Re: [PATCH 11/13] ASoC: wm_adsp: Add support for DSP control flags

From: Mark Brown <broonie@kernel.org>
To: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Cc: alsa-devel@alsa-project.org, patches@opensource.wolfsonmicro.com,
	lgirdwood@gmail.com
Subject: Re: [PATCH 11/13] ASoC: wm_adsp: Add support for DSP control flags
Date: Sat, 18 Apr 2015 18:23:06 +0100	[thread overview]
Message-ID: <20150418172306.GA26185@sirena.org.uk> (raw)
In-Reply-To: <1428928085-20250-12-git-send-email-ckeepax@opensource.wolfsonmicro.com>

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On Mon, Apr 13, 2015 at 01:28:03PM +0100, Charles Keepax wrote:
> The DSP control information contains various hints about the usage of
> the controls use these when handling the control.

> @@ -418,6 +419,9 @@ static int wm_coeff_put(struct snd_kcontrol *kcontrol,
>  	struct wm_coeff_ctl *ctl = (struct wm_coeff_ctl *)kcontrol->private_value;
>  	char *p = ucontrol->value.bytes.data;
>  
> +	if (ctl->flags && !(ctl->flags & WMFW_CTL_FLAG_WRITEABLE))
> +		return -EPERM;
> +
>  	memcpy(ctl->cache, p, ctl->len);
>  
>  	ctl->set = 1;

What would be even better for these would be to apply these at control
creation time so that controls that lack read or write support just
don't have the relevant operations in the first place.  That would not
be simpler and would allow the rest of the stack to do the right thing,
for example setting SNDRV_CTL_ELEM_ACCESS_READ and _WRITE properly.

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