linux-kernel - [PATCH v3 5/8] iio: adc: ti-adc128s052: Simplify using guard(mutex)

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Message-ID: <c4262cbf55748d505a74249d2bf46d7c3594d838.1744022065.git.mazziesaccount@gmail.com>
Date: Mon, 7 Apr 2025 14:36:35 +0300
From: Matti Vaittinen <mazziesaccount@...il.com>
To: Matti Vaittinen <mazziesaccount@...il.com>,
	Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc: Jonathan Cameron <jic23@...nel.org>,
	Lars-Peter Clausen <lars@...afoo.de>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Matti Vaittinen <mazziesaccount@...il.com>,
	Nuno Sa <nuno.sa@...log.com>, David Lechner <dlechner@...libre.com>,
	Javier Carrasco <javier.carrasco.cruz@...il.com>,
	linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v3 5/8] iio: adc: ti-adc128s052: Simplify using guard(mutex)

Error path in ADC reading function can be slighly simplified using the
guard(mutex).

Use guard(mutex) and document the mutex purpose.

Signed-off-by: Matti Vaittinen <mazziesaccount@...il.com>

---
Revision history:
v2 =>
 - No changes
v1 => v2:
 - Protect the shared message data
 - Add message data protection to the mutex doc
 - Reword the commit message
---
 drivers/iio/adc/ti-adc128s052.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
index d90a5caa028f..fa0099356be7 100644
--- a/drivers/iio/adc/ti-adc128s052.c
+++ b/drivers/iio/adc/ti-adc128s052.c
@@ -9,6 +9,7 @@
  * https://www.ti.com/lit/ds/symlink/adc124s021.pdf
  */
 
+#include <linux/cleanup.h>
 #include <linux/err.h>
 #include <linux/iio/iio.h>
 #include <linux/mod_devicetable.h>
@@ -26,6 +27,10 @@ struct adc128 {
 	struct spi_device *spi;
 
 	struct regulator *reg;
+	/*
+	 * Serialize the SPI 'write-channel + read data' accesses and protect
+	 * the shared buffer.
+	 */
 	struct mutex lock;
 
 	union {
@@ -38,19 +43,16 @@ static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
 {
 	int ret;
 
-	mutex_lock(&adc->lock);
+	guard(mutex)(&adc->lock);
 
 	adc->buffer[0] = channel << 3;
 	adc->buffer[1] = 0;
 
 	ret = spi_write(adc->spi, &adc->buffer, sizeof(adc->buffer));
-	if (ret < 0) {
-		mutex_unlock(&adc->lock);
+	if (ret < 0)
 		return ret;
-	}
 
 	ret = spi_read(adc->spi, &adc->buffer16, sizeof(adc->buffer16));
-	mutex_unlock(&adc->lock);
 	if (ret < 0)
 		return ret;
 
-- 
2.49.0


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