From: Antti Palosaari <crope@iki.fi>
To: Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
Wolfram Sang <wsa@the-dreams.de>
Cc: Mark Brown <broonie@kernel.org>,
Lars-Peter Clausen <lars@metafoo.de>,
linux-i2c@vger.kernel.org, linux-media@vger.kernel.org,
Jean Delvare <jdelvare@suse.de>
Subject: Re: [PATCH 21/66] rtl2830: implement own I2C locking
Date: Tue, 03 Feb 2015 20:34:01 +0200 [thread overview]
Message-ID: <54D11499.6080800@iki.fi> (raw)
In-Reply-To: <20150203155301.7ba63776@recife.lan>
On 02/03/2015 07:53 PM, Mauro Carvalho Chehab wrote:
> Em Mon, 02 Feb 2015 21:33:24 +0100
> Wolfram Sang <wsa@the-dreams.de> escreveu:
>
>>
>>>> Ok, this may eventually work ok for now, but a further change at the I2C
>>>> core could easily break it. So, we need to double check about such
>>>> patch with the I2C maintainer.
>>>>
>>>> Jean,
>>>>
>>>> Are you ok with such patch? If so, please ack.
>>
>> Jean handed over I2C to me in late 2012 :)
>
> Sorry for the mess... I mis-read MAINTAINERS.
>
>>> Basic problem here is that I2C-mux itself is controlled by same I2C device
>>> which implements I2C adapter for tuner.
>>>
>>> Here is what connections looks like:
>>> ___________ ____________ ____________
>>> | USB IF | | demod | | tuner |
>>> |-----------| |------------| |------------|
>>> | |--I2C--|-----/ -----|--I2C--| |
>>> |I2C master | | I2C mux | | I2C slave |
>>> |___________| |____________| |____________|
>>>
>>>
>>> So when tuner is called via I2C, it needs recursively call same I2C adapter
>>> which is already locked. More elegant solution would be indeed nice.
>>
>> So, AFAIU this is the same problem that I2C based mux devices have (like
>> drivers/i2c/muxes/i2c-mux-pca954x.c)? They also use the unlocked
>> transfers...
>
> If I understood your comment correct, you're ok with this approach,
> right? I'll then merge the remaining of this 66-patch series.
>
> If latter a better way to lock the I2C mux appears, we can reverse
> this change.
More I am worried about next patch in a serie, which converts all that
to regmap API... Same recursive mux register access comes to problem
there, which I work-arounded by defining own I2C IO... And in that case
I used i2c_lock_adapter/i2c_unlock_adapter so adapter is locked properly.
[PATCH 22/66] rtl2830: convert to regmap API
http://www.spinics.net/lists/linux-media/msg84969.html
regards
Antti
--
http://palosaari.fi/
next prev parent reply other threads:[~2015-02-03 18:34 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-23 20:48 [PATCH 01/66] dvb-usb-v2: add pointer to 'struct usb_interface' for driver usage Antti Palosaari
2014-12-23 20:48 ` [PATCH 02/66] rtl2832: convert driver to I2C binding Antti Palosaari
2014-12-23 20:48 ` [PATCH 03/66] rtl28xxu: switch rtl2832 demod attach " Antti Palosaari
2014-12-23 20:48 ` [PATCH 04/66] rtl28xxu: change module unregister order Antti Palosaari
2014-12-23 20:48 ` [PATCH 05/66] rtl2830: convert driver to kernel I2C model Antti Palosaari
2015-01-27 13:10 ` Mauro Carvalho Chehab
