On Tue, Sep 7, 2021 at 3:41 AM Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > On Sat, 4 Sept 2021 at 02:05, Saravana Kannan <saravanak@xxxxxxxxxx> wrote: > > > > fw_devlink could end up creating device links for bus only devices. > > However, bus only devices don't get probed and can block probe() or > > sync_state() [1] call backs of other devices. To avoid this, probe these > > devices using the simple-pm-bus driver. > > > > However, there are instances of devices that are not simple buses (they > > get probed by their specific drivers) that also list the "simple-bus" > > (or other bus only compatible strings) in their compatible property to > > automatically populate their child devices. We still want these devices > > to get probed by their specific drivers. So, we make sure this driver > > only probes devices that are only buses. > > > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@xxxxxxxxxxxxxx/ > > Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx> > > Tested-by: Saravana Kannan <saravanak@xxxxxxxxxx> > > Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > I will run some tests as soon as I can and let you know the results. Thanks. -Saravana > > Kind regards > Uffe > > > --- > > drivers/bus/simple-pm-bus.c | 32 +++++++++++++++++++++++++++++--- > > 1 file changed, 29 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > > index 01a3d0cd08ed..3e086a9f34cb 100644 > > --- a/drivers/bus/simple-pm-bus.c > > +++ b/drivers/bus/simple-pm-bus.c > > @@ -13,11 +13,26 @@ > > #include <linux/platform_device.h> > > #include <linux/pm_runtime.h> > > > > - > > static int simple_pm_bus_probe(struct platform_device *pdev) > > { > > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > > - struct device_node *np = pdev->dev.of_node; > > + const struct device *dev = &pdev->dev; > > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > > + struct device_node *np = dev->of_node; > > + const struct of_device_id *match; > > + > > + match = of_match_device(dev->driver->of_match_table, dev); > > + > > + /* > > + * These are transparent bus devices (not simple-pm-bus matches) that > > + * have their child nodes populated automatically. So, don't need to > > + * do anything more. > > + */ > > + if (match && match->data) { > > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > > + return 0; > > + else > > + return -ENODEV; > > + } > > > > dev_dbg(&pdev->dev, "%s\n", __func__); > > > > @@ -31,14 +46,25 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > > > > static int simple_pm_bus_remove(struct platform_device *pdev) > > { > > + const void *data = of_device_get_match_data(&pdev->dev); > > + > > + if (data) > > + return 0; > > + > > dev_dbg(&pdev->dev, "%s\n", __func__); > > > > pm_runtime_disable(&pdev->dev); > > return 0; > > } > > > > +#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */ > > + > > static const struct of_device_id simple_pm_bus_of_match[] = { > > { .compatible = "simple-pm-bus", }, > > + { .compatible = "simple-bus", .data = ONLY_BUS }, > > + { .compatible = "simple-mfd", .data = ONLY_BUS }, > > + { .compatible = "isa", .data = ONLY_BUS }, > > + { .compatible = "arm,amba-bus", .data = ONLY_BUS }, > > { /* sentinel */ } > > }; > > MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match); > > -- > > 2.33.0.153.gba50c8fa24-goog > >
