diff mbox series

[v2,5/7] pinctrl: qcom: spmi-gpio: fix gpio-hog related boot issues

Message ID 20181101001149.13453-6-masneyb@onstation.org (mailing list archive)
State Not Applicable, archived
Headers show
Series ARM: qcom: msm8974-hammerhead: add USB OTG support | expand

Commit Message

Brian Masney Nov. 1, 2018, 12:11 a.m. UTC
When attempting to setup up a gpio hog, device probing would repeatedly
fail with -EPROBE_DEFERED errors. It was caused by a circular dependency
between the gpio and pinctrl frameworks. If the gpio-ranges property is
present in device tree, then the gpio framework will handle the gpio pin
registration and eliminate the circular dependency.

See Christian Lamparter's commit a86caa9ba5d7 ("pinctrl: msm: fix
gpio-hog related boot issues") for a detailed commit message that
explains the issue in much more detail. The code comment in this commit
came from Christian's commit.

Signed-off-by: Brian Masney <masneyb@onstation.org>
---
 drivers/pinctrl/qcom/pinctrl-spmi-gpio.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

Comments

Linus Walleij Nov. 9, 2018, 8:59 a.m. UTC | #1
On Thu, Nov 1, 2018 at 1:12 AM Brian Masney <masneyb@onstation.org> wrote:

> When attempting to setup up a gpio hog, device probing would repeatedly
> fail with -EPROBE_DEFERED errors. It was caused by a circular dependency
> between the gpio and pinctrl frameworks. If the gpio-ranges property is
> present in device tree, then the gpio framework will handle the gpio pin
> registration and eliminate the circular dependency.
>
> See Christian Lamparter's commit a86caa9ba5d7 ("pinctrl: msm: fix
> gpio-hog related boot issues") for a detailed commit message that
> explains the issue in much more detail. The code comment in this commit
> came from Christian's commit.
>
> Signed-off-by: Brian Masney <masneyb@onstation.org>

No word from Bjorn but I trust my own intuition and applied it.

Björn: shout if it's wrong.

Question: should this also be done for pinctrl-ssbi-gpio.c?

Yours,
Linus Walleij
Brian Masney Nov. 9, 2018, 10:22 a.m. UTC | #2
On Fri, Nov 09, 2018 at 09:59:08AM +0100, Linus Walleij wrote:
> On Thu, Nov 1, 2018 at 1:12 AM Brian Masney <masneyb@onstation.org> wrote:
> 
> > When attempting to setup up a gpio hog, device probing would repeatedly
> > fail with -EPROBE_DEFERED errors. It was caused by a circular dependency
> > between the gpio and pinctrl frameworks. If the gpio-ranges property is
> > present in device tree, then the gpio framework will handle the gpio pin
> > registration and eliminate the circular dependency.
> >
> > See Christian Lamparter's commit a86caa9ba5d7 ("pinctrl: msm: fix
> > gpio-hog related boot issues") for a detailed commit message that
> > explains the issue in much more detail. The code comment in this commit
> > came from Christian's commit.
> >
> > Signed-off-by: Brian Masney <masneyb@onstation.org>
> 
> No word from Bjorn but I trust my own intuition and applied it.
> 
> Björn: shout if it's wrong.
> 
> Question: should this also be done for pinctrl-ssbi-gpio.c?

Yes, I believe so.

Brian
diff mbox series

Patch

diff --git a/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c b/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
index a29efbe08f48..4c1ff9a1d156 100644
--- a/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
+++ b/drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
@@ -1028,10 +1028,23 @@  static int pmic_gpio_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = gpiochip_add_pin_range(&state->chip, dev_name(dev), 0, 0, npins);
-	if (ret) {
-		dev_err(dev, "failed to add pin range\n");
-		goto err_range;
+	/*
+	 * For DeviceTree-supported systems, the gpio core checks the
+	 * pinctrl's device node for the "gpio-ranges" property.
+	 * If it is present, it takes care of adding the pin ranges
+	 * for the driver. In this case the driver can skip ahead.
+	 *
+	 * In order to remain compatible with older, existing DeviceTree
+	 * files which don't set the "gpio-ranges" property or systems that
+	 * utilize ACPI the driver has to call gpiochip_add_pin_range().
+	 */
+	if (!of_property_read_bool(dev->of_node, "gpio-ranges")) {
+		ret = gpiochip_add_pin_range(&state->chip, dev_name(dev), 0, 0,
+					     npins);
+		if (ret) {
+			dev_err(dev, "failed to add pin range\n");
+			goto err_range;
+		}
 	}
 
 	return 0;