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authorThierry Reding <treding@nvidia.com>2019-06-21 17:17:25 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-03 21:28:20 +0200
commit62a6bc3a1e4f4ee9ae0076fa295f9af1c3725ce3 (patch)
tree86cbb601fb251496a44c484f16dd0f5ddadbebd6 /drivers/pinctrl
parent83b44fe343b5abfcb1b2261289bd0cfcfcfd60a8 (diff)
driver: core: Allow subsystems to continue deferring probe
Some subsystems, such as pinctrl, allow continuing to defer probe indefinitely. This is useful for devices that depend on resources provided by devices that are only probed after the init stage. One example of this can be seen on Tegra, where the DPAUX hardware contains pinmuxing controls for pins that it shares with an I2C controller. The I2C controller is typically used for communication with a monitor over HDMI (DDC). However, other instances of the I2C controller are used to access system critical components, such as a PMIC. The I2C controller driver will therefore usually be a builtin driver, whereas the DPAUX driver is part of the display driver that is loaded from a module to avoid bloating the kernel image with all of the DRM/KMS subsystem. In this particular case the pins used by this I2C/DDC controller become accessible very late in the boot process. However, since the controller is only used in conjunction with display, that's not an issue. Unfortunately the driver core currently outputs a warning message when a device fails to get the pinctrl before the end of the init stage. That can be confusing for the user because it may sound like an unwanted error occurred, whereas it's really an expected and harmless situation. In order to eliminate this warning, this patch allows callers of the driver_deferred_probe_check_state() helper to specify that they want to continue deferring probe, regardless of whether we're past the init stage or not. All of the callers of that function are updated for the new signature, but only the pinctrl subsystem passes a true value in the new persist parameter if appropriate. Signed-off-by: Thierry Reding <treding@nvidia.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20190621151725.20414-1-thierry.reding@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/pinctrl')
-rw-r--r--drivers/pinctrl/devicetree.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c
index f7e354f85518..88ddbb2e30de 100644
--- a/drivers/pinctrl/devicetree.c
+++ b/drivers/pinctrl/devicetree.c
@@ -112,12 +112,11 @@ static int dt_to_map_one_config(struct pinctrl *p,
np_pctldev = of_get_next_parent(np_pctldev);
if (!np_pctldev || of_node_is_root(np_pctldev)) {
of_node_put(np_pctldev);
- ret = driver_deferred_probe_check_state(p->dev);
/* keep deferring if modules are enabled unless we've timed out */
- if (IS_ENABLED(CONFIG_MODULES) && !allow_default && ret == -ENODEV)
- ret = -EPROBE_DEFER;
+ if (IS_ENABLED(CONFIG_MODULES) && !allow_default)
+ return driver_deferred_probe_check_state_continue(p->dev);
- return ret;
+ return driver_deferred_probe_check_state(p->dev);
}
/* If we're creating a hog we can use the passed pctldev */
if (hog_pctldev && (np_pctldev == p->dev->of_node)) {