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From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Linus Walleij <linus.walleij@linaro.org>,
	 Bjorn Andersson <andersson@kernel.org>,
	 Konrad Dybcio <konradybcio@kernel.org>,
	 Alexey Klimov <alexey.klimov@linaro.org>,
	 Lorenzo Bianconi <lorenzo@kernel.org>,
	Sean Wang <sean.wang@kernel.org>,
	 Matthias Brugger <matthias.bgg@gmail.com>,
	 AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	 Paul Cercueil <paul@crapouillou.net>,
	Kees Cook <kees@kernel.org>,  Andy Shevchenko <andy@kernel.org>,
	 Andrew Morton <akpm@linux-foundation.org>,
	 David Hildenbrand <david@redhat.com>,
	 Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
	 "Liam R. Howlett" <Liam.Howlett@oracle.com>,
	 Vlastimil Babka <vbabka@suse.cz>,
	Mike Rapoport <rppt@kernel.org>,
	 Suren Baghdasaryan <surenb@google.com>,
	Michal Hocko <mhocko@suse.com>,
	 Dong Aisheng <aisheng.dong@nxp.com>,
	Fabio Estevam <festevam@gmail.com>,
	 Shawn Guo <shawnguo@kernel.org>, Jacky Bai <ping.bai@nxp.com>,
	 Pengutronix Kernel Team <kernel@pengutronix.de>,
	 NXP S32 Linux Team <s32@nxp.com>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	 Tony Lindgren <tony@atomide.com>,
	 Haojian Zhuang <haojian.zhuang@linaro.org>,
	 Geert Uytterhoeven <geert+renesas@glider.be>,
	 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	 "Rafael J. Wysocki" <rafael@kernel.org>,
	Danilo Krummrich <dakr@kernel.org>
Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
	 linux-arm-msm@vger.kernel.org,
	linux-mediatek@lists.infradead.org,
	 linux-arm-kernel@lists.infradead.org,
	linux-mips@vger.kernel.org,  linux-hardening@vger.kernel.org,
	linux-mm@kvack.org, imx@lists.linux.dev,
	 linux-omap@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	 Bartosz Golaszewski <bartosz.golaszewski@linaro.org>,
	 Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Subject: [PATCH v4 00/15] pinctrl: introduce the concept of a GPIO pin function category
Date: Tue, 12 Aug 2025 10:26:59 +0200	[thread overview]
Message-ID: <20250812-pinctrl-gpio-pinfuncs-v4-0-bb3906c55e64@linaro.org> (raw)

NOTE: This is obviously targetting v6.18.

NOTER: This series is a bit all over the place and looks like it should
be split into at least two separate ones but I figured sending it in its
entirety better shows the whole picture - namely the fact that the
pinfunction handling rework is there to allow using the generic pinux
functions in qualcomm drivers without ballooning up runtime memory
usage.

NOTEST: I tested several Qualcomm platforms but I have no means of
testing Mediatek and others. Tested-by tags are appreciated.

Problem: when pinctrl core binds pins to a consumer device and the
pinmux ops of the underlying driver are marked as strict, the pin in
question can no longer be requested as a GPIO using the GPIO descriptor
API. It will result in the following error:

[    5.095688] sc8280xp-tlmm f100000.pinctrl: pin GPIO_25 already requested by regulator-edp-3p3; cannot claim for f100000.pinctrl:570
[    5.107822] sc8280xp-tlmm f100000.pinctrl: error -EINVAL: pin-25 (f100000.pinctrl:570)

This typically makes sense except when the pins are muxed to a function
that actually says "GPIO". Of course, the function name is just a string
so it has no meaning to the pinctrl subsystem.

We have many Qualcomm SoCs (and I can imagine it's a common pattern in
other platforms as well) where we mux a pin to "gpio" function using the
`pinctrl-X` property in order to configure bias or drive-strength and
then access it using the gpiod API. This makes it impossible to mark the
pin controller module as "strict".

This series proposes to introduce a concept of a sub-category of
pinfunctions: GPIO functions where the above is not true and the pin
muxed as a GPIO can still be accessed via the GPIO consumer API even for
strict pinmuxers.

To that end: we first clean up the drivers that use struct function_desc
and make them use the smaller struct pinfunction instead - which is the
correct structure for drivers to describe their pin functions with. We
also rework pinmux core to not duplicate memory used to store the
pinfunctions unless they're allocated dynamically.

