iio: accel: bma220: reset registers during init stage

Bring all configuration registers to default values during
device probe().
Remove trivial code duplication regarding bma220_power() in
_init()

Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/accel/bma220_core.c b/drivers/iio/accel/bma220_core.c
index 31fbea971230d86e56a1555c2505fe32144cc936..c2ed789f9658a451e4edb2e2c37b2fa9e32cf132 100644 (file)
--- a/drivers/iio/accel/bma220_core.c
+++ b/drivers/iio/accel/bma220_core.c
@@ -29,12 +29,15 @@
 #define BMA220_REG_ACCEL_Z                     0x04
 #define BMA220_REG_RANGE                       0x11
 #define BMA220_REG_SUSPEND                     0x18
+#define BMA220_REG_SOFTRESET                   0x19
 
 #define BMA220_CHIP_ID                         0xDD
 #define BMA220_READ_MASK                       BIT(7)
 #define BMA220_RANGE_MASK                      GENMASK(1, 0)
 #define BMA220_SUSPEND_SLEEP                   0xFF
 #define BMA220_SUSPEND_WAKE                    0x00
+#define BMA220_RESET_MODE                      0xFF
+#define BMA220_NONRESET_MODE                   0x00
 
 #define BMA220_DEVICE_NAME                     "bma220"
 
@@ -203,6 +206,31 @@ static const struct iio_info bma220_info = {
        .read_avail             = bma220_read_avail,
 };
 
+static int bma220_reset(struct spi_device *spi, bool up)
+{
+       int ret;
+       unsigned int i;
+
+       /*
+        * The chip can be reset by a simple register read.
+        * We need up to 2 register reads of the softreset register
+        * to make sure that the device is in the desired state.
+        */
+       for (i = 0; i < 2; i++) {
+               ret = bma220_read_reg(spi, BMA220_REG_SOFTRESET);
+               if (ret < 0)
+                       return ret;
+
+               if (up && ret == BMA220_RESET_MODE)
+                       return 0;
+
+               if (!up && ret == BMA220_NONRESET_MODE)
+                       return 0;
+       }
+
+       return -EBUSY;
+}
+
 static int bma220_power(struct spi_device *spi, bool up)
 {
        int ret;
@@ -247,14 +275,14 @@ static int bma220_init(struct spi_device *spi)
        if (ret != BMA220_CHIP_ID)
                dev_info(dev, "Unknown chip found: 0x%02x\n", ret);
 
-       /* Make sure the chip is powered on */
-       ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
-       if (ret == BMA220_SUSPEND_WAKE)
-               ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
-       if (ret < 0)
-               return ret;
-       if (ret == BMA220_SUSPEND_WAKE)
-               return -EBUSY;
+       /* Make sure the chip is powered on and config registers are reset */
+       ret = bma220_power(spi, true);
+       if (ret)
+               return dev_err_probe(dev, ret, "Failed to power-on chip\n");
+
+       ret = bma220_reset(spi, true);
+       if (ret)
+               return dev_err_probe(dev, ret, "Failed to soft reset chip\n");
 
        return 0;
 }