* [PATCH v2] staging: iio: impedance-analyzer: ad5933: use guard(mutex) in ad5933_show()
@ 2026-10-19 5:07 Nithishvelan M
0 siblings, 0 replies; 3+ messages in thread
From: Nithishvelan M @ 2026-10-19 5:07 UTC (permalink / raw)
To: Jonathan Cameron, Greg Kroah-Hartman
Cc: Nuno Sá, Michael Hennerich, linux-iio, linux-staging,
linux-kernel, Nithishvelan M
Use guard(mutex) to automatically manage the state lock in
ad5933_show(). This simplifies the function by allowing direct returns
from each switch case, eliminating the mutable return variables and
manual mutex_unlock() calls.
Signed-off-by: Nithishvelan M <mnithishvelan@gmail.com>
---
v2:
- Resend using git-send-email to preserve tabs and whitespace (v1 was
sent via Gmail web composer and had mangled whitespace).
- No code changes.
.../staging/iio/impedance-analyzer/ad5933.c | 38 ++++++++-----------
1 file changed, 15 insertions(+), 23 deletions(-)
diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
index 798e62bae2..024c6b5a06 100644
--- a/drivers/staging/iio/impedance-analyzer/ad5933.c
+++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
@@ -6,6 +6,7 @@
*/
#include <linux/bits.h>
+#include <linux/cleanup.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
@@ -333,39 +334,30 @@ static ssize_t ad5933_show(struct device *dev,
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad5933_state *st = iio_priv(indio_dev);
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
- int ret = 0, len = 0;
- mutex_lock(&st->lock);
+ guard(mutex)(&st->lock);
+
switch ((u32)this_attr->address) {
case AD5933_OUT_RANGE:
- len = sysfs_emit(buf, "%u\n",
- st->range_avail[(st->ctrl_hb >> 1) & 0x3]);
- break;
+ return sysfs_emit(buf, "%u\n",
+ st->range_avail[(st->ctrl_hb >> 1) & 0x3]);
case AD5933_OUT_RANGE_AVAIL:
- len = sysfs_emit(buf, "%u %u %u %u\n", st->range_avail[0],
- st->range_avail[3], st->range_avail[2],
- st->range_avail[1]);
- break;
+ return sysfs_emit(buf, "%u %u %u %u\n", st->range_avail[0],
+ st->range_avail[3], st->range_avail[2],
+ st->range_avail[1]);
case AD5933_OUT_SETTLING_CYCLES:
- len = sysfs_emit(buf, "%d\n", st->settling_cycles);
- break;
+ return sysfs_emit(buf, "%d\n", st->settling_cycles);
case AD5933_IN_PGA_GAIN:
- len = sysfs_emit(buf, "%s\n",
- (st->ctrl_hb & AD5933_CTRL_PGA_GAIN_1) ?
- "1" : "0.2");
- break;
+ return sysfs_emit(buf, "%s\n",
+ (st->ctrl_hb & AD5933_CTRL_PGA_GAIN_1) ?
+ "1" : "0.2");
case AD5933_IN_PGA_GAIN_AVAIL:
- len = sysfs_emit(buf, "1 0.2\n");
- break;
+ return sysfs_emit(buf, "1 0.2\n");
case AD5933_FREQ_POINTS:
- len = sysfs_emit(buf, "%d\n", st->freq_points);
- break;
+ return sysfs_emit(buf, "%d\n", st->freq_points);
default:
- ret = -EINVAL;
+ return -EINVAL;
}
-
- mutex_unlock(&st->lock);
- return ret ? ret : len;
}
static ssize_t ad5933_store(struct device *dev,
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH v2] staging: iio: impedance-analyzer: ad5933: use guard(mutex) in ad5933_show()
@ 2026-10-19 15:02 Nithishvelan M
2026-10-19 19:09 ` Andy Shevchenko
0 siblings, 1 reply; 3+ messages in thread
From: Nithishvelan M @ 2026-10-19 15:02 UTC (permalink / raw)
To: Jonathan Cameron, Greg Kroah-Hartman
Cc: Nuno Sa, Michael Hennerich, David Lechner, Andy Shevchenko,
linux-iio, linux-staging, linux-kernel, Nithishvelan M
Use guard(mutex) to automatically manage the state lock in
ad5933_show(). This simplifies the function by allowing direct returns
from each switch case, eliminating the mutable return variables and
manual mutex_unlock() calls.
