linux-kernel - Re: [PATCH v2 01/10] tpm/tpm_i2c_infineon: switch to i2c_lock_bus(..., I2C_LOCK

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Message-ID: <7703d6a2-b22c-104c-7390-b5143a504725@infineon.com>
Date:   Tue, 26 Jun 2018 12:07:21 +0200
From:   Alexander Steffen <Alexander.Steffen@...ineon.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Peter Rosin <peda@...ntia.se>
CC:     <linux-kernel@...r.kernel.org>, Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Brian Norris <computersforpeace@...il.com>,
        Gregory Fong <gregory.0xf0@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        <bcm-kernel-feedback-list@...adcom.com>,
        Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        Haavard Skinnemoen <hskinnemoen@...il.com>,
        Kukjin Kim <kgene@...nel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang@...aro.org>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Guenter Roeck <linux@...ck-us.net>, Crt Mori <cmo@...exis.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Antti Palosaari <crope@....fi>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Michael Krufky <mkrufky@...uxtv.org>,
        Lee Jones <lee.jones@...aro.org>,
        <linux-integrity@...r.kernel.org>, <linux-i2c@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-samsung-soc@...r.kernel.org>, <linux-iio@...r.kernel.org>,
        <linux-input@...r.kernel.org>, <linux-media@...r.kernel.org>
Subject: Re: [PATCH v2 01/10] tpm/tpm_i2c_infineon: switch to
 i2c_lock_bus(..., I2C_LOCK_SEGMENT)

On 25.06.2018 12:24, Jarkko Sakkinen wrote:
> On Wed, Jun 20, 2018 at 07:17:54AM +0200, Peter Rosin wrote:
>> Locking the root adapter for __i2c_transfer will deadlock if the
>> device sits behind a mux-locked I2C mux. Switch to the finer-grained
>> i2c_lock_bus with the I2C_LOCK_SEGMENT flag. If the device does not
>> sit behind a mux-locked mux, the two locking variants are equivalent.
>>
>> Signed-off-by: Peter Rosin <peda@...ntia.se>
> 
> Studied enough so that I can give
> 
> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> 
> Do not have hardware to test this, however.

I don't have a mux-locked I2C mux either, but at least I can confirm 
that this change did not break my existing test setup (SLB9635/SLB9645 
on Raspberry Pi 2B).

Tested-by: Alexander Steffen <Alexander.Steffen@...ineon.com>

Alexander