On Thu, Mar 30, 2023 at 6:26 AM Geert Uytterhoeven <geert+renesas@xxxxxxxxx> wrote: > > When loading a DT overlay that creates a device, the device is not > probed, unless the DT overlay is unloaded and reloaded again. > > After the recent refactoring to improve fw_devlink, it no longer depends > on the "compatible" property to identify which device tree nodes will > become struct devices. fw_devlink now picks up dangling consumers > (consumers pointing to descendent device tree nodes of a device that > aren't converted to child devices) when a device is successfully bound > to a driver. See __fw_devlink_pickup_dangling_consumers(). > > However, during DT overlay, a device's device tree node can have > sub-nodes added/removed without unbinding/rebinding the driver. This > difference in behavior between the normal device instantiation and > probing flow vs. the DT overlay flow has a bunch of implications that > are pointed out elsewhere[1]. One of them is that the fw_devlink logic > to pick up dangling consumers is never exercised. > > This patch solves the fw_devlink issue by marking all DT nodes added by > DT overlays with FWNODE_FLAG_NOT_DEVICE (fwnode that won't become > device), and by clearing the flag when a struct device is actually > created for the DT node. This way, fw_devlink knows not to have > consumers waiting on these newly added DT nodes, and to propagate the > dependency to an ancestor DT node that has the corresponding struct > device. > > Based on a patch by Saravana Kannan, which covered only platform and spi > devices. Doesn't make sense to give a Reviewed-by to something I partially wrote, so: Acked-by: Saravana Kannan <saravanak@xxxxxxxxxx> Thanks for making sure this is fixed Geert! -Saravana > > [1] https://lore.kernel.org/r/CAGETcx_bkuFaLCiPrAWCPQz+w79ccDp6=9e881qmK=vx3hBMyg@xxxxxxxxxxxxxx > > Fixes: 4a032827daa89350 ("of: property: Simplify of_link_to_phandle()") > Link: https://lore.kernel.org/r/CAGETcx_+rhHvaC_HJXGrr5_WAd2+k5f=rWYnkCZ6z5bGX-wj4w@xxxxxxxxxxxxxx > Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> > Acked-by: Mark Brown <broonie@xxxxxxxxxx> > Acked-by: Wolfram Sang <wsa@xxxxxxxxxx> # for I2C > --- > v3: > - Add Acked-by, > - s/instantiate/probe/, > - Improve commit description, > - Add comment before clearing FWNODE_FLAG_NOT_DEVICE, > > v2: > - Add Acked-by, > - Drop RFC. > --- > drivers/bus/imx-weim.c | 6 ++++++ > drivers/i2c/i2c-core-of.c | 5 +++++ > drivers/of/dynamic.c | 1 + > drivers/of/platform.c | 5 +++++ > drivers/spi/spi.c | 5 +++++ > 5 files changed, 22 insertions(+) > > diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c > index 36d42484142aede2..cf463c1d2102c6fb 100644 > --- a/drivers/bus/imx-weim.c > +++ b/drivers/bus/imx-weim.c > @@ -329,6 +329,12 @@ static int of_weim_notify(struct notifier_block *nb, unsigned long action, > "Failed to setup timing for '%pOF'\n", rd->dn); > > if (!of_node_check_flag(rd->dn, OF_POPULATED)) { > + /* > + * Clear the flag before adding the device so that > + * fw_devlink doesn't skip adding consumers to this > + * device. > + */ > + rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE; > if (!of_platform_device_create(rd->dn, NULL, &pdev->dev)) { > dev_err(&pdev->dev, > "Failed to create child device '%pOF'\n", > diff --git a/drivers/i2c/i2c-core-of.c b/drivers/i2c/i2c-core-of.c > index aa93467784c29c89..5c137638689799c8 100644 > --- a/drivers/i2c/i2c-core-of.c > +++ b/drivers/i2c/i2c-core-of.c > @@ -178,6 +178,11 @@ static int of_i2c_notify(struct notifier_block *nb, unsigned long action, > return NOTIFY_OK; > } > > + /* > + * Clear the flag before adding the device so that fw_devlink > + * doesn't skip adding consumers to this device. > + */ > + rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE; > client = of_i2c_register_device(adap, rd->dn); > if (IS_ERR(client)) { > dev_err(&adap->dev, "failed to create client for '%pOF'\n", > diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c > index 07d93753b12f5f4d..e311d406b1705306 100644 > --- a/drivers/of/dynamic.c > +++ b/drivers/of/dynamic.c > @@ -226,6 +226,7 @@ static void __of_attach_node(struct device_node *np) > np->sibling = np->parent->child; > np->parent->child = np; > of_node_clear_flag(np, OF_DETACHED); > + np->fwnode.flags |= FWNODE_FLAG_NOT_DEVICE; > } > > /** > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index b2bd2e783445dd78..78ae8418744905c9 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -737,6 +737,11 @@ static int of_platform_notify(struct notifier_block *nb, > if (of_node_check_flag(rd->dn, OF_POPULATED)) > return NOTIFY_OK; > > + /* > + * Clear the flag before adding the device so that fw_devlink > + * doesn't skip adding consumers to this device. > + */ > + rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE; > /* pdev_parent may be NULL when no bus platform device */ > pdev_parent = of_find_device_by_node(rd->dn->parent); > pdev = of_platform_device_create(rd->dn, NULL, > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > index 37a7be6c5a44c8f9..a12420e28640bbd4 100644 > --- a/drivers/spi/spi.c > +++ b/drivers/spi/spi.c > @@ -4504,6 +4504,11 @@ static int of_spi_notify(struct notifier_block *nb, unsigned long action, > return NOTIFY_OK; > } > > + /* > + * Clear the flag before adding the device so that fw_devlink > + * doesn't skip adding consumers to this device. > + */ > + rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE; > spi = of_register_spi_device(ctlr, rd->dn); > put_device(&ctlr->dev); > > -- > 2.34.1 >
