate clock controllers
downstream of the main clock unit. These include the MMC, USB, and
display engine subsystems.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
