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From: Marek Vasut <marex@denx.de>
To: Mark Brown <broonie@kernel.org>
Cc: Fabio Estevam <fabio.estevam@freescale.com>,
	alsa-devel@alsa-project.org, Shawn Guo <shawn.guo@linaro.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/4] ASoC: sgtl5000: give it a ramping time before writting
Date: Mon, 1 Jul 2013 12:54:18 +0200	[thread overview]
Message-ID: <201307011254.18952.marex@denx.de> (raw)
In-Reply-To: <20130701100710.GB27646@sirena.org.uk>

Dear Mark Brown,

> On Mon, Jul 01, 2013 at 04:16:08PM +0800, Shawn Guo wrote:
> > +	/*
> > +	 * It seems that sgtl5000 takes a longer time to get the registers
> > +	 * ready for write than bread.  Let's give it a ramping time before
> > +	 * the first write goes.
> > +	 */
> > +	msleep(50);
> > +
> > 
> >  	/* Ensure sgtl5000 will start with sane register values */
> >  	ret = sgtl5000_fill_defaults(sgtl5000);
> >  	if (ret)
> 
> This seems like a really odd place to add the sleep - I'd have expected
> this to be a part of or just after the reset operation.  It's a *really*
> long sleep too, though if that's what you need that's what you need.

The delay might also be caused by the I2C driver, I have this in my ToDo to 
check, but I didn't get to it yet. On the other hand, if subsequent IO does 
work, then it's unlikely to be the case.

> Also "bread" :)

Of course, sometimes you want to put a lot of things on it, like bacon and such.

Best regards,
Marek Vasut

WARNING: multiple messages have this Message-ID (diff)
From: marex@denx.de (Marek Vasut)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/4] ASoC: sgtl5000: give it a ramping time before writting
Date: Mon, 1 Jul 2013 12:54:18 +0200	[thread overview]
Message-ID: <201307011254.18952.marex@denx.de> (raw)
In-Reply-To: <20130701100710.GB27646@sirena.org.uk>

Dear Mark Brown,

> On Mon, Jul 01, 2013 at 04:16:08PM +0800, Shawn Guo wrote:
> > +	/*
> > +	 * It seems that sgtl5000 takes a longer time to get the registers
> > +	 * ready for write than bread.  Let's give it a ramping time before
> > +	 * the first write goes.
> > +	 */
> > +	msleep(50);
> > +
> > 
> >  	/* Ensure sgtl5000 will start with sane register values */
> >  	ret = sgtl5000_fill_defaults(sgtl5000);
> >  	if (ret)
> 
> This seems like a really odd place to add the sleep - I'd have expected
> this to be a part of or just after the reset operation.  It's a *really*
> long sleep too, though if that's what you need that's what you need.

The delay might also be caused by the I2C driver, I have this in my ToDo to 
check, but I didn't get to it yet. On the other hand, if subsequent IO does 
work, then it's unlikely to be the case.

> Also "bread" :)

Of course, sometimes you want to put a lot of things on it, like bacon and such.

Best regards,
Marek Vasut

  reply	other threads:[~2013-07-01 10:54 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-01  8:16 [PATCH 0/4] Fix mxs audio regressions Shawn Guo
2013-07-01  8:16 ` Shawn Guo
2013-07-01  8:16 ` [PATCH 1/4] ASoC: sgtl5000: give it a ramping time before writting Shawn Guo
2013-07-01  8:16   ` Shawn Guo
2013-07-01 10:07   ` Mark Brown
2013-07-01 10:07     ` Mark Brown
2013-07-01 10:54     ` Marek Vasut [this message]
2013-07-01 10:54       ` Marek Vasut
2013-07-01 13:55       ` Shawn Guo
2013-07-01 13:55         ` Shawn Guo
2013-07-01 14:12       ` Fabio Estevam
2013-07-01 14:12         ` [alsa-devel] " Fabio Estevam
2013-07-01 14:26         ` Shawn Guo
2013-07-01 14:26           ` [alsa-devel] " Shawn Guo
2013-07-01 14:34           ` Shawn Guo
2013-07-01 14:34             ` [alsa-devel] " Shawn Guo
2013-07-01 15:11             ` Fabio Estevam
2013-07-01 15:11               ` [alsa-devel] " Fabio Estevam
2013-07-01 15:33               ` Shawn Guo
2013-07-01 15:33                 ` [alsa-devel] " Shawn Guo
2013-07-01 15:42                 ` Fabio Estevam
2013-07-01 15:42                   ` [alsa-devel] " Fabio Estevam
2013-07-01 17:43                   ` Marek Vasut
2013-07-01 17:43                     ` [alsa-devel] " Marek Vasut
2013-07-01 19:14                     ` Fabio Estevam
2013-07-01 19:14                       ` [alsa-devel] " Fabio Estevam
2013-07-01 19:28                       ` Alexandre Belloni
2013-07-01 19:28                         ` Alexandre Belloni
2013-07-02  2:16                     ` Shawn Guo
2013-07-02  2:16                       ` [alsa-devel] " Shawn Guo
2013-07-01 19:23                   ` Alexandre Belloni
2013-07-01 19:23                     ` Alexandre Belloni
2013-07-01 14:04     ` Shawn Guo
2013-07-01 14:04       ` Shawn Guo
2013-07-01 10:57   ` Lothar Waßmann
2013-07-01 10:57     ` Lothar Waßmann
2013-07-01  8:16 ` [PATCH 2/4] ASoC: sgtl5000: defer the probe if clock is not found Shawn Guo
2013-07-01  8:16   ` Shawn Guo
2013-07-01  9:45   ` Mark Brown
2013-07-01  9:45     ` Mark Brown
2013-07-01 11:33     ` Russell King - ARM Linux
2013-07-01 11:33       ` Russell King - ARM Linux
2013-07-01 12:51       ` Mark Brown
2013-07-01 12:51         ` Mark Brown
2013-07-01  8:16 ` [PATCH 3/4] ASoC: mxs: register saif mclk to clock framework Shawn Guo
2013-07-01  8:16   ` Shawn Guo
2013-07-01 10:11   ` Mark Brown
2013-07-01 10:11     ` Mark Brown
2013-07-01  8:16 ` [PATCH 4/4] ARM: mxs: saif0 is the clock provider to sgtl5000 Shawn Guo
2013-07-01  8:16   ` Shawn Guo

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