Hi,
On 7/20/26 18:40, Casey Connolly wrote:
This series introduces support for the Linux Common Clock framework in
U-Boot, when enabled it replaces UCLASS_CLK entirely, instead offering
the typical clock provider API from Linux. This has the significant
advantage of allowing one "udevice" to provide an arbitrary number
of clocks without the need to populate U-Boot driver model with dummy
devices.
Historically, U-Boots clock support has focused on being small and
simple, allowing platforms to configure the clocks they need to boot.
But as we support more modern SoCs it's become clear that the existing
API doesn't scale as we need to be able to calculate clock rates, handle
reparenting, and other more complicated configurations. Rather than
trying to re-invent the wheel here (which would likely never leave us
with a truly satisfactory solution) adopting the Linux API solves a
whole host of problems in U-Boot.
With the Linux CCF, complicated Linux clock drivers can now be adopted
with relative ease rather than having to painfully rewrite them to work
in U-Boots limited clock model. This also drastically simplifies the
bringup process for new platforms.
To offer an example, the DSI PHY devices on most Qualcomm platforms
have their own VCO, PLL, dividers, and muxes which are programmed
based on the pixel clock of the display, if it's using D-phy or
C-phy, display stream compression, etc. This isn't directly modelled
in devicetree though since the PHY clock outputs are routed into the
"dispcc" block which is what the DSI controller itself sees. Modelling
the relationship between the pixel/byte clocks in dispcc and their
parents in the phy must be handled by the clock framework and though
assigned-clock-parents, something that U-Boots existing clock framework
simply doesn't support. Additionally, dual-DSI panels are even more
annoying since both sets of pixel/byte clocks are sourced from only one
of the PHYs.
U-Boot did already have some very limited support for "CCF", however
this is essentially just using the driver model to maintain the clock
tree and registering a device for each clock. This simply doesn't
scale well for the huge number of clocks on modern platforms and still
requires significant effort to port drivers from Linux.
There is one notable limitation with the full CCF port, since it
requires the entire clock tree to be modelled before it can actually
manage any clocks it isn't feasible to run pre-relocation making it
unsuitable for platforms that require clocks at this point. My hope is
that we can continue to reduce the complexity of U-Boots pre-relocation
stage to mitigate this issue, but since some platforms are already using
CONFIG_SKIP_EARLY_DM I hope this won't be a blocking issue.
When it comes to U-Boot SPL, it likely doesn't make sense to expect to
use CCF in that environment. Since the scope of SPL is so much smaller
it should still be acceptable to use UCLASS_CLK here and only build with
CCF for full U-Boot images.
-- Overview --
This series contains a few preparatory patches to align U-Boots
existing clock API with upstream and rename clk_ops to clk_ops_uboot to
differentiate UCLASS_CLK ops.
The generic CCF mux/div/fixed clock drivers are in drivers/clk/ccf along
with the CCF core.
Sandbox also gets CCF_FULL support for the purposes of testing.
Lastly, the Qualcomm clock drivers from Linux are ported over with
minimal changes to enable CCF support on the SM8650 platform, this will
be expanded in the future to other Qualcomm platforms. This demonstrates
the ease of porting Linux drivers and acts as a template that others
can follow.
-- Architecture --
The CCF port is fairly straightforward, clk-uclass.c has some its common
API split out into clk-common.c which either calls into clk-uclass or
ccf/clk.c based on the configuration. To keep things simple, CLK_UCLASS
is completely unsupported when CCF is enabled, by not building
clk-uclass.c we don't provide any support for non-CCF clocks and they
won't show up in the device model at runtime.
Devices that provide clocks can be of any uclass, they will be probed
via ofnode lookup and should register their clocks with CCF (via the
typical clk_register helpers) during probe.
Clock consumers still work the same way, although internal API
differences may require changes to some drivers such as the UFS fixes in
this series. Notably it may be necessary to actually call clk_set_rate()
with a suitable rate, I think it's safe to say these calls being
missing and relying on the clock driver to pick a suitable rate is a bug
regardless of CCF.
