On Fri, Oct 19, 2018 at 8:27 PM Dan O'Donovan [off-list ref] wrote:

From: Javier Arteaga <redacted>

Allow userspace to use the on-board LEDs as "upboard:<color>:".

+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/mfd/upboard.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/acpi.h>

For better maintenance keep this ordered.

+       adev = ACPI_COMPANION(dev);
+       if (!adev || strcmp(acpi_device_hid(adev), "AANT0F01"))
+               return -ENODEV;

Why do you need this part?

+       if (led_index >= ARRAY_SIZE(upboard_led_names))
+               return -EINVAL;

+       if (!dev->parent)
+               return -EINVAL;

...I think this check will cover cases when driver is being probed standalone.
Otherwise it's caller's responsibility not to instantiate it if
platform doesn't have this LED feature.

+       regmap = dev_get_regmap(dev->parent, NULL);
+       if (!regmap)
+               return -EINVAL;

-- 
With Best Regards,
Andy Shevchenko