linux-kernel - Re: [PATCH] ASoC: dapm: Add support for multi register mux

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Fri, 04 Apr 2014 09:40:21 +0200
From:	Lars-Peter Clausen <lars@...afoo.de>
To:	Arun Shamanna Lakshmi <aruns@...dia.com>
CC:	"lgirdwood@...il.com" <lgirdwood@...il.com>,
	"broonie@...nel.org" <broonie@...nel.org>,
	"swarren@...dotorg.org" <swarren@...dotorg.org>,
	"perex@...ex.cz" <perex@...ex.cz>, "tiwai@...e.de" <tiwai@...e.de>,
	"alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Songhee Baek <sbaek@...dia.com>
Subject: Re: [PATCH] ASoC: dapm: Add support for multi register mux

On 04/04/2014 09:34 AM, Arun Shamanna Lakshmi wrote:
>
>> -----Original Message-----
>> From: Lars-Peter Clausen [mailto:lars@...afoo.de]
>> Sent: Friday, April 04, 2014 12:32 AM
>> To: Arun Shamanna Lakshmi
>> Cc: lgirdwood@...il.com; broonie@...nel.org;
>> swarren@...dotorg.org; perex@...ex.cz; tiwai@...e.de; alsa-
>> devel@...a-project.org; linux-kernel@...r.kernel.org; Songhee Baek
>> Subject: Re: [PATCH] ASoC: dapm: Add support for multi register mux
>>
>> On 04/03/2014 10:11 PM, Arun Shamanna Lakshmi wrote:
>> [...]
>>>> Here as well, default for bit_pos should be 0.
>>>
>>> This means when 'None' of the options are selected, by default, it
>>> enumerates to 0. Since we are using __ffs, BIT(0) of Register-0 also
>>> enumerates to 0. That's the reason why I used just ffs in the first place.
>>> Let me know your opinion. My value table looks like below.
>>>
>>> #define MUX_VALUE(npart, nbit)	(nbit + 32 * npart)
>>> static const int mux_values[] = {
>>> 	0,
>>> 	MUX_VALUE(0, 0),
>>> 	.
>>> 	.
>>> 	.
>>> 	MUX_VALUE(0, 31),
>>> 	/* above inputs are for part0 mux */
>>> 	MUX_VALUE(1, 0),
>>> 	.
>>> 	.
>>> 	.
>>> 	MUX_VALUE(1, 31),
>>> 	/* above inputs are for part1 mux */
>>> 	MUX_VALUE(2, 0),
>>> 	.
>>> 	.
>>> 	.
>>> 	MUX_VALUE(2, 31),
>>> 	/* above inputs are for part2 mux */
>>> };
>>
>> Ok, so having none of the input selected should be a valid user selectable
>> option?
>
> Yes. If 'None' is selected, it goes and clears the register. So, can we have ffs( )
> instead of __ffs( ) ? It would fix this case.

Yes, but you need to make sure to handle it also correctly in the put 
handler, since all of the registers need to be written to 0 in that case.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/