-- Merging and maintenance --
Given the scope and complexity of this change and that it's entirely
opt-in, I'm hopeful that we can focus on issues that are important to
solve before this can be merged, and focus on improving any rough edges
after the fact. This will also make it easier for others to try it out
and investigate using CCF_FULL for their platforms.
In the short-medium term I'm happy to maintain this port and help others
who are interested in using it. However I very much invite anyone with
an interest in this to co-maintain it or take it over in the future.
I previously sent an RFC for this which can be found below, it has gone
through some significant rework since then and quite a bit of testing
locally as I've used this as the basis for Qualcomm display bringup.
https://lore.kernel.org/u-boot/[email protected]/
---
Casey Connolly (36):
clk: move U-Boot CCF to clk/uccf
clk: rename clk_ops to clk_ops_uboot
clk: move fixed clocks to clk/basic
clk: make clk_set_rate() return signed long
clk: make clk_get_parent_rate return signed long
clk: compat: add clk (un)prepare and associated functions
dm: ofnode: fix parse_phandle_with_args API
clk: import full CCF from Linux
clk: move clock flags to common clk-provider.h
clk/ccf: adapt clk-conf for U-Boot
clk/ccf: adapt CCF core for U-Boot
clk/ccf: adapt CCF generic clocks for U-Boot
clk: split clk-uclass.c into clk-common.c
clk/common: add CCF_FULL support
clk/ccf: optimise orphan clock handling
clk/ccf: debug log enable/disable calls
cmd/clk: add CCF_FULL support
doc: describe Common Clock Framework
clk/sandbox: add a CCF_FULL port of clk_sandbox
clk: sandbox: fix set_rate and move to clk/basic
clk/ccf: add CCF_FULL port of clk_sandbox
test: dm: adjust clk tests for CCF_FULL
configs: add sandbox CCF_FULL defconfig
CI: add sandbox64_ccf_full
MAINTAINERS: add entry for CCF port
clk/qcom: move existing clock drivers to clk/qcom/basic
clk/qcom: drop in Linux Qualcomm CCF drivers
clk/qcom/ccf: drop in Linux rpmh clock driver
clk/qcom/ccf: add sm8650 GCC, dispcc and tcsrcc.
clk/qcom/ccf: add uboot common code
clk/qcom/ccf: adapt common, gdsc, and reset code for U-Boot
clk/qcom/ccf: adapt clocks for U-Boot
clk/qcom/ccf: adapt sm8650 clock drivers for U-Boot
ufs: qcom: use clk_prepare_enable_bulk()
qcom_sm8650_defconfig: enable CCF_FULL
ufs: qcom: fix core clk max rate setting
I tried to apply it to v2026.10-rc1 but it doesn't apply cleanly,
what are the dependencies ?
I'll probably try to port the Linux Amlogic clock drivers with the
CCF FULL, it should probably work 1:1 since we mimic the Linux
behviour with the basic U-Boot clock driver.
Also please share a branch from where to pull the changes for such large
patchsets.
