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From: "Peter Hüwe" <PeterHuewe@gmx.de>
To: Bryan Freed <bfreed@chromium.org>
Cc: Peter Huewe <peter.huewe@infineon.com>,
	Rajiv Andrade <srajiv@linux.vnet.ibm.com>,
	tpmdd@selhorst.net, tpmdd-devel@lists.sourceforge.net,
	linux-kernel@vger.kernel.org, Olof Johansson <olof@lixom.net>
Subject: Re: [PATCH] CHROMIUM: tpm: tpm_tis_i2c: Lock the I2C adapter for a sequence of requests.
Date: Wed, 2 May 2012 22:54:33 +0200	[thread overview]
Message-ID: <201205022254.33707.PeterHuewe@gmx.de> (raw)
In-Reply-To: <CAEYUcX06hvTb1YP=9vCpK9Z19dtZgNTjUcSRnrUvjc3bu-D--Q@mail.gmail.com>

Am Mittwoch 02 Mai 2012, 21:06:14 schrieb Bryan Freed:
> We could (in the unmodified version of this driver) replace all the
> iic_tpm_read() calls of one byte (which sends an address byte before
> reading a data byte) with an i2c_smbus_read_byte_command() call which
> does the same thing.

Unfortunately we have to use two seperate transfers (write/read) for a single 
byte read as the device does not support "repeated start" conditions and will 
simply fail to respond.

The device has some quirks that the driver has to workaround,
one is the repeated start problem, the other is the locking of the device.
If you can come up with a better solution I'd like to try it out if it's 
compatible with the device.

Thanks,
Peter

  parent reply	other threads:[~2012-05-02 20:54 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-02 14:01 [PATCH] char/tpm: Add new driver for Infineon I2C TIS TPM Peter Huewe
2012-05-02 14:03 ` [PATCH] CHROMIUM: tpm: tpm_tis_i2c: Lock the I2C adapter for a sequence of requests Peter Huewe
2012-05-02 15:17   ` Andi Shyti
2012-05-02 17:25     ` Bryan Freed
2012-05-02 18:14       ` Andi Shyti
2012-05-02 19:06         ` Bryan Freed
2012-05-02 20:18           ` Andi Shyti
2012-05-02 21:58             ` Bryan Freed
2012-05-02 20:54           ` Peter Hüwe [this message]
2012-05-02 15:15 ` [PATCH] char/tpm: Add new driver for Infineon I2C TIS TPM Andi Shyti
2012-05-03 11:18   ` Peter.Huewe
2012-05-10  6:49     ` Andi Shyti
  -- strict thread matches above, loose matches on Subject: below --
2011-08-03 21:08 [PATCH] CHROMIUM: tpm: tpm_tis_i2c: Lock the I2C adapter for a sequence of requests Bryan Freed
2011-08-05  7:33 ` Huewe.external
2011-08-05 12:05 ` Huewe.external

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