* [PATCH] iio: dac: ad7303: replace mlock with own lock
@ 2019-09-19 13:13 Alexandru Ardelean
2019-10-05 14:54 ` Jonathan Cameron
2019-10-07 8:26 ` [PATCH v2] " Alexandru Ardelean
0 siblings, 2 replies; 4+ messages in thread
From: Alexandru Ardelean @ 2019-09-19 13:13 UTC (permalink / raw)
To: linux-iio; +Cc: Alexandru Ardelean
This change replaces indio_dev's mlock with the driver's own lock. The lock
is mostly needed to protect state when changing the `config` & `dac_cache`
fields. As such, the lock has been extended to covert the read of these
fields.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/iio/dac/ad7303.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/iio/dac/ad7303.c b/drivers/iio/dac/ad7303.c
index 8de9f40226e6..f45352e80db7 100644
--- a/drivers/iio/dac/ad7303.c
+++ b/drivers/iio/dac/ad7303.c
@@ -41,6 +41,7 @@ struct ad7303_state {
struct regulator *vdd_reg;
struct regulator *vref_reg;
+ struct mutex lock;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
@@ -62,9 +63,13 @@ static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev,
uintptr_t private, const struct iio_chan_spec *chan, char *buf)
{
struct ad7303_state *st = iio_priv(indio_dev);
+ int val;
- return sprintf(buf, "%d\n", (bool)(st->config &
- AD7303_CFG_POWER_DOWN(chan->channel)));
+ mutex_lock(&st->lock);
+ val = (bool)(st->config & AD7303_CFG_POWER_DOWN(chan->channel));
+ mutex_unlock(&st->lock);
+
+ return sprintf(buf, "%d\n", val);
}
static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
@@ -79,7 +84,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
if (ret)
return ret;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
if (pwr_down)
st->config |= AD7303_CFG_POWER_DOWN(chan->channel);
@@ -90,7 +95,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
* mode, so just write one of the DAC channels again */
ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
return len;
}
@@ -116,7 +121,9 @@ static int ad7303_read_raw(struct iio_dev *indio_dev,
switch (info) {
case IIO_CHAN_INFO_RAW:
+ mutex_lock(&st->lock);
*val = st->dac_cache[chan->channel];
+ mutex_unlock(&st->lock);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
vref_uv = ad7303_get_vref(st, chan);
@@ -144,11 +151,11 @@ static int ad7303_write_raw(struct iio_dev *indio_dev,
if (val >= (1 << chan->scan_type.realbits) || val < 0)
return -EINVAL;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
ret = ad7303_write(st, chan->address, val);
if (ret == 0)
st->dac_cache[chan->channel] = val;
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
break;
default:
ret = -EINVAL;
@@ -211,6 +218,8 @@ static int ad7303_probe(struct spi_device *spi)
st->spi = spi;
+ mutex_init(&st->lock);
+
st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd");
if (IS_ERR(st->vdd_reg))
return PTR_ERR(st->vdd_reg);
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] iio: dac: ad7303: replace mlock with own lock
2019-09-19 13:13 [PATCH] iio: dac: ad7303: replace mlock with own lock Alexandru Ardelean
@ 2019-10-05 14:54 ` Jonathan Cameron
2019-10-07 8:26 ` [PATCH v2] " Alexandru Ardelean
1 sibling, 0 replies; 4+ messages in thread
From: Jonathan Cameron @ 2019-10-05 14:54 UTC (permalink / raw)
To: Alexandru Ardelean; +Cc: linux-iio
On Thu, 19 Sep 2019 16:13:28 +0300
Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:
> This change replaces indio_dev's mlock with the driver's own lock. The lock
> is mostly needed to protect state when changing the `config` & `dac_cache`
> fields. As such, the lock has been extended to covert the read of these
> fields.
This last bit would be needed if we had anywhere that needed to see a consistent
state across those two fields. I can't immediately see where that happens.
>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
See below.
> ---
> drivers/iio/dac/ad7303.c | 21 +++++++++++++++------
> 1 file changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/dac/ad7303.c b/drivers/iio/dac/ad7303.c
> index 8de9f40226e6..f45352e80db7 100644
> --- a/drivers/iio/dac/ad7303.c
> +++ b/drivers/iio/dac/ad7303.c
> @@ -41,6 +41,7 @@ struct ad7303_state {
> struct regulator *vdd_reg;
> struct regulator *vref_reg;
>
> + struct mutex lock;
> /*
> * DMA (thus cache coherency maintenance) requires the
> * transfer buffers to live in their own cache lines.
