[PATCH 00/18] pwm: Provide devm_pwmchip_alloc() function

Tue Jul 18 11:18:31 PDT 2023

Hello,

my eventual goal is to provide a chardev API to PWMs similar to the gpioctl
API. For that to work flawlessly it's required that a pwmchip stays
around while the corresponding device is opened even if the respective
lowlevel driver goes away. See Wolfram's EOSS talk[1] for some more
details.

This series provides a new function devm_pwmchip_alloc() that allocates
a struct pwm_chip together with driver data. Currently this is still
using devm_kzalloc and so goes away when the device is unbound from the
driver. However this can be changed without having to touch all drivers
again.

The function devm_pwmchip_alloc() is modelled after similar functions
from spi, counter and networking code. The first patch provides the
allocator function and an accessor for driver data, the following
patches convert a subset of the available drivers to this new API.

The series is fully bisectable and the only interdependency is that
patch #1 is needed for all other patches. The idea is to complete
conversion of all remaining drivers and then add a struct device to
struct pwm_chip and so make pwm_chip reference counted. There are still
a few more drivers to convert, but I thought to send out the current
patch set to get some early feedback.

The base for this series is v6.5-rc1 plus the following series:

[PATCH v2 0/8] pwm: Get rid of pwm_[sg]et_chip_data()
        20230705080650.2353391-1-u.kleine-koenig at pengutronix.de
[PATCH 0/2] pwm: stm32: A (small) fix and a cleanup
        20230713155142.2454010-1-u.kleine-koenig at pengutronix.de
[PATCH 00/10] pwm: Constistenly name pwm_chip variables "chip"
        20230714205623.2496590-1-u.kleine-koenig at pengutronix.de
[PATCH] staging: greybus: pwm: Drop unused member from driver struct
        20230714201622.2490792-1-u.kleine-koenig at pengutronix.de
[PATCH] pwm: lpc18xx-sct: Simplify using devm_clk_get_enabled()
        20230718144128.371818-1-u.kleine-koenig at pengutronix.de
[PATCH] pwm: lpc32xx: remove handling of PWM channels
        20230717155257.2568627-1-u.kleine-koenig at pengutronix.de
[PATCH] pwm: pxa: Don't reimplement of_device_get_match_data()
        20230718150657.1728166-1-u.kleine-koenig at pengutronix.de
[PATCH] pwm: ntxec: Drop a write-only variable from driver data
        20230718152327.2583886-1-u.kleine-koenig at pengutronix.de
[PATCH] gpio: mvebu: Make use of devm_pwmchip_add
        20230717142743.2555739-1-u.kleine-koenig at pengutronix.de
[PATCH] pwm: ntxec: Use device_set_of_node_from_dev()
        20230718175310.3946687-1-u.kleine-koenig at pengutronix.de
[PATCH] pwm: berlin: Simplify using devm functions
        20230718175545.3946935-1-u.kleine-koenig at pengutronix.de

I'm not sure the build bots can properly handle that, so it would be
great to get these base series into next soon.

Best regards
Uwe

[1] https://static.sched.com/hosted_files/eoss2023/e3/LifecycleIssues_WolframSang_2023.pdf

Uwe Kleine-König (18):
  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: berlin: Make use of devm_pwmchip_alloc() function
  pwm: clk: 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: imx1: Make use of devm_pwmchip_alloc() function
  pwm: imx27: 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: lpc18xx-sct: Make use of devm_pwmchip_alloc() function
  pwm: lpc32xx: 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: pxa: Make use of devm_pwmchip_alloc() function
  pwm: stm32: Make use of devm_pwmchip_alloc() function
  gpio: mvebu: Make use of devm_pwmchip_alloc() function

 .../driver-api/driver-model/devres.rst        |  1 +
 Documentation/driver-api/pwm.rst              | 10 ++--
 drivers/gpio/gpio-mvebu.c                     | 17 +++----
 drivers/pwm/core.c                            | 23 +++++++++
 drivers/pwm/pwm-ab8500.c                      | 17 +++----
 drivers/pwm/pwm-apple.c                       | 17 +++----
 drivers/pwm/pwm-berlin.c                      | 28 ++++++-----
 drivers/pwm/pwm-clk.c                         | 26 +++++-----
 drivers/pwm/pwm-fsl-ftm.c                     | 47 ++++++++++---------
 drivers/pwm/pwm-hibvt.c                       | 26 +++++-----
 drivers/pwm/pwm-imx1.c                        | 16 +++----
 drivers/pwm/pwm-imx27.c                       | 19 ++++----
 drivers/pwm/pwm-jz4740.c                      | 25 +++++-----
 drivers/pwm/pwm-keembay.c                     | 16 +++----
 drivers/pwm/pwm-lpc18xx-sct.c                 | 24 +++++-----
 drivers/pwm/pwm-lpc32xx.c                     | 18 +++----
 drivers/pwm/pwm-mxs.c                         | 19 ++++----
 drivers/pwm/pwm-ntxec.c                       | 27 +++++------
 drivers/pwm/pwm-pxa.c                         | 20 ++++----
 drivers/pwm/pwm-stm32.c                       | 42 +++++++++++------
 include/linux/pwm.h                           |  4 ++
 21 files changed, 249 insertions(+), 193 deletions(-)

base-commit: 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5
prerequisite-patch-id: c856e0baabfc22d250b7ce881427cdb74613e69a
prerequisite-patch-id: 2a5f9c04e4b5794b5a5d0b30280f75b76a05092b
prerequisite-patch-id: a48b05b94b61f8029b4bb9a78ae1f2cd8c476d80
prerequisite-patch-id: c7dfd3798f024b27b6e236da1eae40b79bb3e281
prerequisite-patch-id: 313ada72ab57438a8d54df0df9c0926bb4f69b36
prerequisite-patch-id: 318824c08f3e7d6500e3c5a47a11c5daffaea34a
prerequisite-patch-id: ea75bfd48ea4d0132c637172564bc1a57061377a
prerequisite-patch-id: 278b25a8d5fef49f7e5c46b627d4862d0b24baaf
prerequisite-patch-id: a3b11e0a7c8f6564e668e2ed1b637351e5fd9dd2
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prerequisite-patch-id: 0e86da52c02300d407d4c0b6f2b9f8293e3320dc
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prerequisite-patch-id: cb6d75be9b72cc04069b6952ba9e5ac80a26a1ab
prerequisite-patch-id: c8fa7296a736f42ec49ab1334cb19947d647a2b4
prerequisite-patch-id: b601ea695815fb65ed704349302ba66442277fc3
prerequisite-patch-id: 7a0daa2918f8a317333e57c1d1698078a1968720
prerequisite-patch-id: b6762f6deeb74aaf73afe2d8dd816d48cec4e1ee
prerequisite-patch-id: a0c8d63424241e64c3e5f9991ea04018a51fcc94
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2.39.2