Re: [RFC PATCH v2 3/5] hw/gpio: Move the pcf8574 struct to header

[Paolo Bonzini <pbonzini@redhat.com>]

On Tue, Oct 28, 2025 at 11:18 AM chenmiao <chenmiao@openatom.club> wrote:
>
> To better implement the Rust PCF8574 bindings, move its struct definition to
> the header file.

This should not be needed, the struct is entirely hidden within the C
implementation and the same should be true for the Rust one.

Paolo

> Signed-off-by: chenmiao <chenmiao@openatom.club>
> ---
>  hw/gpio/pcf8574.c         | 32 --------------------------------
>  include/hw/gpio/pcf8574.h | 36 ++++++++++++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+), 32 deletions(-)
>
> diff --git a/hw/gpio/pcf8574.c b/hw/gpio/pcf8574.c
> index 274b44bb61..670fc006bb 100644
> --- a/hw/gpio/pcf8574.c
> +++ b/hw/gpio/pcf8574.c
> @@ -15,38 +15,6 @@
>  #include "qemu/module.h"
>  #include "qom/object.h"
>
> -/*
> - * PCF8574 and compatible chips incorporate quasi-bidirectional
> - * IO. Electrically it means that device sustain pull-up to line
> - * unless IO port is configured as output _and_ driven low.
> - *
> - * IO access is implemented as simple I2C single-byte read
> - * or write operation. So, to configure line to input user write 1
> - * to corresponding bit. To configure line to output and drive it low
> - * user write 0 to corresponding bit.
> - *
> - * In essence, user can think of quasi-bidirectional IO as
> - * open-drain line, except presence of builtin rising edge acceleration
> - * embedded in PCF8574 IC
> - *
> - * PCF8574 has interrupt request line, which is being pulled down when
> - * port line state differs from last read. Port read operation clears
> - * state and INT line returns to high state via pullup.
> - */
> -
> -OBJECT_DECLARE_SIMPLE_TYPE(PCF8574State, PCF8574)
> -
> -#define PORTS_COUNT (8)
> -
> -struct PCF8574State {
> -    I2CSlave parent_obj;
> -    uint8_t  lastrq;     /* Last requested state. If changed - assert irq */
> -    uint8_t  input;      /* external electrical line state */
> -    uint8_t  output;     /* Pull-up (1) or drive low (0) on bit */
> -    qemu_irq handler[PORTS_COUNT];
> -    qemu_irq intrq;      /* External irq request */
> -};
> -
>  static void pcf8574_reset(DeviceState *dev)
>  {
>      PCF8574State *s = PCF8574(dev);
> diff --git a/include/hw/gpio/pcf8574.h b/include/hw/gpio/pcf8574.h
> index 3291d7dbbc..fe1ce891b7 100644
> --- a/include/hw/gpio/pcf8574.h
> +++ b/include/hw/gpio/pcf8574.h
> @@ -10,6 +10,42 @@
>  #ifndef _HW_GPIO_PCF8574
>  #define _HW_GPIO_PCF8574
>
> +#include "qemu/osdep.h"
> +#include "hw/i2c/i2c.h"
> +#include "qom/object.h"
> +
>  #define TYPE_PCF8574 "pcf8574"
>
> +/*
> + * PCF8574 and compatible chips incorporate quasi-bidirectional
> + * IO. Electrically it means that device sustain pull-up to line
> + * unless IO port is configured as output _and_ driven low.
> + *
> + * IO access is implemented as simple I2C single-byte read
> + * or write operation. So, to configure line to input user write 1
> + * to corresponding bit. To configure line to output and drive it low
> + * user write 0 to corresponding bit.
> + *
> + * In essence, user can think of quasi-bidirectional IO as
> + * open-drain line, except presence of builtin rising edge acceleration
> + * embedded in PCF8574 IC
> + *
> + * PCF8574 has interrupt request line, which is being pulled down when
> + * port line state differs from last read. Port read operation clears
> + * state and INT line returns to high state via pullup.
> + */
> +
> +OBJECT_DECLARE_SIMPLE_TYPE(PCF8574State, PCF8574)
> +
> +#define PORTS_COUNT (8)
> +
> +struct PCF8574State {
> +    I2CSlave parent_obj;
> +    uint8_t  lastrq;     /* Last requested state. If changed - assert irq */
> +    uint8_t  input;      /* external electrical line state */
> +    uint8_t  output;     /* Pull-up (1) or drive low (0) on bit */
> +    qemu_irq handler[PORTS_COUNT];
> +    qemu_irq intrq;      /* External irq request */
> +};
> +
>  #endif /* _HW_GPIO_PCF8574 */
> --
> 2.43.0
>