[PATCH v2 04/16] iio: adc: lpc32xx_adc: do not use internal iio_dev lock

Nuno Sá
2022-10-04T13:50:46Z

The iio_device lock is only meant for internal use. Hence define a
device local lock to protect against concurrent accesses.

While at it, properly include "mutex.h" for mutex related APIs.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
drivers/iio/adc/lpc32xx_adc.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/adc/lpc32xx_adc.c b/drivers/iio/adc/lpc32xx_adc.c
index b56ce15255cf..732c924a976d 100644
--- a/drivers/iio/adc/lpc32xx_adc.c
+++ b/drivers/iio/adc/lpc32xx_adc.c
@@ -15,6 +15,7 @@
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>

@@ -49,6 +50,8 @@ struct lpc32xx_adc_state {
struct clk *clk;
struct completion completion;
struct regulator *vref;
+ /* lock to protect against multiple access to the device */
+ struct mutex lock;

u32 value;
};
@@ -64,10 +67,10 @@ static int lpc32xx_read_raw(struct iio_dev *indio_dev,

switch (mask) {
case IIO_CHAN_INFO_RAW:
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
ret = clk_prepare_enable(st->clk);
if (ret) {
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
return ret;
}
/* Measurement setup */
@@ -80,7 +83,7 @@ static int lpc32xx_read_raw(struct iio_dev *indio_dev,
wait_for_completion(&st->completion); /* set by ISR */
clk_disable_unprepare(st->clk);
*val = st->value;
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);

return IIO_VAL_INT;

@@ -201,6 +204,8 @@ static int lpc32xx_adc_probe(struct platform_device *pdev)
iodev->modes = INDIO_DIRECT_MODE;
iodev->num_channels = ARRAY_SIZE(lpc32xx_adc_iio_channels);

+ mutex_init(&st->lock);
+
retval = devm_iio_device_register(&pdev->dev, iodev);
if (retval)
return retval;
--
2.37.3