First: provide the kmemdup_const() helper which only duplicates memory
if it's not in the .rodata section. Then rework all pinctrl drivers that
instantiate objects of type struct function_desc as they should only be
created by pinmux core. Next constify the return value of the accessor
used to expose these structures to users and finally convert the
pinfunction object within struct function_desc to a pointer and use
kmemdup_const() to assign it. With this done proceed to add
infrastructure for the GPIO pin function category and use it in Qualcomm
drivers. At the very end: make the Qualcomm pinmuxer strict.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
Changes in v4:
- Update the GPIO pin function definitions to include the new qcom
  driver (milos)
- Provide devm_kmemdup_const() instead of a non-managed kmemdup_const()
  as a way to avoid casting out the 'const' modifier when passing the
  const pointer to devm_add_action_or_reset()
- Use devm_krealloc_array() where applicable instead of devm_krealloc()
- Fix typos
- Fix kerneldocs
- Improve commit messages
- Small tweaks as pointed out by Andy
- Rebased on top of v6.17-rc1
- Link to v3: https://lore.kernel.org/r/20250724-pinctrl-gpio-pinfuncs-v3-0-af4db9302de4@linaro.org

Changes in v3:
- Add more patches in front: convert pinctrl drivers to stop defining
  their own struct function_desc objects and make pinmux core not
  duplicate .rodata memory in which struct pinfunction objects are
  stored.
- Add a patch constifying pinmux_generic_get_function().
- Drop patches that were applied upstream.
- Link to v2: https://lore.kernel.org/r/20250709-pinctrl-gpio-pinfuncs-v2-0-b6135149c0d9@linaro.org

Changes in v2:
- Extend the series with providing pinmux_generic_add_pinfunction(),
  using it in several drivers and converting pinctrl-msm to using
  generic pinmux helpers
- Add a generic function_is_gpio() callback for pinmux_ops
- Convert all qualcomm drivers to using the new GPIO pin category so
  that we can actually enable the strict flag
- Link to v1: https://lore.kernel.org/r/20250702-pinctrl-gpio-pinfuncs-v1-0-ed2bd0f9468d@linaro.org

---
Bartosz Golaszewski (15):
      devres: provide devm_kmemdup_const()
      pinctrl: ingenic: use struct pinfunction instead of struct function_desc
      pinctrl: airoha: replace struct function_desc with struct pinfunction
      pinctrl: mediatek: mt7988: use PINCTRL_PIN_FUNCTION()
      pinctrl: mediatek: moore: replace struct function_desc with struct pinfunction
      pinctrl: imx: don't access the pin function radix tree directly
      pinctrl: keembay: release allocated memory in detach path
      pinctrl: keembay: use a dedicated structure for the pinfunction description
      pinctrl: constify pinmux_generic_get_function()
      pinctrl: make struct pinfunction a pointer in struct function_desc
      pinctrl: qcom: use generic pin function helpers
      pinctrl: allow to mark pin functions as requestable GPIOs
      pinctrl: qcom: add infrastructure for marking pin functions as GPIOs
      pinctrl: qcom: mark the `gpio` and `egpio` pins function as non-strict functions
      pinctrl: qcom: make the pinmuxing strict

