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From: Ulrich Hecht <uli@fpond.eu>
To: Wolfram Sang <wsa@the-dreams.de>, Ulrich Hecht <uli+renesas@fpond.eu>
Cc: linux-renesas-soc@vger.kernel.org, geert@linux-m68k.org,
	linux-i2c@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>
Subject: Re: [PATCH v4] i2c: sh_mobile: implement atomic transfers
Date: Tue, 6 Oct 2020 09:59:21 +0200 (CEST)	[thread overview]
Message-ID: <1440786741.680679.1601971161395@webmail.strato.com> (raw)
In-Reply-To: <20201002154423.GA16758@ninjato>


> On 10/02/2020 5:44 PM Wolfram Sang <wsa@the-dreams.de> wrote:
> > +				if (sr & (ICSR_AL   | ICSR_TACK |
> > +					  ICSR_WAIT | ICSR_DTE)) {
> > +					sh_mobile_i2c_isr(0, pd);
> > +					udelay(150);
> > +				} else {
> 
> And where does the value 150us come from?

Anything more than (IIRC) 50us or so works, but I tried to be conservative. Not waiting at all does not work, though. It is not quite clear to me why, because the bits tested here are the conditions for an interrupt to be triggered.

CU
Uli

  parent reply	other threads:[~2020-10-06  8:02 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-28 15:59 [PATCH v4] i2c: sh_mobile: implement atomic transfers Ulrich Hecht
2020-10-02 15:44 ` Wolfram Sang
2020-10-05  7:36   ` Geert Uytterhoeven
2020-10-06  7:59   ` Ulrich Hecht [this message]
2020-10-05  7:39 ` Geert Uytterhoeven
2020-10-06  6:40   ` Wolfram Sang
2020-10-08  9:48 ` Wolfram Sang
2020-11-06 14:27   ` Wolfram Sang

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