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Message-Id: <1516898408-8129-1-git-send-email-shreeya.patel23498@gmail.com>
Date: Thu, 25 Jan 2018 22:10:08 +0530
From: Shreeya Patel <shreeya.patel23498@...il.com>
To: lars@...afoo.de, Michael.Hennerich@...log.com, jic23@...nel.org,
knaack.h@....de, pmeerw@...erw.net, gregkh@...uxfoundation.org,
linux-iio@...r.kernel.org, devel@...verdev.osuosl.org,
linux-kernel@...r.kernel.org
Cc: Shreeya Patel <shreeya.patel23498@...il.com>
Subject: [PATCH v2] Staging: iio: ade7758: expand buf_lock to cover both buffer and state protection
iio_dev->mlock is to be used only by the IIO core for protecting
device mode changes between INDIO_DIRECT and INDIO_BUFFER.
This patch replaces the use of mlock with the already established
buf_lock mutex.
Introducing 'unlocked' __ade7758_spi_write_reg_8 and
__ade7758_spi_read_reg_8 functions to be used by ade7758_write_samp_freq
and ade7758_read_samp_freq which avoids nested locks and maintains
atomicity between bus and device frequency changes.
Signed-off-by: Shreeya Patel <shreeya.patel23498@...il.com>
---
Changes in v2
-Add static keyword to newly introduced functions and remove some
added comments which are not required.
drivers/staging/iio/meter/ade7758.h | 2 +-
drivers/staging/iio/meter/ade7758_core.c | 47 +++++++++++++++++++++++---------
2 files changed, 35 insertions(+), 14 deletions(-)
diff --git a/drivers/staging/iio/meter/ade7758.h b/drivers/staging/iio/meter/ade7758.h
index 6ae78d8..2de81b5 100644
--- a/drivers/staging/iio/meter/ade7758.h
+++ b/drivers/staging/iio/meter/ade7758.h
@@ -111,7 +111,7 @@
* @trig: data ready trigger registered with iio
* @tx: transmit buffer
* @rx: receive buffer
- * @buf_lock: mutex to protect tx and rx
+ * @buf_lock: mutex to protect tx, rx, read and write frequency
**/
struct ade7758_state {
struct spi_device *us;
diff --git a/drivers/staging/iio/meter/ade7758_core.c b/drivers/staging/iio/meter/ade7758_core.c
index 7b7ffe5..fed4684 100644
--- a/drivers/staging/iio/meter/ade7758_core.c
+++ b/drivers/staging/iio/meter/ade7758_core.c
@@ -24,17 +24,25 @@
#include "meter.h"
#include "ade7758.h"
-int ade7758_spi_write_reg_8(struct device *dev, u8 reg_address, u8 val)
+static int __ade7758_spi_write_reg_8(struct device *dev, u8 reg_address, u8 val)
{
- int ret;
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ade7758_state *st = iio_priv(indio_dev);
- mutex_lock(&st->buf_lock);
st->tx[0] = ADE7758_WRITE_REG(reg_address);
st->tx[1] = val;
- ret = spi_write(st->us, st->tx, 2);
+ return spi_write(st->us, st->tx, 2);
+}
+
+int ade7758_spi_write_reg_8(struct device *dev, u8 reg_address, u8 val)
+{
+ int ret;
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct ade7758_state *st = iio_priv(indio_dev);
+
+ mutex_lock(&st->buf_lock);
+ ret = __ade7758_spi_write_reg_8(dev, reg_address, val);
mutex_unlock(&st->buf_lock);
return ret;
@@ -91,7 +99,7 @@ static int ade7758_spi_write_reg_24(struct device *dev, u8 reg_address,
return ret;
}
-int ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
+static int __ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ade7758_state *st = iio_priv(indio_dev);
@@ -111,7 +119,6 @@ int ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
},
};
- mutex_lock(&st->buf_lock);
st->tx[0] = ADE7758_READ_REG(reg_address);
st->tx[1] = 0;
@@ -124,7 +131,19 @@ int ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
*val = st->rx[0];
error_ret:
+ return ret;
+}
+
+int ade7758_spi_read_reg_8(struct device *dev, u8 reg_address, u8 *val)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct ade7758_state *st = iio_priv(indio_dev);
+ int ret;
+
+ mutex_lock(&st->buf_lock);
+ ret = __ade7758_spi_read_reg_8(dev, reg_address, val);
mutex_unlock(&st->buf_lock);
+
return ret;
}
@@ -470,7 +489,7 @@ static int ade7758_read_samp_freq(struct device *dev, int *val)
int ret;
u8 t;
- ret = ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, &t);
+ ret = __ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, &t);
if (ret)
return ret;
@@ -503,14 +522,14 @@ static int ade7758_write_samp_freq(struct device *dev, int val)
goto out;
}
- ret = ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, ®);
+ ret = __ade7758_spi_read_reg_8(dev, ADE7758_WAVMODE, ®);
if (ret)
goto out;
reg &= ~(5 << 3);
reg |= t << 5;
- ret = ade7758_spi_write_reg_8(dev, ADE7758_WAVMODE, reg);
+ ret = __ade7758_spi_write_reg_8(dev, ADE7758_WAVMODE, reg);
out:
return ret;
@@ -523,12 +542,13 @@ static int ade7758_read_raw(struct iio_dev *indio_dev,
long mask)
{
int ret;
+ struct ade7758_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_SAMP_FREQ:
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->buf_lock);
ret = ade7758_read_samp_freq(&indio_dev->dev, val);
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->buf_lock);
return ret;
default:
return -EINVAL;
@@ -542,14 +562,15 @@ static int ade7758_write_raw(struct iio_dev *indio_dev,
int val, int val2, long mask)
{
int ret;
+ struct ade7758_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_SAMP_FREQ:
if (val2)
return -EINVAL;
- mutex_lock(&indio_dev->mlock);
+ mutex_lock(&st->buf_lock);
ret = ade7758_write_samp_freq(&indio_dev->dev, val);
- mutex_unlock(&indio_dev->mlock);
+ mutex_unlock(&st->buf_lock);
return ret;
default:
return -EINVAL;
--
2.7.4
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