The driver needs to insure atomicity during frequency
changes of bus and device. The iiodev->mlock as used
was not doing that. Replace it with the drivers existing
buffer lock and introduce an auxiliary spi_write() that does
not hold the lock.
Signed-off-by: Gargi Sharma <gs051095@xxxxxxxxx>
---
Changes in v2:
- Added auxiliary function.
- Updated the buf_lock comment appropriately.
---
drivers/staging/iio/meter/ade7754.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/iio/meter/ade7754.c b/drivers/staging/iio/meter/ade7754.c
index c8d2d4c..f371030 100644
--- a/drivers/staging/iio/meter/ade7754.c
+++ b/drivers/staging/iio/meter/ade7754.c
@@ -97,7 +97,7 @@
/**
* struct ade7754_state - device instance specific data
* @us: actual spi_device
- * @buf_lock: mutex to protect tx and rx
+ * @buf_lock: mutex to protect tx, rx and write frequency
* @tx: transmit buffer
* @rx: receive buffer
**/
@@ -108,17 +108,29 @@ struct ade7754_state {
u8 rx[ADE7754_MAX_RX];
};
-static int ade7754_spi_write_reg_8(struct device *dev, u8 reg_address, u8 val)
+/* Unlocked version of ade7754_spi_write_reg_8 function */
+static int __ade7754_spi_write_reg_8(struct device *dev, u8 reg_address, u8 val)
{
int ret;
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ade7754_state *st = iio_priv(indio_dev);
- mutex_lock(&st->buf_lock);
st->tx[0] = ADE7754_WRITE_REG(reg_address);
st->tx[1] = val;
ret = spi_write(st->us, st->tx, 2);
+
+ return ret;
+}
+
+static int ade7754_spi_write_reg_8(struct device *dev, u8 reg_address, u8 val)
+{
+ int ret;
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct ade7754_state *st = iio_priv(indio_dev);
+
+ mutex_lock(&st->buf_lock);
+ ret = __ade7754_spi_write_reg_8(dev, reg_address, val);
mutex_unlock(&st->buf_lock);
return ret;
@@ -513,7 +525,7 @@ static ssize_t ade7754_write_frequency(struct device *dev,
if (!val)
return -EINVAL;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->buf_lock);
t = 26000 / val;
if (t > 0)
@@ -531,10 +543,10 @@ static ssize_t ade7754_write_frequency(struct device *dev,
reg &= ~(3 << 3);
reg |= t << 3;
- ret = ade7754_spi_write_reg_8(dev, ADE7754_WAVMODE, reg);
+ ret = __ade7754_spi_write_reg_8(dev, ADE7754_WAVMODE, reg);
out:
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->buf_lock);
return ret ? ret : len;
}
--
2.7.4
--
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