Merge tag 'asm-generic-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd...

[linux-2.6-microblaze.git] / drivers / iio / dac / ti-dac7612.c

diff --git a/drivers/iio/dac/ti-dac7612.c b/drivers/iio/dac/ti-dac7612.c
index 07c9f39..4c0f4b5 100644 (file)
--- a/drivers/iio/dac/ti-dac7612.c
+++ b/drivers/iio/dac/ti-dac7612.c
@@ -22,6 +22,14 @@ struct dac7612 {
        struct gpio_desc *loaddacs;
        uint16_t cache[2];
 
+       /*
+        * Lock to protect the state of the device from potential concurrent
+        * write accesses from userspace. The write operation requires an
+        * SPI write, then toggling of a GPIO, so the lock aims to protect
+        * the sanity of the entire sequence of operation.
+        */
+       struct mutex lock;
+
        /*
         * DMA (thus cache coherency maintenance) requires the
         * transfer buffers to live in their own cache lines.
@@ -101,9 +109,9 @@ static int dac7612_write_raw(struct iio_dev *iio_dev,
        if (val == priv->cache[chan->channel])
                return 0;
 
-       mutex_lock(&iio_dev->mlock);
+       mutex_lock(&priv->lock);
        ret = dac7612_cmd_single(priv, chan->channel, val);
-       mutex_unlock(&iio_dev->mlock);
+       mutex_unlock(&priv->lock);
 
        return ret;
 }
@@ -145,6 +153,8 @@ static int dac7612_probe(struct spi_device *spi)
        iio_dev->num_channels = ARRAY_SIZE(priv->cache);
        iio_dev->name = spi_get_device_id(spi)->name;
 
+       mutex_init(&priv->lock);
+
        for (i = 0; i < ARRAY_SIZE(priv->cache); i++) {
                ret = dac7612_cmd_single(priv, i, 0);
                if (ret)