On 15:49-20241028, Markus Schneider-Pargmann wrote:
> Hi Nishanth,
>
> On Fri, Oct 25, 2024 at 12:42:04PM GMT, Nishanth Menon wrote:
> > On 16:39-20241012, Markus Schneider-Pargmann wrote:
> > [...]
> > >
> > > The possible wakeup devices are found by checking which devices are
> > > powered by the regulator supplying the "vddshv_canuart" line. These are
> > > considered possible wakeup sources. Only wakeup sources that are
> > > actually enabled by the user will be considered as a an active wakeup
> > > source. If none of the wakeup sources are enabled the system will do a
> > > normal poweroff. If at least one wakeup source is enabled it will
> > > instead send a TI_SCI_MSG_PREPARE_SLEEP message from the sys_off
> > > handler. Sending this message will result in an immediate shutdown of
> > > the system. No execution is expected after this point. The code will
> > > wait for 5s and do an emergency_restart afterwards if Partial-IO wasn't
> > > entered at that point.
> > >
> > [...]
> >
> > > +static bool tisci_canuart_wakeup_enabled(struct ti_sci_info *info)
> > > +{
> > > + static const char canuart_name[] = "vddshv_canuart";
> > > + struct device_node *wakeup_node = NULL;
> > > +
> > > + for (wakeup_node = of_find_node_with_property(NULL, "vio-supply");
> > > + wakeup_node;
> > > + wakeup_node = of_find_node_with_property(wakeup_node, "vio-supply")) {
> > > + struct device_node *supply_node;
> > > + const char *supply_name;
> > > + struct platform_device *pdev;
> > > + int ret;
> > > +
> > > + supply_node = of_parse_phandle(wakeup_node, "vio-supply", 0);
> > > + if (!supply_node)
> > > + continue;
> > > +
> > > + ret = of_property_read_string(supply_node, "regulator-name", &supply_name);
> > > + of_node_put(supply_node);
> > > + if (ret) {
> > > + dev_warn(info->dev, "Failed to parse vio-supply phandle at %pOF %d\n",
> > > + wakeup_node, ret);
> > > + continue;
> > > + }
> > > +
> > > + if (strncmp(canuart_name, supply_name, strlen(canuart_name)))
> > > + continue;
> > > +
> > > + pdev = of_find_device_by_node(wakeup_node);
> > > + if (!pdev)
> > > + continue;
> > > +
> > > + if (device_may_wakeup(&pdev->dev)) {
> > > + dev_dbg(info->dev, "%pOF identified as wakeup source for Partial-IO\n",
> > > + wakeup_node);
> > > + put_device(&pdev->dev);
> > > + of_node_put(wakeup_node);
> > > + return true;
> > > + }
> > > + put_device(&pdev->dev);
> > > + }
> > > +
> > > + return false;
> > > +}
> > > +
> >
> > What is the binding that supports this? I just do not think that
> > scanning the entire tree for vio-supply implies you will get thr right
> > property here.
> >
> > Just giving an example to illustrate this point:
> > Documentation/devicetree/bindings/net/wireless/ti,wl1251.txt says it
> > needs vio-supply -> so i have a node with the wireless supply as
> > vio-supply -> Since we are scanning from NULL for vio-supply, we hit
> > that, that is a bad choice for enabling io-retention.
>
> There is no bining that specifically supports this as I think it is not
> needed. The devices that are capable to wakeup the system from
> Partial-IO are all powered through one supply line that is always-on. It
> is called 'vddshv_canuart' and the name of this supply is checked
> in the above code as well. Yes I am using 'vio-supply', but only to
In effect, you are looking for nodes that have vio-supply pointing to
a regulator called vddshv_canuart. Not only is it too specific to a
device, but a board as well. Without documentation in binding, users
who don't have sufficient information is bound to mess this up. Further,
vddshv_canuart may not even be a regulator - there will need to be
checks for that on top of just a strncmp.
> search for the potential consumers of this supply.
> So wl1251 will be skipped in above code at
>
> if (strncmp(canuart_name, supply_name, strlen(canuart_name)))
Aah, thanks, but sorry, but I would prefer the drivers handle the
specifics. If a new peripheral comes on to the list for a different
device, or a different regulator name appears for can, we would be
dealing with name mapping etc.
--
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3 1A34 DDB5 849D 1736 249D
