linux-kernel - Re: [PATCH 5/6] RTC: SMBus support for the M41T80, etc. driver (#2)

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Date:	Sat, 17 May 2008 21:46:35 +0100 (BST)
From:	"Maciej W. Rozycki" <macro@...ux-mips.org>
To:	Atsushi Nemoto <anemo@....ocn.ne.jp>
cc:	khali@...ux-fr.org, a.zummo@...ertech.it,
	akpm@...ux-foundation.org, dwmw2@...radead.org,
	ralf@...ux-mips.org, tglx@...utronix.de,
	rtc-linux@...glegroups.com, i2c@...sensors.org,
	linux-mips@...ux-mips.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/6] RTC: SMBus support for the M41T80, etc. driver (#2)

On Sun, 18 May 2008, Atsushi Nemoto wrote:

> I suppose the "off by one second" issue is not the matter each driver
> should take care of.  This race is common for most RTC chip.

 I agree, but with the reread it comes for free here.  Given you have two 
values of seconds available here, which one would you choose?  You can't 
take both at once. ;-)

> I do not have strong opinion for optimization suggested by Jean.  It
> might be better, but I'm OK with current your patch.

 Hmm, it looks as simple as putting a clause like:

	if (i2c_check_functionality(client->adapter, 
				    I2C_FUNC_SMBUS_READ_I2C_BLOCK)
		break;

into the loop and even at 400kHz it saves a considerable amount of time.
It sounds plausible -- I'll do that.

  Maciej
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