Re: [Qemu-devel] [PATCH v2 2/3] audio: use object link instead of qdev property to pass wm8750 reference

[Philippe Mathieu-Daudé]

Hi Mao,

On 12/10/2018 10:30, Mao Zhongyi wrote:
> According to qdev-properties.h, properties of pointer type should
> be avoided, it seems a link type property is a good substitution.
> 
> Cc: Jan Kiszka <address@hidden>
> Cc: Peter Maydell <address@hidden>
> Cc: Gerd Hoffmann <address@hidden>
> To: address@hidden
> 
> Signed-off-by: Mao Zhongyi <address@hidden>
> ---
>  hw/arm/musicpal.c          |  3 ++-
>  hw/audio/marvell_88w8618.c | 14 ++++++--------
>  2 files changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/arm/musicpal.c b/hw/arm/musicpal.c
> index 3dafb41b0b..ac266f9253 100644
> --- a/hw/arm/musicpal.c
> +++ b/hw/arm/musicpal.c
> @@ -1695,7 +1695,8 @@ static void musicpal_init(MachineState *machine)
>      wm8750_dev = i2c_create_slave(i2c, TYPE_WM8750, MP_WM_ADDR);
>      dev = qdev_create(NULL, "mv88w8618_audio");
>      s = SYS_BUS_DEVICE(dev);
> -    qdev_prop_set_ptr(dev, TYPE_WM8750, wm8750_dev);
> +    object_property_set_link(OBJECT(dev), OBJECT(wm8750_dev),
> +                             TYPE_WM8750, NULL);
>      qdev_init_nofail(dev);
>      sysbus_mmio_map(s, 0, MP_AUDIO_BASE);
>      sysbus_connect_irq(s, 0, pic[MP_AUDIO_IRQ]);
> diff --git a/hw/audio/marvell_88w8618.c b/hw/audio/marvell_88w8618.c
> index cf6ce6979b..baab4a3d53 100644
> --- a/hw/audio/marvell_88w8618.c
> +++ b/hw/audio/marvell_88w8618.c
> @@ -15,6 +15,7 @@
>  #include "hw/i2c/i2c.h"
>  #include "hw/audio/wm8750.h"
>  #include "audio/audio.h"
> +#include "qapi/error.h"
>  
>  #define MP_AUDIO_SIZE           0x00001000
>  
> @@ -252,6 +253,11 @@ static void mv88w8618_audio_init(Object *obj)
>      memory_region_init_io(&s->iomem, obj, &mv88w8618_audio_ops, s,
>                            "audio", MP_AUDIO_SIZE);
>      sysbus_init_mmio(dev, &s->iomem);
> +
> +    object_property_add_link(OBJECT(dev), "mv88w8618", TYPE_WM8750,
> +                             (Object **) &s->wm,
> +                             qdev_prop_allow_set_link_before_realize,
> +                             0, &error_abort);
>  }
>  
>  static void mv88w8618_audio_realize(DeviceState *dev, Error **errp)
> @@ -279,11 +285,6 @@ static const VMStateDescription mv88w8618_audio_vmsd = {
>      }
>  };
>  
> -static Property mv88w8618_audio_properties[] = {
> -    DEFINE_PROP_PTR(TYPE_WM8750, mv88w8618_audio_state, wm),
> -    {/* end of list */},
> -};
> -
>  static void mv88w8618_audio_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -291,9 +292,6 @@ static void mv88w8618_audio_class_init(ObjectClass 
> *klass, void *data)
>      dc->realize = mv88w8618_audio_realize;
>      dc->reset = mv88w8618_audio_reset;
>      dc->vmsd = &mv88w8618_audio_vmsd;
> -    dc->props = mv88w8618_audio_properties;
> -    /* Reason: pointer property "wm8750" */
> -    dc->user_creatable = false;

Having a link property isn't it the same restriction?

>  }
>  
>  static const TypeInfo mv88w8618_audio_info = {
>