2015-02-02 17:50 ` Antti Palosaari
2014-12-23 20:48 ` [PATCH 06/66] rtl28xxu: use I2C binding for RTL2830 demod driver Antti Palosaari
2014-12-23 20:49 ` [PATCH 07/66] rtl2830: get rid of legacy DVB driver binding Antti Palosaari
2014-12-23 20:49 ` [PATCH 08/66] rtl2830: rename 'priv' to 'dev' Antti Palosaari
2014-12-23 20:49 ` [PATCH 09/66] rtl2830: carry pointer to I2C client for every function Antti Palosaari
2014-12-23 20:49 ` [PATCH 10/66] rtl2830: fix logging Antti Palosaari
2014-12-23 20:49 ` [PATCH 11/66] rtl2830: get rid of internal config data Antti Palosaari
2014-12-23 20:49 ` [PATCH 12/66] rtl2830: style related changes Antti Palosaari
2014-12-23 20:49 ` [PATCH 13/66] rtl2830: implement DVBv5 CNR statistic Antti Palosaari
2014-12-23 20:49 ` [PATCH 14/66] rtl2830: implement DVBv5 signal strength statistics Antti Palosaari
2014-12-23 20:49 ` [PATCH 15/66] rtl2830: implement DVBv5 BER statistic Antti Palosaari
2014-12-23 20:49 ` [PATCH 16/66] rtl2830: wrap DVBv5 signal strength to DVBv3 Antti Palosaari
2014-12-23 20:49 ` [PATCH 17/66] rtl2830: wrap DVBv5 BER " Antti Palosaari
2014-12-23 20:49 ` [PATCH 18/66] rtl2830: wrap DVBv5 CNR to DVBv3 SNR Antti Palosaari
2014-12-23 20:49 ` [PATCH 19/66] rtl2830: implement PID filter Antti Palosaari
2014-12-23 20:49 ` [PATCH 20/66] rtl28xxu: add support for RTL2831U/RTL2830 " Antti Palosaari
2014-12-23 20:49 ` [PATCH 21/66] rtl2830: implement own I2C locking Antti Palosaari
2015-02-02 20:07 ` Mauro Carvalho Chehab
2015-02-02 20:23 ` Antti Palosaari
2015-02-02 20:33 ` Wolfram Sang
2015-02-02 20:47 ` Lars-Peter Clausen
2015-02-03 17:53 ` Mauro Carvalho Chehab
2015-02-03 18:34 ` Antti Palosaari [this message]
2015-02-04 10:47 ` Mark Brown
2015-02-02 20:56 ` Jean Delvare
2015-02-02 21:13 ` Antti Palosaari
2014-12-23 20:49 ` [PATCH 22/66] rtl2830: convert to regmap API Antti Palosaari
2014-12-23 20:49 ` [PATCH 23/66] rtl2832: add platform data callbacks for exported resources Antti Palosaari
2014-12-23 20:49 ` [PATCH 24/66] rtl28xxu: use rtl2832 demod callbacks accessing its resources Antti Palosaari
2014-12-23 20:49 ` [PATCH 25/66] rtl2832: remove exported resources Antti Palosaari
2014-12-23 20:49 ` [PATCH 26/66] rtl2832: rename driver state variable from 'priv' to 'dev' Antti Palosaari
2014-12-23 20:49 ` [PATCH 27/66] rtl2832: enhance / fix logging Antti Palosaari
2014-12-23 20:49 ` [PATCH 28/66] rtl2832: move all configuration to platform data struct Antti Palosaari
2014-12-23 20:49 ` [PATCH 29/66] rtl28xxu: use platform data config for rtl2832 demod Antti Palosaari
2014-12-23 20:49 ` [PATCH 30/66] rtl2832: convert to regmap API Antti Palosaari
2014-12-23 20:49 ` [PATCH 31/66] rtl2832: implement DVBv5 CNR statistic Antti Palosaari
2014-12-23 20:49 ` [PATCH 32/66] rtl2832: implement DVBv5 BER statistic Antti Palosaari
2014-12-23 20:49 ` [PATCH 33/66] rtl2832: wrap DVBv5 CNR to DVBv3 SNR Antti Palosaari
2014-12-23 20:49 ` [PATCH 34/66] rtl2832: wrap DVBv5 BER to DVBv3 Antti Palosaari
2014-12-23 20:49 ` [PATCH 35/66] rtl2832: implement DVBv5 signal strength statistics Antti Palosaari
