[PATCH 20/29] hwmon: (sfctemp) Rely on subsystem locking

[Guenter Roeck <linux@roeck-us.net>]

Attribute access is now serialized in the hardware monitoring core,
so locking in the driver code is no longer necessary. Drop it.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/sfctemp.c | 36 ++++++++----------------------------
 1 file changed, 8 insertions(+), 28 deletions(-)

diff --git a/drivers/hwmon/sfctemp.c b/drivers/hwmon/sfctemp.c
index fb1da93383d7..b78b2c099a12 100644
--- a/drivers/hwmon/sfctemp.c
+++ b/drivers/hwmon/sfctemp.c
@@ -10,7 +10,6 @@
 #include <linux/hwmon.h>
 #include <linux/io.h>
 #include <linux/module.h>
-#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
@@ -49,8 +48,6 @@
 #define SFCTEMP_K1000	81100L
 
 struct sfctemp {
-	/* serialize access to hardware register and enabled below */
-	struct mutex lock;
 	void __iomem *regs;
 	struct clk *clk_sense;
 	struct clk *clk_bus;
@@ -92,15 +89,14 @@ static void sfctemp_stop(struct sfctemp *sfctemp)
 
 static int sfctemp_enable(struct sfctemp *sfctemp)
 {
-	int ret = 0;
+	int ret;
 
-	mutex_lock(&sfctemp->lock);
 	if (sfctemp->enabled)
-		goto done;
+		return 0;
 
 	ret = clk_prepare_enable(sfctemp->clk_bus);
 	if (ret)
-		goto err;
+		return ret;
 	ret = reset_control_deassert(sfctemp->rst_bus);
 	if (ret)
 		goto err_disable_bus;
@@ -115,9 +111,7 @@ static int sfctemp_enable(struct sfctemp *sfctemp)
 	sfctemp_power_up(sfctemp);
 	sfctemp_run(sfctemp);
 	sfctemp->enabled = true;
-done:
-	mutex_unlock(&sfctemp->lock);
-	return ret;
+	return 0;
 
 err_disable_sense:
 	clk_disable_unprepare(sfctemp->clk_sense);
@@ -125,16 +119,13 @@ static int sfctemp_enable(struct sfctemp *sfctemp)
 	reset_control_assert(sfctemp->rst_bus);
 err_disable_bus:
 	clk_disable_unprepare(sfctemp->clk_bus);
-err:
-	mutex_unlock(&sfctemp->lock);
 	return ret;
 }
 
 static int sfctemp_disable(struct sfctemp *sfctemp)
 {
-	mutex_lock(&sfctemp->lock);
 	if (!sfctemp->enabled)
-		goto done;
+		return 0;
 
 	sfctemp_stop(sfctemp);
 	sfctemp_power_down(sfctemp);
@@ -143,8 +134,6 @@ static int sfctemp_disable(struct sfctemp *sfctemp)
 	reset_control_assert(sfctemp->rst_bus);
 	clk_disable_unprepare(sfctemp->clk_bus);
 	sfctemp->enabled = false;
-done:
-	mutex_unlock(&sfctemp->lock);
 	return 0;
 }
 
@@ -155,22 +144,14 @@ static void sfctemp_disable_action(void *data)
 
 static int sfctemp_convert(struct sfctemp *sfctemp, long *val)
 {
-	int ret;
-
-	mutex_lock(&sfctemp->lock);
-	if (!sfctemp->enabled) {
-		ret = -ENODATA;
-		goto out;
-	}
+	if (!sfctemp->enabled)
+		return -ENODATA;
 
 	/* calculate temperature in milli Celcius */
 	*val = (long)((readl(sfctemp->regs) & SFCTEMP_DOUT_MSK) >> SFCTEMP_DOUT_POS)
 		* SFCTEMP_Y1000 / SFCTEMP_Z - SFCTEMP_K1000;
 
-	ret = 0;
-out:
-	mutex_unlock(&sfctemp->lock);
-	return ret;
+	return 0;
 }
 
 static umode_t sfctemp_is_visible(const void *data, enum hwmon_sensor_types type,
@@ -263,7 +244,6 @@ static int sfctemp_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	dev_set_drvdata(dev, sfctemp);
-	mutex_init(&sfctemp->lock);
 
 	sfctemp->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(sfctemp->regs))
-- 
2.45.2