[PATCH v2 0/3] clk: Implement a clock request API

Maxime Ripard maxime at cerno.tech
Tue Sep 14 09:35:12 UTC 2021


Hi,

This is a follow-up of the discussion here:
https://lore.kernel.org/linux-clk/20210319150355.xzw7ikwdaga2dwhv@gilmour/

This implements a mechanism to raise and lower clock rates based on consumer
workloads, with an example of such an implementation for the RaspberryPi4 HDMI
controller.

There's a couple of things worth discussing:

  - The name is in conflict with clk_request_rate, and even though it feels
    like the right name to me, we should probably avoid any confusion

  - The code so far implements a policy of always going for the lowest rate
    possible. While we don't have an use-case for something else, this should
    maybe be made more flexible?

Let me know what you think
Maxime

Changes from v1:
  - Return NULL in clk_request_start if clk pointer is NULL
  - Test for clk_req pointer in clk_request_done
  - Add another user in vc4
  - Rebased on top of v5.15-rc1

Dom Cobley (1):
  drm/vc4: hvs: Convert to the new clock request API

Maxime Ripard (2):
  clk: Introduce a clock request API
  drm/vc4: hdmi: Convert to the new clock request API

 drivers/clk/clk.c              | 126 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/vc4/vc4_hdmi.c |  15 ++--
 drivers/gpu/drm/vc4/vc4_hdmi.h |   3 +
 drivers/gpu/drm/vc4/vc4_kms.c  |   5 +-
 include/linux/clk.h            |   4 ++
 5 files changed, 146 insertions(+), 7 deletions(-)

-- 
2.31.1



More information about the dri-devel mailing list