From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Eddie James <eajames@linux.vnet.ibm.com>,
Wolfram Sang <wsa@the-dreams.de>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, robh+dt@kernel.org, joel@jms.id.au,
mark.rutland@arm.com, gregkh@linuxfoundation.org,
rdunlap@infradead.org, andy.shevchenko@gmail.com,
peda@axentia.se
Subject: Re: [PATCH v11 5/8] i2c: fsi: Add transfer implementation
Date: Wed, 11 Jul 2018 09:39:15 +1000 [thread overview]
Message-ID: <f3085f807e19d9c5d36ef9cded2b3ee59e560899.camel@kernel.crashing.org> (raw)
In-Reply-To: <d7128886-148f-d255-fb33-3727cad01569@linux.vnet.ibm.com>
On Tue, 2018-07-10 at 12:52 -0500, Eddie James wrote:
>
> On 07/09/2018 05:41 PM, Wolfram Sang wrote:
> > > + cmd |= FIELD_PREP(I2C_CMD_ADDR, msg->addr >> 1);
> >
> > I just noticed this and wonder: Don't you need the LSB of the address?
> > It is not the RW flag, this is encoded in msg->flags.
>
> So, the hardware interprets the LSB as the RW flag. It wouldn't be
> possible to have a device addressed with the LSB set on this I2C master.
What do you mean ? That doesn't sound right...
>
> >
> > Also, no seperate handling for 10 bit addresses? Technically, 7-bit 0x50
> > is different on the wire from 10-bit 0x050. This is minor, though. There
> > are no 10-bit devices out there. Still, did you test 10-bit support?
>
> Indeed, real 10-bit addresses require some additional manipulation of
> this I2C master in order to work. We don't support it right now.
>
> Thanks,
> Eddie
>
> >
> > Rest looks good.
> >
next prev parent reply other threads:[~2018-07-10 23:39 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-05 18:40 [PATCH v11 0/8] i2c: Add FSI-attached I2C master algorithm Eddie James
2018-07-05 18:40 ` [PATCH v11 1/8] dt-bindings: i2c: Add FSI-attached I2C master dt binding documentation Eddie James
2018-07-05 18:40 ` [PATCH v11 2/8] i2c: Add FSI-attached I2C master algorithm Eddie James
2018-07-05 18:40 ` [PATCH v11 3/8] i2c: fsi: Add port structures Eddie James
2018-07-05 18:40 ` [PATCH v11 4/8] i2c: fsi: Add abort and hardware reset procedures Eddie James
2018-07-05 18:40 ` [PATCH v11 5/8] i2c: fsi: Add transfer implementation Eddie James
2018-07-09 22:41 ` Wolfram Sang
2018-07-10 17:52 ` Eddie James
2018-07-10 18:50 ` Wolfram Sang
2018-07-10 19:14 ` Eddie James
2018-07-10 19:39 ` Wolfram Sang
2018-07-10 20:59 ` Eddie James
2018-07-11 4:29 ` Joel Stanley
2018-07-11 7:34 ` Wolfram Sang
2018-07-10 23:39 ` Benjamin Herrenschmidt [this message]
2018-07-05 18:40 ` [PATCH v11 6/8] i2c: fsi: Add I2C master locking Eddie James
2018-07-05 18:40 ` [PATCH v11 7/8] i2c: fsi: Add bus recovery Eddie James
2018-07-05 18:40 ` [PATCH v11 8/8] MAINTAINERS: Add Eddie as the maintainer for the FSI-attached I2C driver Eddie James
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