linux-kernel - [PATCH 0/2] clk: Implement a clock request API

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Message-Id: <20210413101320.321584-1-maxime@cerno.tech>
Date:   Tue, 13 Apr 2021 12:13:18 +0200
From:   Maxime Ripard <maxime@...no.tech>
To:     Mike Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        dri-devel@...ts.freedesktop.org,
        Daniel Vetter <daniel.vetter@...el.com>,
        David Airlie <airlied@...ux.ie>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Maxime Ripard <maxime@...no.tech>
Cc:     Eric Anholt <eric@...olt.net>, Daniel Vetter <daniel@...ll.ch>,
        linux-kernel@...r.kernel.org, Russell King <linux@...linux.org.uk>,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Phil Elwell <phil@...pberrypi.com>,
        Tim Gover <tim.gover@...pberrypi.com>,
        Dom Cobley <dom@...pberrypi.com>, linux-clk@...r.kernel.org,
        Maxime Ripard <mripard@...nel.org>
Subject: [PATCH 0/2] clk: Implement a clock request API

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

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

 drivers/clk/clk.c              | 121 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/vc4/vc4_hdmi.c |  19 ++++--
 drivers/gpu/drm/vc4/vc4_hdmi.h |   3 +
 include/linux/clk.h            |   4 ++
 4 files changed, 140 insertions(+), 7 deletions(-)

-- 
2.30.2