Re: [RFC PATCH v2 0/5] rust/hw: Add the I2C and the first GPIO device

["Chen Miao" <chenmiao@openatom.club>]

On 11/25/2025 6:47 PM, Paolo Bonzini wrote:
> On Tue, Oct 28, 2025 at 11:18 AM chenmiao <chenmiao@openatom.club> wrote:
>> We have implemented I2C and the first GPIO device in Rust for QEMU.
>> Additionally, in the respective patches, we have shared our insights and
>> experiences regarding the use of Rust for device modeling within QEMU.
>>
>> 1. The first patch implements the BusState for the I2CBus infrastructure.
>> 2. The second patch implements the I2CBus and I2CSlave infrastructure, along
>>     with a discussion of the challenges encountered during the implementation.
>> 3. The third patch moves the struct definition of the PCF8574 to the
>>     corresponding header file.
>> 4. The fourth patch provides a set of necessary helper functions for the PCF8574
>>     GPIO device.
>> 5. The fifth patch implements the PCF8574 GPIO device, along with a discussion
>>     of the issues and considerations addressed during the implementation.
>>
>> Regarding this series of patches, we have found that Rust for QEMU is indeed
>> still not mature enough and requires continuous iteration. Additionally, the
>> lack of basic documentation also needs to be addressed. In this regard, I hope
>> our team(HUST OpenAtom Open Source Club) can contribute to the documentation
>> efforts for Rust for QEMU.
>>
>> Link: https://groups.google.com/g/hust-os-kernel-patches/c/z7vHWg3xvDc
>>
>> Signed-off-by: Chao Liu <chao.liu@openatom.club>
>> Signed-off-by: Chen Miao <chenmiao@openatom.club>
> Hi! Are you going to send v3?
>
> Thanks,
>
> Paolo

Hello,

I've been a bit busy lately, but I believe we will complete V3 and send it out 
before mid-December.

Regards,

Chen Miao

>
>> ---
>> Changes in V2:
>>    - According to Zhao's suggestions, some modifications were made to the first
>>      and second patches respectively, such as changing some bus names, adding
>>      some Safety comments, and adding callbacks for I2CSlave.
>>    - While we were making changes to the first PATCH, Chao Liu pointed out that
>>      the realize function was unnecessary in the bus. After discussion, we
>>      removed the bus::realize function. Since no other components are currently
>>      using the bus, we added a TODO comment for clarification.
>>
>> chenmiao (5):
>>    rust/hw/core: Add the BusState of rust version
>>    rust/hw/core: Add rust bindings/funcs for i2c bus
>>    hw/gpio: Move the pcf8574 struct to header
>>    rust/hw/core: Provide some interfaces for the GPIO device
>>    rust/hw/gpio: Add the the first gpio device pcf8574
>>
>>   hw/gpio/Kconfig                      |   5 +
>>   hw/gpio/meson.build                  |   2 +-
>>   hw/gpio/pcf8574.c                    |  32 --
>>   include/hw/gpio/pcf8574.h            |  36 +++
>>   rust/Cargo.lock                      |  21 +-
>>   rust/Cargo.toml                      |   1 +
>>   rust/hw/Kconfig                      |   1 +
>>   rust/hw/core/meson.build             |   2 +
>>   rust/hw/core/src/bus.rs              |  44 +++
>>   rust/hw/core/src/i2c.rs              | 421 +++++++++++++++++++++++++++
>>   rust/hw/core/src/irq.rs              |   6 +-
>>   rust/hw/core/src/lib.rs              |   6 +
>>   rust/hw/core/src/qdev.rs             |  12 +-
>>   rust/hw/core/wrapper.h               |   1 +
>>   rust/hw/gpio/Kconfig                 |   2 +
>>   rust/hw/gpio/meson.build             |   1 +
>>   rust/hw/gpio/pcf8574/Cargo.toml      |  31 ++
>>   rust/hw/gpio/pcf8574/build.rs        |   1 +
>>   rust/hw/gpio/pcf8574/meson.build     |  50 ++++
>>   rust/hw/gpio/pcf8574/src/bindings.rs |  29 ++
>>   rust/hw/gpio/pcf8574/src/device.rs   | 180 ++++++++++++
>>   rust/hw/gpio/pcf8574/src/lib.rs      |   4 +
>>   rust/hw/gpio/pcf8574/wrapper.h       |  51 ++++
>>   rust/hw/meson.build                  |   1 +
>>   24 files changed, 902 insertions(+), 38 deletions(-)
>>   create mode 100644 rust/hw/core/src/bus.rs
>>   create mode 100644 rust/hw/core/src/i2c.rs
>>   create mode 100644 rust/hw/gpio/Kconfig
>>   create mode 100644 rust/hw/gpio/meson.build
>>   create mode 100644 rust/hw/gpio/pcf8574/Cargo.toml
>>   create mode 120000 rust/hw/gpio/pcf8574/build.rs
>>   create mode 100644 rust/hw/gpio/pcf8574/meson.build
>>   create mode 100644 rust/hw/gpio/pcf8574/src/bindings.rs
>>   create mode 100644 rust/hw/gpio/pcf8574/src/device.rs
>>   create mode 100644 rust/hw/gpio/pcf8574/src/lib.rs
>>   create mode 100644 rust/hw/gpio/pcf8574/wrapper.h
>>
>> --
>> 2.43.0
>>