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* Re: [PATCH 3/3] lirc_zilog: Remove use of deprecated struct i2c_adapter.id field
@ 2011-01-13 16:34 Andy Walls
  2011-01-13 16:48 ` Jean Delvare
  2011-01-13 17:04 ` Devin Heitmueller
  0 siblings, 2 replies; 26+ messages in thread
From: Andy Walls @ 2011-01-13 16:34 UTC (permalink / raw)
  To: Devin Heitmueller, Jean Delvare
  Cc: linux-media, Jarod Wilson, Janne Grunau, Mauro Carvalho Chehab

Devin,

You've seen the clock stretch with your I2C analyzer?

Jean,

How should clock stretches by slaves be handled using i2c-algo-bit?

Regards,
Andy

Devin Heitmueller <dheitmueller@kernellabs.com> wrote:

>On Thu, Jan 13, 2011 at 8:21 AM, Jean Delvare <khali@linux-fr.org> wrote:
>> My bet is that register at 0x00 is a control register, and writing bit
>> 7 (value 0x80) makes the chip busy enough that it can't process I2C
>> requests at the same time. The following naks would be until the
>> chip is operational again.
>
>Correct.  Poking bit 7 of 0xE0:00 triggers the "send" for all the
>bytes that were previously loaded into the device.  It puts the chip
>into a busy state, doing an i2c clock stretch until it is available
>again.  During that time it cannot see any i2c traffic, which is why
>you are getting NAKs.
>
>Devin
>
>-- 
>Devin J. Heitmueller - Kernel Labs
>http://www.kernellabs.com
>--
>To unsubscribe from this list: send the line "unsubscribe linux-media" in
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^ permalink raw reply	[flat|nested] 26+ messages in thread
* Re: [PATCH 3/3] lirc_zilog: Remove use of deprecated struct i2c_adapter.id field
@ 2011-01-13 16:59 Andy Walls
  0 siblings, 0 replies; 26+ messages in thread
From: Andy Walls @ 2011-01-13 16:59 UTC (permalink / raw)
  To: Jean Delvare
  Cc: Devin Heitmueller, linux-media, Jarod Wilson, Janne Grunau,
	Mauro Carvalho Chehab

Jean,

Yes, however, I asked because ivtv and cx18 use i2c-algo-bit and also provide Zilog z8 IR I2C clients for lirc_zilog to use.  So if those get clock stretch handling "for free", that's great. 

Regards,
Andy
 

Jean Delvare <khali@linux-fr.org> wrote:

>On Thu, 13 Jan 2011 11:34:42 -0500, Andy Walls wrote:
>> How should clock stretches by slaves be handled using i2c-algo-bit?
>
>It is already handled. But hdpvr-i2c doesn't use i2c-algo-bit. I2C
>support is done with USB commands instead. Maybe the hardware
>implementation doesn't support clock stretching by slaves. Apparently
>it doesn't support repeated start conditions either, so it wouldn't
>surprise me.
>
>-- 
>Jean Delvare
>--
>To unsubscribe from this list: send the line "unsubscribe linux-media" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html

^ permalink raw reply	[flat|nested] 26+ messages in thread

end of thread, other threads:[~2011-01-13 17:20 UTC | newest]

Thread overview: 26+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
     [not found] <1293587067.3098.10.camel@localhost>
2010-12-29  1:46 ` [PATCH 1/3] hdpvr: Add I2C and ir-kdb-i2c registration of the Zilog Z8 IR chip Andy Walls
2010-12-29 11:08   ` Mauro Carvalho Chehab
2010-12-29 13:40     ` Andy Walls
2011-01-05 12:50   ` Jean Delvare
2011-01-05 22:44     ` Andy Walls
2010-12-29  1:47 ` [PATCH 2/3] ir-kbd-i2c: Add HD PVR IR Rx support to ir-kbd-i2c Andy Walls
2010-12-29 11:12   ` Mauro Carvalho Chehab
2010-12-29 14:14     ` Andy Walls
2011-01-05 12:53   ` Jean Delvare
2010-12-29  1:49 ` [PATCH 3/3] lirc_zilog: Remove use of deprecated struct i2c_adapter.id field Andy Walls
2011-01-05 14:45   ` Jean Delvare
2011-01-05 17:34     ` Mauro Carvalho Chehab
2011-01-05 21:51       ` Jean Delvare
2011-01-05 22:02         ` Mauro Carvalho Chehab
2011-01-06  1:20           ` Andy Walls
2011-01-13  9:46             ` Jean Delvare
2011-01-13 13:31           ` Jean Delvare
2011-01-06  0:46     ` Andy Walls
2011-01-13 13:21       ` Jean Delvare
2011-01-13 14:12         ` Devin Heitmueller
2011-01-13 16:34 Andy Walls
2011-01-13 16:48 ` Jean Delvare
2011-01-13 17:07   ` Devin Heitmueller
2011-01-13 17:19     ` Jean Delvare
2011-01-13 17:04 ` Devin Heitmueller
  -- strict thread matches above, loose matches on Subject: below --
2011-01-13 16:59 Andy Walls

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