iio: adc: imx7d_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>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/20221004134909.1692021-4-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/imx7d_adc.c b/drivers/iio/adc/imx7d_adc.c
index 86caff1d006b93e1b4c1c606df46c2d1df9e7597..22da81bac97f16a207bad3cae09868a2e24e953d 100644 (file)
--- a/drivers/iio/adc/imx7d_adc.c
+++ b/drivers/iio/adc/imx7d_adc.c
@@ -13,6 +13,7 @@
 #include <linux/kernel.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 
@@ -108,7 +109,8 @@ struct imx7d_adc {
        struct device *dev;
        void __iomem *regs;
        struct clk *clk;
-
+       /* lock to protect against multiple access to the device */
+       struct mutex lock;
        u32 vref_uv;
        u32 value;
        u32 channel;
@@ -293,7 +295,7 @@ static int imx7d_adc_read_raw(struct iio_dev *indio_dev,
 
        switch (mask) {
        case IIO_CHAN_INFO_RAW:
-               mutex_lock(&indio_dev->mlock);
+               mutex_lock(&info->lock);
                reinit_completion(&info->completion);
 
                channel = chan->channel & 0x03;
@@ -303,16 +305,16 @@ static int imx7d_adc_read_raw(struct iio_dev *indio_dev,
                ret = wait_for_completion_interruptible_timeout
                                (&info->completion, IMX7D_ADC_TIMEOUT);
                if (ret == 0) {
-                       mutex_unlock(&indio_dev->mlock);
+                       mutex_unlock(&info->lock);
                        return -ETIMEDOUT;
                }
                if (ret < 0) {
-                       mutex_unlock(&indio_dev->mlock);
+                       mutex_unlock(&info->lock);
                        return ret;
                }
 
                *val = info->value;
-               mutex_unlock(&indio_dev->mlock);
+               mutex_unlock(&info->lock);
                return IIO_VAL_INT;
 
        case IIO_CHAN_INFO_SCALE:
@@ -531,6 +533,8 @@ static int imx7d_adc_probe(struct platform_device *pdev)
        if (ret)
                return ret;
 
+       mutex_init(&info->lock);
+
        ret = devm_iio_device_register(dev, indio_dev);
        if (ret) {
                dev_err(&pdev->dev, "Couldn't register the device.\n");