[PATCH AUTOSEL for 4.15 049/102] iio: health: max30102: Add power enable parameter to get_temp function

[Sasha Levin]

From: Peter Meerwald-Stadler <pme...@pmeerw.net>

[ Upstream commit a9c47abbdd71dceeaf1b923e5ce10e700e036905 ]

Chip must not be in shutdown for reading temperature, so briefly leave
shutdown if buffer is not already running

Signed-off-by: Peter Meerwald-Stadler <pme...@pmeerw.net>
Acked-by: Matt Ranostay <matt.ranos...@konsulko.com>
Signed-off-by: Jonathan Cameron <jonathan.came...@huawei.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
---
 drivers/iio/health/max30102.c | 36 +++++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/drivers/iio/health/max30102.c b/drivers/iio/health/max30102.c
index 147a8c14235f..a14fc2eb1fe9 100644
--- a/drivers/iio/health/max30102.c
+++ b/drivers/iio/health/max30102.c
@@ -329,20 +329,31 @@ static int max30102_read_temp(struct max30102_data *data, 
int *val)
        return 0;
 }
 
-static int max30102_get_temp(struct max30102_data *data, int *val)
+static int max30102_get_temp(struct max30102_data *data, int *val, bool en)
 {
        int ret;
 
+       if (en) {
+               ret = max30102_set_powermode(data, true);
+               if (ret)
+                       return ret;
+       }
+
        /* start acquisition */
        ret = regmap_update_bits(data->regmap, MAX30102_REG_TEMP_CONFIG,
                                 MAX30102_REG_TEMP_CONFIG_TEMP_EN,
                                 MAX30102_REG_TEMP_CONFIG_TEMP_EN);
        if (ret)
-               return ret;
+               goto out;
 
        msleep(35);
+       ret = max30102_read_temp(data, val);
+
+out:
+       if (en)
+               max30102_set_powermode(data, false);
 
-       return max30102_read_temp(data, val);
+       return ret;
 }
 
 static int max30102_read_raw(struct iio_dev *indio_dev,
@@ -355,20 +366,19 @@ static int max30102_read_raw(struct iio_dev *indio_dev,
        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                /*
-                * Temperature reading can only be acquired while engine
-                * is running
+                * Temperature reading can only be acquired when not in
+                * shutdown; leave shutdown briefly when buffer not running
                 */
                mutex_lock(&indio_dev->mlock);
-
                if (!iio_buffer_enabled(indio_dev))
-                       ret = -EBUSY;
-               else {
-                       ret = max30102_get_temp(data, val);
-                       if (!ret)
-                               ret = IIO_VAL_INT;
-               }
-
+                       ret = max30102_get_temp(data, val, true);
+               else
+                       ret = max30102_get_temp(data, val, false);
                mutex_unlock(&indio_dev->mlock);
+               if (ret)
+                       return ret;
+
+               ret = IIO_VAL_INT;
                break;
        case IIO_CHAN_INFO_SCALE:
                *val = 1000;  /* 62.5 */
-- 
2.14.1