iio: magnetometer: Add ACPI support for MMC35240

We assume that ACPI device tables use MMC35240 to
identify MEMSIC's 3 axis magnetic sensor.

Signed-off-by: Daniel Baluta <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/magnetometer/mmc35240.c

···
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/regmap.h>
+#include <linux/acpi.h>
 #include <linux/pm.h>
 
 #include <linux/iio/iio.h>
···
 	SET_SYSTEM_SLEEP_PM_OPS(mmc35240_suspend, mmc35240_resume)
 };
 
+static const struct acpi_device_id mmc35240_acpi_match[] = {
+	{"MMC35240", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
+
 static const struct i2c_device_id mmc35240_id[] = {
 	{"MMC35240", 0},
 	{}
···
 	.driver = {
 		.name = MMC35240_DRV_NAME,
 		.pm = &mmc35240_pm_ops,
+		.acpi_match_table = ACPI_PTR(mmc35240_acpi_match),
 	},
 	.probe		= mmc35240_probe,
 	.id_table	= mmc35240_id,