On Tue, 2018-01-23 at 02:32 +0530, Shreeya Patel wrote:
> iio_dev->mlock is to be used only by the IIO core for protecting
> device mode changes between INDIO_DIRECT and INDIO_BUFFER.
>
> This patch replaces the use of mlock with the already established
> buf_lock mutex.
>
> Introducing 'unlocked' __ade7758_spi_write_reg_8 and
> __ade7758_spi_read_reg_8 functions to be used by ade7758_write_samp_freq
> and ade7758_read_samp_freq which avoids nested locks and maintains
> atomicity between bus and device frequency changes.
>
hey,
note: i took the liberty of re-adjusting the reply list ;
initial scope seemed too wide ;
added Barry Song, as he's listed as the author of the driver ;
about the patch:
overall looks good
comments inline
> Signed-off-by: Shreeya Patel <shreeya.patel23498@xxxxxxxxx>
> ---
> drivers/staging/iio/meter/ade7758.h | 2 +-
> drivers/staging/iio/meter/ade7758_core.c | 49 +++++++++++++++++++++++---------
> 2 files changed, 37 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/staging/iio/meter/ade7758.h b/drivers/staging/iio/meter/ade7758.h
> index 6ae78d8..2de81b5 100644
> --- a/drivers/staging/iio/meter/ade7758.h
> +++ b/drivers/staging/iio/meter/ade7758.h
> @@ -111,7 +111,7 @@
> * @trig: data ready trigger registered with iio
> * @tx: transmit buffer
> * @rx: receive buffer
> - * @buf_lock: mutex to protect tx and rx
> + * @buf_lock: mutex to protect tx, rx, read and write frequency
> **/
> struct ade7758_state {
> struct spi_device *us;
> diff --git a/drivers/staging/iio/meter/ade7758_core.c b/drivers/staging/iio/meter/ade7758_core.c
> index 7b7ffe5..7f8f8c4 100644
> --- a/drivers/staging/iio/meter/ade7758_core.c
> +++ b/drivers/staging/iio/meter/ade7758_core.c
> @@ -24,17 +24,26 @@
> #include "meter.h"
> #include "ade7758.h"
>
> -int ade7758_spi_write_reg_8(struct device *dev, u8 reg_address, u8 val)
> +/* Unlocked version of ade7758_spi_write_reg_8 function */
you can probably remove this comment
> +int __ade7758_spi_write_reg_8(struct device *dev, u8 reg_address, u8 val)
maybe make this static ;
this function does not seem to be exported outside of this file
> {
> - int ret;
> struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> struct ade7758_state *st = iio_priv(indio_dev);
>
> - mutex_lock(&st->buf_lock);
> st->tx[0] = ADE7758_WRITE_REG(reg_address);
> st->tx[1] = val;
>
> - ret = spi_write(st->us, st->tx, 2);
> + return spi_write(st->us, st->tx, 2);
> +}
> +
> +int ade7758_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 ade7758_state *st = iio_priv(indio_dev);
> +
> + mutex_lock(&st->buf_lock);
> + ret = __ade7758_spi_write_reg_8(dev, reg_address, val);
> mutex_unlock(&st->buf_lock);
>
> return ret;
> @@ -91,7 +100,8 @@ static int ade7758_spi_write_reg_24(struct device *dev, u8 reg_address,
> return ret;
> }
>
> -int ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
> +/* Unlocked version of ade7758_spi_read_reg_16 function */
you can probably remove this comment as well
> +int __ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
make this static as well
> {
> struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> struct ade7758_state *st = iio_priv(indio_dev);
> @@ -111,7 +121,6 @@ int ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
> },
> };
>
> - mutex_lock(&st->buf_lock);
> st->tx[0] = ADE7758_READ_REG(reg_address);
> st->tx[1] = 0;
>
> @@ -124,7 +133,19 @@ int ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
> *val = st->rx[0];
>
> error_ret:
> + return ret;
> +}
> +
> +int ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct ade7758_state *st = iio_priv(indio_dev);
> + int ret;
> +
> + mutex_lock(&st->buf_lock);
> + ret = __ade7758_spi_read_reg_8(dev, reg_address, val);
> mutex_unlock(&st->buf_lock);
> +
> return ret;
> }
>
> @@ -470,7 +491,7 @@ static int ade7758_read_samp_freq(struct device *dev, int *val)
> int ret;
> u8 t;
>
> - ret = ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, &t);
> + ret = __ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, &t);
> if (ret)
> return ret;
>
> @@ -503,14 +524,14 @@ static int ade7758_write_samp_freq(struct device *dev, int val)
> goto out;
> }
>
> - ret = ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, ®);
> + ret = __ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, ®);
> if (ret)
> goto out;
>
> reg &= ~(5 << 3);
> reg |= t << 5;
>
> - ret = ade7758_spi_write_reg_8(dev, ADE7758_WAVMODE, reg);
> + ret = __ade7758_spi_write_reg_8(dev, ADE7758_WAVMODE, reg);
>
> out:
> return ret;
> @@ -523,12 +544,13 @@ static int ade7758_read_raw(struct iio_dev *indio_dev,
> long mask)
> {
> int ret;
> + struct ade7758_state *st = iio_priv(indio_dev);
>
> switch (mask) {
> case IIO_CHAN_INFO_SAMP_FREQ:
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->buf_lock);
This may be ok.
I did not seem to find a general consensus on which lock should be held here.
Some drivers use buf_lock, some use the device's mlock.
I guess someone more familiar with the IIO framework would be more suited to comment here.
> ret = ade7758_read_samp_freq(&indio_dev->dev, val);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->buf_lock);
> return ret;
> default:
> return -EINVAL;
> @@ -542,14 +564,15 @@ static int ade7758_write_raw(struct iio_dev *indio_dev,
> int val, int val2, long mask)
> {
> int ret;
> + struct ade7758_state *st = iio_priv(indio_dev);
>
> switch (mask) {
> case IIO_CHAN_INFO_SAMP_FREQ:
> if (val2)
> return -EINVAL;
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->buf_lock);
same here about the lock
> ret = ade7758_write_samp_freq(&indio_dev->dev, val);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->buf_lock);
> return ret;
> default:
> return -EINVAL;��.n��������+%������w��{.n�����{��(��)�� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
