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From: Takashi Iwai <tiwai@suse.de>
To: Sriram Periyasamy <sriram.oqensourz@gmail.com>
Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
	tiwai@suse.com, lgirdwood@gmail.com,
	Jeff Chang <richtek.jeff.chang@gmail.com>,
	broonie@kernel.org, matthias.bgg@gmail.com,
	jeff_chang@richtek.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [alsa-devel] [PATCH v4] ASoC: Add MediaTek MT6660 Speaker Amp Driver
Date: Thu, 09 Jan 2020 19:57:34 +0100	[thread overview]
Message-ID: <s5h36comp9d.wl-tiwai@suse.de> (raw)
In-Reply-To: <20200109171833.GA2709@sriram-VirtualBox>

On Thu, 09 Jan 2020 18:18:36 +0100,
Sriram Periyasamy wrote:
> 
> On Tue, Jan 07, 2020 at 11:09:05AM +0800, Jeff Chang wrote:
> > From: Jeff Chang <jeff_chang@richtek.com>
> > 
> > The MT6660 is a boosted BTL class-D amplifier with V/I sensing.
> > A built-in DC-DC step-up converter is used to provide efficient
> > power for class-D amplifier with multi-level class-G operation.
> > The digital audio interface supports I2S, left-justified,
> > right-justified, TDM and DSP A/B format for audio in with a data
> > out used for chip information like voltage sense and current
> > sense, which are able to be monitored via DATAO through proper
> > 
> > diff --git a/sound/soc/codecs/mt6660.c b/sound/soc/codecs/mt6660.c
> > new file mode 100644
> > index 0000000..b8fc53b
> > --- /dev/null
> > +++ b/sound/soc/codecs/mt6660.c
> > @@ -0,0 +1,628 @@
> 
> > +
> > +struct codec_reg_val {
> > +	u32 addr;
> > +	u32 mask;
> > +	u32 data;
> > +};
> 
> packed structures could have been better.

It depends.  Packing may break alignment and the performance may
suffer from it.  So, in general, __packed is recommended when the size
matters (e.g. lots of objects / arrays are created) or it's about ABI
that needs the fixed consistent size.


thanks,

Takashi
_______________________________________________
Alsa-devel mailing list
Alsa-devel@alsa-project.org
https://mailman.alsa-project.org/mailman/listinfo/alsa-devel

WARNING: multiple messages have this Message-ID (diff)
From: Takashi Iwai <tiwai@suse.de>
To: Sriram Periyasamy <sriram.oqensourz@gmail.com>
Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
	tiwai@suse.com, lgirdwood@gmail.com,
	Jeff Chang <richtek.jeff.chang@gmail.com>,
	broonie@kernel.org, matthias.bgg@gmail.com,
	jeff_chang@richtek.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [alsa-devel] [PATCH v4] ASoC: Add MediaTek MT6660 Speaker Amp Driver
Date: Thu, 09 Jan 2020 19:57:34 +0100	[thread overview]
Message-ID: <s5h36comp9d.wl-tiwai@suse.de> (raw)
In-Reply-To: <20200109171833.GA2709@sriram-VirtualBox>

On Thu, 09 Jan 2020 18:18:36 +0100,
Sriram Periyasamy wrote:
> 
> On Tue, Jan 07, 2020 at 11:09:05AM +0800, Jeff Chang wrote:
> > From: Jeff Chang <jeff_chang@richtek.com>
> > 
> > The MT6660 is a boosted BTL class-D amplifier with V/I sensing.
> > A built-in DC-DC step-up converter is used to provide efficient
> > power for class-D amplifier with multi-level class-G operation.
> > The digital audio interface supports I2S, left-justified,
> > right-justified, TDM and DSP A/B format for audio in with a data
> > out used for chip information like voltage sense and current
> > sense, which are able to be monitored via DATAO through proper
> > 
> > diff --git a/sound/soc/codecs/mt6660.c b/sound/soc/codecs/mt6660.c
> > new file mode 100644
> > index 0000000..b8fc53b
> > --- /dev/null
> > +++ b/sound/soc/codecs/mt6660.c
> > @@ -0,0 +1,628 @@
> 
> > +
> > +struct codec_reg_val {
> > +	u32 addr;
> > +	u32 mask;
> > +	u32 data;
> > +};
> 
> packed structures could have been better.

It depends.  Packing may break alignment and the performance may
suffer from it.  So, in general, __packed is recommended when the size
matters (e.g. lots of objects / arrays are created) or it's about ABI
that needs the fixed consistent size.


thanks,

Takashi

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Takashi Iwai <tiwai@suse.de>
To: Sriram Periyasamy <sriram.oqensourz@gmail.com>
Cc: Jeff Chang <richtek.jeff.chang@gmail.com>,
	lgirdwood@gmail.com, alsa-devel@alsa-project.org,
	linux-kernel@vger.kernel.org, tiwai@suse.com,
	jeff_chang@richtek.com, broonie@kernel.org,
	matthias.bgg@gmail.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [alsa-devel] [PATCH v4] ASoC: Add MediaTek MT6660 Speaker Amp Driver
Date: Thu, 09 Jan 2020 19:57:34 +0100	[thread overview]
Message-ID: <s5h36comp9d.wl-tiwai@suse.de> (raw)
In-Reply-To: <20200109171833.GA2709@sriram-VirtualBox>

On Thu, 09 Jan 2020 18:18:36 +0100,
Sriram Periyasamy wrote:
> 
> On Tue, Jan 07, 2020 at 11:09:05AM +0800, Jeff Chang wrote:
> > From: Jeff Chang <jeff_chang@richtek.com>
> > 
> > The MT6660 is a boosted BTL class-D amplifier with V/I sensing.
> > A built-in DC-DC step-up converter is used to provide efficient
> > power for class-D amplifier with multi-level class-G operation.
> > The digital audio interface supports I2S, left-justified,
> > right-justified, TDM and DSP A/B format for audio in with a data
> > out used for chip information like voltage sense and current
> > sense, which are able to be monitored via DATAO through proper
> > 
> > diff --git a/sound/soc/codecs/mt6660.c b/sound/soc/codecs/mt6660.c
> > new file mode 100644
> > index 0000000..b8fc53b
> > --- /dev/null
> > +++ b/sound/soc/codecs/mt6660.c
> > @@ -0,0 +1,628 @@
> 
> > +
> > +struct codec_reg_val {
> > +	u32 addr;
> > +	u32 mask;
> > +	u32 data;
> > +};
> 
> packed structures could have been better.

It depends.  Packing may break alignment and the performance may
suffer from it.  So, in general, __packed is recommended when the size
matters (e.g. lots of objects / arrays are created) or it's about ABI
that needs the fixed consistent size.


thanks,

Takashi

  reply	other threads:[~2020-01-09 18:58 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-07  3:09 [alsa-devel] [PATCH v4] ASoC: Add MediaTek MT6660 Speaker Amp Driver Jeff Chang
2020-01-07  3:09 ` Jeff Chang
2020-01-07  3:09 ` Jeff Chang
2020-01-09 17:18 ` [alsa-devel] " Sriram Periyasamy
2020-01-09 17:18   ` Sriram Periyasamy
2020-01-09 17:18   ` Sriram Periyasamy
2020-01-09 18:57   ` Takashi Iwai [this message]
2020-01-09 18:57     ` Takashi Iwai
2020-01-09 18:57     ` Takashi Iwai
  -- strict thread matches above, loose matches on Subject: below --
2019-12-26  2:30 Jeff Chang

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