On 07/27/13 16:31, Peter Meerwald wrote:
> 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>
Applied to the togreg branch of iio.git.
Thanks
> ---
> 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);
>
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