On 04/10/2023 01:31, Dmitry Baryshkov wrote:
clk_rcg2_shared_ops implements support for the case of the RCG which
must not be completely turned off. However its design has one major
drawback: it doesn't allow us to properly implement the is_enabled
callback, which causes different kinds of misbehaviour from the CCF.
Follow the idea behind clk_regmap_phy_mux_ops and implement the new
clk_rcg2_parked_ops. It also targets the clocks which must not be fully
switched off (and shared most of the implementation with
clk_rcg2_shared_ops). The major difference is that it requires that the
parent map doesn't conain the safe (parked) clock source. Instead if the
CFG_REG register points to the safe source, the clock is considered to
be disabled.
Why not have a new bit in .flags ?
Instead of lying about the clock being off, mark the clock as "parked",
or "safe parked" or whatever term we choose for it ?
I feel 'disabled' should mean disabled and 'enabled' should me enabled
when I read a value from debugfs and if we are parking a clock it should
have a clear means of being flagged as a clock that should be parked.
An example. I recently inherited some autogenerated code for camcc on
sc8280xp.
One of the clocks is marked as CLK_IS_CRITICAL by the autogen code
meaning "never switch off" but CLK_IS_CRITICAL stops the camcc driver
from doing runtime pm_ops to power collapse.
The solution I have is to remove CLK_IS_CRITICAL and to hard-code in
probe() the clock to always on.
But if we had a CLK_DISABLE_SAFE_PARK flag - then not just for rcg but
for branch clocks we could differentiate away from hard-coded always on
in probe...
?
---
bod
