gpio: Fix return value mismatch of function gpiod_get_from_of_node()

In case the requested gpio property is not found in the device tree, some callers of gpiod_get_from_of_node() expect a return value of NULL, others expect -ENOENT.
In particular devm_fwnode_get_index_gpiod_from_child() expects -ENOENT. Currently it gets a NULL, which breaks the loop that tries all gpio_suffixes. The result is that a gpio property is not found, even though it is there.

This patch changes gpiod_get_from_of_node() to return -ENOENT instead of NULL when the requested gpio property is not found in the device tree. Additionally it modifies all calling functions to properly evaluate the return value.

Another approach would be to leave the return value of gpiod_get_from_of_node() as is and fix the bug in devm_fwnode_get_index_gpiod_from_child(). Other callers would still need to be reworked. The effort would be the same as with the chosen solution.

Signed-off-by Georg Waibel <[email protected]>

---
 drivers/gpio/gpiolib.c                 | 6 +-----
 drivers/regulator/da9211-regulator.c   | 2 ++
 drivers/regulator/s2mps11.c            | 4 +++-
 drivers/regulator/s5m8767.c            | 4 +++-
 drivers/regulator/tps65090-regulator.c | 7 ++++---
 5 files changed, 13 insertions(+), 10 deletions(-)

drivers/gpio/gpiolib.c +1 -5

index e013d417a936..be1d1d2f8aaa 100644
@@ -4244,8 +4244,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_index);
  *
  * Returns:
  * On successful request the GPIO pin is configured in accordance with
- * provided @dflags. If the node does not have the requested GPIO
- * property, NULL is returned.
+ * provided @dflags.
  *
  * In case of error an ERR_PTR() is returned.
  */

@@ -4267,9 +4266,6 @@ struct gpio_desc *gpiod_get_from_of_node(struct device_node *node,
                                        index, &flags);
 
        if (!desc || IS_ERR(desc)) {
-               /* If it is not there, just return NULL */
-               if (PTR_ERR(desc) == -ENOENT)
-                       return NULL;
                return desc;
        }
 

drivers/regulator/da9211-regulator.c +2 -0

index da37b4ccd834..0309823d2c72 100644
@@ -289,6 +289,8 @@ static struct da9211_pdata *da9211_parse_regulators_dt(
                                  0,
                                  GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE,
                                  "da9211-enable");
+               if (IS_ERR(pdata->gpiod_ren[n]))
+                       pdata->gpiod_ren[n] = NULL;
                n++;
        }
 

drivers/regulator/s2mps11.c +3 -1

index 134c62db36c5..b518a81f75a3 100644
@@ -821,7 +821,9 @@ static void s2mps14_pmic_dt_parse_ext_control_gpio(struct platform_device *pdev,
                                0,
                                GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE,
                                "s2mps11-regulator");
-               if (IS_ERR(gpio[reg])) {
+               if (PTR_ERR(gpio[reg]) == -ENOENT)
+                       gpio[reg] = NULL;
+               else if (IS_ERR(gpio[reg])) {
                        dev_err(&pdev->dev, "Failed to get control GPIO for %d/%s\n",
                                reg, rdata[reg].name);
                        continue;

drivers/regulator/s5m8767.c +0 -0

index bb9d1a083299..6ca27e9d5ef7 100644

In case the requested gpio property is not found in the device tree, some callers of gpiod_get_from_of_node() expect a return value of NULL, others expect -ENOENT.
In particular devm_fwnode_get_index_gpiod_from_child() expects -ENOENT. Currently it gets a NULL, which breaks the loop that tries all gpio_suffixes. The result is that a gpio property is not found, even though it is there.

This patch changes gpiod_get_from_of_node() to return -ENOENT instead of NULL when the requested gpio property is not found in the device tree. Additionally it modifies all calling functions to properly evaluate the return value.

Another approach would be to leave the return value of gpiod_get_from_of_node() as is and fix the bug in devm_fwnode_get_index_gpiod_from_child(). Other callers would still need to be reworked. The effort would be the same as with the chosen solution.

