From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: eajames <eajames@linux.vnet.ibm.com>,
Alistair Popple <alistair@popple.id.au>
Cc: openbmc@lists.ozlabs.org, joel@jms.id.au,
Christopher Bostic <cbostic@linux.vnet.ibm.com>,
Eddie James <eajames@us.ibm.com>
Subject: Re: [PATCH v2 1/3] drivers/fsi: Add slave interrupt polling
Date: Sat, 04 Feb 2017 07:33:46 +1100 [thread overview]
Message-ID: <1486154026.4850.58.camel@kernel.crashing.org> (raw)
In-Reply-To: <0c659ead9fa7a83478ae3c1c9648838a@linux.vnet.ibm.com>
On Fri, 2017-02-03 at 10:18 -0600, eajames wrote:
> The problem here is that there is no hardware irq. FSI is using GPIO
> lines to access slave registers. The only indication that we have an
> interrupt is a bit set in the "slave interrupt status register". So
> we
> have to poll that register and handle the results. I'm not aware of
> any
> way to turn that into a kernel irq and use the existing kernel
> framework. But if it can be done, agreed, we should implement that!
The existing kernel i2c framework doesn't require IRQs.
You can poll, which sucks, but you can. With delays of course.
Also, if you know your i2c bit freq, you can always use a timer.
Cheers,
Ben.
next prev parent reply other threads:[~2017-02-03 20:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-02 23:25 [PATCH linux v1 0/8] drivers: fsi: interrupt polling, i2c client eajames
2017-02-02 23:25 ` [PATCH linux v1 4/8] drivers: fsi: Add i2c client driver eajames
2017-02-03 0:56 ` Alistair Popple
2017-02-03 0:58 ` Joel Stanley
2017-02-02 23:25 ` [PATCH linux v1 5/8] drivers: fsi: i2c: Add engine access wrappers eajames
2017-02-02 23:25 ` [PATCH linux v1 6/8] drivers: fsi: i2c: probe fsi device for i2c client eajames
2017-02-02 23:26 ` [PATCH linux v1 7/8] drivers: fsi: i2c: add driver file operations and bus locking eajames
2017-02-02 23:26 ` [PATCH linux v1 8/8] drivers: fsi: i2c: boe engine eajames
2017-02-02 23:26 ` [PATCH v2 1/3] drivers/fsi: Add slave interrupt polling eajames
2017-02-03 1:11 ` Alistair Popple
2017-02-03 16:18 ` eajames
2017-02-03 20:33 ` Benjamin Herrenschmidt [this message]
2017-02-02 23:26 ` [PATCH v2 2/3] drivers/fsi: Add Client IRQ Enable / Disable eajames
2017-02-02 23:26 ` [PATCH v2 3/3] drivers/fsi: Add sysfs file to adjust i-poll period eajames
2017-02-03 0:55 ` [PATCH linux v1 0/8] drivers: fsi: interrupt polling, i2c client Joel Stanley
2017-02-03 16:36 ` eajames
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