[PATCH v2 06/16] iio: adc: meson_saradc: do not use internal iio_dev lock

Nuno Sá
2022-10-04T13:49:51Z

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>
---
drivers/iio/adc/meson_saradc.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
index 1a68b099d323..85b6826cc10c 100644
--- 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;
--
2.37.3