[PATCH v2] iio: light: acpi-als: Properly enable on ASUS Zenbooks

[Josef Gajdusek <atx@atx.name>]

ASUS Zenbooks need several special ACPI calls to enable the ALS peripheral.
Otherwise, reads just return 0.

Signed-off-by: Josef Gajdusek <atx@atx.name>
---
 drivers/iio/light/acpi-als.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/iio/light/acpi-als.c b/drivers/iio/light/acpi-als.c
index f0b47c5..ccd5787 100644
--- a/drivers/iio/light/acpi-als.c
+++ b/drivers/iio/light/acpi-als.c
@@ -39,6 +39,9 @@
 #define ACPI_ALS_DEVICE_NAME		"acpi-als"
 #define ACPI_ALS_NOTIFY_ILLUMINANCE	0x80
 
+#define ACPI_ALS_ASUS_TALS		"\\_SB.PCI0.LPCB.EC0.TALS"
+#define ACPI_ALS_ASUS_ALSC		"\\_SB.ATKD.ALSC"
+
 ACPI_MODULE_NAME("acpi-als");
 
 /*
@@ -170,6 +173,16 @@ static int acpi_als_read_raw(struct iio_dev *indio_dev,
 	return IIO_VAL_INT;
 }
 
+static void acpi_als_quirk_asus(struct acpi_als *als)
+{
+	acpi_execute_simple_method(NULL, ACPI_ALS_ASUS_TALS, 1);
+	acpi_execute_simple_method(NULL, ACPI_ALS_ASUS_ALSC, 1);
+}
+
+static void (*acpi_als_quirks[])(struct acpi_als *als) = {
+	acpi_als_quirk_asus,
+};
+
 static const struct iio_info acpi_als_info = {
 	.driver_module		= THIS_MODULE,
 	.read_raw		= acpi_als_read_raw,
@@ -180,6 +193,7 @@ static int acpi_als_add(struct acpi_device *device)
 	struct acpi_als *als;
 	struct iio_dev *indio_dev;
 	struct iio_buffer *buffer;
+	int i;
 
 	indio_dev = devm_iio_device_alloc(&device->dev, sizeof(*als));
 	if (!indio_dev)
@@ -191,6 +205,9 @@ static int acpi_als_add(struct acpi_device *device)
 	als->device = device;
 	mutex_init(&als->lock);
 
+	for (i = 0; i < ARRAY_SIZE(acpi_als_quirks); i++)
+		acpi_als_quirks[i](als);
+
 	indio_dev->name = ACPI_ALS_DEVICE_NAME;
 	indio_dev->dev.parent = &device->dev;
 	indio_dev->info = &acpi_als_info;
-- 
2.10.2