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* [PATCH v1 0/6] clk: switch dividers to .determine_rate
@ 2021-07-02 22:51 Martin Blumenstingl
  2021-07-02 22:51 ` [PATCH v1 1/6] clk: divider: Implement and wire up .determine_rate by default Martin Blumenstingl
                   ` (6 more replies)
  0 siblings, 7 replies; 32+ messages in thread
From: Martin Blumenstingl @ 2021-07-02 22:51 UTC (permalink / raw)
  To: linux-clk, sboyd; +Cc: linux-arm-kernel, linux-kernel, Martin Blumenstingl

This is a continuation of patch #2 ("clk: divider: Switch from
.round_rate to .determine_rate by default", [0]) from my other series:
"clk: meson: rounding for fast clocks on 32-bit SoCs" [1]

That patch caused NULL dereferences in various drivers which are still
accessing clk_divider_ops.round_rate directly (which got removed in the
mentioned patch).

Guenter Roeck found this issue first on Freescale i.MX6 Ultralite and
reported it here: [2]
Later on Marek Szyprowski reported that BCM2835 is also affected: [3]

With this improved version of the patch I am taking a more definsive
approach as suggested by Stephen Boyd. Instead of dropping
clk_divider_ops.round_rate we're now keeping it and adding
clk_divider_ops.determine_rate. CCF core already prefers
.determine_rate over .round_rate so the new implementation is used by
default.

To simplify the transition to .determine_rate in the future this
updated series now has five extra patches to port over the drivers
which used clk_divider_ops.round_rate over to
clk_divider_ops.determine_rate.

I have compile-tested all patches. Additionally the imx patch is
runtime-tested using Guenter Roeck's suggestion (thanks!):
$ qemu-system-arm -M mcimx6ul-evk -m 512M -kernel arch/arm/boot/zImage -dtb arch/arm/boot/dts/imx6ul-14x14-evk.dtb -append "console=ttymxc0 loglevel=8 earlycon earlyprintk" -monitor stdio

This series is based on clk-next commit 783d08bd02f5d3 ("Revert "clk:
divider: Switch from .round_rate to .determine_rate by default"clk-next").
My suggestion is to let all patches go through clk-next (instead of
individual driver trees) as the first patch in this series is a pre-
condition for the other ones.


[0] https://patchwork.kernel.org/project/linux-clk/patch/20210627223959.188139-3-martin.blumenstingl@googlemail.com/
[1] https://patchwork.kernel.org/project/linux-clk/cover/20210627223959.188139-1-martin.blumenstingl@googlemail.com/
[2] https://lore.kernel.org/linux-clk/20210701202540.GA1085600@roeck-us.net/
[3] https://lore.kernel.org/linux-clk/e21c34a3-2586-057d-013b-6c8ec094d1a8@samsung.com/


Martin Blumenstingl (6):
  clk: divider: Implement and wire up .determine_rate by default
  clk: imx: clk-divider-gate: Switch to clk_divider.determine_rate
  clk: bcm2835: Switch to clk_divider.determine_rate
  clk: stm32f4: Switch to clk_divider.determine_rate
  clk: stm32h7: Switch to clk_divider.determine_rate
  clk: stm32mp1: Switch to clk_divider.determine_rate

 drivers/clk/bcm/clk-bcm2835.c      |  9 ++++-----
 drivers/clk/clk-divider.c          | 23 +++++++++++++++++++++++
 drivers/clk/clk-stm32f4.c          |  8 ++++----
 drivers/clk/clk-stm32h7.c          |  8 ++++----
 drivers/clk/clk-stm32mp1.c         | 10 +++-------
 drivers/clk/imx/clk-divider-gate.c | 10 +++++-----
 6 files changed, 43 insertions(+), 25 deletions(-)

-- 
2.32.0


^ permalink raw reply	[flat|nested] 32+ messages in thread

end of thread, other threads:[~2021-11-02 21:40 UTC | newest]

Thread overview: 32+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-02 22:51 [PATCH v1 0/6] clk: switch dividers to .determine_rate Martin Blumenstingl
2021-07-02 22:51 ` [PATCH v1 1/6] clk: divider: Implement and wire up .determine_rate by default Martin Blumenstingl
2021-08-06  1:10   ` Stephen Boyd
2021-10-14  9:55   ` Alex Bee
2021-10-14 12:11     ` Martin Blumenstingl
2021-10-14 21:34       ` Martin Blumenstingl
2021-10-14 22:52         ` Stephen Boyd
2021-10-15 12:05           ` [PATCH] clk: composite: Also consider .determine_rate for rate + mux composites Martin Blumenstingl
2021-10-15 21:27             ` Stephen Boyd
2021-11-01 20:19             ` Guillaume Tucker
2021-11-01 20:58               ` Martin Blumenstingl
2021-11-01 21:59                 ` Robin Murphy
2021-11-01 22:11                   ` Robin Murphy
2021-11-01 22:41                     ` Alex Bee
2021-11-02  7:58                       ` Guillaume Tucker
2021-11-02 21:40                         ` LABBE Corentin
2021-10-15 19:14         ` [PATCH v1 1/6] clk: divider: Implement and wire up .determine_rate by default Alex Bee
2021-10-15 21:31           ` Stephen Boyd
2021-07-02 22:51 ` [PATCH v1 2/6] clk: imx: clk-divider-gate: Switch to clk_divider.determine_rate Martin Blumenstingl
2021-07-19 10:43   ` Abel Vesa
2021-07-29 11:30   ` Abel Vesa
2021-07-02 22:51 ` [PATCH v1 3/6] clk: bcm2835: " Martin Blumenstingl
2021-07-05  6:57   ` Marek Szyprowski
2021-08-06  1:10   ` Stephen Boyd
2021-07-02 22:51 ` [PATCH v1 4/6] clk: stm32f4: " Martin Blumenstingl
2021-08-06  1:10   ` Stephen Boyd
2021-07-02 22:51 ` [PATCH v1 5/6] clk: stm32h7: " Martin Blumenstingl
2021-08-06  1:10   ` Stephen Boyd
2021-07-02 22:51 ` [PATCH v1 6/6] clk: stm32mp1: " Martin Blumenstingl
2021-08-06  1:10   ` Stephen Boyd
2021-08-03 19:32 ` [PATCH v1 0/6] clk: switch dividers to .determine_rate Martin Blumenstingl
2021-08-03 20:16   ` Stephen Boyd

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