Hello,
this is v3 of the series improving life-time tracking for PWM chips. The
urgency is gone as device links now work as expected and so all
in-kernel users are fine since commit 2e84dc379200 ("driver core:
Release all resources during unbind before updating device links").
However proper lifetime tracking is a precondition to have robust
character device support, as we cannot kill a userspace process if the
used pwm driver goes away.
Changes since v2:
- Cc: the relevant maintainers for wider testing/review audience
- Rebase to v6.7-rc1 + https://lore.kernel.org/linux-pwm/20231121112029.gyv3gqirlycysyr4@xxxxxxxxxxxxxx
- Improvements for things pointed out during review and my own
findings here and there.
- Implementation for a few more ioctls in the WIP commit that adds
character support
To go forward I'd like to get in patches up to #103 (i.e. adding
pwmchip_parent() (#2), devm_pwmchip_alloc() (#37) and the conversions of
the drivers to make use of these additions).
The few commits that touch drivers not living in drivers/pwm (i.e. #36,
#100-#103) can go in either via the pwm tree with the rest, or later
---when the used functions are in---via their trees.
After all in-tree drivers are prepared with the patches up to #103, we
can think about when and how we go on with the remaining bits.
Note that patch #104 breaks all drivers that don't use
devm_pwmchip_alloc(), so this is the commit that needs coordination with the
maintainers of
drivers/gpio/gpio-mvebu.c
drivers/gpu/drm/bridge/ti-sn65dsi86.c
drivers/leds/rgb/leds-qcom-lpg.c
drivers/staging/greybus/pwm.c
The motivation for this series is the last patch. It allows to control a
pwm device via ioctl. Compared to the sysfs API this already now has
some advantages:
- It changes all parameters in a single call.
This simplifies things similar to the introduction of
pwm_apply_state(). With sysfs it can happen that you want to
switch polarity but that's refused because
pwm_get_state(mypwm, &state);
state.polarity = new_value;
sometimes yield an invalid state, e.g. because state.period is
in some cases 0 after bootup. Theoretically it can even happen that you have
to change two parameters before reaching an applicable state, then you're
stuck with sysfs.
- It's faster than sysfs. In my measurements with stm32 about a factor
4.
A userspace lib to make use of this can be found at
https://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/libpwm.git/ .
It makes use of the character devices if available and falls back to
sysfs. So it's somewhat useful already now.
Best regards
Uwe
Uwe Kleine-König (108):
pwm: cros-ec: Change prototype of helper to prepare further changes
pwm: Provide a macro to get the parent device of a given chip
pwm: ab8500: Make use of pwmchip_parent() macro
pwm: atmel: Make use of pwmchip_parent() macro
pwm: atmel-tcb: Make use of pwmchip_parent() macro
pwm: bcm-kona: Make use of pwmchip_parent() macro
pwm: crc: Make use of pwmchip_parent() macro
pwm: cros-ec: Make use of pwmchip_parent() macro
pwm: dwc: Make use of pwmchip_parent() macro
pwm: ep93xx: Make use of pwmchip_parent() macro
pwm: fsl-ftm: Make use of pwmchip_parent() macro
pwm: img: Make use of parent device pointer in driver data
pwm: imx27: Make use of pwmchip_parent() macro
pwm: jz4740: Make use of pwmchip_parent() macro
pwm: lpc18xx-sct: Make use of parent device pointer in driver data
pwm: lpss: Make use of pwmchip_parent() macro
pwm: mediatek: Make use of pwmchip_parent() macro
pwm: meson: Make use of pwmchip_parent() macro
pwm: mtk-disp: Make use of pwmchip_parent() macro
pwm: omap: Make use of pwmchip_parent() macro
pwm: pca9685: Store parent device in driver data
pwm: raspberrypi-poe: Make use of pwmchip_parent() macro
pwm: rcar: Make use of pwmchip_parent() macro
