clk: Provide option to unprepare unused clocks at late init

From: Ulf Hansson <[email protected]>

The disable_unused sequence executed at late init, is already handling the fast unused ungated clocks to be gated. This patchset extends this sequence to include the slow unused prepared clocks to be unprepared.

The default behavior will not change in this patchset. To unprepare unused clocks during the disable_unused sequence, the clk_hw needs to implement the new optional callback, is_prepared.

The motivation for this patchset is to save power. Clocks that is from bootloaders prepared|enabled, but not used should be unprepared|disabled.

Patch 4 is specific for ux500, which implements the is_prepared callback for it's PRMCU clocks.

Note that patch 1-3 has been sent earlier, but since a proof of concept patch could be useful, as patch 4 is, the hole patchset is resent.

Ulf Hansson (4):
clk: Introduce optional is_prepared callback
clk: Unprepare the unused prepared slow clocks at late init
clk: Introduce optional unprepare_unused callback
clk: ux500: Support is_prepared callback for clk-prcmu

 drivers/clk/clk.c             |   53 ++++++++++++++++
 drivers/clk/ux500/clk-prcmu.c |  134 ++++++++++++++++++++++++-----------------
 include/linux/clk-provider.h  |   11 ++++
 3 files changed, 144 insertions(+), 54 deletions(-)

Signature · 1 line

1.7.10