On Tue, 2018-02-06 at 01:10 +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' forms of read and write registers. The
> read/write frequency functions now require buf_lock to be held.
> That's not obvious so avoid this but moving the locking inside
> the functions where it is then clear that they are taking the
> unlocked forms of the register read/write.
>
> It isn't readily apparent that write frequency function requires
> the locks to be taken, so move it inside the function to where it
> is required to protect.
Removed linux-kernel list & Greg from reply list.
>
> Signed-off-by: Shreeya Patel <shreeya.patel23498@xxxxxxxxx>
> ---
>
> Changes in v2
> -Add static keyword to newly introduced functions and remove some
> added comments which are not required.
>
> Changes in v3
> -Remove some useless mlocks and send it as another patch.
> Also make the necessary change in the current patch associated with
> the new patch with commit id 88eba33. Make commit message more
> appropriate.
>
> Changes in v4
> -Write frequency function do not require lock so move it inside
> the function to where it is required to protect.
>
> Changes in v5
> -Remove goto statement and make the code to return -EINVAL there
> itself.
>
> drivers/staging/iio/meter/ade7758.h | 2 +-
> drivers/staging/iio/meter/ade7758_core.c | 52 +++++++++++++++++++++++------
> ---
> 2 files changed, 39 insertions(+), 15 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 227dbfc..dfe8e97 100644
> --- a/drivers/staging/iio/meter/ade7758_core.c
> +++ b/drivers/staging/iio/meter/ade7758_core.c
> @@ -24,17 +24,25 @@
> #include "meter.h"
> #include "ade7758.h"
>
> -int ade7758_spi_write_reg_8(struct device *dev, u8 reg_address, u8 val)
> +static 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);
> 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 +99,7 @@ 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)
> +static 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);
> @@ -111,7 +119,6 @@ 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 +131,19 @@ 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;
> }
>
> @@ -480,10 +499,12 @@ static int ade7758_read_samp_freq(struct device *dev,
> int *val)
> return 0;
> }
>
> -static int ade7758_write_samp_freq(struct device *dev, int val)
> +static int ade7758_write_samp_freq(struct iio_dev *indio_dev, int val)
Maybe keep the declaration the same.
The same construct for accessing indio_dev could be used as above.
So: "struct iio_dev *indio_dev = dev_to_iio_dev(dev);"
> {
> int ret;
> u8 reg, t;
> + struct ade7758_state *st = iio_priv(indio_dev);
> + struct device *dev = &indio_dev->dev;
>
> switch (val) {
> case 26040:
> @@ -499,20 +520,23 @@ static int ade7758_write_samp_freq(struct device *dev,
> int val)
> t = 3;
> break;
> default:
> - ret = -EINVAL;
> - goto out;
> + return -EINVAL;
> }
>
> - ret = ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, ®);
> + mutex_lock(&st->buf_lock);
> +
> + 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:
> + mutex_unlock(&st->buf_lock);
> +
> return ret;
> }
>
> @@ -545,9 +569,9 @@ static int ade7758_write_raw(struct iio_dev *indio_dev,
> case IIO_CHAN_INFO_SAMP_FREQ:
> if (val2)
> return -EINVAL;
> - mutex_lock(&indio_dev->mlock);
> - ret = ade7758_write_samp_freq(&indio_dev->dev, val);
> - mutex_unlock(&indio_dev->mlock);
> +
> + ret = ade7758_write_samp_freq(indio_dev, val);
> +
> return ret;
> default:
> return -EINVAL;
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