Signed-off-by Georg Waibel <[email protected]>

---

V2: Rebased on top of [PATCH] regulator: s2mps11: Fix ERR_PTR dereference on GPIO lookup failure

---
 drivers/gpio/gpiolib.c                 | 6 +-----
 drivers/regulator/da9211-regulator.c   | 2 ++
 drivers/regulator/s2mps11.c            | 4 +++-
 drivers/regulator/s5m8767.c            | 4 +++-
 drivers/regulator/tps65090-regulator.c | 7 ++++---
 5 files changed, 13 insertions(+), 10 deletions(-)

drivers/gpio/gpiolib.c +1 -5

index e013d41..be1d1d2 100644
@@ -4244,8 +4244,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_index);
  *
  * Returns:
  * On successful request the GPIO pin is configured in accordance with
- * provided @dflags. If the node does not have the requested GPIO
- * property, NULL is returned.
+ * provided @dflags.
  *
  * In case of error an ERR_PTR() is returned.
  */

@@ -4267,9 +4266,6 @@ struct gpio_desc *gpiod_get_from_of_node(struct device_node *node,
                                        index, &flags);
 
        if (!desc || IS_ERR(desc)) {
-               /* If it is not there, just return NULL */
-               if (PTR_ERR(desc) == -ENOENT)
-                       return NULL;
                return desc;
        }
 

drivers/regulator/da9211-regulator.c +2 -0

index da37b4c..0309823 100644
@@ -289,6 +289,8 @@ static struct da9211_pdata *da9211_parse_regulators_dt(
                                  0,
                                  GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE,
                                  "da9211-enable");
+               if (IS_ERR(pdata->gpiod_ren[n]))
+                       pdata->gpiod_ren[n] = NULL;
                n++;
        }
 

drivers/regulator/s2mps11.c +3 -1

index af9bf10..209d1ff 100644
@@ -821,7 +821,9 @@ static void s2mps14_pmic_dt_parse_ext_control_gpio(struct platform_device *pdev,
                                0,
                                GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE,
                                "s2mps11-regulator");
-               if (IS_ERR(gpio[reg])) {
+               if (PTR_ERR(gpio[reg]) == -ENOENT)
+                       gpio[reg] = NULL;
+               else if (IS_ERR(gpio[reg])) {
                        dev_err(&pdev->dev, "Failed to get control GPIO for %d/%s\n",
                                reg, rdata[reg].name);
                        gpio[reg] = NULL;

drivers/regulator/s5m8767.c +3 -1

index bb9d1a0..6ca27e9 100644
@@ -574,7 +574,9 @@ static int s5m8767_pmic_dt_parse_pdata(struct platform_device *pdev,
                        0,
                        GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE,
                        "s5m8767");
-               if (IS_ERR(rdata->ext_control_gpiod))
+               if (PTR_ERR(rdata->ext_control_gpiod) == -ENOENT)
+                       rdata->ext_control_gpiod = NULL;
+               else if (IS_ERR(rdata->ext_control_gpiod))
                        return PTR_ERR(rdata->ext_control_gpiod);
 
                rdata->id = i;

drivers/regulator/tps65090-regulator.c +4 -4

index ca39b3d..10ea4b5 100644
@@ -371,11 +371,12 @@ static struct tps65090_platform_data *tps65090_parse_dt_reg_data(
                                                                    "dcdc-ext-control-gpios", 0,
                                                                    gflags,
                                                                    "tps65090");
-                       if (IS_ERR(rpdata->gpiod))
-                               return ERR_CAST(rpdata->gpiod);
-                       if (!rpdata->gpiod)
+                       if (PTR_ERR(rpdata->gpiod) == -ENOENT) {
                                dev_err(&pdev->dev,
                                        "could not find DCDC external control GPIO\n");
+                               rpdata->gpiod = NULL;
+                       } else if (IS_ERR(rpdata->gpiod))
+                               return ERR_CAST(rpdata->gpiod);
                }
 
                if (of_property_read_u32(tps65090_matches[idx].of_node,
--

2.7.4

In case the requested gpio property is not found in the device tree, some callers of gpiod_get_from_of_node() expect a return value of NULL, others expect -ENOENT.
In particular devm_fwnode_get_index_gpiod_from_child() expects -ENOENT. Currently it gets a NULL, which breaks the loop that tries all gpio_suffixes. The result is that a gpio property is not found, even though it is there.

This patch changes gpiod_get_from_of_node() to return -ENOENT instead of NULL when the requested gpio property is not found in the device tree. Additionally it modifies all calling functions to properly evaluate the return value.

Another approach would be to leave the return value of gpiod_get_from_of_node() as is and fix the bug in devm_fwnode_get_index_gpiod_from_child(). Other callers would still need to be reworked. The effort would be the same as with the chosen solution.

Signed-off-by Georg Waibel <[email protected]>

---

V2: Rebased on top of [PATCH] regulator: s2mps11: Fix ERR_PTR dereference on GPIO lookup failure

In case the requested gpio property is not found in the device tree, some callers of gpiod_get_from_of_node() expect a return value of NULL, others expect -ENOENT.
In particular devm_fwnode_get_index_gpiod_from_child() expects -ENOENT. Currently it gets a NULL, which breaks the loop that tries all gpio_suffixes. The result is that a gpio property is not found, even though it is there.