Thanks,
Neil
.gitlab-ci.yml | 5 +
MAINTAINERS | 7 +
arch/arm/cpu/armv7/bcm281xx/clk-core.c | 8 +-
arch/arm/cpu/armv7/bcm281xx/clk-core.h | 14 +-
arch/sandbox/dts/test.dts | 4 +-
arch/sandbox/include/asm/clk.h | 2 +-
cmd/clk.c | 21 +-
configs/qcom_sm8650_defconfig | 1 +
configs/sandbox64_ccf_full_defconfig | 5 +
doc/api/clk.rst | 25 +
doc/develop/ccf.rst | 35 +
doc/develop/index.rst | 1 +
drivers/clk/Kconfig | 54 +-
drivers/clk/Makefile | 21 +-
drivers/clk/adi/clk-adi-pll.c | 2 +-
drivers/clk/adi/clk-shared.c | 4 +-
drivers/clk/adi/clk.h | 2 +-
drivers/clk/airoha/clk-airoha.c | 4 +-
drivers/clk/altera/clk-agilex.c | 2 +-
drivers/clk/altera/clk-agilex5.c | 2 +-
drivers/clk/altera/clk-arria10.c | 2 +-
drivers/clk/altera/clk-mem-n5x.c | 2 +-
drivers/clk/altera/clk-n5x.c | 2 +-
drivers/clk/aspeed/clk_ast2500.c | 4 +-
drivers/clk/aspeed/clk_ast2600.c | 4 +-
drivers/clk/aspeed/clk_ast2700.c | 4 +-
drivers/clk/at91/clk-generic.c | 4 +-
drivers/clk/at91/clk-main.c | 8 +-
drivers/clk/at91/clk-master.c | 8 +-
drivers/clk/at91/clk-peripheral.c | 6 +-
drivers/clk/at91/clk-programmable.c | 4 +-
drivers/clk/at91/clk-sam9x60-pll.c | 10 +-
drivers/clk/at91/clk-sam9x60-usb.c | 4 +-
drivers/clk/at91/clk-system.c | 2 +-
drivers/clk/at91/clk-utmi.c | 4 +-
drivers/clk/at91/compat.c | 30 +-
drivers/clk/at91/pmc.c | 2 +-
drivers/clk/at91/pmc.h | 2 +-
drivers/clk/at91/sckc.c | 4 +-
drivers/clk/basic/Makefile | 8 +
drivers/clk/{ => basic}/clk_fixed_factor.c | 2 +-
drivers/clk/{ => basic}/clk_fixed_rate.c | 4 +-
drivers/clk/{ => basic}/clk_sandbox.c | 12 +-
drivers/clk/ccf/Kconfig | 8 +
drivers/clk/ccf/Makefile | 19 +
drivers/clk/ccf/clk-composite.c | 495 +++
drivers/clk/ccf/clk-conf.c | 189 +
drivers/clk/ccf/clk-divider.c | 663 ++++
drivers/clk/ccf/clk-fixed-factor.c | 409 +++
drivers/clk/ccf/clk-fixed-rate.c | 217 ++
drivers/clk/ccf/clk-gate.c | 260 ++
drivers/clk/ccf/clk-mux.c | 282 ++
drivers/clk/ccf/clk.c | 3250 +++++++++++++++++
drivers/clk/ccf/clk.h | 53 +
drivers/clk/ccf/clk_sandbox.c | 281 ++
drivers/clk/ccf/clk_sandbox_ccf_full.c | 220 ++
drivers/clk/clk-cdce9xx.c | 4 +-
drivers/clk/clk-common.c | 255 ++
drivers/clk/clk-common.h | 45 +
drivers/clk/clk-gpio.c | 2 +-
drivers/clk/clk-hsdk-cgu.c | 4 +-
drivers/clk/clk-stub.c | 4 +-
drivers/clk/clk-uclass.c | 202 +-
drivers/clk/clk-xlnx-clock-wizard.c | 4 +-
drivers/clk/clk_bcm6345.c | 2 +-
drivers/clk/clk_boston.c | 2 +-
drivers/clk/clk_k210.c | 8 +-
drivers/clk/clk_octeon.c | 2 +-
drivers/clk/clk_pic32.c | 4 +-
drivers/clk/clk_sandbox_test.c | 2 +-
drivers/clk/clk_scmi.c | 6 +-
drivers/clk/clk_versaclock.c | 22 +-
drivers/clk/clk_versal.c | 4 +-