> @@ -62,9 +63,13 @@ static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev,
> uintptr_t private, const struct iio_chan_spec *chan, char *buf)
> {
> struct ad7303_state *st = iio_priv(indio_dev);
> + int val;
>
> - return sprintf(buf, "%d\n", (bool)(st->config &
> - AD7303_CFG_POWER_DOWN(chan->channel)));
> + mutex_lock(&st->lock);
> + val = (bool)(st->config & AD7303_CFG_POWER_DOWN(chan->channel));
> + mutex_unlock(&st->lock);
I think the read of st->config should be atomic anyway so you'll either
get the value before or after some concurrent write. That's true
even with the locks, so I don't htink they are needed here.
> +
> + return sprintf(buf, "%d\n", val);
> }
>
> static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
> @@ -79,7 +84,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
> if (ret)
> return ret;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
>
> if (pwr_down)
> st->config |= AD7303_CFG_POWER_DOWN(chan->channel);
> @@ -90,7 +95,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
> * mode, so just write one of the DAC channels again */
> ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);
>
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
> return len;
> }
>
> @@ -116,7 +121,9 @@ static int ad7303_read_raw(struct iio_dev *indio_dev,
>
> switch (info) {
> case IIO_CHAN_INFO_RAW:
> + mutex_lock(&st->lock);
> *val = st->dac_cache[chan->channel];
> + mutex_unlock(&st->lock);
> return IIO_VAL_INT;
> case IIO_CHAN_INFO_SCALE:
> vref_uv = ad7303_get_vref(st, chan);
> @@ -144,11 +151,11 @@ static int ad7303_write_raw(struct iio_dev *indio_dev,
> if (val >= (1 << chan->scan_type.realbits) || val < 0)
> return -EINVAL;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> ret = ad7303_write(st, chan->address, val);
> if (ret == 0)
> st->dac_cache[chan->channel] = val;
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
> break;
> default:
> ret = -EINVAL;
> @@ -211,6 +218,8 @@ static int ad7303_probe(struct spi_device *spi)
>
> st->spi = spi;
>
> + mutex_init(&st->lock);
> +
> st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd");
> if (IS_ERR(st->vdd_reg))
> return PTR_ERR(st->vdd_reg);
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v2] iio: dac: ad7303: replace mlock with own lock
2019-09-19 13:13 [PATCH] iio: dac: ad7303: replace mlock with own lock Alexandru Ardelean
2019-10-05 14:54 ` Jonathan Cameron
@ 2019-10-07 8:26 ` Alexandru Ardelean
2019-10-12 13:45 ` Jonathan Cameron
1 sibling, 1 reply; 4+ messages in thread
From: Alexandru Ardelean @ 2019-10-07 8:26 UTC (permalink / raw)
To: linux-iio; +Cc: jic23, Alexandru Ardelean
This change replaces indio_dev's mlock with the driver's own lock. The lock
is mostly needed to protect state when changing the `dac_cache` info.
The lock has been extended to `ad7303_read_raw()`, to make sure that the
cache is updated if an SPI-write is already in progress.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
Changelog v1 -> v2:
* remove lock from `ad7303_read_dac_powerdown()`
drivers/iio/dac/ad7303.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/dac/ad7303.c b/drivers/iio/dac/ad7303.c
index 8de9f40226e6..14bbac6bee98 100644
--- a/drivers/iio/dac/ad7303.c
+++ b/drivers/iio/dac/ad7303.c
@@ -41,6 +41,7 @@ struct ad7303_state {
struct regulator *vdd_reg;
struct regulator *vref_reg;
+ struct mutex lock;
/*
* DMA (thus cache coherency maintenance) requires the
* transfer buffers to live in their own cache lines.
