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iio: adc: spear_adc: Replace indio_dev->mlock with own device lock

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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>
Link: https://lore.kernel.org/r/20200928131333.36646-1-mircea.caprioru@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Sergiu Cuciurean 2020-09-28 16:13:29 +03:00 committed by Jonathan Cameron
parent 2a94469f73
commit 31e2d42a86
1 changed files with 16 additions and 4 deletions
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20
drivers/iio/adc/spear_adc.c
View file

@ -75,6 +75,15 @@ struct spear_adc_state {
struct adc_regs_spear6xx __iomem *adc_base_spear6xx;
struct clk *clk;
struct completion completion;
/*
* 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 completion callback,
* 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;
u32 current_clk;
u32 sampling_freq;
u32 avg_samples;
@ -146,7 +155,7 @@ static int spear_adc_read_raw(struct iio_dev *indio_dev,
switch (mask) {
case IIO_CHAN_INFO_RAW:
mutex_lock(&indio_dev->mlock);
mutex_lock(&st->lock);
status = SPEAR_ADC_STATUS_CHANNEL_NUM(chan->channel) |
SPEAR_ADC_STATUS_AVG_SAMPLE(st->avg_samples) |
@ -159,7 +168,7 @@ static int spear_adc_read_raw(struct iio_dev *indio_dev,
wait_for_completion(&st->completion); /* set by ISR */
*val = st->value;
mutex_unlock(&indio_dev->mlock);
mutex_unlock(&st->lock);
return IIO_VAL_INT;
@ -187,7 +196,7 @@ static int spear_adc_write_raw(struct iio_dev *indio_dev,
if (mask != IIO_CHAN_INFO_SAMP_FREQ)
return -EINVAL;
mutex_lock(&indio_dev->mlock);
mutex_lock(&st->lock);
if ((val < SPEAR_ADC_CLK_MIN) ||
(val > SPEAR_ADC_CLK_MAX) ||
@ -199,7 +208,7 @@ static int spear_adc_write_raw(struct iio_dev *indio_dev,
spear_adc_set_clk(st, val);
out:
mutex_unlock(&indio_dev->mlock);
mutex_unlock(&st->lock);
return ret;
}
@ -271,6 +280,9 @@ static int spear_adc_probe(struct platform_device *pdev)
}
st = iio_priv(indio_dev);
mutex_init(&st->lock);
st->np = np;
/*