pwm: rz-mtu3: Make use of pwmchip_parent() macro
pwm: samsung: Make use of pwmchip_parent() macro
pwm: sifive: Make use of pwmchip_parent() macro
pwm: stm32-lp: Make use of pwmchip_parent() macro
pwm: stm32: Make use of pwmchip_parent() macro
pwm: stmpe: Make use of pwmchip_parent() macro
pwm: sun4i: Make use of pwmchip_parent() macro
pwm: tiecap: Make use of pwmchip_parent() macro
pwm: tiehrpwm: Make use of pwmchip_parent() macro
pwm: twl-led: Make use of pwmchip_parent() macro
pwm: twl: Make use of pwmchip_parent() macro
pwm: vt8500: Make use of pwmchip_parent() macro
staging: greybus: pwm: Make use of pwmchip_parent() macro
pwm: Provide devm_pwmchip_alloc() function
pwm: ab8500: Make use of devm_pwmchip_alloc() function
pwm: apple: Make use of devm_pwmchip_alloc() function
pwm: atmel-hlcdc: Make use of devm_pwmchip_alloc() function
pwm: atmel: Make use of devm_pwmchip_alloc() function
pwm: atmel-tcb: Make use of devm_pwmchip_alloc() function
pwm: bcm2835: Make use of devm_pwmchip_alloc() function
pwm: bcm-iproc: Make use of devm_pwmchip_alloc() function
pwm: bcm-kona: Make use of devm_pwmchip_alloc() function
pwm: berlin: Make use of devm_pwmchip_alloc() function
pwm: brcmstb: Make use of devm_pwmchip_alloc() function
pwm: clk: Make use of devm_pwmchip_alloc() function
pwm: clps711x: Make use of devm_pwmchip_alloc() function
pwm: crc: Make use of devm_pwmchip_alloc() function
pwm: cros-ec: Make use of devm_pwmchip_alloc() function
pwm: dwc: Make use of devm_pwmchip_alloc() function
pwm: ep93xx: Make use of devm_pwmchip_alloc() function
pwm: fsl-ftm: Make use of devm_pwmchip_alloc() function
pwm: hibvt: Make use of devm_pwmchip_alloc() function
pwm: img: Make use of devm_pwmchip_alloc() function
pwm: imx1: Make use of devm_pwmchip_alloc() function
pwm: imx27: Make use of devm_pwmchip_alloc() function
pwm: imx-tpm: Make use of devm_pwmchip_alloc() function
pwm: intel-lgm: Make use of devm_pwmchip_alloc() function
pwm: iqs620a: Make use of devm_pwmchip_alloc() function
pwm: jz4740: Make use of devm_pwmchip_alloc() function
pwm: keembay: Make use of devm_pwmchip_alloc() function
pwm: lp3943: Make use of devm_pwmchip_alloc() function
pwm: lpc18xx-sct: Make use of devm_pwmchip_alloc() function
pwm: lpc32xx: Make use of devm_pwmchip_alloc() function
pwm: lpss-*: Make use of devm_pwmchip_alloc() function
pwm: mediatek: Make use of devm_pwmchip_alloc() function
pwm: meson: Make use of devm_pwmchip_alloc() function
pwm: microchip-core: Make use of devm_pwmchip_alloc() function
pwm: mtk-disp: Make use of devm_pwmchip_alloc() function
pwm: mxs: Make use of devm_pwmchip_alloc() function
pwm: ntxec: Make use of devm_pwmchip_alloc() function
pwm: omap-dmtimer: Make use of devm_pwmchip_alloc() function
pwm: pca9685: Make use of devm_pwmchip_alloc() function
pwm: pxa: Make use of devm_pwmchip_alloc() function
pwm: raspberrypi-poe: Make use of devm_pwmchip_alloc() function
pwm: rcar: Make use of devm_pwmchip_alloc() function
pwm: renesas-tpu: Make use of devm_pwmchip_alloc() function
pwm: rockchip: Make use of devm_pwmchip_alloc() function
pwm: rz-mtu3: Make use of devm_pwmchip_alloc() function
pwm: samsung: Make use of devm_pwmchip_alloc() function
pwm: sifive: Make use of devm_pwmchip_alloc() function
pwm: sl28cpld: Make use of devm_pwmchip_alloc() function
pwm: spear: Make use of devm_pwmchip_alloc() function
pwm: sprd: Make use of devm_pwmchip_alloc() function
pwm: sti: Make use of devm_pwmchip_alloc() function
pwm: stm32-lp: Make use of devm_pwmchip_alloc() function
pwm: stm32: Make use of devm_pwmchip_alloc() function
pwm: stmpe: Make use of devm_pwmchip_alloc() function
pwm: sun4i: Make use of devm_pwmchip_alloc() function
pwm: sunplus: Make use of devm_pwmchip_alloc() function
pwm: tegra: Make use of devm_pwmchip_alloc() function
