[PATCH v10 00/12] Convert PWM period and duty cycle to u64

[Guru Das Srinagesh]

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 v9:
  - Gathered the received "Reviewed-by: " tag
  - Added back the clk-pwm.c patch because kbuild test robot complained [3]
    and addressed received review comments.
  - clps711x: Addressed review comments.

Changes from v8:
  - Gathered all received "Acked-by: " and "Reviewed-by: " tags
  - Dropped patch to clk-pwm.c for reasons mentiond in [2]
  - Expanded audience of unreviewed patches

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/
[2] https://lore.kernel.org/lkml/20200312190859.GA19605@codeaurora.org/
[3] https://www.spinics.net/lists/linux-pwm/msg11906.html

Guru Das Srinagesh (12):
  drm/i915: Use 64-bit division macro
  hwmon: pwm-fan: Use 64-bit division macro
  ir-rx51: Use 64-bit division macro
  pwm: clps711x: Cast period to u32 before use as divisor
  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
  clk: pwm: Assign u64 divisor to unsigned int before use
  pwm: core: Convert period and duty cycle to u64

 drivers/clk/clk-pwm.c                      |  4 +++-
 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                 |  5 ++++-
 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, 31 insertions(+), 25 deletions(-)

Cc: Lee Jones <lee.jones at linaro.org>
Cc: Daniel Thompson <daniel.thompson at linaro.org>
Cc: Jingoo Han <jingoohan1 at gmail.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
Cc: linux-fbdev at vger.kernel.org
Cc: Maxime Ripard <mripard at kernel.org>
Cc: Chen-Yu Tsai <wens at csie.org>
Cc: Philipp Zabel <p.zabel at pengutronix.de>
Cc: Fabrice Gasnier <fabrice.gasnier at st.com>
Cc: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
Cc: Alexandre Torgue <alexandre.torgue at st.com>
Cc: Palmer Dabbelt <palmer at dabbelt.com>
Cc: Paul Walmsley <paul.walmsley at sifive.com>
Cc: linux-riscv at lists.infradead.org
Cc: Yash Shah <yash.shah at sifive.com>
Cc: Atish Patra <atish.patra at wdc.com>
Cc: Shawn Guo <shawnguo at kernel.org>
Cc: Sascha Hauer <s.hauer at pengutronix.de>
Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: NXP Linux Team <linux-imx at nxp.com>
Cc: Sascha Hauer <s.hauer at pengutronix.de>
Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: NXP Linux Team <linux-imx at nxp.com>
Cc: Alexander Shiyan <shc_work at mail.ru>
Cc: Mauro Carvalho Chehab <mchehab at kernel.org>
Cc: Richard Fontana <rfontana at redhat.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Kate Stewart <kstewart at linuxfoundation.org>
Cc: Allison Randal <allison at lohutok.net>
Cc: linux-media at vger.kernel.org
Cc: Kamil Debski <kamil at wypas.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
Cc: Jean Delvare <jdelvare at suse.com>
Cc: Guenter Roeck <linux at roeck-us.net>
Cc: Liam Girdwood <lgirdwood at gmail.com>
Cc: Mark Brown <broonie at kernel.org>
Cc: linux-hwmon at vger.kernel.org
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: David Airlie <airlied at linux.ie>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: "Ville Syrjälä" <ville.syrjala at linux.intel.com>
Cc: intel-gfx at lists.freedesktop.org
Cc: dri-devel at lists.freedesktop.org
Cc: Michael Turquette <mturquette at baylibre.com>
Cc: Stephen Boyd <sboyd at kernel.org>
Cc: linux-clk at vger.kernel.org
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Arnd Bergmann <arnd at arndb.de>
Cc: Mukesh Ojha <mojha at codeaurora.org>
Cc: Dan Carpenter <dan.carpenter at oracle.com>
Cc: Anson Huang <Anson.Huang at nxp.com>
Cc: Gerald Baeza <gerald.baeza at st.com>
Cc: Benjamin Gaignard <benjamin.gaignard at linaro.org>
Cc: Axel Lin <axel.lin at ingics.com>
Cc: Ding Xiang <dingxiang at cmss.chinamobile.com>
Cc: Wesley W. Terpstra <wesley at sifive.com>

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