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From: Mika Westerberg <mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org,
	Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>,
	Andy Shevchenko
	<andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
	Christian Ruppert
	<christian.ruppert-ux6zf3SgZrrQT0dZR+AlfA@public.gmane.org>
Subject: Re: [5/7] i2c-designware: enable/disable the controller properly
Date: Tue, 9 Apr 2013 12:39:03 +0300	[thread overview]
Message-ID: <20130409093903.GI21818@intel.com> (raw)
In-Reply-To: <20130409092857.GE3624-z923LK4zBo2bacvFa/9K2g@public.gmane.org>

On Tue, Apr 09, 2013 at 11:28:57AM +0200, Wolfram Sang wrote:
> On Tue, Apr 09, 2013 at 12:28:36PM +0300, Mika Westerberg wrote:
> > On Tue, Apr 09, 2013 at 11:09:14AM +0200, Wolfram Sang wrote:
> > > 
> > > > +static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
> > > > +{
> > > > +	int timeout = 100;
> > > > +
> > > > +	do {
> > > > +		dw_writel(dev, enable, DW_IC_ENABLE);
> > > > +		if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == enable)
> > > > +			return;
> > > > +
> > > > +		usleep_range(25, 250);
> > > 
> > > This would wait 25ms max. Is there a timeout value specified in the docs?
> > 
> > The datasheet says something like:
> > 
> > 	1. Define a timer interval (t_i2c_poll) equal 10 times the highest
> > 	signaling period. For 400kHz this is 25us.
> > 
> > 	2. Define max timeout parameter, MAX_T_POLL_COUNT, such that if any
> > 	repeated operation exeeds this maximum, an error is reported.
> > 
> > In this case I have:
> > 
> > 	t_i2c_poll = 25 (to 250 us)
> > 	MAX_T_POLL_COUNT = 100
> 
> Maybe worth a comment?

I'll add it in the next revision.

> Other than that, the series looks fine to me.

Thanks!

  parent reply	other threads:[~2013-04-09  9:39 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-21 12:09 [PATCH 1/7] i2c-designware: move to managed functions (devm_*) Mika Westerberg
2013-03-21 12:09 ` [PATCH 3/7] i2c-designware-pci: use managed functions pcim_* and devm_* Mika Westerberg
     [not found]   ` <1363867800-23861-3-git-send-email-mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2013-04-09  9:03     ` [3/7] " Wolfram Sang
2013-03-21 12:09 ` [PATCH 4/7] i2c-designware: use dynamic adapter numbering on Lynxpoint Mika Westerberg
     [not found]   ` <1363867800-23861-4-git-send-email-mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2013-04-09  9:06     ` [4/7] " Wolfram Sang
2013-04-09  9:23       ` Mika Westerberg
2013-04-09  9:29         ` Wolfram Sang
     [not found]           ` <20130409092923.GF3624-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
2013-04-09  9:37             ` Mika Westerberg
2013-03-21 12:09 ` [PATCH 5/7] i2c-designware: enable/disable the controller properly Mika Westerberg
2013-04-09  9:09   ` [5/7] " Wolfram Sang
2013-04-09  9:28     ` Mika Westerberg
2013-04-09  9:28       ` Wolfram Sang
     [not found]         ` <20130409092857.GE3624-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
2013-04-09  9:39           ` Mika Westerberg [this message]
2013-03-21 12:09 ` [PATCH 6/7] i2c-designware: use usleep_range() in the busy-loop Mika Westerberg
2013-03-21 12:10 ` [PATCH 7/7] i2c-designware: switch to use runtime PM autosuspend Mika Westerberg
     [not found] ` <1363867800-23861-1-git-send-email-mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2013-03-21 12:09   ` [PATCH 2/7] i2c-designware-pci: use dev_err() instead of printk() Mika Westerberg
2013-04-08 11:04   ` [PATCH 1/7] i2c-designware: move to managed functions (devm_*) Mika Westerberg
2013-04-09  9:00 ` [1/7] " Wolfram Sang
2013-04-09  9:22   ` Mika Westerberg
2013-04-09  9:20     ` Wolfram Sang

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