From 63d5d525cbbc8938d9fa3d6d6fbd4183e784b6e9 Mon Sep 17 00:00:00 2001
From: Gregor Boirie <gregor.boirie@parrot.com>
Date: Thu, 3 Mar 2016 11:44:05 +0100
Subject: iio:magnetometer:ak8975: power regulator support

Add support for an optional regulator which, if found into device-tree,
will power on device at probing time.
The regulator is declared into ak8975 DTS entry as a "vdd-supply" property.

Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/iio/magnetometer/ak8975.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'drivers/iio/magnetometer/ak8975.c')

diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
index 896b13e39dae..72c03d9fbeb2 100644
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -32,6 +32,7 @@
 #include <linux/gpio.h>
 #include <linux/of_gpio.h>
 #include <linux/acpi.h>
+#include <linux/regulator/consumer.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -379,8 +380,23 @@ static int ak8975_who_i_am(struct i2c_client *client,
 			   enum asahi_compass_chipset type)
 {
 	u8 wia_val[2];
+	struct regulator *vdd = devm_regulator_get_optional(&client->dev,
+							    "vdd");
 	int ret;
 
+	/* Enable attached regulator if any. */
+	if (!IS_ERR(vdd)) {
+		ret = regulator_enable(vdd);
+		if (ret) {
+			dev_err(&client->dev, "Failed to enable Vdd supply\n");
+			return ret;
+		}
+	} else {
+		ret = PTR_ERR(vdd);
+		if (ret != -ENODEV)
+			return ret;
+	}
+
 	/*
 	 * Signature for each device:
 	 * Device   |  WIA1      |  WIA2
-- 
cgit