Subject: Re: [alsa-devel] [RFC 2/2] sound: ppc: keywest: drop using attach adapter

From: Takashi Iwai <[email-masked]>
Date: Thu, 04 Dec 2014 17:58:55 +0100

At Thu,  4 Dec 2014 17:41:53 +0100,
Wolfram Sang wrote:
> 
> As we now have deferred probing, we can use a custom mechanism and
> finally get rid of the legacy interface from the i2c core.
> 
> Signed-off-by: Wolfram Sang <[email-masked]>
> ---
>  sound/ppc/keywest.c | 21 ++++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/ppc/keywest.c b/sound/ppc/keywest.c
> index 0d1c27e911b8..a957f32368fa 100644
> --- a/sound/ppc/keywest.c
> +++ b/sound/ppc/keywest.c
> @@ -52,7 +52,7 @@ static int keywest_attach_adapter(struct i2c_adapter *adapter)
>  		return -EINVAL;
>  
>  	if (strncmp(adapter->name, "mac-io", 6))
> -		return 0; /* ignored */
> +		return -EINVAL; /* ignored */
>  
>  	memset(&info, 0, sizeof(struct i2c_board_info));
>  	strlcpy(info.type, "keywest", I2C_NAME_SIZE);
> @@ -100,7 +100,6 @@ static struct i2c_driver keywest_driver = {
>  	.driver = {
>  		.name = "PMac Keywest Audio",
>  	},
> -	.attach_adapter = keywest_attach_adapter,
>  	.probe = keywest_probe,
>  	.remove = keywest_remove,
>  	.id_table = keywest_i2c_id,
> @@ -132,16 +131,32 @@ int snd_pmac_tumbler_post_init(void)
>  /* exported */
>  int snd_pmac_keywest_init(struct pmac_keywest *i2c)
>  {
> -	int err;
> +	struct i2c_adapter *adap;
> +	int err, i = 0;
>  
>  	if (keywest_ctx)
>  		return -EBUSY;
>  
> +	adap = i2c_get_adapter(0);
> +	if (!adap)
> +		return -EPROBE_DEFER;
> +
>  	keywest_ctx = i2c;
>  
>  	if ((err = i2c_add_driver(&keywest_driver))) {
>  		snd_printk(KERN_ERR "cannot register keywest i2c driver\n");
> +		i2c_put_adapter(adap);
>  		return err;
>  	}
> +
> +	/* We assume Macs have consecutive I2C bus numbers starting at 0 */
> +	while (adap) {
> +		err = keywest_attach_adapter(adap);
> +		if (!err)
> +			break;
> +		i2c_put_adapter(adap);
> +		adap = i2c_get_adapter(++i);
> +	}
> +
>  	return 0;

What if adap is NULL in the last while loop?  Isn't it supposed to
return an error?

thanks,

Takashi