gpio: store reflect the label to userspace

The gpio_chip label is useful for userspace to understand what
kind of GPIO chip it is dealing with. Let's store a copy of this
label in the gpio_device, add it to the struct passed to userspace
for GPIO_GET_CHIPINFO_IOCTL and modify lsgpio to show it.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index ff96d0f9fceb..639607658ed8 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -21,7 +21,8 @@ struct gpio_device;
 
 /**
  * struct gpio_chip - abstract a GPIO controller
- * @label: for diagnostics
+ * @label: a functional name for the GPIO device, such as a part
+ *      number or the name of the SoC IP-block implementing it.
  * @gpiodev: the internal state holder, opaque struct
  * @parent: optional parent device providing the GPIOs
  * @owner: helps prevent removal of modules exporting active GPIOs