 drivers/base/devres.c                            | 21 +++++++++
 drivers/pinctrl/freescale/pinctrl-imx.c          | 42 ++++++-----------
 drivers/pinctrl/mediatek/pinctrl-airoha.c        | 18 ++++----
 drivers/pinctrl/mediatek/pinctrl-moore.c         | 10 ++--
 drivers/pinctrl/mediatek/pinctrl-moore.h         |  7 +--
 drivers/pinctrl/mediatek/pinctrl-mt7622.c        |  2 +-
 drivers/pinctrl/mediatek/pinctrl-mt7623.c        |  2 +-
 drivers/pinctrl/mediatek/pinctrl-mt7629.c        |  2 +-
 drivers/pinctrl/mediatek/pinctrl-mt7981.c        |  2 +-
 drivers/pinctrl/mediatek/pinctrl-mt7986.c        |  2 +-
 drivers/pinctrl/mediatek/pinctrl-mt7988.c        | 44 +++++++-----------
 drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.h |  2 +-
 drivers/pinctrl/pinctrl-equilibrium.c            |  2 +-
 drivers/pinctrl/pinctrl-ingenic.c                | 49 +++++++++-----------
 drivers/pinctrl/pinctrl-keembay.c                | 26 +++++++----
 drivers/pinctrl/pinctrl-single.c                 |  4 +-
 drivers/pinctrl/pinmux.c                         | 59 ++++++++++++++++++++----
 drivers/pinctrl/pinmux.h                         |  9 ++--
 drivers/pinctrl/qcom/pinctrl-ipq5018.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-ipq5332.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-ipq5424.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-ipq6018.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-ipq8074.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-ipq9574.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-mdm9607.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-mdm9615.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-milos.c             |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm.c               | 45 ++++++------------
 drivers/pinctrl/qcom/pinctrl-msm.h               |  5 ++
 drivers/pinctrl/qcom/pinctrl-msm8226.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8660.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8909.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8916.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8917.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8953.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8960.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8976.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8994.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8996.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8998.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-msm8x74.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-qcm2290.c           |  4 +-
 drivers/pinctrl/qcom/pinctrl-qcs404.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-qcs615.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-qcs8300.c           |  4 +-
 drivers/pinctrl/qcom/pinctrl-qdu1000.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-sa8775p.c           |  4 +-
 drivers/pinctrl/qcom/pinctrl-sar2130p.c          |  2 +-
 drivers/pinctrl/qcom/pinctrl-sc7180.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sc7280.c            |  4 +-
 drivers/pinctrl/qcom/pinctrl-sc8180x.c           |  2 +-
 drivers/pinctrl/qcom/pinctrl-sc8280xp.c          |  4 +-
 drivers/pinctrl/qcom/pinctrl-sdm660.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sdm670.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sdm845.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sdx55.c             |  2 +-
 drivers/pinctrl/qcom/pinctrl-sdx65.c             |  2 +-
 drivers/pinctrl/qcom/pinctrl-sdx75.c             |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm4450.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm6115.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm6125.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm6350.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm6375.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm7150.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm8150.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm8250.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm8350.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm8450.c            |  4 +-
 drivers/pinctrl/qcom/pinctrl-sm8550.c            |  2 +-
 drivers/pinctrl/qcom/pinctrl-sm8650.c            |  4 +-
 drivers/pinctrl/qcom/pinctrl-sm8750.c            |  4 +-
 drivers/pinctrl/qcom/pinctrl-x1e80100.c          |  2 +-
 drivers/pinctrl/renesas/pinctrl-rza1.c           |  2 +-
 drivers/pinctrl/renesas/pinctrl-rza2.c           |  2 +-
 drivers/pinctrl/renesas/pinctrl-rzg2l.c          |  2 +-
 drivers/pinctrl/renesas/pinctrl-rzv2m.c          |  2 +-
 include/linux/device/devres.h                    |  2 +
 include/linux/pinctrl/pinctrl.h                  | 14 ++++++
 include/linux/pinctrl/pinmux.h                   |  2 +
 79 files changed, 274 insertions(+), 225 deletions(-)
---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20250701-pinctrl-gpio-pinfuncs-de82bd9aac43

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>


             reply	other threads:[~2025-08-12  8:27 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-12  8:26 Bartosz Golaszewski [this message]
2025-08-12  8:27 ` [PATCH v4 01/15] devres: provide devm_kmemdup_const() Bartosz Golaszewski
2025-08-12  9:16   ` Andy Shevchenko
2025-08-12  8:27 ` [PATCH v4 02/15] pinctrl: ingenic: use struct pinfunction instead of struct function_desc Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 03/15] pinctrl: airoha: replace struct function_desc with struct pinfunction Bartosz Golaszewski
2025-08-13 16:57   ` Andy Shevchenko
2025-08-14  7:37     ` Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 04/15] pinctrl: mediatek: mt7988: use PINCTRL_PIN_FUNCTION() Bartosz Golaszewski
2025-08-14  3:57   ` Chen-Yu Tsai
2025-08-12  8:27 ` [PATCH v4 05/15] pinctrl: mediatek: moore: replace struct function_desc with struct pinfunction Bartosz Golaszewski
2025-08-14  3:55   ` Chen-Yu Tsai
2025-08-12  8:27 ` [PATCH v4 06/15] pinctrl: imx: don't access the pin function radix tree directly Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 07/15] pinctrl: keembay: release allocated memory in detach path Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 08/15] pinctrl: keembay: use a dedicated structure for the pinfunction description Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 09/15] pinctrl: constify pinmux_generic_get_function() Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 10/15] pinctrl: make struct pinfunction a pointer in struct function_desc Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 11/15] pinctrl: qcom: use generic pin function helpers Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 12/15] pinctrl: allow to mark pin functions as requestable GPIOs Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 13/15] pinctrl: qcom: add infrastructure for marking pin functions as GPIOs Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 14/15] pinctrl: qcom: mark the `gpio` and `egpio` pins function as non-strict functions Bartosz Golaszewski
2025-08-12  8:27 ` [PATCH v4 15/15] pinctrl: qcom: make the pinmuxing strict Bartosz Golaszewski

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