Re: "status" property checks

On Thu, 2010-01-07 at 20:35 -0600, Hunter Cobbs wrote:

I think that is definitely a solution.  It does centralize the testing
for this particular issue.  The only thing question I have is if its
really better to have the upper level do the check.  Shouldn't the
driver itself handle the hardware and device node status?

Practically speaking, all drivers doing the checks today just return
-ENODEV. They don't try to do anything to "handle" the situation.

The definition of the status property implies it's outside of software's
control, for example:
        "disabled"
        "Indicates that the device is not presently operational, but it
        might become operational in the future (for example, something
        is not plugged in, or switched off)."

If a device is "not operational" in this sense, I don't think there's
anything for a device driver to do.

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Hollis Blanchard
Mentor Graphics, Embedded Systems Division

On Thu, 2010-01-07 at 15:07 -0800, Hollis Blanchard wrote:

quoted

Right now, a number of drivers honor the "status" property on device
nodes (via of_device_is_available() checks), but it's open-coded in eac=

h

quoted

driver. I'm thinking of "hiding" arbitrary devices from the kernel, and
setting this property seems like the best approach, but at the moment
that would require modifying all OF drivers to check for it.
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Wouldn't the better approach be to have of_platform_device_probe()
itself do the check, and not call the driver's probe() routine if the
device isn't available?
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