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Commit b71244b6 authored by Gargi Sharma's avatar Gargi Sharma Committed by Jonathan Cameron
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staging: iio: update locking method during frequency writes 



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: default avatarGargi Sharma <gs051095@gmail.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 5e13b6f0

drivers/staging/iio/meter/ade7754.c

+16 −8
Original line number Original line Diff line number Diff line
@@ -96,7 +96,7 @@ 
/**

/**

 * struct ade7754_state - device instance specific data

 * struct ade7754_state - device instance specific data

 * @us:			actual spi_device

 * @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

 * @tx:			transmit buffer

 * @rx:			receive buffer

 * @rx:			receive buffer

 **/

 **/
@@ -107,17 +107,25 @@ struct ade7754_state { 
	u8			rx[ADE7754_MAX_RX];

	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 iio_dev *indio_dev = dev_to_iio_dev(dev);

	struct ade7754_state *st = iio_priv(indio_dev);

	struct ade7754_state *st = iio_priv(indio_dev);





	mutex_lock(&st->buf_lock);

	st->tx[0] = ADE7754_WRITE_REG(reg_address);

	st->tx[0] = ADE7754_WRITE_REG(reg_address);

	st->tx[1] = val;

	st->tx[1] = val;

	return spi_write(st->us, st->tx, 2);

}





	ret = spi_write(st->us, st->tx, 2);

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);

	mutex_unlock(&st->buf_lock);





	return ret;

	return ret;
@@ -512,7 +520,7 @@ static ssize_t ade7754_write_frequency(struct device *dev, 
	if (!val)

	if (!val)

		return -EINVAL;

		return -EINVAL;





	mutex_lock(&indio_dev->mlock);

	mutex_lock(&st->buf_lock);





	t = 26000 / val;

	t = 26000 / val;

	if (t > 0)

	if (t > 0)
@@ -530,10 +538,10 @@ static ssize_t ade7754_write_frequency(struct device *dev, 
	reg &= ~(3 << 3);

	reg &= ~(3 << 3);

	reg |= t << 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:

out:

	mutex_unlock(&indio_dev->mlock);

	mutex_unlock(&st->buf_lock);





	return ret ? ret : len;

	return ret ? ret : len;

}

}