iio: adc: lpc32xx_adc: do not use internal iio_dev lock

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>
Link: https://lore.kernel.org/r/20221004134909.1692021-5-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/lpc32xx_adc.c b/drivers/iio/adc/lpc32xx_adc.c
index b56ce15255cfb5c92f3f6e2f34c0f8b2ef41f593..732c924a976dd91f9ef902230a4c0af63bdd07ca 100644 (file)
--- 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;