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Subject[PATCH v2 0/7] cpufreq support for Raspberry Pi
Date
Hi all,
this aims at adding cpufreq support to the Raspberry Pi family of
boards.

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,
Nicolas

[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

--
2.21.0

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