From: Andrew Lunn <andrew@lunn.ch>
To: Lee Jones <lee.jones@linaro.org>
Cc: linux-kernel@vger.kernel.org, Emeric Dupont <emeric.dupont@zii.aero>
Subject: Re: [PATCH v5] mfd: tqmx86: IO controller with i2c, wachdog and gpio
Date: Thu, 7 Feb 2019 14:37:45 +0100 [thread overview]
Message-ID: <20190207133745.GB23970@lunn.ch> (raw)
In-Reply-To: <20190207102356.GB20638@dell>
> > + dev_warn(dev, "GPIO interrupts not supported.\n");
>
> Do you know why they wouldn't be supported?
>
> Isn't that the point of the device?
Hi Lee
I don't know the history of this device, but i suspect it has been
through a number of revisions. The vendor driver suggests some
versions support interrupts from the I2C bus master, but the version i
have does not. As a result the i2c bus master has to do polled
IO. GPIO interrupts are optional in the GPIO world. So it could be
some versions don't support it. But the version i have does.
It seems like if you write to bits of the interrupt configuration
register on a revision which don't support interrupts, the write does
not stick. So reading it back then lets you know this. The GPIO still
works for plain I and O, but don't expect interrupts to work.
Andrew
prev parent reply other threads:[~2019-02-07 13:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-07 2:37 [PATCH v5] mfd: tqmx86: IO controller with i2c, wachdog and gpio Andrew Lunn
2019-02-07 10:23 ` Lee Jones
2019-02-07 13:37 ` Andrew Lunn [this message]
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