diff options
| -rw-r--r-- | Documentation/gpio/consumer.txt | 6 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib.c | 34 |
2 files changed, 22 insertions, 18 deletions
diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt index 07c74a3765a0..e42f77d8d4ca 100644 --- a/Documentation/gpio/consumer.txt +++ b/Documentation/gpio/consumer.txt @@ -38,7 +38,11 @@ device that displays digits), an additional index argument can be specified: const char *con_id, unsigned int idx) Both functions return either a valid GPIO descriptor, or an error code checkable -with IS_ERR(). They will never return a NULL pointer. +with IS_ERR() (they will never return a NULL pointer). -ENOENT will be returned +if and only if no GPIO has been assigned to the device/function/index triplet, +other error codes are used for cases where a GPIO has been assigned but an error +occured while trying to acquire it. This is useful to discriminate between mere +errors and an absence of GPIO for optional GPIO parameters. Device-managed variants of these functions are also defined: diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 12e47dfabd8d..c0b06a9adad9 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2367,7 +2367,7 @@ static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id, unsigned int idx, enum gpio_lookup_flags *flags) { - struct gpio_desc *desc = ERR_PTR(-ENODEV); + struct gpio_desc *desc = ERR_PTR(-ENOENT); struct gpiod_lookup_table *table; struct gpiod_lookup *p; @@ -2389,19 +2389,22 @@ static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id, chip = find_chip_by_name(p->chip_label); if (!chip) { - dev_warn(dev, "cannot find GPIO chip %s\n", - p->chip_label); - continue; + dev_err(dev, "cannot find GPIO chip %s\n", + p->chip_label); + return ERR_PTR(-ENODEV); } if (chip->ngpio <= p->chip_hwnum) { - dev_warn(dev, "GPIO chip %s has %d GPIOs\n", - chip->label, chip->ngpio); - continue; + dev_err(dev, + "requested GPIO %d is out of range [0..%d] for chip %s\n", + idx, chip->ngpio, chip->label); + return ERR_PTR(-EINVAL); } desc = gpiochip_offset_to_desc(chip, p->chip_hwnum); *flags = p->flags; + + return desc; } return desc; @@ -2413,7 +2416,8 @@ static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id, * @con_id: function within the GPIO consumer * * Return the GPIO descriptor corresponding to the function con_id of device - * dev, or an IS_ERR() condition if an error occured. + * dev, -ENOENT if no GPIO has been assigned to the requested function, or + * another IS_ERR() code if an error occured while trying to acquire the GPIO. */ struct gpio_desc *__must_check gpiod_get(struct device *dev, const char *con_id) { @@ -2430,7 +2434,9 @@ EXPORT_SYMBOL_GPL(gpiod_get); * This variant of gpiod_get() allows to access GPIOs other than the first * defined one for functions that define several GPIOs. * - * Return a valid GPIO descriptor, or an IS_ERR() condition in case of error. + * Return a valid GPIO descriptor, -ENOENT if no GPIO has been assigned to the + * requested function and/or index, or another IS_ERR() code if an error + * occured while trying to acquire the GPIO. */ struct gpio_desc *__must_check gpiod_get_index(struct device *dev, const char *con_id, @@ -2455,15 +2461,9 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev, * Either we are not using DT or ACPI, or their lookup did not return * a result. In that case, use platform lookup as a fallback. */ - if (!desc || IS_ERR(desc)) { - struct gpio_desc *pdesc; - + if (!desc || desc == ERR_PTR(-ENOENT)) { dev_dbg(dev, "using lookup tables for GPIO lookup"); - pdesc = gpiod_find(dev, con_id, idx, &flags); - - /* If used as fallback, do not replace the previous error */ - if (!IS_ERR(pdesc) || !desc) - desc = pdesc; + desc = gpiod_find(dev, con_id, idx, &flags); } if (IS_ERR(desc)) { |