[PATCH 22/29] hwmon: (ltc4282) 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/ltc4282.c | 32 ++++----------------------------
 1 file changed, 4 insertions(+), 28 deletions(-)

diff --git a/drivers/hwmon/ltc4282.c b/drivers/hwmon/ltc4282.c
index 44102879694a..b9cad89f2cd9 100644
--- a/drivers/hwmon/ltc4282.c
+++ b/drivers/hwmon/ltc4282.c
@@ -17,7 +17,6 @@
 #include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
-#include <linux/mutex.h>
 #include <linux/regmap.h>
 #include <linux/property.h>
 #include <linux/string.h>
@@ -131,8 +130,6 @@ struct ltc4282_cache {
 
 struct ltc4282_state {
 	struct regmap *map;
-	/* Protect against multiple accesses to the device registers */
-	struct mutex lock;
 	struct clk_hw clk_hw;
 	/*
 	 * Used to cache values for VDD/VSOURCE depending which will be used
@@ -281,14 +278,12 @@ static int __ltc4282_read_alarm(struct ltc4282_state *st, u32 reg, u32 mask,
 static int ltc4282_read_alarm(struct ltc4282_state *st, u32 reg, u32 mask,
 			      long *val)
 {
-	guard(mutex)(&st->lock);
 	return __ltc4282_read_alarm(st, reg, mask, val);
 }
 
 static int ltc4282_vdd_source_read_in(struct ltc4282_state *st, u32 channel,
 				      long *val)
 {
-	guard(mutex)(&st->lock);
 	if (!st->in0_1_cache[channel].en)
 		return -ENODATA;
 
@@ -300,7 +295,6 @@ static int ltc4282_vdd_source_read_hist(struct ltc4282_state *st, u32 reg,
 {
 	int ret;
 
-	guard(mutex)(&st->lock);
 	if (!st->in0_1_cache[channel].en) {
 		*val = *cached;
 		return 0;
@@ -317,7 +311,6 @@ static int ltc4282_vdd_source_read_hist(struct ltc4282_state *st, u32 reg,
 static int ltc4282_vdd_source_read_lim(struct ltc4282_state *st, u32 reg,
 				       u32 channel, u32 *cached, long *val)
 {
-	guard(mutex)(&st->lock);
 	if (!st->in0_1_cache[channel].en)
 		return ltc4282_read_voltage_byte_cached(st, reg, st->vfs_out,
 							val, cached);
@@ -328,7 +321,6 @@ static int ltc4282_vdd_source_read_lim(struct ltc4282_state *st, u32 reg,
 static int ltc4282_vdd_source_read_alm(struct ltc4282_state *st, u32 mask,
 				       u32 channel, long *val)
 {
-	guard(mutex)(&st->lock);
 	if (!st->in0_1_cache[channel].en) {
 		/*
 		 * Do this otherwise alarms can get confused because we clear
@@ -412,9 +404,7 @@ static int ltc4282_read_in(struct ltc4282_state *st, u32 attr, long *val,
 						   channel,
 						   &st->in0_1_cache[channel].in_min_raw, val);
 	case hwmon_in_enable:
-		scoped_guard(mutex, &st->lock) {
-			*val = st->in0_1_cache[channel].en;
-		}
+		*val = st->in0_1_cache[channel].en;
 		return 0;
 	case hwmon_in_fault:
 		/*
@@ -612,15 +602,11 @@ static int ltc4282_read(struct device *dev, enum hwmon_sensor_types type,
 	case hwmon_power:
 		return ltc4282_read_power(st, attr, val);
 	case hwmon_energy:
-		scoped_guard(mutex, &st->lock) {
-			*val = st->energy_en;
-		}
+		*val = st->energy_en;
 		return 0;
 	case hwmon_energy64:
-		scoped_guard(mutex, &st->lock) {
-			if (st->energy_en)
-				return ltc4282_read_energy(st, (s64 *)val);
-		}
+		if (st->energy_en)
+			return ltc4282_read_energy(st, (s64 *)val);
 		return -ENODATA;
 	default:
 		return -EOPNOTSUPP;
@@ -688,7 +674,6 @@ static int __ltc4282_in_write_history(const struct ltc4282_state *st, u32 reg,
 static int ltc4282_in_write_history(struct ltc4282_state *st, u32 reg,
 				    long lowest, long highest, u32 fs)
 {
-	guard(mutex)(&st->lock);
 	return __ltc4282_in_write_history(st, reg, lowest, highest, fs);
 }
 
@@ -696,8 +681,6 @@ static int ltc4282_power_reset_hist(struct ltc4282_state *st)
 {
 	int ret;
 
-	guard(mutex)(&st->lock);
-
 	ret = ltc4282_write_power_word(st, LTC4282_POWER_LOWEST,
 				       st->power_max);
 	if (ret)
@@ -803,7 +786,6 @@ static int ltc4282_vdd_source_write_lim(struct ltc4282_state *st, u32 reg,
 {
 	int ret;
 
-	guard(mutex)(&st->lock);
 	if (st->in0_1_cache[channel].en)
 		ret = ltc4282_write_voltage_byte(st, reg, st->vfs_out, val);
 	else
@@ -821,7 +803,6 @@ static int ltc4282_vdd_source_reset_hist(struct ltc4282_state *st, int channel)
 	if (channel == LTC4282_CHAN_VDD)
 		lowest = st->vdd;
 
-	guard(mutex)(&st->lock);
 	if (st->in0_1_cache[channel].en) {
 		ret = __ltc4282_in_write_history(st, LTC4282_VSOURCE_LOWEST,
 						 lowest, 0, st->vfs_out);
@@ -861,7 +842,6 @@ static int ltc4282_vdd_source_enable(struct ltc4282_state *st, int channel,
 	int ret, other_chan = ~channel & 0x1;
 	u8 __val = val;
 
-	guard(mutex)(&st->lock);
 	if (st->in0_1_cache[channel].en == !!val)
 		return 0;
 
@@ -938,8 +918,6 @@ static int ltc4282_curr_reset_hist(struct ltc4282_state *st)
 {
 	int ret;
 
-	guard(mutex)(&st->lock);
-
 	ret = __ltc4282_in_write_history(st, LTC4282_VSENSE_LOWEST,
 					 st->vsense_max, 0, 40 * MILLI);
 	if (ret)
@@ -974,7 +952,6 @@ static int ltc4282_energy_enable_set(struct ltc4282_state *st, long val)
 {
 	int ret;
 
-	guard(mutex)(&st->lock);
 	/* setting the bit halts the meter */
 	ret = regmap_update_bits(st->map, LTC4282_ADC_CTRL,
 				 LTC4282_METER_HALT_MASK,
@@ -1699,7 +1676,6 @@ static int ltc4282_probe(struct i2c_client *i2c)
 	if (ret)
 		return ret;
 
-	mutex_init(&st->lock);
 	hwmon = devm_hwmon_device_register_with_info(dev, "ltc4282", st,
 						     &ltc4282_chip_info, NULL);
 	if (IS_ERR(hwmon))
-- 
2.45.2