[PATCH 0/2] pinctrl: bcm2835: Fix gpio hogs and pin reinitialisation

Tackle two problems with the pinctrl-bcm2835 driver and its Device Tree
configuration:

1. The pinctrl-bcm2835 driver is a combined pinctrl/gpio driver.
Currently the gpio side is registered first, but this breaks gpio hogs
(which are configured during gpiochip_add_data).

2. Since [1], a "gpio-ranges" property is required in order for pins
to be returned to inputs when freed. Note that without patch 1, the
device never gets out of EPROBE_DEFER.

Note that the Fixes: tags are little more than hooks to hang the back-ports
on - no blame is intended.

[1] commit 2ab73c6d8323 ("gpio: Support GPIO controllers without
        pin-ranges")

Phil Elwell (2):
  pinctrl: bcm2835: Change init order for gpio hogs
  ARM: dts: gpio-ranges property is now required

 arch/arm/boot/dts/bcm2711.dtsi        |  2 ++
 arch/arm/boot/dts/bcm283x.dtsi        |  2 ++
 drivers/pinctrl/bcm/pinctrl-bcm2835.c | 29 +++++++++++++++------------
 3 files changed, 20 insertions(+), 13 deletions(-)

-- 
2.25.1

...and gpio-ranges

pinctrl-bcm2835 is a combined pinctrl/gpio driver. Currently the gpio
side is registered first, but this breaks gpio hogs (which are
configured during gpiochip_add_data). Part of the hog initialisation
is a call to pinctrl_gpio_request, and since the pinctrl driver hasn't
yet been registered this results in an -EPROBE_DEFER from which it can
never recover.

Change the initialisation sequence to register the pinctrl driver
first.

This also solves a similar problem with the gpio-ranges property, which
is required in order for released pins to be returned to inputs.

Fixes: 73345a18d464b ("pinctrl: bcm2835: Pass irqchip when adding
                       gpiochip")
Signed-off-by: Phil Elwell <redacted>
---
 drivers/pinctrl/bcm/pinctrl-bcm2835.c | 29 +++++++++++++++------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
index 2abcc6ce4eba..b607d10e4cbd 100644
--- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
+++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c

@@ -1244,6 +1244,18 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 		raw_spin_lock_init(&pc->irq_lock[i]);
 	}
 
+	pc->pctl_desc = *pdata->pctl_desc;
+	pc->pctl_dev = devm_pinctrl_register(dev, &pc->pctl_desc, pc);
+	if (IS_ERR(pc->pctl_dev)) {
+		gpiochip_remove(&pc->gpio_chip);
+		return PTR_ERR(pc->pctl_dev);
+	}
+
+	pc->gpio_range = *pdata->gpio_range;
+	pc->gpio_range.base = pc->gpio_chip.base;
+	pc->gpio_range.gc = &pc->gpio_chip;
+	pinctrl_add_gpio_range(pc->pctl_dev, &pc->gpio_range);
+
 	girq = &pc->gpio_chip.irq;
 	girq->chip = &bcm2835_gpio_irq_chip;
 	girq->parent_handler = bcm2835_gpio_irq_handler;

@@ -1251,8 +1263,10 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 	girq->parents = devm_kcalloc(dev, BCM2835_NUM_IRQS,
 				     sizeof(*girq->parents),
 				     GFP_KERNEL);
-	if (!girq->parents)
+	if (!girq->parents) {
+		pinctrl_remove_gpio_range(pc->pctl_dev, &pc->gpio_range);
 		return -ENOMEM;
+	}
 
 	if (is_7211) {
 		pc->wake_irq = devm_kcalloc(dev, BCM2835_NUM_IRQS,

@@ -1307,21 +1321,10 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 	err = gpiochip_add_data(&pc->gpio_chip, pc);
 	if (err) {
 		dev_err(dev, "could not add GPIO chip\n");
+		pinctrl_remove_gpio_range(pc->pctl_dev, &pc->gpio_range);
 		return err;
 	}
 
-	pc->pctl_desc = *pdata->pctl_desc;
-	pc->pctl_dev = devm_pinctrl_register(dev, &pc->pctl_desc, pc);
-	if (IS_ERR(pc->pctl_dev)) {
-		gpiochip_remove(&pc->gpio_chip);
-		return PTR_ERR(pc->pctl_dev);
-	}
-
-	pc->gpio_range = *pdata->gpio_range;
-	pc->gpio_range.base = pc->gpio_chip.base;
-	pc->gpio_range.gc = &pc->gpio_chip;
-	pinctrl_add_gpio_range(pc->pctl_dev, &pc->gpio_range);
-
 	return 0;
 }
 

-- 
2.25.1

Since [1], added in 5.7, the absence of a gpio-ranges property has
prevented GPIOs from being restored to inputs when released.
Add those properties for BCM283x and BCM2711 devices.

[1] commit 2ab73c6d8323 ("gpio: Support GPIO controllers without
    pin-ranges")

Fixes: 2ab73c6d8323 ("gpio: Support GPIO controllers without
                      pin-ranges")
Signed-off-by: Phil Elwell <redacted>
---
 arch/arm/boot/dts/bcm2711.dtsi | 2 ++
 arch/arm/boot/dts/bcm283x.dtsi | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/bcm2711.dtsi b/arch/arm/boot/dts/bcm2711.dtsi
index 9e01dbca4a01..dff18fc9a906 100644
--- a/arch/arm/boot/dts/bcm2711.dtsi
+++ b/arch/arm/boot/dts/bcm2711.dtsi

@@ -582,6 +582,8 @@ &gpio {
 		     <GIC_SPI 115 IRQ_TYPE_LEVEL_HIGH>,
 		     <GIC_SPI 116 IRQ_TYPE_LEVEL_HIGH>;
 
+	gpio-ranges = <&gpio 0 0 58>;
+
 	gpclk0_gpio49: gpclk0_gpio49 {
 		pin-gpclk {
 			pins = "gpio49";

diff --git a/arch/arm/boot/dts/bcm283x.dtsi b/arch/arm/boot/dts/bcm283x.dtsi
index a3e06b680947..c113661a6668 100644
--- a/arch/arm/boot/dts/bcm283x.dtsi
+++ b/arch/arm/boot/dts/bcm283x.dtsi

@@ -126,6 +126,8 @@ gpio: gpio@7e200000 {
 			interrupt-controller;
 			#interrupt-cells = <2>;
 
+			gpio-ranges = <&gpio 0 0 54>;
+
 			/* Defines common pin muxing groups
 			 *
 			 * While each pin can have its mux selected

-- 
2.25.1

On Mon, Nov 29, 2021 at 11:56 AM Phil Elwell [off-list ref] wrote:

Since [1], added in 5.7, the absence of a gpio-ranges property has
prevented GPIOs from being restored to inputs when released.
Add those properties for BCM283x and BCM2711 devices.

[1] commit 2ab73c6d8323 ("gpio: Support GPIO controllers without
    pin-ranges")

Fixes: 2ab73c6d8323 ("gpio: Support GPIO controllers without
                      pin-ranges")
Signed-off-by: Phil Elwell <redacted>

With the funny linebreak fixed:
Reviewed-by: Linus Walleij <redacted>
Please merge this patch through the Broadcom/SoC tree.

Yours,
Linus Walleij