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staging: iio: ade7753: expanding buffer lock to cover both buffer and state protection 

Dropping the extra lock (used for protecting the write frequency) by
expanding the buffer lock to cover both buffer and state protection.

Doing this by introducing a new function (__ade7753_spi_write_reg_16)
making buffer changes without locking the state, to avoid nested locks
while making device frequency changes.

Signed-off-by: Himanshi Jain <himshijain.hj@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Himanshi Jain 2017-10-01 01:35:21 +05:30 committed by Jonathan Cameron
parent ca48139856
commit 68c91e7a40
1 changed files with 18 additions and 11 deletions
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29
drivers/staging/iio/meter/ade7753.c
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@ -80,13 +80,11 @@
* @us: actual spi_device
* @tx: transmit buffer
* @rx: receive buffer
* @buf_lock: mutex to protect tx and rx
* @lock: protect sensor data
* @buf_lock: mutex to protect tx, rx and write frequency
**/
struct ade7753_state {
struct spi_device *us;
struct mutex buf_lock;
struct mutex lock; /* protect sensor data */
u8 tx[ADE7753_MAX_TX] ____cacheline_aligned;
u8 rx[ADE7753_MAX_RX];
};
@ -109,6 +107,19 @@ static int ade7753_spi_write_reg_8(struct device *dev,
return ret;
}
static int __ade7753_spi_write_reg_16(struct device *dev, u8 reg_address,
u16 value)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ade7753_state *st = iio_priv(indio_dev);
st->tx[0] = ADE7753_WRITE_REG(reg_address);
st->tx[1] = (value >> 8) & 0xFF;
st->tx[2] = value & 0xFF;
return spi_write(st->us, st->tx, 3);
}
static int ade7753_spi_write_reg_16(struct device *dev, u8 reg_address,
u16 value)
{
@ -117,10 +128,7 @@ static int ade7753_spi_write_reg_16(struct device *dev, u8 reg_address,
struct ade7753_state *st = iio_priv(indio_dev);
mutex_lock(&st->buf_lock);
st->tx[0] = ADE7753_WRITE_REG(reg_address);
st->tx[1] = (value >> 8) & 0xFF;
st->tx[2] = value & 0xFF;
ret = spi_write(st->us, st->tx, 3);
ret = __ade7753_spi_write_reg_16(dev, reg_address, value);
mutex_unlock(&st->buf_lock);
return ret;
@ -485,7 +493,7 @@ static ssize_t ade7753_write_frequency(struct device *dev,
if (!val)
return -EINVAL;
mutex_lock(&st->lock);
mutex_lock(&st->buf_lock);
t = 27900 / val;
if (t > 0)
@ -503,10 +511,10 @@ static ssize_t ade7753_write_frequency(struct device *dev,
reg &= ~(3 << 11);
reg |= t << 11;
ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
ret = __ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);
out:
mutex_unlock(&st->lock);
mutex_unlock(&st->buf_lock);
return ret ? ret : len;
}
@ -581,7 +589,6 @@ static int ade7753_probe(struct spi_device *spi)
st = iio_priv(indio_dev);
st->us = spi;
mutex_init(&st->buf_lock);
mutex_init(&st->lock);
indio_dev->name = spi->dev.driver->name;
indio_dev->dev.parent = &spi->dev;