@@ -79,7 +80,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
if (ret)
return ret;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
if (pwr_down)
st->config |= AD7303_CFG_POWER_DOWN(chan->channel);
@@ -90,7 +91,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
* mode, so just write one of the DAC channels again */
ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
return len;
}
@@ -116,7 +117,9 @@ static int ad7303_read_raw(struct iio_dev *indio_dev,
switch (info) {
case IIO_CHAN_INFO_RAW:
+ mutex_lock(&st->lock);
*val = st->dac_cache[chan->channel];
+ mutex_unlock(&st->lock);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
vref_uv = ad7303_get_vref(st, chan);
@@ -144,11 +147,11 @@ static int ad7303_write_raw(struct iio_dev *indio_dev,
if (val >= (1 << chan->scan_type.realbits) || val < 0)
return -EINVAL;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->lock);
ret = ad7303_write(st, chan->address, val);
if (ret == 0)
st->dac_cache[chan->channel] = val;
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->lock);
break;
default:
ret = -EINVAL;
@@ -211,6 +214,8 @@ static int ad7303_probe(struct spi_device *spi)
st->spi = spi;
+ mutex_init(&st->lock);
+
st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd");
if (IS_ERR(st->vdd_reg))
return PTR_ERR(st->vdd_reg);
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] iio: dac: ad7303: replace mlock with own lock
2019-10-07 8:26 ` [PATCH v2] " Alexandru Ardelean
@ 2019-10-12 13:45 ` Jonathan Cameron
0 siblings, 0 replies; 4+ messages in thread
From: Jonathan Cameron @ 2019-10-12 13:45 UTC (permalink / raw)
To: Alexandru Ardelean; +Cc: linux-iio
On Mon, 7 Oct 2019 11:26:42 +0300
Alexandru Ardelean <alexandru.ardelean@analog.com> wrote:
> This change replaces indio_dev's mlock with the driver's own lock. The lock
> is mostly needed to protect state when changing the `dac_cache` info.
> The lock has been extended to `ad7303_read_raw()`, to make sure that the
> cache is updated if an SPI-write is already in progress.
>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.
Thanks,
Jonathan
> ---
>
> Changelog v1 -> v2:
> * remove lock from `ad7303_read_dac_powerdown()`
>
> drivers/iio/dac/ad7303.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iio/dac/ad7303.c b/drivers/iio/dac/ad7303.c
> index 8de9f40226e6..14bbac6bee98 100644
> --- a/drivers/iio/dac/ad7303.c
> +++ b/drivers/iio/dac/ad7303.c
> @@ -41,6 +41,7 @@ struct ad7303_state {
> struct regulator *vdd_reg;
> struct regulator *vref_reg;
>
> + struct mutex lock;
> /*
> * DMA (thus cache coherency maintenance) requires the
> * transfer buffers to live in their own cache lines.
> @@ -79,7 +80,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
> if (ret)
> return ret;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
>
> if (pwr_down)
> st->config |= AD7303_CFG_POWER_DOWN(chan->channel);
> @@ -90,7 +91,7 @@ static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
> * mode, so just write one of the DAC channels again */
> ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);
>
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
> return len;
> }
>
> @@ -116,7 +117,9 @@ static int ad7303_read_raw(struct iio_dev *indio_dev,
>
> switch (info) {
> case IIO_CHAN_INFO_RAW:
> + mutex_lock(&st->lock);
> *val = st->dac_cache[chan->channel];
> + mutex_unlock(&st->lock);
> return IIO_VAL_INT;
> case IIO_CHAN_INFO_SCALE:
> vref_uv = ad7303_get_vref(st, chan);
> @@ -144,11 +147,11 @@ static int ad7303_write_raw(struct iio_dev *indio_dev,
> if (val >= (1 << chan->scan_type.realbits) || val < 0)
> return -EINVAL;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> ret = ad7303_write(st, chan->address, val);
> if (ret == 0)
> st->dac_cache[chan->channel] = val;
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
> break;
> default:
> ret = -EINVAL;
> @@ -211,6 +214,8 @@ static int ad7303_probe(struct spi_device *spi)
>
> st->spi = spi;
>
> + mutex_init(&st->lock);
> +
> st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd");
> if (IS_ERR(st->vdd_reg))
> return PTR_ERR(st->vdd_reg);
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-10-12 13:45 UTC | newest]
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2019-09-19 13:13 [PATCH] iio: dac: ad7303: replace mlock with own lock Alexandru Ardelean
2019-10-05 14:54 ` Jonathan Cameron
2019-10-07 8:26 ` [PATCH v2] " Alexandru Ardelean
2019-10-12 13:45 ` Jonathan Cameron
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