[PATCH 2/5] ACPI / gpio: Add support for naming GPIOs

Mika Westerberg
2016-09-23T14:57:16Z

DT has property 'gpio-line-names' to name GPIO lines the controller has if
present. Use this very same property in ACPI as well to provide nice names
for the GPIOS.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
Documentation/acpi/gpio-properties.txt | 21 +++++++++++++++++
drivers/gpio/gpiolib-acpi.c | 43 ++++++++++++++++++++++++++++++++++
2 files changed, 64 insertions(+)

diff --git a/Documentation/acpi/gpio-properties.txt b/Documentation/acpi/gpio-properties.txt
index 5aafe0b351a1..7875974823ae 100644
--- a/Documentation/acpi/gpio-properties.txt
+++ b/Documentation/acpi/gpio-properties.txt
@@ -51,6 +51,27 @@ it to 1 marks the GPIO as active low.
In our Bluetooth example the "reset-gpios" refers to the second GpioIo()
resource, second pin in that resource with the GPIO number of 31.

+Other supported properties
+--------------------------
+
+Following Device Tree compatible device properties are also supported by
+_DSD device properties for GPIO controllers:
+
+- gpio-line-names
+
+Example:
+
+ Package () {
+ "gpio-line-names",
+ Package () {
+ "SPI0_CS_N", "EXP2_INT", "MUX6_IO", "UART0_RXD", "MUX7_IO",
+ "LVL_C_A1", "MUX0_IO", "SPI1_MISO"
+ }
+ }
+
+See Documentation/devicetree/bindings/gpio/gpio.tx for more information
+about these properties.
+
ACPI GPIO Mappings Provided by Drivers
--------------------------------------

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index af514618d7fb..202cf1b842de 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -805,6 +805,46 @@ static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
}
}

+static void acpi_gpiochip_set_names(struct acpi_gpio_chip *achip)
+{
+ struct gpio_chip *chip = achip->chip;
+ struct gpio_device *gdev = chip->gpiodev;
+ const char **names;
+ int ret, i;
+
+ ret = device_property_read_string_array(chip->parent, "gpio-line-names",
+ NULL, 0);
+ if (ret < 0)
+ return;
+
+ if (ret != gdev->ngpio) {
+ dev_warn(chip->parent,
+ "names %d do not match number of GPIOs %d\n", ret,
+ gdev->ngpio);
+ return;
+ }
+
+ names = kcalloc(gdev->ngpio, sizeof(*names), GFP_KERNEL);
+ if (!names)
+ return;
+
+ ret = device_property_read_string_array(chip->parent, "gpio-line-names",
+ names, gdev->ngpio);
+ if (ret < 0) {
+ dev_warn(chip->parent, "Failed to read GPIO line names\n");
+ return;
+ }
+
+ /*
+ * It is fine to assign the name, it will be allocated as long as
+ * the ACPI device exists.
+ */
+ for (i = 0; i < gdev->ngpio; i++)
+ gdev->descs[i].name = names[i];
+
+ kfree(names);
+}
+
void acpi_gpiochip_add(struct gpio_chip *chip)
{
struct acpi_gpio_chip *acpi_gpio;
@@ -835,6 +875,9 @@ void acpi_gpiochip_add(struct gpio_chip *chip)
return;
}

+ if (!chip->names)
+ acpi_gpiochip_set_names(acpi_gpio);
+
acpi_gpiochip_request_regions(acpi_gpio);
acpi_walk_dep_device_list(handle);
}
--
2.9.3