drivers: fuel_gauge: make read-only pointer args const in api

For the lists of properties passed as a pointer to the get_props and
set_props functions, there is no reason to not make the pointer const as
the called functions will not and should not alter the pointed-to data.

In practice, not having the pointers const can cause compilation errors
if trying to pass in a const array of properties.

Signed-off-by: Mikkel Jakobsen <mikkel.aunsbjerg@escolifesciences.com>

Author: aunsbjerg

drivers/fuel_gauge/fuel_gauge_syscall_handlers.c

@@ -26,7 +26,8 @@ static inline int z_vrfy_fuel_gauge_get_prop(const struct device *dev, fuel_gaug
 
 #include <zephyr/syscalls/fuel_gauge_get_prop_mrsh.c>
 
-static inline int z_vrfy_fuel_gauge_get_props(const struct device *dev, fuel_gauge_prop_t *props,
+static inline int z_vrfy_fuel_gauge_get_props(const struct device *dev,
+					      const fuel_gauge_prop_t *props,
 					      union fuel_gauge_prop_val *vals, size_t len)
 {
 	union fuel_gauge_prop_val k_vals[len];
@@ -58,8 +59,9 @@ static inline int z_vrfy_fuel_gauge_set_prop(const struct device *dev, fuel_gaug
 
 #include <zephyr/syscalls/fuel_gauge_set_prop_mrsh.c>
 
-static inline int z_vrfy_fuel_gauge_set_props(const struct device *dev, fuel_gauge_prop_t *props,
-					      union fuel_gauge_prop_val *vals, size_t len)
+static inline int z_vrfy_fuel_gauge_set_props(const struct device *dev,
+					      const fuel_gauge_prop_t *props,
+					      const union fuel_gauge_prop_val *vals, size_t len)
 {
 	union fuel_gauge_prop_val k_vals[len];
 	fuel_gauge_prop_t k_props[len];
@@ -71,9 +73,6 @@ static inline int z_vrfy_fuel_gauge_set_props(const struct device *dev, fuel_gau
 
 	int ret = z_impl_fuel_gauge_set_props(dev, k_props, k_vals, len);
 
-	/* We only copy back vals because props will never be modified */
-	K_OOPS(k_usermode_to_copy(vals, k_vals, len * sizeof(union fuel_gauge_prop_val)));
-
 	return ret;
 }
 

include/zephyr/drivers/fuel_gauge.h

@@ -288,10 +288,10 @@ static inline int z_impl_fuel_gauge_get_prop(const struct device *dev, fuel_gaug
  * @return 0 if successful, negative errno code of first failing property
  */
 
-__syscall int fuel_gauge_get_props(const struct device *dev, fuel_gauge_prop_t *props,
+__syscall int fuel_gauge_get_props(const struct device *dev, const fuel_gauge_prop_t *props,
 				   union fuel_gauge_prop_val *vals, size_t len);
 static inline int z_impl_fuel_gauge_get_props(const struct device *dev,
-					      fuel_gauge_prop_t *props,
+					      const fuel_gauge_prop_t *props,
 					      union fuel_gauge_prop_val *vals, size_t len)
 {
 	const struct fuel_gauge_driver_api *api = (const struct fuel_gauge_driver_api *)dev->api;
@@ -342,12 +342,12 @@ static inline int z_impl_fuel_gauge_set_prop(const struct device *dev, fuel_gaug
  *
  * @return return=0 if successful. Otherwise, return array index of failing property.
  */
-__syscall int fuel_gauge_set_props(const struct device *dev, fuel_gauge_prop_t *props,
-				   union fuel_gauge_prop_val *vals, size_t len);
+__syscall int fuel_gauge_set_props(const struct device *dev, const fuel_gauge_prop_t *props,
+				   const union fuel_gauge_prop_val *vals, size_t len);
 
 static inline int z_impl_fuel_gauge_set_props(const struct device *dev,
-					      fuel_gauge_prop_t *props,
-					      union fuel_gauge_prop_val *vals, size_t len)
+					      const fuel_gauge_prop_t *props,
+					      const union fuel_gauge_prop_val *vals, size_t len)
 {
 	for (size_t i = 0; i < len; i++) {
 		int ret = fuel_gauge_set_prop(dev, props[i], vals[i]);

tests/drivers/fuel_gauge/sbs_gauge/src/test_sbs_gauge.c

@@ -42,7 +42,7 @@ ZTEST_USER_F(sbs_gauge_new_api, test_get_some_props_failed_returns_bad_status)
 		/* Valid property */
 		FUEL_GAUGE_VOLTAGE,
 	};
-	union fuel_gauge_prop_val props[ARRAY_SIZE(prop_types)];
+	union fuel_gauge_prop_val props[ARRAY_SIZE(prop_types)] = {0};
 
 	int ret = fuel_gauge_get_props(fixture->dev, prop_types, props, ARRAY_SIZE(props));
 
@@ -55,7 +55,7 @@ ZTEST_USER_F(sbs_gauge_new_api, test_set_all_props_failed_returns_err)
 		/* Invalid property */
 		FUEL_GAUGE_PROP_MAX,
 	};
-	union fuel_gauge_prop_val props[ARRAY_SIZE(prop_types)];
+	union fuel_gauge_prop_val props[ARRAY_SIZE(prop_types)] = {0};
 
 	int ret = fuel_gauge_set_props(fixture->dev, prop_types, props, ARRAY_SIZE(props));
 
@@ -166,7 +166,7 @@ ZTEST_USER_F(sbs_gauge_new_api, test_get_props__returns_ok)
 		FUEL_GAUGE_SBS_REMAINING_TIME_ALARM,
 	};
 
-	union fuel_gauge_prop_val props[ARRAY_SIZE(prop_types)];
+	union fuel_gauge_prop_val props[ARRAY_SIZE(prop_types)] = {0};
 
 	zassert_ok(fuel_gauge_get_props(fixture->dev, prop_types, props, ARRAY_SIZE(props)));
 }
@@ -181,7 +181,7 @@ ZTEST_USER_F(sbs_gauge_new_api, test_set_props__returns_ok)
 		FUEL_GAUGE_SBS_REMAINING_CAPACITY_ALARM,
 
 	};
-	union fuel_gauge_prop_val props[ARRAY_SIZE(prop_types)];
+	union fuel_gauge_prop_val props[ARRAY_SIZE(prop_types)] = {0};
 
 	zassert_ok(fuel_gauge_set_props(fixture->dev, prop_types, props, ARRAY_SIZE(props)));
 }