* Rob Herring <robh+dt@xxxxxxxxxx> [160829 17:24]:
> On Mon, Aug 29, 2016 at 5:35 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote:
> > It seems we can use the ePAPR 1.1 status fail-sss to do this.
> > Quoting "Table 2-4 Values for status property" we have "fail-sss":
> >
> > "Indicates that the device is not operational. A serious error was
> > detected in the device and it is unlikely to become operational
> > without repair. The sss portion of the value is specific to the
> > device and indicates the error condition detected."
>
> I had read this as 'sss' is just 3 characters, but I guess that doesn't matter.
Yeah I'd assume it does not matter for the length.
> > We can handle these fail states can be handled in a generic
> > way. So let's introduce a generic status = "fail-" that
> > describes a situation where a device driver probe should just
> > shut down or idle the device if possible and then bail out.
> > This allows the SoC variant and board specific dts files to set
> > the status as needed.
> >
> > The suggested usage in a device driver probe is:
> >
> > static int foo_probe(struct platform_device *pdev)
> > {
> > int err;
> > const char *status;
> > ...
> >
> > pm_runtime_enable(&pdev->dev);
> > pm_runtime_get_sync(&pdev->dev);
> > pm_runtime_use_autosuspend(&pdev->dev);
> > ...
> >
> > /* Configure device, load firmware, idle device */
> > ...
> >
> > if (of_device_is_incomplete(pdev->dev.of_node, status)) {
>
> &status
Oops, I guess I should compile test the example.
> > if (!strcmp("hw-incomplete-pins", status)) {
> > dev_info(&pdev->dev,
> > "Unusable hardware: Not pinned out\n");
> > err = -ENODEV;
> > goto out;
> > }
> > if (!strcmp("hw-missing-daughter-card")) {
> > err = -EPROBE_DEFER;
>
> This implies we're going to change this on the fly? I guess
> disabled->okay can already happen.
Well let's assume the bootloader sets some i2c controlled daughter
board with "fail-hw-missing-daughter-card", then in theory kernel
could probe it if it pops up on the i2c bus later on. Not sure if
we want to do this, but it seems we could..
> > +static bool __of_device_is_incomplete(const struct device_node *device,
> > + const char **status)
> > +{
> > + const char *s, *m = "fail-";
> > + int slen, mlen;
> > +
> > + if (!device)
> > + return false;
> > +
> > + s = __of_get_property(device, "status", &slen);
>
> You can use the string helper function here (or is the lock a problem?).
I'll check.
> Overall, seems okay to me.
OK thanks for looking.
Regards,
Tony
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