Because period and duty cycle are defined in the PWM framework structs as ints
with units of nanoseconds, the maximum time duration that can be set is limited
to ~2.147 seconds. Consequently, applications desiring to set greater time
periods via the PWM framework are not be able to do so - like, for instance,
causing an LED to blink at an interval of 5 seconds.
Redefining the period and duty cycle struct members in the core PWM framework
structs as u64 values will enable larger time durations to be set and solve
this problem. Such a change to the framework mandates that drivers using these
struct members (and corresponding helper functions) also be modified correctly
in order to prevent compilation errors.
This patch series introduces the changes to all the drivers first, followed by
the framework change at the very end so that when the latter is applied, all
the drivers are in good shape and there are no compilation errors.
Changes from v7:
- Changed commit messages of all patches to be brief and to the point.
- Added explanation of change in cover letter.
- Dropped change to pwm-sti.c as upon review it was unnecessary as struct
pwm_capture is not being modified in the PWM core.
Changes from v6:
- Split out the driver changes out into separate patches, one patch per file
for ease of reviewing.
Changes from v5:
- Dropped the conversion of struct pwm_capture to u64 for reasons mentioned
in https://www.spinics.net/lists/linux-pwm/msg11541.html
Changes from v4:
- Split the patch into two: one for changes to the drivers, and the actual
switch to u64 for ease of reverting should the need arise.
- Re-examined the patch and made the following corrections:
* intel_panel.c:
DIV64_U64_ROUND_UP -> DIV_ROUND_UP_ULL (as only the numerator would be
64-bit in this case).
* pwm-sti.c:
do_div -> div_u64 (do_div is optimized only for x86 architectures, and
div_u64's comment block suggests to use this as much as possible).
Changes from v3:
- Rebased to current tip of for-next.
Changes from v2:
- Fixed %u -> %llu in a dev_dbg in pwm-stm32-lp.c, thanks to kbuild test robot
- Added a couple of fixes to pwm-imx-tpm.c and pwm-sifive.c
Changes from v1:
- Fixed compilation errors seen when compiling for different archs.
v1:
- Reworked the change pushed upstream earlier [1] so as to not add an
extension to an obsolete API. With this change, pwm_ops->apply() can be
used to set pwm_state parameters as usual.
[1] https://lore.kernel.org/lkml/20190916140048.GB7488@ulmo/
Cc: Lee Jones <lee.jones@xxxxxxxxxx>
Cc: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Cc: linux-fbdev@xxxxxxxxxxxxxxx
Cc: Maxime Ripard <mripard@xxxxxxxxxx>
Cc: Chen-Yu Tsai <wens@xxxxxxxx>
Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Cc: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
Cc: Alexandre Torgue <alexandre.torgue@xxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
Cc: Yash Shah <yash.shah@xxxxxxxxxx>
Cc: Atish Patra <atish.patra@xxxxxxx>
Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Cc: Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>
Cc: Fabio Estevam <festevam@xxxxxxxxx>
Cc: NXP Linux Team <linux-imx@xxxxxxx>
Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Cc: Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>
Cc: Fabio Estevam <festevam@xxxxxxxxx>
Cc: NXP Linux Team <linux-imx@xxxxxxx>
Cc: Alexander Shiyan <shc_work@xxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: Richard Fontana <rfontana@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Kate Stewart <kstewart@xxxxxxxxxxxxxxxxxxx>
Cc: Allison Randal <allison@xxxxxxxxxxx>
Cc: linux-media@xxxxxxxxxxxxxxx
Cc: Kamil Debski <kamil@xxxxxxxxx>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
Cc: Jean Delvare <jdelvare@xxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: linux-hwmon@xxxxxxxxxxxxxxx
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: "Ville Syrjälä" <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: Michael Turquette <mturquette@xxxxxxxxxxxx>
Cc: Stephen Boyd <sboyd@xxxxxxxxxx>
Cc: linux-clk@xxxxxxxxxxxxxxx
Guru Das Srinagesh (12):
clk: pwm: Use 64-bit division function
drm/i915: Use 64-bit division macro
hwmon: pwm-fan: Use 64-bit division macro
ir-rx51: Use 64-bit division macro
pwm: clps711x: Use 64-bit division macro
pwm: pwm-imx-tpm: Use 64-bit division macro
pwm: imx27: Use 64-bit division macro and function
pwm: sifive: Use 64-bit division macro
pwm: stm32-lp: Use %llu format specifier for period
pwm: sun4i: Use 64-bit division function
backlight: pwm_bl: Use 64-bit division function
pwm: core: Convert period and duty cycle to u64
drivers/clk/clk-pwm.c | 2 +-
drivers/gpu/drm/i915/display/intel_panel.c | 2 +-
drivers/hwmon/pwm-fan.c | 2 +-
drivers/media/rc/ir-rx51.c | 3 ++-
drivers/pwm/core.c | 4 ++--
drivers/pwm/pwm-clps711x.c | 2 +-
drivers/pwm/pwm-imx-tpm.c | 2 +-
drivers/pwm/pwm-imx27.c | 5 ++---
drivers/pwm/pwm-sifive.c | 2 +-
drivers/pwm/pwm-stm32-lp.c | 2 +-
drivers/pwm/pwm-sun4i.c | 2 +-
drivers/pwm/sysfs.c | 8 ++++----
drivers/video/backlight/pwm_bl.c | 3 ++-
include/linux/pwm.h | 12 ++++++------
14 files changed, 26 insertions(+), 25 deletions(-)
--
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a Linux Foundation Collaborative Project
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