Re: [PATCH RESEND] hw/i2c: Enable an id for the pca954x devices

[Corey Minyard <cminyard@mvista.com>]

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On Tue, Mar 21, 2023 at 11:27:44AM -0700, Patrick Venture wrote:
> This allows the devices to be more readily found and specified.
> Without setting the id field, they can only be found by device type
> name, which doesn't let you specify the second of the same device type
> behind a bus.

So basically, this helps you find a specific device if you have more
than one of them.  Yeah, probably a good idea in this case.

> 
> Tested: Verified that by default the device was findable with the id
> 'pca954x[77]', for an instance attached at that address.
> 
> Signed-off-by: Patrick Venture <venture@google.com>
> Reviewed-by: Hao Wu <wuhaotsh@google.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  hw/i2c/i2c_mux_pca954x.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/hw/i2c/i2c_mux_pca954x.c b/hw/i2c/i2c_mux_pca954x.c
> index a9517b612a..4f8c2d6ae1 100644
> --- a/hw/i2c/i2c_mux_pca954x.c
> +++ b/hw/i2c/i2c_mux_pca954x.c
> @@ -20,6 +20,7 @@
>  #include "hw/i2c/i2c_mux_pca954x.h"
>  #include "hw/i2c/smbus_slave.h"
>  #include "hw/qdev-core.h"
> +#include "hw/qdev-properties.h"
>  #include "hw/sysbus.h"
>  #include "qemu/log.h"
>  #include "qemu/module.h"
> @@ -43,6 +44,8 @@ typedef struct Pca954xState {
>  
>      bool enabled[PCA9548_CHANNEL_COUNT];
>      I2CBus *bus[PCA9548_CHANNEL_COUNT];
> +
> +    char *id;
>  } Pca954xState;
>  
>  /*
> @@ -181,6 +184,17 @@ static void pca9548_class_init(ObjectClass *klass, void *data)
>      s->nchans = PCA9548_CHANNEL_COUNT;
>  }
>  
> +static void pca954x_realize(DeviceState *dev, Error **errp)
> +{
> +    Pca954xState *s = PCA954X(dev);
> +    DeviceState *d = DEVICE(s);
> +    if (s->id) {
> +        d->id = g_strdup(s->id);
> +    } else {
> +        d->id = g_strdup_printf("pca954x[%x]", s->parent.i2c.address);
> +    }
> +}
> +
>  static void pca954x_init(Object *obj)
>  {
>      Pca954xState *s = PCA954X(obj);
> @@ -197,6 +211,11 @@ static void pca954x_init(Object *obj)
>      }
>  }
>  
> +static Property pca954x_props[] = {
> +    DEFINE_PROP_STRING("id", Pca954xState, id),
> +    DEFINE_PROP_END_OF_LIST()
> +};

There is already an "id=" thing in qemu for doing links between front
ends and back ends.  That's probably not the best name to use.  Several
devices, like network devices, use "name" for identification in the
monitor.

-corey

> +
>  static void pca954x_class_init(ObjectClass *klass, void *data)
>  {
>      I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
> @@ -209,9 +228,12 @@ static void pca954x_class_init(ObjectClass *klass, void *data)
>      rc->phases.enter = pca954x_enter_reset;
>  
>      dc->desc = "Pca954x i2c-mux";
> +    dc->realize = pca954x_realize;
>  
>      k->write_data = pca954x_write_data;
>      k->receive_byte = pca954x_read_byte;
> +
> +    device_class_set_props(dc, pca954x_props);
>  }
>  
>  static const TypeInfo pca954x_info[] = {
> -- 
> 2.35.1.894.gb6a874cedc-goog
> 

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