diff options
| -rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio.txt | 19 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib-of.c | 49 |
2 files changed, 68 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt index c88d2ccb05ca..68d28f62a6f4 100644 --- a/Documentation/devicetree/bindings/gpio/gpio.txt +++ b/Documentation/devicetree/bindings/gpio/gpio.txt @@ -152,6 +152,21 @@ additional bitmask is needed to specify which GPIOs are actually in use, and which are dummies. The bindings for this case has not yet been specified, but should be specified if/when such hardware appears. +Optionally, a GPIO controller may have a "gpio-line-names" property. This is +an array of strings defining the names of the GPIO lines going out of the +GPIO controller. This name should be the most meaningful producer name +for the system, such as a rail name indicating the usage. Package names +such as pin name are discouraged: such lines have opaque names (since they +are by definition generic purpose) and such names are usually not very +helpful. For example "MMC-CD", "Red LED Vdd" and "ethernet reset" are +reasonable line names as they describe what the line is used for. "GPIO0" +is not a good name to give to a GPIO line. Placeholders are discouraged: +rather use the "" (blank string) if the use of the GPIO line is undefined +in your design. The names are assigned starting from line offset 0 from +left to right from the passed array. An incomplete array (where the number +of passed named are less than ngpios) will still be used up until the last +provided valid line index. + Example: gpio-controller@00000000 { @@ -160,6 +175,10 @@ gpio-controller@00000000 { gpio-controller; #gpio-cells = <2>; ngpios = <18>; + gpio-line-names = "MMC-CD", "MMC-WP", "VDD eth", "RST eth", "LED R", + "LED G", "LED B", "Col A", "Col B", "Col C", "Col D", + "Row A", "Row B", "Row C", "Row D", "NMI button", + "poweroff", "reset"; } The GPIO chip may contain GPIO hog definitions. GPIO hogging is a mechanism diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c index d81dbd8e90d9..d22dcc38179d 100644 --- a/drivers/gpio/gpiolib-of.c +++ b/drivers/gpio/gpiolib-of.c @@ -196,6 +196,51 @@ static struct gpio_desc *of_parse_own_gpio(struct device_node *np, } /** + * of_gpiochip_set_names() - set up the names of the lines + * @chip: GPIO chip whose lines should be named, if possible + */ +static void of_gpiochip_set_names(struct gpio_chip *gc) +{ + struct gpio_device *gdev = gc->gpiodev; + struct device_node *np = gc->of_node; + int i; + int nstrings; + + nstrings = of_property_count_strings(np, "gpio-line-names"); + if (nstrings <= 0) + /* Lines names not present */ + return; + + /* This is normally not what you want */ + if (gdev->ngpio != nstrings) + dev_info(&gdev->dev, "gpio-line-names specifies %d line " + "names but there are %d lines on the chip\n", + nstrings, gdev->ngpio); + + /* + * Make sure to not index beyond the end of the number of descriptors + * of the GPIO device. + */ + for (i = 0; i < gdev->ngpio; i++) { + const char *name; + int ret; + + ret = of_property_read_string_index(np, + "gpio-line-names", + i, + &name); + if (ret) { + if (ret != -ENODATA) + dev_err(&gdev->dev, + "unable to name line %d: %d\n", + i, ret); + break; + } + gdev->descs[i].name = name; + } +} + +/** * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions * @chip: gpio chip to act on * @@ -445,6 +490,10 @@ int of_gpiochip_add(struct gpio_chip *chip) if (status) return status; + /* If the chip defines names itself, these take precedence */ + if (!chip->names) + of_gpiochip_set_names(chip); + of_node_get(chip->of_node); return of_gpiochip_scan_gpios(chip); |