Re: [PATCH 06/17] hw/misc/max111x: provide QOM properties for setting initial values

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 6/28/20 4:24 PM, Peter Maydell wrote:
> Add some QOM properties to the max111x ADC device to allow the
> initial values to be configured. Currently this is done by
> board code calling max111x_set_input() after it creates the
> device, which doesn't work on system reset.
> 
> This requires us to implement a reset method for this device,
> so while we're doing that make sure we reset the other parts
> of the device state.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  hw/misc/max111x.c | 57 ++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 47 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/misc/max111x.c b/hw/misc/max111x.c
> index 2b87bdee5b7..d0e5534e4f5 100644
> --- a/hw/misc/max111x.c
> +++ b/hw/misc/max111x.c
> @@ -15,11 +15,15 @@
>  #include "hw/ssi/ssi.h"
>  #include "migration/vmstate.h"
>  #include "qemu/module.h"
> +#include "hw/qdev-properties.h"
>  
>  typedef struct {
>      SSISlave parent_obj;
>  
>      qemu_irq interrupt;
> +    /* Values of inputs at system reset (settable by QOM property) */
> +    uint8_t reset_input[8];
> +
>      uint8_t tb1, rb2, rb3;
>      int cycle;
>  

An eventual improvement is to make 'inputs' a class property:

  MAX111xClass {
      SSISlaveClass parent_obj;

      unsigned input_count;
  }

"eventual" because from a QOM point it is cleaner, but we'd have
to add more boiler-plate casts, so code less clear.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>