iio: adc: meson_saradc: 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: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20221004134909.1692021-7-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 1a68b099d323c1f57fe0da2586278a7ba110b5a9..85b6826cc10cf9a2b82a1666bd10ed9ef4c29dee 100644 (file)
--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -12,6 +12,7 @@
 #include <linux/io.h>
 #include <linux/iio/iio.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/nvmem-consumer.h>
 #include <linux/interrupt.h>
 #include <linux/of.h>
@@ -276,6 +277,8 @@ struct meson_sar_adc_priv {
        struct clk                              *adc_div_clk;
        struct clk_divider                      clk_div;
        struct completion                       done;
+       /* lock to protect against multiple access to the device */
+       struct mutex                            lock;
        int                                     calibbias;
        int                                     calibscale;
        struct regmap                           *tsc_regmap;
@@ -486,7 +489,7 @@ static int meson_sar_adc_lock(struct iio_dev *indio_dev)
        struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
        int val, ret;
 
-       mutex_lock(&indio_dev->mlock);
+       mutex_lock(&priv->lock);
 
        if (priv->param->has_bl30_integration) {
                /* prevent BL30 from using the SAR ADC while we are using it */
@@ -504,7 +507,7 @@ static int meson_sar_adc_lock(struct iio_dev *indio_dev)
                                                      !(val & MESON_SAR_ADC_DELAY_BL30_BUSY),
                                                      1, 10000);
                if (ret) {
-                       mutex_unlock(&indio_dev->mlock);
+                       mutex_unlock(&priv->lock);
                        return ret;
                }
        }
@@ -521,7 +524,7 @@ static void meson_sar_adc_unlock(struct iio_dev *indio_dev)
                regmap_update_bits(priv->regmap, MESON_SAR_ADC_DELAY,
                                   MESON_SAR_ADC_DELAY_KERNEL_BUSY, 0);
 
-       mutex_unlock(&indio_dev->mlock);
+       mutex_unlock(&priv->lock);
 }
 
 static void meson_sar_adc_clear_fifo(struct iio_dev *indio_dev)
@@ -1250,6 +1253,8 @@ static int meson_sar_adc_probe(struct platform_device *pdev)
        if (ret)
                goto err;
 
+       mutex_init(&priv->lock);
+
        ret = meson_sar_adc_hw_enable(indio_dev);
        if (ret)
                goto err;