| Message ID | 20200928131333.36646-3-mircea.caprioru@analog.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/5] iio: adc: spear_adc: Replace indio_dev->mlock with own device lock | expand |
On Mon, 28 Sep 2020 16:13:31 +0300 Mircea Caprioru <mircea.caprioru@analog.com> wrote: > From: Sergiu Cuciurean <sergiu.cuciurean@analog.com> > > As part of the general cleanup of indio_dev->mlock, this change replaces > it with a local lock on the device's state structure. > > This is part of a bigger cleanup. > Link: https://lore.kernel.org/linux-iio/CA+U=Dsoo6YABe5ODLp+eFNPGFDjk5ZeQEceGkqjxXcVEhLWubw@mail.gmail.com/ > > Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com> > Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com> Applied, thanks, Jonathan > --- > drivers/iio/adc/npcm_adc.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/adc/npcm_adc.c b/drivers/iio/adc/npcm_adc.c > index d9d105920001..f7bc0bb7f112 100644 > --- a/drivers/iio/adc/npcm_adc.c > +++ b/drivers/iio/adc/npcm_adc.c > @@ -25,6 +25,15 @@ struct npcm_adc { > wait_queue_head_t wq; > struct regulator *vref; > struct reset_control *reset; > + /* > + * Lock to protect the device state during a potential concurrent > + * read access from userspace. Reading a raw value requires a sequence > + * of register writes, then a wait for a event and finally a register > + * read, during which userspace could issue another read request. > + * This lock protects a read access from ocurring before another one > + * has finished. > + */ > + struct mutex lock; > }; > > /* ADC registers */ > @@ -135,9 +144,9 @@ static int npcm_adc_read_raw(struct iio_dev *indio_dev, > > switch (mask) { > case IIO_CHAN_INFO_RAW: > - mutex_lock(&indio_dev->mlock); > + mutex_lock(&info->lock); > ret = npcm_adc_read(info, val, chan->channel); > - mutex_unlock(&indio_dev->mlock); > + mutex_unlock(&info->lock); > if (ret) { > dev_err(info->dev, "NPCM ADC read failed\n"); > return ret; > @@ -187,6 +196,8 @@ static int npcm_adc_probe(struct platform_device *pdev) > return -ENOMEM; > info = iio_priv(indio_dev); > > + mutex_init(&info->lock); > + > info->dev = &pdev->dev; > > info->regs = devm_platform_ioremap_resource(pdev, 0);
diff --git a/drivers/iio/adc/npcm_adc.c b/drivers/iio/adc/npcm_adc.c index d9d105920001..f7bc0bb7f112 100644 --- a/drivers/iio/adc/npcm_adc.c +++ b/drivers/iio/adc/npcm_adc.c @@ -25,6 +25,15 @@ struct npcm_adc { wait_queue_head_t wq; struct regulator *vref; struct reset_control *reset; + /* + * Lock to protect the device state during a potential concurrent + * read access from userspace. Reading a raw value requires a sequence + * of register writes, then a wait for a event and finally a register + * read, during which userspace could issue another read request. + * This lock protects a read access from ocurring before another one + * has finished. + */ + struct mutex lock; }; /* ADC registers */ @@ -135,9 +144,9 @@ static int npcm_adc_read_raw(struct iio_dev *indio_dev, switch (mask) { case IIO_CHAN_INFO_RAW: - mutex_lock(&indio_dev->mlock); + mutex_lock(&info->lock); ret = npcm_adc_read(info, val, chan->channel); - mutex_unlock(&indio_dev->mlock); + mutex_unlock(&info->lock); if (ret) { dev_err(info->dev, "NPCM ADC read failed\n"); return ret; @@ -187,6 +196,8 @@ static int npcm_adc_probe(struct platform_device *pdev) return -ENOMEM; info = iio_priv(indio_dev); + mutex_init(&info->lock); + info->dev = &pdev->dev; info->regs = devm_platform_ioremap_resource(pdev, 0);