[RFC 0/6] firmware: scmi: add SCMI pinctrl protocol support
Peng Fan
peng.fan at oss.nxp.com
Fri Sep 8 14:14:37 CEST 2023
On 9/7/2023 5:58 PM, AKASHI Takahiro wrote:
> Hi Peng,
>
> On Wed, Sep 06, 2023 at 12:09:45AM -0300, Fabio Estevam wrote:
>> Adding Peng Fan, who is working on scmi/pinctrl support for i.MX9:
Thanks for looping me.
>>
>> https://lore.kernel.org/all/ZO9GLG5tQynYyAvR@pluto/T/
>
> I made a comment there.
Thanks for help reviewing.
>
> BTW, do you already have your own implementation of SCMI pin control
> protocol at SCMI firmware(server)?
We follow the SCMI 3.2 pinctrl protocol, but use OEM config type.
> Is it public available?
The firmware is not public for now, but I could share
the config set array, something like this:
MUX TYPE, MUX REG, CONF_TYPE, CONF REG,
DAISY TYPE, DAISY ID, DAISY VALUE.
Regards,
Peng.
>
> -Takahiro Akashi
>
>
>> On Tue, Sep 5, 2023 at 11:41 PM AKASHI Takahiro
>> <takahiro.akashi at linaro.org> wrote:
>>>
>>> This is an RFC and meant to get feedback from other developers as
>>> - the specification (pinctrl part) is still in a draft
>>> - the upstream patch for linux, including dt bindings, is still WIP
>>> - I'm not confident the drivers are generic enough to cover most HWs
>>> - The tests ("ut") doesn't cover all the features yet
>>>
>>>
>>> This patch series allows users to access SCMI pin control protocol provided
>>> by SCMI server (platform). See SCMI specification document v3.2 beta 2[1]
>>> for more details about SCMI pin control protocol.
>>>
>>> The implementation consists of two layers:
>>> - basic helper functions for SCMI pin control protocol
>>> in drivers/firmware/scmi/pinctrl.c (patch#2)
>>> - DM-compliant pinctrl/gpio drivers, which utilizes the helper functions,
>>> in drivers/pinctrl/pinctrl-scmi.c (patch#3,#4)
>>>
>>> [1] https://developer.arm.com/documentation/den0056/e/?lang=en
>>>
>>> DT bindings
>>> ===========
>>> Upstream pinctrl patch for linux defines the bindings in [2] though
>>> it doesn't say much.
>>> I expect that my implementation basically complies with U-Boot's generic
>>> bindings described in [3], but not all the features are verified.
>>>
>>> As for gpio, unless you hard-code pin assignments directly in a device
>>> driver, my implementation allows the following alternatives in DT.
>>> Either way, we may need an additional binding description for gpio.
>>>
>>> (A)
>>> scmi {
>>> ... // other protocols
>>> scmi_pinctrl: protocol at 19 { // Pin control protocol
>>> ...
>>> {pinmux definitions}... // if any, including GPIO?
>>> }
>>> }
>>> scmi_gpio: scmi_gpio {
>>> compatible = "arm,scmi-gpio-generic";
>>> gpio-controller;
>>> #gpio-cells = <2>;
>>> gpio-ranges = <&scmi_pinctrl 0 5 4>,
>>> <&scmi_pinctrl 4 0 0>;
>>> gpio-ranges-group-names = "",
>>> "ANOTHER_GPIO_GROUP";
>>> }
>>> some_device {
>>> ...
>>> reset-gpios = <&scmi_gpio 0 GPIO_ACTIVE_HIGH>;
>>> }
>>> (B)
>>> scmi {
>>> ... // other protocols
>>> scmi_pinctrl: protocol at 19 { // Pin control protocol
>>> ...
>>> {pinmux definitions}... // if any, including GPIO?
>>>
>>> scmi_gpio: scmi_gpio {
>>> // no need for "compatible"
>>> gpio-controller;
>>> #gpio-cells = <2>;
>>> gpio-ranges = <&scmi_pinctrl 0 5 4>,
>>> <&scmi_pinctrl 4 0 0>;
>>> gpio-ranges-group-names = "",
>>> "ANOTHER_GPIO_GROUP";
>>> }
>>> }
>>> }
>>> some_device {
>>> ...
>>> reset-gpios = <&scmi_gpio 0 GPIO_ACTIVE_HIGH>;
>>> }
>>> (C)
>>> if "gpio-ranges" is missing in gpio definition, assume 1:1 mapping,
>>> i.e. use a native pinctrl pin number (5).
>>> some_device {
>>> ...
>>> reset-gpios = <&scmi_gpio 5 GPIO_ACTIVE_HIGH>;
>>> }
>>>
>>>
>>> [2] https://lkml.iu.edu/hypermail/linux/kernel/2308.1/01084.html
>>> [3] <u-boot>/doc/device-tree-bindings/pinctrl/pinctrl-bindings.txt
>>> <u-boot>/doc/device-tree-bindings/gpio/gpio.txt
>>>
>>> Test
>>> ====
>>> The patch series was tested on the following platforms:
>>> * sandbox ("ut dm pinmux" and manually using gpio command)
>>>
>>>
>>> Prerequisite:
>>> =============
>>> * This patch series is based on my WIP "Base protocol support" patches
>>> on v2023.10-rc3. You can fetch the whole code from [4].
>>>
>>> [4] https://git.linaro.org/people/takahiro.akashi/u-boot.git
>>> branch:scmi/pinctrl
>>>
>>>
>>> Patches:
>>> ========
>>> Patch#1: Add SCMI base protocol driver
>>> Patch#2-#4: Add drivers
>>> Patch#5-#6: Test related
>>>
>>>
>>> Change history:
>>> ===============
>>> RFC (Sep 6, 2023)
>>> * initial release as RFC
>>>
>>> AKASHI Takahiro (6):
>>> firmware: scmi: fix protocol enumeration logic
>>> firmware: scmi: add pinctrl protocol support
>>> pinctrl: add scmi driver
>>> gpio: add scmi driver based on pinctrl
>>> firmware: scmi: add pseudo pinctrl protocol support on sandbox
>>> test: dm: add SCMI pinctrl test
>>>
>>> arch/sandbox/dts/test.dts | 115 +++
>>> cmd/scmi.c | 1 +
>>> drivers/firmware/scmi/Kconfig | 3 +
>>> drivers/firmware/scmi/Makefile | 1 +
>>> drivers/firmware/scmi/pinctrl.c | 412 ++++++++
>>> drivers/firmware/scmi/sandbox-scmi_agent.c | 722 +++++++++++++
>>> drivers/firmware/scmi/scmi_agent-uclass.c | 18 +-
>>> drivers/pinctrl/Kconfig | 11 +
>>> drivers/pinctrl/Makefile | 1 +
>>> drivers/pinctrl/pinctrl-scmi.c | 1071 ++++++++++++++++++++
>>> include/scmi_agent-uclass.h | 2 +
>>> include/scmi_protocols.h | 435 ++++++++
>>> test/dm/scmi.c | 62 ++
>>> 13 files changed, 2852 insertions(+), 2 deletions(-)
>>> create mode 100644 drivers/firmware/scmi/pinctrl.c
>>> create mode 100644 drivers/pinctrl/pinctrl-scmi.c
>>>
>>> --
>>> 2.34.1
>>>
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