drivers/clk/clk_vexpress_osc.c | 4 +-
drivers/clk/clk_zynq.c | 8 +-
drivers/clk/clk_zynqmp.c | 6 +-
drivers/clk/exynos/clk-exynos7420.c | 6 +-
drivers/clk/exynos/clk-pll.c | 4 +-
drivers/clk/exynos/clk.h | 2 +-
drivers/clk/ics8n3qv01.c | 4 +-
drivers/clk/imx/clk-composite-8m.c | 6 +-
drivers/clk/imx/clk-composite-93.c | 2 +-
drivers/clk/imx/clk-fracn-gppll.c | 4 +-
drivers/clk/imx/clk-gate-93.c | 4 +-
drivers/clk/imx/clk-gate2.c | 4 +-
drivers/clk/imx/clk-imx6q.c | 2 +-
drivers/clk/imx/clk-imx6ul.c | 2 +-
drivers/clk/imx/clk-imx8.c | 4 +-
drivers/clk/imx/clk-imx8.h | 2 +-
drivers/clk/imx/clk-imx8qm.c | 2 +-
drivers/clk/imx/clk-imx8qxp.c | 2 +-
drivers/clk/imx/clk-imxrt1020.c | 2 +-
drivers/clk/imx/clk-imxrt1170.c | 4 +-
drivers/clk/imx/clk-pfd.c | 4 +-
drivers/clk/imx/clk-pll14xx.c | 8 +-
drivers/clk/imx/clk-pllv3.c | 18 +-
drivers/clk/intel/clk_intel.c | 2 +-
drivers/clk/mediatek/clk-mtk.c | 14 +-
drivers/clk/mediatek/clk-mtk.h | 10 +-
drivers/clk/meson/a1.c | 8 +-
drivers/clk/meson/axg-ao.c | 2 +-
drivers/clk/meson/axg.c | 2 +-
drivers/clk/meson/clk-measure.c | 2 +-
drivers/clk/meson/g12a-ao.c | 2 +-
drivers/clk/meson/g12a.c | 10 +-
drivers/clk/meson/gxbb.c | 8 +-
drivers/clk/microchip/mpfs_clk_cfg.c | 4 +-
drivers/clk/microchip/mpfs_clk_msspll.c | 2 +-
drivers/clk/microchip/mpfs_clk_periph.c | 2 +-
drivers/clk/mpc83xx_clk.c | 2 +-
drivers/clk/mtmips/clk-mt7620.c | 2 +-
drivers/clk/mtmips/clk-mt7621.c | 2 +-
drivers/clk/mtmips/clk-mt7628.c | 2 +-
drivers/clk/mvebu/armada-37xx-periph.c | 4 +-
drivers/clk/mvebu/armada-37xx-tbg.c | 2 +-
drivers/clk/nuvoton/clk_npcm.c | 4 +-
drivers/clk/nuvoton/clk_npcm.h | 2 +-
drivers/clk/owl/clk_owl.c | 6 +-
drivers/clk/qcom/Kconfig | 1 +
drivers/clk/qcom/Makefile | 31 +-
drivers/clk/qcom/basic/Makefile | 28 +
drivers/clk/qcom/{ => basic}/clock-apq8016.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-apq8096.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-ipq4019.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-ipq5424.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-ipq9574.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-milos.c | 4 +-
drivers/clk/qcom/{ => basic}/clock-qcm2290.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-qcom.c | 4 +-
drivers/clk/qcom/{ => basic}/clock-qcom.h | 2 +-
drivers/clk/qcom/{ => basic}/clock-qcs404.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-qcs615.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-qcs8300.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-sa8775p.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-sc7280.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-sdm845.c | 4 +-