pwm: tiecap: Make use of devm_pwmchip_alloc() function
pwm: twl-led: Make use of devm_pwmchip_alloc() function
pwm: twl: Make use of devm_pwmchip_alloc() function
pwm: visconti: Make use of devm_pwmchip_alloc() function
pwm: vt8500: Make use of devm_pwmchip_alloc() function
pwm: xilinx: Make use of devm_pwmchip_alloc() function
gpio: mvebu: Make use of devm_pwmchip_alloc() function
drm/bridge: ti-sn65dsi86: Make use of devm_pwmchip_alloc() function
leds: qcom-lpg: Make use of devm_pwmchip_alloc() function
staging: greybus: pwm: Make use of devm_pwmchip_alloc() function
pwm: Ensure that pwm_chips are allocated using pwmchip_alloc()
pwm: Ensure a struct pwm has the same lifetime as its pwm_chip
pwm: Ensure the memory backing a PWM chip isn't freed while used
pwm: Add more locking
WIP: pwm: Add support for pwmchip devices for faster and easier
userspace access
.../driver-api/driver-model/devres.rst | 1 +
Documentation/driver-api/pwm.rst | 10 +-
drivers/gpio/gpio-mvebu.c | 18 +-
drivers/gpu/drm/bridge/ti-sn65dsi86.c | 25 +-
drivers/leds/rgb/leds-qcom-lpg.c | 30 +-
drivers/pwm/Kconfig | 4 -
drivers/pwm/Makefile | 3 +-
drivers/pwm/core.c | 480 +++++++++++++++---
drivers/pwm/pwm-ab8500.c | 36 +-
drivers/pwm/pwm-apple.c | 18 +-
drivers/pwm/pwm-atmel-hlcdc.c | 35 +-
drivers/pwm/pwm-atmel-tcb.c | 26 +-
drivers/pwm/pwm-atmel.c | 37 +-
drivers/pwm/pwm-bcm-iproc.c | 19 +-
drivers/pwm/pwm-bcm-kona.c | 21 +-
drivers/pwm/pwm-bcm2835.c | 17 +-
drivers/pwm/pwm-berlin.c | 29 +-
drivers/pwm/pwm-brcmstb.c | 17 +-
drivers/pwm/pwm-clk.c | 27 +-
drivers/pwm/pwm-clps711x.c | 21 +-
drivers/pwm/pwm-crc.c | 26 +-
drivers/pwm/pwm-cros-ec.c | 51 +-
drivers/pwm/pwm-dwc-core.c | 25 +-
drivers/pwm/pwm-dwc.c | 18 +-
drivers/pwm/pwm-dwc.h | 9 +-
drivers/pwm/pwm-ep93xx.c | 21 +-
drivers/pwm/pwm-fsl-ftm.c | 48 +-
drivers/pwm/pwm-hibvt.c | 25 +-
drivers/pwm/pwm-img.c | 51 +-
drivers/pwm/pwm-imx-tpm.c | 34 +-
drivers/pwm/pwm-imx1.c | 17 +-
drivers/pwm/pwm-imx27.c | 26 +-
drivers/pwm/pwm-intel-lgm.c | 17 +-
drivers/pwm/pwm-iqs620a.c | 37 +-
drivers/pwm/pwm-jz4740.c | 35 +-
drivers/pwm/pwm-keembay.c | 17 +-
drivers/pwm/pwm-lp3943.c | 17 +-
drivers/pwm/pwm-lpc18xx-sct.c | 35 +-
drivers/pwm/pwm-lpc32xx.c | 19 +-
drivers/pwm/pwm-lpss-pci.c | 10 +-
drivers/pwm/pwm-lpss-platform.c | 10 +-
drivers/pwm/pwm-lpss.c | 34 +-
drivers/pwm/pwm-lpss.h | 1 -
drivers/pwm/pwm-mediatek.c | 28 +-
drivers/pwm/pwm-meson.c | 57 ++-
drivers/pwm/pwm-microchip-core.c | 17 +-
drivers/pwm/pwm-mtk-disp.c | 25 +-
drivers/pwm/pwm-mxs.c | 32 +-
drivers/pwm/pwm-ntxec.c | 30 +-
drivers/pwm/pwm-omap-dmtimer.c | 46 +-
drivers/pwm/pwm-pca9685.c | 98 ++--
drivers/pwm/pwm-pxa.c | 21 +-
drivers/pwm/pwm-raspberrypi-poe.c | 20 +-
drivers/pwm/pwm-rcar.c | 25 +-
drivers/pwm/pwm-renesas-tpu.c | 18 +-
drivers/pwm/pwm-rockchip.c | 24 +-
drivers/pwm/pwm-rz-mtu3.c | 38 +-
drivers/pwm/pwm-samsung.c | 56 +-
drivers/pwm/pwm-sifive.c | 30 +-
drivers/pwm/pwm-sl28cpld.c | 13 +-
drivers/pwm/pwm-spear.c | 17 +-
drivers/pwm/pwm-sprd.c | 50 +-
drivers/pwm/pwm-sti.c | 34 +-
drivers/pwm/pwm-stm32-lp.c | 29 +-
drivers/pwm/pwm-stm32.c | 53 +-
drivers/pwm/pwm-stmpe.c | 58 ++-
drivers/pwm/pwm-sun4i.c | 38 +-
drivers/pwm/pwm-sunplus.c | 17 +-
drivers/pwm/pwm-tegra.c | 27 +-
drivers/pwm/pwm-tiecap.c | 55 +-
drivers/pwm/pwm-tiehrpwm.c | 72 +--
drivers/pwm/pwm-twl-led.c | 58 ++-
drivers/pwm/pwm-twl.c | 50 +-
drivers/pwm/pwm-visconti.c | 17 +-
drivers/pwm/pwm-vt8500.c | 41 +-
drivers/pwm/pwm-xilinx.c | 34 +-
drivers/pwm/sysfs.c | 64 +--
drivers/staging/greybus/pwm.c | 130 ++---
include/linux/platform_data/x86/pwm-lpss.h | 4 +-
include/linux/pwm.h | 36 +-
include/uapi/linux/pwm.h | 23 +
81 files changed, 1651 insertions(+), 1291 deletions(-)
create mode 100644 include/uapi/linux/pwm.h
base-commit: 869de350ff3834145273a6d39faedea878c6715a
--
2.42.0
