From: Alexandru Ardelean <alexandru.ardelean@analog.com>
To: <linux-iio@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: <ribalda@kernel.org>, <jic23@kernel.org>,
Sergiu Cuciurean <sergiu.cuciurean@analog.com>,
Alexandru Ardelean <alexandru.ardelean@analog.com>
Subject: [PATCH v2] iio: dac: ti-dac7612: Replace indio_dev->mlock with own device lock
Date: Wed, 16 Sep 2020 12:25:35 +0300 [thread overview]
Message-ID: <20200916092535.76527-1-alexandru.ardelean@analog.com> (raw)
In-Reply-To: <20200826064028.51540-1-alexandru.ardelean@analog.com>
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 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 <sergiu.cuciurean@analog.com>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---
drivers/iio/dac/ti-dac7612.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/dac/ti-dac7612.c b/drivers/iio/dac/ti-dac7612.c
index 07c9f39d54f1..4c0f4b5e9ff4 100644
--- a/drivers/iio/dac/ti-dac7612.c
+++ b/drivers/iio/dac/ti-dac7612.c
@@ -22,6 +22,14 @@ struct dac7612 {
struct gpio_desc *loaddacs;
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)
--
2.17.1
next prev parent reply other threads:[~2020-09-16 9:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-26 6:40 [PATCH] iio: dac: ti-dac7612: Replace indio_dev->mlock with own device lock Alexandru Ardelean
2020-08-29 15:47 ` Jonathan Cameron
2020-09-16 9:25 ` Alexandru Ardelean [this message]
2020-09-16 17:56 ` [PATCH v2] " Jonathan Cameron
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