drivers/clk/qcom/{ => basic}/clock-sm6115.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-sm6125.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-sm6350.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-sm7150.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-sm8150.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-sm8250.c | 2 +-
drivers/clk/qcom/{ => basic}/clock-sm8550.c | 4 +-
drivers/clk/qcom/{ => basic}/clock-sm8650.c | 4 +-
drivers/clk/qcom/{ => basic}/clock-x1e80100.c | 4 +-
drivers/clk/qcom/ccf/Makefile | 21 +
drivers/clk/qcom/ccf/clk-alpha-pll.c | 3196 ++++++++++++++++
drivers/clk/qcom/ccf/clk-alpha-pll.h | 251 ++
drivers/clk/qcom/ccf/clk-branch.c | 203 ++
drivers/clk/qcom/ccf/clk-branch.h | 125 +
drivers/clk/qcom/ccf/clk-rcg.h | 217 ++
drivers/clk/qcom/ccf/clk-rcg2.c | 1765 +++++++++
drivers/clk/qcom/ccf/clk-regmap-divider.c | 90 +
drivers/clk/qcom/ccf/clk-regmap-divider.h | 22 +
drivers/clk/qcom/ccf/clk-regmap-mux-div.c | 232 ++
drivers/clk/qcom/ccf/clk-regmap-mux-div.h | 44 +
drivers/clk/qcom/ccf/clk-regmap-mux.c | 57 +
drivers/clk/qcom/ccf/clk-regmap-mux.h | 23 +
drivers/clk/qcom/ccf/clk-regmap-phy-mux.c | 62 +
drivers/clk/qcom/ccf/clk-regmap-phy-mux.h | 33 +
drivers/clk/qcom/ccf/clk-regmap.c | 104 +
drivers/clk/qcom/ccf/clk-regmap.h | 38 +
drivers/clk/qcom/ccf/clk-rpmh.c | 1030 ++++++
drivers/clk/qcom/ccf/common-uboot.c | 188 +
drivers/clk/qcom/ccf/common-uboot.h | 34 +
drivers/clk/qcom/ccf/common.c | 248 ++
drivers/clk/qcom/ccf/common.h | 106 +
drivers/clk/qcom/ccf/dispcc-sm8550.c | 1825 ++++++++++
drivers/clk/qcom/ccf/gcc-sm8650.c | 3846 ++++++++++++++++++++
drivers/clk/qcom/ccf/gdsc.c | 545 +++
drivers/clk/qcom/ccf/gdsc.h | 103 +
drivers/clk/qcom/ccf/reset.c | 112 +
drivers/clk/qcom/ccf/reset.h | 29 +
drivers/clk/qcom/ccf/tcsrcc-sm8650.c | 174 +
drivers/clk/qcom/clock-sc7180.c | 2 +-
drivers/clk/renesas/clk-rcar-gen2.c | 4 +-
drivers/clk/renesas/clk-rcar-gen3.c | 4 +-
drivers/clk/renesas/compound-clock.c | 4 +-
drivers/clk/renesas/r8a78000-cpg.c | 6 +-
drivers/clk/renesas/r9a06g032-clocks.c | 6 +-
drivers/clk/renesas/rcar-gen2-cpg.h | 2 +-
drivers/clk/renesas/rcar-gen3-cpg.h | 2 +-
drivers/clk/renesas/rzg2l-cpg.c | 8 +-
drivers/clk/rockchip/clk_px30.c | 12 +-
drivers/clk/rockchip/clk_rk3036.c | 4 +-
drivers/clk/rockchip/clk_rk3066.c | 4 +-
drivers/clk/rockchip/clk_rk3128.c | 4 +-
drivers/clk/rockchip/clk_rk3188.c | 4 +-
drivers/clk/rockchip/clk_rk322x.c | 4 +-
drivers/clk/rockchip/clk_rk3288.c | 4 +-
drivers/clk/rockchip/clk_rk3308.c | 4 +-
drivers/clk/rockchip/clk_rk3328.c | 4 +-
drivers/clk/rockchip/clk_rk3368.c | 4 +-