2014-12-23 20:49 ` [PATCH 36/66] rtl28xxu: use demod mux I2C adapter for every tuner Antti Palosaari
2014-12-23 20:49 ` [PATCH 37/66] rtl2832: drop FE i2c gate control support Antti Palosaari
2014-12-23 20:49 ` [PATCH 38/66] rtl2832: define more demod lock statuses Antti Palosaari
2014-12-23 20:49 ` [PATCH 39/66] rtl2832: implement PID filter Antti Palosaari
2014-12-23 20:49 ` [PATCH 40/66] rtl28xxu: add support for RTL2832U/RTL2832 " Antti Palosaari
2014-12-23 20:49 ` [PATCH 41/66] rtl2832: use regmap reg cache Antti Palosaari
2014-12-23 20:49 ` [PATCH 42/66] rtl2832: remove unneeded software reset from init() Antti Palosaari
2014-12-23 20:49 ` [PATCH 43/66] rtl2832: merge reg page as a part of reg address Antti Palosaari
2014-12-23 20:49 ` [PATCH 44/66] rtl2832: provide register IO callbacks Antti Palosaari
2014-12-23 20:49 ` [PATCH 45/66] rtl2832_sdr: rename state variable from 's' to 'dev' Antti Palosaari
2014-12-23 20:49 ` [PATCH 46/66] rtl2832_sdr: convert to platform driver Antti Palosaari
2014-12-23 20:49 ` [PATCH 47/66] rtl28xxu: switch SDR module " Antti Palosaari
2014-12-23 20:49 ` [PATCH 48/66] rtl28xxu: use master I2C adapter for slave demods Antti Palosaari
2014-12-24 0:45 ` Benjamin Larsson
2014-12-24 11:03 ` Antti Palosaari
2014-12-23 20:49 ` [PATCH 49/66] rtl2832_sdr: fix logging Antti Palosaari
2014-12-23 20:49 ` [PATCH 50/66] rtl2832_sdr: cleanups Antti Palosaari
2014-12-23 20:49 ` [PATCH 51/66] rtl2832: cleanups and minor changes Antti Palosaari
2014-12-23 20:49 ` [PATCH 52/66] rtl2832: claim copyright and module author Antti Palosaari
2014-12-23 20:49 ` [PATCH 53/66] rtl2832: implement sleep Antti Palosaari
2014-12-23 20:49 ` [PATCH 54/66] rtl28xxu: fix DVB FE callback Antti Palosaari
2014-12-23 20:49 ` [PATCH 55/66] rtl28xxu: simplify FE callback handling Antti Palosaari
2014-12-23 20:49 ` [PATCH 56/66] rtl28xxu: do not refcount rtl2832_sdr module Antti Palosaari
2014-12-23 20:49 ` [PATCH 57/66] rtl2832_sdr: refcount to rtl28xxu Antti Palosaari
2014-12-23 20:49 ` [PATCH 58/66] rtl2832: remove internal mux I2C adapter Antti Palosaari
2014-12-23 20:49 ` [PATCH 59/66] rtl28xxu: rename state variable 'priv' to 'dev' Antti Palosaari
2014-12-23 20:49 ` [PATCH 60/66] rtl28xxu: fix logging Antti Palosaari
2014-12-23 20:49 ` [PATCH 61/66] rtl28xxu: move usb buffers to state Antti Palosaari
2014-12-23 20:49 ` [PATCH 62/66] rtl28xxu: add heuristic to detect chip type Antti Palosaari
2014-12-23 20:49 ` [PATCH 63/66] rtl28xxu: merge chip type specific all callbacks Antti Palosaari
2014-12-23 20:49 ` [PATCH 64/66] rtl28xxu: merge rtl2831u and rtl2832u properties Antti Palosaari
2014-12-23 20:49 ` [PATCH 65/66] rtl28xxu: correct reg access routine name prefixes Antti Palosaari
2014-12-23 20:49 ` [PATCH 66/66] rtl2832: implement own lock for regmap Antti Palosaari
2015-01-19 12:49 ` [PATCH 01/66] dvb-usb-v2: add pointer to 'struct usb_interface' for driver usage Hans Verkuil
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