avoid polling data ready bit forever; msleep() may be too long
for high sampling frequencies but the driver interface does not
support buffering
Signed-off-by: Peter Meerwald <pmeerw@xxxxxxxxxx>
Cc: Shubhrajyoti Datta <shubhrajyoti@xxxxxx>
---
drivers/staging/iio/magnetometer/hmc5843.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/iio/magnetometer/hmc5843.c b/drivers/staging/iio/magnetometer/hmc5843.c
index c281342..79117ad 100644
--- a/drivers/staging/iio/magnetometer/hmc5843.c
+++ b/drivers/staging/iio/magnetometer/hmc5843.c
@@ -26,6 +26,7 @@
#include <linux/types.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
+#include <linux/delay.h>
#define HMC5843_CONFIG_REG_A 0x00
#define HMC5843_CONFIG_REG_B 0x01
@@ -210,11 +211,22 @@ static int hmc5843_read_measurement(struct iio_dev *indio_dev,
struct i2c_client *client = to_i2c_client(indio_dev->dev.parent);
struct hmc5843_data *data = iio_priv(indio_dev);
s32 result;
+ int tries = 150;
mutex_lock(&data->lock);
- result = i2c_smbus_read_byte_data(client, HMC5843_STATUS_REG);
- while (!(result & HMC5843_DATA_READY))
- result = i2c_smbus_read_byte_data(client, HMC5843_STATUS_REG);
+ while (tries-- > 0) {
+ result = i2c_smbus_read_byte_data(client,
+ HMC5843_STATUS_REG);
+ if (result & HMC5843_DATA_READY)
+ break;
+ msleep(20);
+ }
+
+ if (tries < 0) {
+ dev_err(&client->dev, "data not ready\n");
+ mutex_unlock(&data->lock);
+ return -EIO;
+ }
result = i2c_smbus_read_word_data(client, address);
mutex_unlock(&data->lock);
--
1.8.3.4
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