Signed-off-by: Nithishvelan M <mnithishvelan@gmail.com>
---
Changes in v2:
- Extract range index into local variable 'ridx' to prevent static
analysis warnings (Andy Shevchenko)
- Keep short return sysfs_emit() call on a single line (Andy Shevchenko)
- Split AD5933_OUT_RANGE_AVAIL arguments logically across lines (Andy Shevchenko)
- Remove redundant parentheses in AD5933_IN_PGA_GAIN ternary (Andy Shevchenko)
.../staging/iio/impedance-analyzer/ad5933.c | 38 ++++++++-----------
1 file changed, 15 insertions(+), 23 deletions(-)
diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
index 798e62bae2..7c3af47e0c 100644
--- a/drivers/staging/iio/impedance-analyzer/ad5933.c
+++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
@@ -6,6 +6,7 @@
*/
#include <linux/bits.h>
+#include <linux/cleanup.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
@@ -333,39 +334,30 @@ static ssize_t ad5933_show(struct device *dev,
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad5933_state *st = iio_priv(indio_dev);
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
- int ret = 0, len = 0;
+ unsigned int ridx;
+
+ guard(mutex)(&st->lock);
- mutex_lock(&st->lock);
switch ((u32)this_attr->address) {
case AD5933_OUT_RANGE:
- len = sysfs_emit(buf, "%u\n",
- st->range_avail[(st->ctrl_hb >> 1) & 0x3]);
- break;
+ ridx = (st->ctrl_hb >> 1) & 0x03;
+ return sysfs_emit(buf, "%u\n", st->range_avail[ridx]);
case AD5933_OUT_RANGE_AVAIL:
- len = sysfs_emit(buf, "%u %u %u %u\n", st->range_avail[0],
- st->range_avail[3], st->range_avail[2],
- st->range_avail[1]);
- break;
+ return sysfs_emit(buf, "%u %u %u %u\n",
+ st->range_avail[0], st->range_avail[3],
+ st->range_avail[2], st->range_avail[1]);
case AD5933_OUT_SETTLING_CYCLES:
- len = sysfs_emit(buf, "%d\n", st->settling_cycles);
- break;
+ return sysfs_emit(buf, "%d\n", st->settling_cycles);
case AD5933_IN_PGA_GAIN:
- len = sysfs_emit(buf, "%s\n",
- (st->ctrl_hb & AD5933_CTRL_PGA_GAIN_1) ?
- "1" : "0.2");
- break;
+ return sysfs_emit(buf, "%s\n",
+ st->ctrl_hb & AD5933_CTRL_PGA_GAIN_1 ? "1" : "0.2");
case AD5933_IN_PGA_GAIN_AVAIL:
- len = sysfs_emit(buf, "1 0.2\n");
- break;
+ return sysfs_emit(buf, "1 0.2\n");
case AD5933_FREQ_POINTS:
- len = sysfs_emit(buf, "%d\n", st->freq_points);
- break;
+ return sysfs_emit(buf, "%d\n", st->freq_points);
default:
- ret = -EINVAL;
+ return -EINVAL;
}
-
- mutex_unlock(&st->lock);
- return ret ? ret : len;
}
static ssize_t ad5933_store(struct device *dev,
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] staging: iio: impedance-analyzer: ad5933: use guard(mutex) in ad5933_show()
2026-10-19 15:02 Nithishvelan M
@ 2026-10-19 19:09 ` Andy Shevchenko
0 siblings, 0 replies; 3+ messages in thread
From: Andy Shevchenko @ 2026-10-19 19:09 UTC (permalink / raw)
To: Nithishvelan M
Cc: Jonathan Cameron, Greg Kroah-Hartman, Nuno Sa, Michael Hennerich,
David Lechner, Andy Shevchenko, linux-iio, linux-staging,
linux-kernel
On Mon, Oct 19, 2026 at 03:02:48PM +0000, Nithishvelan M wrote:
> Use guard(mutex) to automatically manage the state lock in
> ad5933_show(). This simplifies the function by allowing direct returns
> from each switch case, eliminating the mutable return variables and
> manual mutex_unlock() calls.
...
> case AD5933_IN_PGA_GAIN:
> - len = sysfs_emit(buf, "%s\n",
> - (st->ctrl_hb & AD5933_CTRL_PGA_GAIN_1) ?
> - "1" : "0.2");
> - break;
> + return sysfs_emit(buf, "%s\n",
> + st->ctrl_hb & AD5933_CTRL_PGA_GAIN_1 ? "1" : "0.2");
You can (re-)use ridx here as well
ridx = st->ctrl_hb & AD5933_CTRL_PGA_GAIN_1;
return sysfs_emit(buf, "%s\n", ridx ? "1" : "0.2");
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-10-19 19:09 ` Andy Shevchenko
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