drivers/clk/rockchip/clk_rk3399.c | 8 +-
drivers/clk/rockchip/clk_rk3506.c | 4 +-
drivers/clk/rockchip/clk_rk3528.c | 10 +-
drivers/clk/rockchip/clk_rk3568.c | 14 +-
drivers/clk/rockchip/clk_rk3576.c | 8 +-
drivers/clk/rockchip/clk_rk3588.c | 12 +-
drivers/clk/rockchip/clk_rv1108.c | 4 +-
drivers/clk/rockchip/clk_rv1126.c | 12 +-
drivers/clk/sifive/sifive-prci.c | 4 +-
drivers/clk/sophgo/clk-cv1800b.c | 4 +-
drivers/clk/sophgo/clk-ip.c | 30 +-
drivers/clk/sophgo/clk-ip.h | 18 +-
drivers/clk/sophgo/clk-pll.c | 8 +-
drivers/clk/sophgo/clk-pll.h | 4 +-
drivers/clk/starfive/clk-jh7110-pll.c | 4 +-
drivers/clk/starfive/clk.h | 2 +-
drivers/clk/stm32/clk-stm32-core.c | 22 +-
drivers/clk/stm32/clk-stm32-core.h | 2 +-
drivers/clk/stm32/clk-stm32f.c | 4 +-
drivers/clk/stm32/clk-stm32h7.c | 2 +-
drivers/clk/stm32/clk-stm32mp1.c | 4 +-
drivers/clk/sunxi/clk_sun6i_rtc.c | 2 +-
drivers/clk/sunxi/clk_sunxi.c | 2 +-
drivers/clk/tegra/tegra-car-clk.c | 4 +-
drivers/clk/tegra/tegra186-clk.c | 4 +-
drivers/clk/thead/clk-th1520-ap.c | 8 +-
drivers/clk/ti/clk-am3-dpll-x2.c | 2 +-
drivers/clk/ti/clk-am3-dpll.c | 4 +-
drivers/clk/ti/clk-ctrl.c | 2 +-
drivers/clk/ti/clk-divider.c | 4 +-
drivers/clk/ti/clk-gate.c | 2 +-
drivers/clk/ti/clk-k3-pll.c | 4 +-
drivers/clk/ti/clk-k3.c | 6 +-
drivers/clk/ti/clk-mux.c | 4 +-
drivers/clk/ti/clk-sci.c | 4 +-
drivers/clk/uccf/Kconfig | 22 +
drivers/clk/uccf/Makefile | 11 +
drivers/clk/{ => uccf}/clk-composite.c | 20 +-
drivers/clk/{ => uccf}/clk-divider.c | 4 +-
drivers/clk/{ => uccf}/clk-fixed-factor.c | 2 +-
drivers/clk/{ => uccf}/clk-gate.c | 2 +-
drivers/clk/{ => uccf}/clk-mux.c | 2 +-
drivers/clk/{ => uccf}/clk.c | 4 +-
.../{clk_sandbox_ccf.c => uccf/clk_sandbox_uccf.c} | 12 +-
drivers/clk/uniphier/clk-uniphier-core.c | 6 +-
drivers/core/ofnode.c | 4 +-
drivers/phy/cadence/phy-cadence-sierra.c | 2 +-
drivers/phy/cadence/phy-cadence-torrent.c | 2 +-
drivers/phy/phy-stm32-usbphyc.c | 2 +-
drivers/phy/phy-ti-am654.c | 2 +-
drivers/phy/rockchip/phy-rockchip-inno-usb2.c | 2 +-
drivers/phy/ti/phy-j721e-wiz.c | 6 +-
drivers/power/domain/imx8mp-hsiomix.c | 2 +-
drivers/ufs/ufs-qcom.c | 31 +-
include/clk-uclass.h | 6 +-
include/clk.h | 102 +-
include/linux/clk-provider-ccf_full.h | 1461 ++++++++
include/linux/clk-provider-uccf.h | 256 ++
include/linux/clk-provider.h | 253 +-
include/linux/clk/clk-conf.h | 22 +
include/sandbox-clk.h | 5 +-
test/dm/Makefile | 3 +-
test/dm/clk.c | 32 +-
test/dm/clk_ccf.c | 117 +-
test/test-main.c | 6 +
258 files changed, 24032 insertions(+), 997 deletions(-)
---
base-commit: e0ef25054db31fee49d031ac337099b12c67e5b8
Casey Connolly <[email protected]>
