[PATCH 4/7] iio: inv_mpu6050: Cache non-volatile bits of user_ctrl

[Crestez Dan Leonard]

Signed-off-by: Crestez Dan Leonard <leonard.cres...@intel.com>
---
 drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h     | 2 ++
 drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c    | 9 ++++++---
 drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c | 4 +++-
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h 
b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
index 297b0ef..bd2c0fd 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
@@ -80,6 +80,7 @@ enum inv_devices {
  *  @enable:           master enable state.
  *  @accl_fifo_enable: enable accel data output
  *  @gyro_fifo_enable: enable gyro data output
+ *  @user_ctrl:                The non-volatile bits of user_ctrl
  *  @fifo_rate:                FIFO update rate.
  */
 struct inv_mpu6050_chip_config {
@@ -89,6 +90,7 @@ struct inv_mpu6050_chip_config {
        unsigned int enable:1;
        unsigned int accl_fifo_enable:1;
        unsigned int gyro_fifo_enable:1;
+       u8 user_ctrl;
        u16 fifo_rate;
 };
 
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c 
b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
index 3fc0b71..56ee1e2 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
@@ -53,13 +53,15 @@ int inv_reset_fifo(struct iio_dev *indio_dev)
        if (result)
                goto reset_fifo_fail;
        /* disable fifo reading */
-       result = regmap_write(st->map, st->reg->user_ctrl, 0);
+       st->chip_config.user_ctrl &= ~INV_MPU6050_BIT_FIFO_EN;
+       result = regmap_write(st->map, st->reg->user_ctrl,
+                             st->chip_config.user_ctrl);
        if (result)
                goto reset_fifo_fail;
 
        /* reset FIFO*/
        result = regmap_write(st->map, st->reg->user_ctrl,
-                             INV_MPU6050_BIT_FIFO_RST);
+                             st->chip_config.user_ctrl | 
INV_MPU6050_BIT_FIFO_RST);
        if (result)
                goto reset_fifo_fail;
 
@@ -76,8 +78,9 @@ int inv_reset_fifo(struct iio_dev *indio_dev)
                        return result;
        }
        /* enable FIFO reading and I2C master interface*/
+       st->chip_config.user_ctrl |= INV_MPU6050_BIT_FIFO_EN;
        result = regmap_write(st->map, st->reg->user_ctrl,
-                             INV_MPU6050_BIT_FIFO_EN);
+                             st->chip_config.user_ctrl);
        if (result)
                goto reset_fifo_fail;
        /* enable sensor output to FIFO */
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c 
b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
index 1a6bad3..fc55923 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
@@ -74,7 +74,9 @@ static int inv_mpu6050_set_enable(struct iio_dev *indio_dev, 
bool enable)
                if (result)
                        return result;
 
-               result = regmap_write(st->map, st->reg->user_ctrl, 0);
+               st->chip_config.user_ctrl &= ~INV_MPU6050_BIT_FIFO_EN;
+               result = regmap_write(st->map, st->reg->user_ctrl,
+                                     st->chip_config.user_ctrl);
                if (result)
                        return result;
 
-- 
2.5.5