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Commit 4dedf31c authored by Peter Meerwald's avatar Peter Meerwald Committed by Jonathan Cameron
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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: default avatarPeter Meerwald <pmeerw@pmeerw.net>
Cc: Shubhrajyoti Datta <shubhrajyoti@ti.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent a34778f3

drivers/staging/iio/magnetometer/hmc5843.c

+15 −3
Original line number Diff line number Diff line
@@ -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);