diff mbox series

[v1] ASoC: tas2781: mark const variables tas2563_dvc_table as __maybe_unused

Message ID 20240822063205.662-1-shenghao-ding@ti.com
State Accepted
Commit 1a9e3b0af301413210319e6946fb4b0b1ad71ccc
Headers show
Series [v1] ASoC: tas2781: mark const variables tas2563_dvc_table as __maybe_unused | expand

Commit Message

Shenghao Ding Aug. 22, 2024, 6:32 a.m. UTC
In case of tas2781, tas2563_dvc_table will be unused,
so mark it as __maybe_unused.

Signed-off-by: Shenghao Ding <shenghao-ding@ti.com>
---
 include/sound/tas2563-tlv.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Shenghao Ding Aug. 24, 2024, 6:33 a.m. UTC | #1
Hi Andy
Glad to answer your question.

> -----Original Message-----
> From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Sent: Friday, August 23, 2024 9:34 PM
> To: Ding, Shenghao <shenghao-ding@ti.com>
> Cc: broonie@kernel.org; lgirdwood@gmail.com; perex@perex.cz; pierre-
> louis.bossart@linux.intel.com; 13916275206@139.com; zhourui@huaqin.com;
> alsa-devel@alsa-project.org; Salazar, Ivan <i-salazar@ti.com>;
> liam.r.girdwood@intel.com; Yue, Jaden <jaden-yue@ti.com>; yung-
> chuan.liao@linux.intel.com; Rao, Dipa <dipa@ti.com>; yuhsuan@google.com;
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> ji@ti.com>; darren.ye@mediatek.com; antheas.dk@gmail.com;
> Jerry2.Huang@lcfuturecenter.com; jim.shil@goertek.com
> Subject: Re: [EXTERNAL] Re: [PATCH v1] ASoC: tas2781: mark const variables
> tas2563_dvc_table as __maybe_unused
> 
> On Fri, Aug 23, 2024 at 02: 24: 17AM +0000, Ding, Shenghao wrote: > > From:
> Andy Shevchenko <andriy. shevchenko@ linux. intel. com> > > Sent: Thursday,
> August 22, 2024 9: 37 PM > > To: Ding, Shenghao <shenghao-ding@ ti. com>
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> On Fri, Aug 23, 2024 at 02:24:17AM +0000, Ding, Shenghao wrote:
> > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > Sent: Thursday, August 22, 2024 9:37 PM
> > > To: Ding, Shenghao <shenghao-ding@ti.com> On Thu, Aug 22, 2024 at
> > > 02:32:02PM +0800, Shenghao Ding wrote:
> 
> ...
> 
> > > >  /* pow(10, db/20) * pow(2,30) */
> > > > -static const unsigned char tas2563_dvc_table[][4] = {
> > > > +static const __maybe_unused unsigned char tas2563_dvc_table[][4]
> > > > += {
> > > >  	{ 0X00, 0X00, 0X00, 0X00 }, /* -121.5db */
> > > >  	{ 0X00, 0X00, 0X03, 0XBC }, /* -121.0db */
> > > >  	{ 0X00, 0X00, 0X03, 0XF5 }, /* -120.5db */
> > >
> > > As far as I can see in the latest Linux Next the above mentioned
> > > table is used solely in sound/soc/codecs/tas2781-i2c.c. Why not
> > > moving it to the C file instead?
> > We have a big plan to implement the digital gain for tas2563 in the
> > side codec driver too, so abstracted this table into a separated header file.
> 
> So, this __maybe_unused is a temporary stub, correct? Just don't forget to
> remove it when the mentioned functionality will be ready.
> 
> Thanks for the explanation.
To add __maybe_unused is not temporary, because this driver support both 
tas2563 and tas2781, if the hardware only contains tas2781 chips, 
tas2563_dvc_table is obviously useless, so marked it as __maybe_unused.
> 
> --
> With Best Regards,
> Andy Shevchenko
>
Andy Shevchenko Aug. 26, 2024, 10:02 a.m. UTC | #2
On Sat, Aug 24, 2024 at 06:33:41AM +0000, Ding, Shenghao wrote:
> > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Sent: Friday, August 23, 2024 9:34 PM
> > On Fri, Aug 23, 2024 at 02:24:17AM +0000, Ding, Shenghao wrote:
> > > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > > Sent: Thursday, August 22, 2024 9:37 PM
> > > > To: Ding, Shenghao <shenghao-ding@ti.com> On Thu, Aug 22, 2024 at
> > > > 02:32:02PM +0800, Shenghao Ding wrote:

...

> > > > >  /* pow(10, db/20) * pow(2,30) */
> > > > > -static const unsigned char tas2563_dvc_table[][4] = {
> > > > > +static const __maybe_unused unsigned char tas2563_dvc_table[][4]
> > > > > += {
> > > > >  	{ 0X00, 0X00, 0X00, 0X00 }, /* -121.5db */
> > > > >  	{ 0X00, 0X00, 0X03, 0XBC }, /* -121.0db */
> > > > >  	{ 0X00, 0X00, 0X03, 0XF5 }, /* -120.5db */
> > > >
> > > > As far as I can see in the latest Linux Next the above mentioned
> > > > table is used solely in sound/soc/codecs/tas2781-i2c.c. Why not
> > > > moving it to the C file instead?
> > > We have a big plan to implement the digital gain for tas2563 in the
> > > side codec driver too, so abstracted this table into a separated header file.
> > 
> > So, this __maybe_unused is a temporary stub, correct? Just don't forget to
> > remove it when the mentioned functionality will be ready.
> > 
> > Thanks for the explanation.
> To add __maybe_unused is not temporary, because this driver support both 
> tas2563 and tas2781, if the hardware only contains tas2781 chips, 
> tas2563_dvc_table is obviously useless, so marked it as __maybe_unused.

You got me confused.

__maybe_unused is a compile-time (okay, link-time) attribute. If what you are
telling is true, why do you need it and can't use respective #ifdef?

Otherwise, why is it in the _header_ file and not in the C-file?
diff mbox series

Patch

diff --git a/include/sound/tas2563-tlv.h b/include/sound/tas2563-tlv.h
index faa3e194f73b..bb269b21f460 100644
--- a/include/sound/tas2563-tlv.h
+++ b/include/sound/tas2563-tlv.h
@@ -18,7 +18,7 @@ 
 static const __maybe_unused DECLARE_TLV_DB_SCALE(tas2563_dvc_tlv, -12150, 50, 1);
 
 /* pow(10, db/20) * pow(2,30) */
-static const unsigned char tas2563_dvc_table[][4] = {
+static const __maybe_unused unsigned char tas2563_dvc_table[][4] = {
 	{ 0X00, 0X00, 0X00, 0X00 }, /* -121.5db */
 	{ 0X00, 0X00, 0X03, 0XBC }, /* -121.0db */
 	{ 0X00, 0X00, 0X03, 0XF5 }, /* -120.5db */