[PATCH v6 0/4] firmware: arm_scmi: Add SCMI v3.2 pincontrol protocol basic support

[Peng Fan (OSS)]

This patchset is a rework from Oleksii's RFC v5 patchset
https://lore.kernel.org/all/cover.1698353854.git.oleksii_moisieiev@xxxxxxxx/

This patchset introduces some changes based on RFC v5:
- introduce helper get_max_msg_size
- support compatible string
- iterate the id_table
- Support multiple configs in one command
- Added i.MX support
- Patch 5 firmware: arm_scmi: Add SCMI v3.2 pincontrol protocol basic support
  is almost same as RFCv5 expect multiple configs support.
- Patch 4 the dt-bindings includes compatible string to support i.MX
- Rebased on 2023-12-15 linux-next/master

If any comments from RFC v5 are missed, I am sorry in advance.

This PINCTRL Protocol is following Version 3.2 SCMI Spec Beta release.

On ARM-based systems, a separate Cortex-M based System Control Processor
(SCP) provides control on pins, as well as with power, clocks, reset
controllers. So implement the driver to support such cases.

The i.MX95 Example as below:

Configuration:
The scmi-pinctrl driver can be configured using DT bindings.
For example:
/ {
	sram0: sram@445b1000 {
		compatible = "mmio-sram";
		reg = <0x0 0x445b1000 0x0 0x400>;

		#address-cells = <1>;
		#size-cells = <1>;
		ranges = <0x0 0x0 0x445b1000 0x400>;

		scmi_buf0: scmi-sram-section@0 {
			compatible = "arm,scmi-shmem";
			reg = <0x0 0x80>;
		};

		scmi_buf1: scmi-sram-section@80 {
			compatible = "arm,scmi-shmem";
			reg = <0x80 0x80>;
		};
	};

	firmware {
		scmi {
			compatible = "arm,scmi";
			mboxes = <&mu2 5 0>, <&mu2 3 0>, <&mu2 3 1>;
			shmem = <&scmi_buf0>, <&scmi_buf1>;
			#address-cells = <1>;
			#size-cells = <0>;

			scmi_iomuxc: protocol@19 {
				compatible = "fsl,imx95-scmi-pinctrl";
				reg = <0x19>;
			};
		};
	};
};

&scmi_iomuxc {
	pinctrl_tpm3: tpm3grp {
		fsl,pins = <
			IMX95_PAD_GPIO_IO12__TPM3_CH2(0x51e)
		>;
	};
};

This patchset has been tested on i.MX95-19x19-EVK board.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
Changes in v6:
- Update pinctrl driver following ARM SCMI 3.2 public release
- Addressed Dan's comments, and followed Dan's suggestions, thanks.
- Dropped R-b/T-b in patch 3/4 and patch 4/4,
- Link to v5: https://lore.kernel.org/r/20240314-pinctrl-scmi-v5-0-b19576e557f2@xxxxxxx

Changes in v5:
- Rebased to linux-next next-20240313
- Link to v4: https://lore.kernel.org/r/20240223-pinctrl-scmi-v4-0-10eb5a379274@xxxxxxx

Changes in v4:
- Rebased to next-20240222
- Drop pinctrl-scmi-imx and compatible patches in V3
- Add T-b and R-b collected from v3
- Link to v3: https://lore.kernel.org/r/20240121-pinctrl-scmi-v3-0-8d94ba79dca8@xxxxxxx

Changes in v3:
- Add R-b for dt-binding patch
- Use 80 chars per line to align with other scmi drivers
- Add pinctrl_scmi_alloc_configs pinctrl_scmi_free_configs to replace
  driver global config_value and config_type array to avoid in parrell
  access issue. When num_configs is larger than 4, use alloc, else use
  stack.
- Drop the separate MAITAINERS entry for firmware scmi pinctrl
- Use enum type, not u8 when referring the scmi or generic pin conf type
- Drop scmi_pinctrl_config_get_all which is not used at all for now.
- Update copyright year to 2024
- Move the enum scmi_pinctrl_conf_type above pinctrl_proto_ops for consistency
- Link to v2: https://lore.kernel.org/r/20240104-pinctrl-scmi-v2-0-a9bd86ab5a84@xxxxxxx

Changes in v2:
 Added comments, and added R-b for Patch 1
 Moved the compatile string and i.MX patch to the end, marked NOT APPLY
 Patchset based on lore.kernel.org/all/20231221151129.325749-1-cristian.marussi@xxxxxxx/
 Addressed the binding doc issue, dropped i.MX content.
 For the firmware pinctrl scmi driver, addressed the comments from Cristian
 For the pinctrl scmi driver, addressed comments from Cristian

 For the i.MX95 OEM stuff, I not have good idea, expect using compatbile
 string. Maybe the firmware public an protocol attribute to indicate it is
 VENDOR stuff or NXP use a new protocol id, not 0x19. But I think
 current pinctrl-scmi.c not able to support OEM config, should we extend
 it with some method? Anyway if patch 1-4 is good enough, they could
 be picked up first.

 Since I am only able to test the patch on i.MX95 which not support
 geneirc pinconf, only OEM configs are tested in my side.

---
Peng Fan (4):
      firmware: arm_scmi: introduce helper get_max_msg_size
      dt-bindings: firmware: arm,scmi: support pinctrl protocol
      firmware: arm_scmi: Add SCMI v3.2 pincontrol protocol basic support
      pinctrl: Implementation of the generic scmi-pinctrl driver

 .../devicetree/bindings/firmware/arm,scmi.yaml     |  50 ++
 MAINTAINERS                                        |   1 +
 drivers/firmware/arm_scmi/Makefile                 |   1 +
 drivers/firmware/arm_scmi/driver.c                 |  17 +
 drivers/firmware/arm_scmi/pinctrl.c                | 922 +++++++++++++++++++++
 drivers/firmware/arm_scmi/protocols.h              |   3 +
 drivers/pinctrl/Kconfig                            |  11 +
 drivers/pinctrl/Makefile                           |   1 +
 drivers/pinctrl/pinctrl-scmi.c                     | 564 +++++++++++++
 include/linux/scmi_protocol.h                      |  75 ++
 10 files changed, 1645 insertions(+)
---
base-commit: 70ca90deeca172d343bd18bf7fb2f992214c23c0
change-id: 20231215-pinctrl-scmi-4c5b0374f4c6

Best regards,
-- 
Peng Fan <peng.fan@xxxxxxx>