From: Lars-Peter Clausen <lars@xxxxxxxxxx>
This is also part of a long term effort to make the use of mlock opaque and
single purpose.
This lock is required for accessing device registers. Some operations
require multiple consecutive R/W operations, during which the device
shouldn't be interrupted.
Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
V3 -> V4:
* updated comment/description of the lock
drivers/iio/frequency/ad9523.c | 32 ++++++++++++++++++++++----------
1 file changed, 22 insertions(+), 10 deletions(-)
diff --git a/drivers/iio/frequency/ad9523.c b/drivers/iio/frequency/ad9523.c
index ddb6a334ae68..2ab175a0664d 100644
--- a/drivers/iio/frequency/ad9523.c
+++ b/drivers/iio/frequency/ad9523.c
@@ -274,6 +274,13 @@ struct ad9523_state {
unsigned long vco_out_freq[AD9523_NUM_CLK_SRC];
unsigned char vco_out_map[AD9523_NUM_CHAN_ALT_CLK_SRC];
+ /*
+ * Lock for accessing device registers. Some operations require
+ * multiple consecutive R/W operations, during which the device
+ * shouldn't be interrupted.
+ */
+ struct mutex lock;
+
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
@@ -500,6 +507,7 @@ static ssize_t ad9523_store(struct device *dev,
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+ struct ad9523_state *st = iio_priv(indio_dev);
bool state;
int ret;
@@ -510,7 +518,7 @@ static ssize_t ad9523_store(struct device *dev,
if (!state)
return 0;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
switch ((u32)this_attr->address) {
case AD9523_SYNC:
ret = ad9523_sync(indio_dev);
@@ -521,7 +529,7 @@ static ssize_t ad9523_store(struct device *dev,
default:
ret = -ENODEV;
}
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
return ret ? ret : len;
}
@@ -532,15 +540,16 @@ static ssize_t ad9523_show(struct device *dev,
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+ struct ad9523_state *st = iio_priv(indio_dev);
int ret;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
ret = ad9523_read(indio_dev, AD9523_READBACK_0);
if (ret >= 0) {
ret = sprintf(buf, "%d\n", !!(ret & (1 <<
(u32)this_attr->address)));
}
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
return ret;
}
@@ -623,9 +632,9 @@ static int ad9523_read_raw(struct iio_dev *indio_dev,
unsigned int code;
int ret;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
ret = ad9523_read(indio_dev, AD9523_CHANNEL_CLOCK_DIST(chan->channel));
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
if (ret < 0)
return ret;
@@ -659,7 +668,7 @@ static int ad9523_write_raw(struct iio_dev *indio_dev,
unsigned int reg;
int ret, tmp, code;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
ret = ad9523_read(indio_dev, AD9523_CHANNEL_CLOCK_DIST(chan->channel));
if (ret < 0)
goto out;
@@ -705,7 +714,7 @@ static int ad9523_write_raw(struct iio_dev *indio_dev,
ad9523_io_update(indio_dev);
out:
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
return ret;
}
@@ -713,9 +722,10 @@ static int ad9523_reg_access(struct iio_dev *indio_dev,
unsigned int reg, unsigned int writeval,
unsigned int *readval)
{
+ struct ad9523_state *st = iio_priv(indio_dev);
int ret;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
if (readval == NULL) {
ret = ad9523_write(indio_dev, reg | AD9523_R1B, writeval);
ad9523_io_update(indio_dev);
@@ -728,7 +738,7 @@ static int ad9523_reg_access(struct iio_dev *indio_dev,
}
out_unlock:
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
return ret;
}
@@ -967,6 +977,8 @@ static int ad9523_probe(struct spi_device *spi)
st = iio_priv(indio_dev);
+ mutex_init(&st->lock);
+
st->reg = devm_regulator_get(&spi->dev, "vcc");
if (!IS_ERR(st->reg)) {
ret = regulator_enable(st->reg);
--
2.17.1
--
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