staging:iio:magnetometer:ak8975 use standard i2c_smbus read functions.

Now the mysterious NOSTART flag is gone from the read, we can use the
i2c_smbus_read_byte/word/i2c_block_data functions instead of the
local reimplementation of these standard functions.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Laxman Dewangan <ldewangan@nvidia.com>

diff --git a/drivers/staging/iio/magnetometer/ak8975.c b/drivers/staging/iio/magnetometer/ak8975.c
index 1428849..af6c320 100644 (file)
--- a/drivers/staging/iio/magnetometer/ak8975.c
+++ b/drivers/staging/iio/magnetometer/ak8975.c
@@ -123,35 +123,6 @@ static int ak8975_write_data(struct i2c_client *client,
 }
 
 /*
- * Helper function to read a contiguous set of the I2C device's registers.
- */
-static int ak8975_read_data(struct i2c_client *client,
-                           u8 reg, u8 length, u8 *buffer)
-{
-       int ret;
-       struct i2c_msg msg[2] = {
-               {
-                       .addr = client->addr,
-                       .len = 1,
-                       .buf = &reg,
-               }, {
-                       .addr = client->addr,
-                       .flags = I2C_M_RD,
-                       .len = length,
-                       .buf = buffer,
-               }
-       };
-
-       ret = i2c_transfer(client->adapter, msg, 2);
-       if (ret < 0) {
-               dev_err(&client->dev, "Read from device fails\n");
-               return ret;
-       }
-
-       return 0;
-}
-
-/*
  * Perform some start-of-day setup, including reading the asa calibration
  * values and caching them.
  */
@@ -163,11 +134,12 @@ static int ak8975_setup(struct i2c_client *client)
        int ret;
 
        /* Confirm that the device we're talking to is really an AK8975. */
-       ret = ak8975_read_data(client, AK8975_REG_WIA, 1, &device_id);
+       ret = i2c_smbus_read_byte_data(client, AK8975_REG_WIA);
        if (ret < 0) {
                dev_err(&client->dev, "Error reading WIA\n");
                return ret;
        }
+       device_id = ret;
        if (device_id != AK8975_DEVICE_ID) {
                dev_err(&client->dev, "Device ak8975 not found\n");
                return -ENODEV;
@@ -185,7 +157,8 @@ static int ak8975_setup(struct i2c_client *client)
        }
 
        /* Get asa data and store in the device data. */
-       ret = ak8975_read_data(client, AK8975_REG_ASAX, 3, data->asa);
+       ret = i2c_smbus_read_i2c_block_data(client, AK8975_REG_ASAX,
+                                           3, data->asa);
        if (ret < 0) {
                dev_err(&client->dev, "Not able to read asa data\n");
                return ret;
@@ -247,7 +220,6 @@ static int ak8975_setup(struct i2c_client *client)
 static int wait_conversion_complete_gpio(struct ak8975_data *data)
 {
        struct i2c_client *client = data->client;
-       u8 read_status;
        u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
        int ret;
 
@@ -263,12 +235,11 @@ static int wait_conversion_complete_gpio(struct ak8975_data *data)
                return -EINVAL;
        }
 
-       ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status);
-       if (ret < 0) {
+       ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1);
+       if (ret < 0)
                dev_err(&client->dev, "Error in reading ST1\n");
-               return ret;
-       }
-       return read_status;
+
+       return ret;
 }
 
 static int wait_conversion_complete_polled(struct ak8975_data *data)
@@ -281,11 +252,12 @@ static int wait_conversion_complete_polled(struct ak8975_data *data)
        /* Wait for the conversion to complete. */
        while (timeout_ms) {
                msleep(AK8975_CONVERSION_DONE_POLL_TIME);
-               ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status);
+               ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1);
                if (ret < 0) {
                        dev_err(&client->dev, "Error in reading ST1\n");
                        return ret;
                }
+               read_status = ret;
                if (read_status)
                        break;
                timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
@@ -306,7 +278,6 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
        struct i2c_client *client = data->client;
        u16 meas_reg;
        s16 raw;
-       u8 read_status;
        int ret;
 
        mutex_lock(&data->lock);
@@ -330,18 +301,15 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
        if (ret < 0)
                goto exit;
 
-       read_status = ret;
-
-       if (read_status & AK8975_REG_ST1_DRDY_MASK) {
-               ret = ak8975_read_data(client, AK8975_REG_ST2, 1, &read_status);
+       if (ret & AK8975_REG_ST1_DRDY_MASK) {
+               ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST2);
                if (ret < 0) {
                        dev_err(&client->dev, "Error in reading ST2\n");
                        goto exit;
                }
-               if (read_status & (AK8975_REG_ST2_DERR_MASK |
-                                  AK8975_REG_ST2_HOFL_MASK)) {
-                       dev_err(&client->dev, "ST2 status error 0x%x\n",
-                               read_status);
+               if (ret & (AK8975_REG_ST2_DERR_MASK |
+                          AK8975_REG_ST2_HOFL_MASK)) {
+                       dev_err(&client->dev, "ST2 status error 0x%x\n", ret);
                        ret = -EINVAL;
                        goto exit;
                }
@@ -349,12 +317,12 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
 
        /* Read the flux value from the appropriate register
           (the register is specified in the iio device attributes). */
-       ret = ak8975_read_data(client, ak8975_index_to_reg[index],
-                              2, (u8 *)&meas_reg);
+       ret = i2c_smbus_read_word_data(client, ak8975_index_to_reg[index]);
        if (ret < 0) {
                dev_err(&client->dev, "Read axis data fails\n");
                goto exit;
        }
+       meas_reg = ret;
 
        mutex_unlock(&data->lock);