pinctrl: devicetree: do not goto err when probing hogs in pinctrl_dt_to_map

[ Upstream commit c98868e816209e568c9d72023ba0bc1e4d96e611 ]

Cross case in pinctrl framework make impossible to an hogged pin and
another, not hogged, used within the same device-tree node. For example
with this simplified device-tree :

  &pinctrl {
    pinctrl_pin_1: pinctrl-pin-1 {
      pins = "dummy-pinctrl-pin";
    };
  };

  &rtc {
    pinctrl-names = "default"
    pinctrl-0 = <&pinctrl_pin_1 &rtc_pin_1>

    rtc_pin_1: rtc-pin-1 {
      pins = "dummy-rtc-pin";
    };
  };

"pinctrl_pin_1" configuration is never set. This produces this path in
the code:

  really_probe()
    pinctrl_bind_pins()
    | devm_pinctrl_get()
    |   pinctrl_get()
    |     create_pinctrl()
    |       pinctrl_dt_to_map()
    |         // Hog pin create an abort for all pins of the node
    |         ret = dt_to_map_one_config()
    |         | /* Do not defer probing of hogs (circular loop) */
    |         | if (np_pctldev == p->dev->of_node)
    |         |   return -ENODEV;
    |         if (ret)
    |           goto err
    |
    call_driver_probe()
      stm32_rtc_probe()
        pinctrl_enable()
          pinctrl_claim_hogs()
            create_pinctrl()
              for_each_maps(maps_node, i, map)
                // Not hog pin is skipped
                if (pctldev && strcmp(dev_name(pctldev->dev),
                                      map->ctrl_dev_name))
                  continue;

At the first call of create_pinctrl() the hogged pin produces an abort to
avoid a defer of hogged pins. All other pin configurations are trashed.

At the second call, create_pinctrl is now called with pctldev parameter to
get hogs, but in this context only hogs are set. And other pins are
skipped.

To handle this, do not produce an abort in the first call of
create_pinctrl(). Classic pin configuration will be set in
pinctrl_bind_pins() context. And the hogged pin configuration will be set
in pinctrl_claim_hogs() context.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/20250116170009.2075544-1-valentin.caron@foss.st.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c
index 5ee746cb81f5..6520b88db110 100644
--- a/drivers/pinctrl/devicetree.c
+++ b/drivers/pinctrl/devicetree.c
@@ -143,10 +143,14 @@ static int dt_to_map_one_config(struct pinctrl *p,
 		pctldev = get_pinctrl_dev_from_of_node(np_pctldev);
 		if (pctldev)
 			break;
-		/* Do not defer probing of hogs (circular loop) */
+		/*
+		 * Do not defer probing of hogs (circular loop)
+		 *
+		 * Return 1 to let the caller catch the case.
+		 */
 		if (np_pctldev == p->dev->of_node) {
 			of_node_put(np_pctldev);
-			return -ENODEV;
+			return 1;
 		}
 	}
 	of_node_put(np_pctldev);
@@ -265,6 +269,8 @@ int pinctrl_dt_to_map(struct pinctrl *p, struct pinctrl_dev *pctldev)
 			ret = dt_to_map_one_config(p, pctldev, statename,
 						   np_config);
 			of_node_put(np_config);
+			if (ret == 1)
+				continue;
 			if (ret < 0)
 				goto err;
 		}