iio: adc: fsl-imx25-gcq: Replace indio_dev->mlock with own device lock (8a0f412f) · Commits · 戴 / test

As part of the general cleanup of indio_dev->mlock, this change replaces it with a local lock, to protect against any other accesses during the reading of sample. Reading a sample requires multiple consecutive regmap operations and a completion callback, so this requires that no other read occurs until it completes. 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:

Alexandru Ardelean <alexandru.ardelean@analog.com> Link: https://lore.kernel.org/r/20200916092928.78026-1-alexandru.ardelean@analog.com Signed-off-by:

Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/fsl-imx25-gcq.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -40,6 +40,15 @@ struct mx25_gcq_priv {
		int irq;
		struct regulator *vref[4];
		u32 channel_vref_mv[MX25_NUM_CFGS];
		/*
		* 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;
		};

		#define MX25_CQG_CHAN(chan, id) {\
		@@ -137,9 +146,9 @@ static int mx25_gcq_read_raw(struct iio_dev *indio_dev,

		switch (mask) {
		case IIO_CHAN_INFO_RAW:
		mutex_lock(&indio_dev->mlock);
		mutex_lock(&priv->lock);
		ret = mx25_gcq_get_raw_value(&indio_dev->dev, chan, priv, val);
		mutex_unlock(&indio_dev->mlock);
		mutex_unlock(&priv->lock);
		return ret;

		case IIO_CHAN_INFO_SCALE:
		@@ -314,6 +323,8 @@ static int mx25_gcq_probe(struct platform_device *pdev)
		return PTR_ERR(priv->regs);
		}

		mutex_init(&priv->lock);

		init_completion(&priv->completed);

		ret = mx25_gcq_setup_cfgs(pdev, priv);

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