[PATCH v2 0/7] cpufreq support for Raspberry Pi

Nicolas Saenz Julienne nsaenzjulienne at suse.de
Thu Jun 6 07:22:47 PDT 2019

Hi all,
this aims at adding cpufreq support to the Raspberry Pi family of

The series first factors out 'pllb' from clk-bcm2385 and creates a new
clk driver that operates it over RPi's firmware interface[1]. We are
forced to do so as the firmware 'owns' the pll and we're not allowed to
change through the register interface directly as we might race with the
over-temperature and under-voltage protections provided by the firmware.

Next it creates a minimal cpufreq driver that populates the CPU's opp
table, and registers cpufreq-dt. Which is needed as the firmware
controls the max and min frequencies available.

This was tested on a RPi3b+ and RPI2b, both using multi_v7_defconfig and
arm64's defconfig.

@Eric: Even though some things change, namely to properly support being
       built as a module, I still added your Acked-by as it didn't
       change the overall design. I hope it's OK.

That's all,
kind regards,

[1] https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface


Changes since v1:
  - Enabled by default on the whole family of devices
  - Added/Fixed module support
  - clk device now registered by firmware driver
  - raspberrypi-cpufreq device now registered by clk driver
  - Reimplemented clk rounding unsing determine_rate()
  - Enabled in configs for arm and arm64

Changes since RFC:
  - Move firmware clk device into own driver

Nicolas Saenz Julienne (7):
  clk: bcm2835: remove pllb
  clk: bcm283x: add driver interfacing with Raspberry Pi's firmware
  firmware: raspberrypi: register clk device
  cpufreq: add driver for Raspbery Pi
  clk: raspberrypi: register platform device for raspberrypi-cpufreq
  ARM: defconfig: enable cpufreq driver for RPi
  arm64: defconfig: enable cpufreq support for RPi3

 arch/arm/configs/bcm2835_defconfig    |   9 +
 arch/arm/configs/multi_v7_defconfig   |   2 +
 arch/arm64/configs/defconfig          |   2 +
 drivers/clk/bcm/Kconfig               |   7 +
 drivers/clk/bcm/Makefile              |   1 +
 drivers/clk/bcm/clk-bcm2835.c         |  28 +--
 drivers/clk/bcm/clk-raspberrypi.c     | 316 ++++++++++++++++++++++++++
 drivers/cpufreq/Kconfig.arm           |   8 +
 drivers/cpufreq/Makefile              |   1 +
 drivers/cpufreq/raspberrypi-cpufreq.c | 100 ++++++++
 drivers/firmware/raspberrypi.c        |  10 +
 11 files changed, 460 insertions(+), 24 deletions(-)
 create mode 100644 drivers/clk/bcm/clk-raspberrypi.c
 create mode 100644 drivers/cpufreq/raspberrypi-cpufreq.c


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