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Commit 984fb244 authored by Narcisa Ana Maria Vasile's avatar Narcisa Ana Maria Vasile Committed by Jonathan Cameron
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staging: iio: ad5933: Protect DIRECT mode using claim/release helpers 



This device operates in DIRECT_MODE and BUFFER_HARDWARE mode.
Replace usages of iio_dev->mlock with iio_device_{claim|release}_direct_mode()
helper functions to guarantee DIRECT mode and consequently protect
BUFFER mode too.

Add and use a device private lock to protect against conflicting access of the
state data.
This helps with IIO subsystem redefining iio_dev->mlock to be used by
the IIO core only for protecting device operating mode changes.
ie. Changes between INDIO_DIRECT_MODE, INDIO_BUFFER_* modes.

Protect changing of attributes inside ad5933_store(). Attributes
can no longer be changed while in buffered mode.

Remove lock from ad5933_work() because buffer mode should be enabled
when we reach this, and claiming DIRECT mode in all the other places
should protect it.

Signed-off-by: default avatarNarcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent a9e9c715

drivers/staging/iio/impedance-analyzer/ad5933.c

+28 −22
Original line number Diff line number Diff line
@@ -98,6 +98,7 @@ struct ad5933_state { 
	struct i2c_client		*client;

	struct regulator		*reg;

	struct delayed_work		work;

	struct mutex			lock; /* Protect sensor state */

	unsigned long			mclk_hz;

	unsigned char			ctrl_hb;

	unsigned char			ctrl_lb;
@@ -306,9 +307,11 @@ static ssize_t ad5933_show_frequency(struct device *dev, 
		u8 d8[4];

	} dat;



	mutex_lock(&indio_dev->mlock);

	ret = iio_device_claim_direct_mode(indio_dev);

	if (ret)

		return ret;

	ret = ad5933_i2c_read(st->client, this_attr->address, 3, &dat.d8[1]);

	mutex_unlock(&indio_dev->mlock);

	iio_device_release_direct_mode(indio_dev);

	if (ret < 0)

		return ret;
@@ -338,9 +341,11 @@ static ssize_t ad5933_store_frequency(struct device *dev, 
	if (val > AD5933_MAX_OUTPUT_FREQ_Hz)

		return -EINVAL;



	mutex_lock(&indio_dev->mlock);

	ret = iio_device_claim_direct_mode(indio_dev);

	if (ret)

		return ret;

	ret = ad5933_set_freq(st, this_attr->address, val);

	mutex_unlock(&indio_dev->mlock);

	iio_device_release_direct_mode(indio_dev);



	return ret ? ret : len;

}
@@ -364,7 +369,7 @@ static ssize_t ad5933_show(struct device *dev, 
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

	int ret = 0, len = 0;



	mutex_lock(&indio_dev->mlock);

	mutex_lock(&st->lock);

	switch ((u32)this_attr->address) {

	case AD5933_OUT_RANGE:

		len = sprintf(buf, "%u\n",
@@ -393,7 +398,7 @@ static ssize_t ad5933_show(struct device *dev, 
		ret = -EINVAL;

	}



	mutex_unlock(&indio_dev->mlock);

	mutex_unlock(&st->lock);

	return ret ? ret : len;

}
@@ -415,7 +420,10 @@ static ssize_t ad5933_store(struct device *dev, 
			return ret;

	}



	mutex_lock(&indio_dev->mlock);

	ret = iio_device_claim_direct_mode(indio_dev);

	if (ret)

		return ret;

	mutex_lock(&st->lock);

	switch ((u32)this_attr->address) {

	case AD5933_OUT_RANGE:

		ret = -EINVAL;
@@ -465,7 +473,8 @@ static ssize_t ad5933_store(struct device *dev, 
		ret = -EINVAL;

	}



	mutex_unlock(&indio_dev->mlock);

	mutex_unlock(&st->lock);

	iio_device_release_direct_mode(indio_dev);

	return ret ? ret : len;

}
@@ -532,11 +541,9 @@ static int ad5933_read_raw(struct iio_dev *indio_dev, 


	switch (m) {

	case IIO_CHAN_INFO_RAW:

		mutex_lock(&indio_dev->mlock);

		if (iio_buffer_enabled(indio_dev)) {

			ret = -EBUSY;

			goto out;

		}

		ret = iio_device_claim_direct_mode(indio_dev);

		if (ret)

			return ret;

		ret = ad5933_cmd(st, AD5933_CTRL_MEASURE_TEMP);

		if (ret < 0)

			goto out;
@@ -549,7 +556,7 @@ static int ad5933_read_raw(struct iio_dev *indio_dev, 
				      2, (u8 *)&dat);

		if (ret < 0)

			goto out;

		mutex_unlock(&indio_dev->mlock);

		iio_device_release_direct_mode(indio_dev);

		*val = sign_extend32(be16_to_cpu(dat), 13);



		return IIO_VAL_INT;
@@ -561,7 +568,7 @@ static int ad5933_read_raw(struct iio_dev *indio_dev, 


	return -EINVAL;

out:

	mutex_unlock(&indio_dev->mlock);

	iio_device_release_direct_mode(indio_dev);

	return ret;

}
@@ -657,18 +664,17 @@ static void ad5933_work(struct work_struct *work) 
	unsigned char status;

	int ret;



	mutex_lock(&indio_dev->mlock);

	if (st->state == AD5933_CTRL_INIT_START_FREQ) {

		/* start sweep */

		ad5933_cmd(st, AD5933_CTRL_START_SWEEP);

		st->state = AD5933_CTRL_START_SWEEP;

		schedule_delayed_work(&st->work, st->poll_time_jiffies);

		goto out;

		return;

	}



	ret = ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);

	if (ret)

		goto out;

		return;



	if (status & AD5933_STAT_DATA_VALID) {

		int scan_count = bitmap_weight(indio_dev->active_scan_mask,
@@ -678,7 +684,7 @@ static void ad5933_work(struct work_struct *work) 
				AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA,

				scan_count * 2, (u8 *)buf);

		if (ret)

			goto out;

			return;



		if (scan_count == 2) {

			val[0] = be16_to_cpu(buf[0]);
@@ -690,7 +696,7 @@ static void ad5933_work(struct work_struct *work) 
	} else {

		/* no data available - try again later */

		schedule_delayed_work(&st->work, st->poll_time_jiffies);

		goto out;

		return;

	}



	if (status & AD5933_STAT_SWEEP_DONE) {
@@ -703,8 +709,6 @@ static void ad5933_work(struct work_struct *work) 
		ad5933_cmd(st, AD5933_CTRL_INC_FREQ);

		schedule_delayed_work(&st->work, st->poll_time_jiffies);

	}

out:

	mutex_unlock(&indio_dev->mlock);

}



static int ad5933_probe(struct i2c_client *client,
@@ -723,6 +727,8 @@ static int ad5933_probe(struct i2c_client *client, 
	i2c_set_clientdata(client, indio_dev);

	st->client = client;



	mutex_init(&st->lock);



	if (!pdata)

		pdata = &ad5933_default_pdata;