Re: [PATCH] i2c: mux: reg: use device property accessors

[Abdurrahman Hussain]

On Thu Jan 15, 2026 at 11:16 AM PST, Abdurrahman Hussain wrote:
>
>
>> On Jan 15, 2026, at 3:03 AM, Peter Rosin <peda@xxxxxxxxxx> wrote:
>>
>> Hi!
>>
>> 2026-01-15 at 01:35, Abdurrahman Hussain wrote:
>>> [You don't often get email from abdurrahman@xxxxxxxxxx. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>>
>>> This makes the driver work on non-OF platforms.
>>
>> What measures have been taken to make sure that things continues
>> to work on OF platforms?
>>
>> Cheers,
>> Peter
>
> Unfortunately, I don’t have an OF platform available where I could test this.
> I am open to give this a try though if I could borrow a device that uses the driver.

Hi Peter,

I haven't heard back from you and was wondering if you had any comments
regarding the code. This change makes the driver work on ACPI based systems.
I have tested this change on a AMD (x86-64) based embedded system with a
custom Xilinx based FPGA which maps a 32bit register as a mux for several
Xilinx I2C IP blocks on the same FPGA (i2c-xiic driver). The FPGA itself is
a PCIe device and the firmware (ACPI) description looks like this:

    Scope (_SB.PCI0.GPP6)
    {
        Device (FPGA)
        {
            Name (_ADR, 0x00000000)

            Device (MUX0) {
                Name (_HID, "PRP0001")
                Name (_CRS, ResourceTemplate () {
                    Memory32Fixed (ReadWrite, 0x80900010, 0x00000004)
                })
                Name (_DSD, Package () {
                    ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
                    Package () {
                        Package () { "compatible", "i2c-mux-reg" },
                        Package () { "i2c-parent", \_SB.PCI0.GPP6.FPGA.II00 },
                    }
                })

                Device (CH0) {
                    Name (_ADR, 0)

                    Device (EEP1) {
                        Name (_HID, "PRP0001")
                        Name (_STR, Unicode ("PSU1 EEPROM"))
                        Name (_CRS, ResourceTemplate () {
                            I2cSerialBusV2 (0x50,, 100000,,
                                "\\_SB.PCI0.GPP6.FPGA.MUX0.CH0")
                        })
                        Name (_DSD, Package () {
                            ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
                            Package () {
                                Package () { "compatible", "atmel,24c02" },
                                Package () { "pagesize", 8 },
                                Package () { "read-only", 1 },
                                Package () { "label", "psu" },
                            }
                        })
                    }
                }
            }
        }
    }

As I mentioned earlier, I don't have access to an OF platform using this driver
to test things out. If you could point me to a readily available OF device I am
willing to test it out.

Thanks,
Abdurrahman