From 4dedf31cd1c28c732a17ddeb9cfdf90b5b860faa Mon Sep 17 00:00:00 2001 From: Peter Meerwald Date: Sat, 27 Jul 2013 16:31:00 +0100 Subject: staging:iio:hmc5843: Implement timeout in read function 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 Cc: Shubhrajyoti Datta Signed-off-by: Jonathan Cameron --- 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 c281342899eb..79117ad978d1 100644 --- a/drivers/staging/iio/magnetometer/hmc5843.c +++ b/drivers/staging/iio/magnetometer/hmc5843.c @@ -26,6 +26,7 @@ #include #include #include +#include #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); -- cgit v1.2.3