From: Sergiu Cuciurean Date: Wed, 16 Sep 2020 09:25:35 +0000 (+0300) Subject: iio: dac: ti-dac7612: Replace indio_dev->mlock with own device lock X-Git-Tag: v5.10.7~1420^2~64^2~113 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=20be66c193be1a758c507fe28e8f77ad407d5039;p=platform%2Fkernel%2Flinux-rpi.git iio: dac: ti-dac7612: Replace indio_dev->mlock with own device lock As part of the general cleanup of indio_dev->mlock, this change replaces it with a local lock on the device's state from potential concurrent write accesses from userspace. The write operation requires an SPI write, then toggling of a GPIO, so the lock aims to protect the sanity of the entire sequence of operation. 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 Signed-off-by: Alexandru Ardelean Link: https://lore.kernel.org/r/20200916092535.76527-1-alexandru.ardelean@analog.com Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/dac/ti-dac7612.c b/drivers/iio/dac/ti-dac7612.c index 07c9f39..4c0f4b5 100644 --- a/drivers/iio/dac/ti-dac7612.c +++ b/drivers/iio/dac/ti-dac7612.c @@ -23,6 +23,14 @@ struct dac7612 { uint16_t cache[2]; /* + * Lock to protect the state of the device from potential concurrent + * write accesses from userspace. The write operation requires an + * SPI write, then toggling of a GPIO, so the lock aims to protect + * the sanity of the entire sequence of operation. + */ + struct mutex lock; + + /* * DMA (thus cache coherency maintenance) requires the * transfer buffers to live in their own cache lines. */ @@ -101,9 +109,9 @@ static int dac7612_write_raw(struct iio_dev *iio_dev, if (val == priv->cache[chan->channel]) return 0; - mutex_lock(&iio_dev->mlock); + mutex_lock(&priv->lock); ret = dac7612_cmd_single(priv, chan->channel, val); - mutex_unlock(&iio_dev->mlock); + mutex_unlock(&priv->lock); return ret; } @@ -145,6 +153,8 @@ static int dac7612_probe(struct spi_device *spi) iio_dev->num_channels = ARRAY_SIZE(priv->cache); iio_dev->name = spi_get_device_id(spi)->name; + mutex_init(&priv->lock); + for (i = 0; i < ARRAY_SIZE(priv->cache); i++) { ret = dac7612_cmd_single(priv, i, 0); if (ret)