Re: [PATCH] AC97 bus interface for ad-hoc drivers

[Takashi Iwai <tiwai@suse.de>]

At Tue, 19 Jul 2005 13:20:24 +0100,
Liam Girdwood wrote:
> 
> This patch adds support for ad-hoc AC97 device drivers (e.g WM97xx and
> UCB touchscreen drivers) and was originally posted to the list by
> Nicolas Pitre as an RFC. 
> 
> Changes from RFC version :-
> 
>   o Now matches codec name within codec group.
>   o Added ac97_dev_release() to stop kernel complaining about no release
> method for device.

Thanks for the patch.  The idea is fine, and the code looks almost
OK except for the below.

Could you describe the full changelog (or paste Nicolas' RFC) ?


> diff --git a/sound/pci/ac97/Makefile b/sound/pci/ac97/Makefile
> --- a/sound/pci/ac97/Makefile
> +++ b/sound/pci/ac97/Makefile
> @@ -12,7 +12,7 @@ endif
>  snd-ak4531-codec-objs := ak4531_codec.o
>  
>  # Toplevel Module Dependency
> -obj-$(CONFIG_SND_AC97_CODEC) += snd-ac97-codec.o
> +obj-$(CONFIG_SND_AC97_CODEC) += snd-ac97-codec.o ac97_bus.o

Better to keep snd- prefix for ac97_bus module (although it can be
used independently from ALSA)...?  It's an open question.

> diff --git a/sound/pci/ac97/ac97_bus.c b/sound/pci/ac97/ac97_bus.c
> new file mode 100644
> --- /dev/null
> +++ b/sound/pci/ac97/ac97_bus.c
(snip)
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/device.h>
> +#include <linux/string.h>
> +
> +#include <sound/driver.h>
> +#include <sound/core.h>
> +#include <sound/ac97_codec.h>

Don't include unnecessary header files.

> diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c
> --- a/sound/pci/ac97/ac97_codec.c
> +++ b/sound/pci/ac97/ac97_codec.c
(snip)
> @@ -2117,6 +2124,14 @@ int snd_ac97_mixer(ac97_bus_t *bus, ac97
>  		snd_ac97_free(ac97);
>  		return err;
>  	}
> +
> +	ac97->dev.bus = &ac97_bus_type;
> +	ac97->dev.parent = ac97->bus->card->dev;
> +	ac97->dev.platform_data = ac97;
> +	ac97->dev.release = ac97_dev_release;
> +	strncpy(ac97->dev.bus_id, snd_ac97_get_short_name(ac97), BUS_ID_SIZE);
> +	if ((err = device_register(&ac97->dev)) < 0)
> +		return err;

Need to call snd_ac97_free() in the error path (but reset dev.bus to
NULL to avoid unregister).


Takashi


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