staging: regulator: hi6421v600-regulator: port it to upstream

The driver was originally written for Kernel 4.9. It needs to
be ported to upstream:

	- Got rid of timeval;
	- Removed a bogus dependency;
	- Did cleanups at the header file.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/9e34400d2cc15ef501a8478f69a95c9abc5c4d8d.1597647359.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/hikey9xx/hi6421v600-regulator.c

@@ -49,7 +49,6 @@ struct hisi_regulator_register_info {
 struct hisi_regulator {
 	const char *name;
 	struct hisi_regulator_register_info register_info;
-	struct timeval last_off_time;
 	u32 off_on_delay;
 	u32 eco_uA;
 	struct regulator_desc rdesc;
@@ -57,8 +56,6 @@ struct hisi_regulator {
 };
 
 static DEFINE_MUTEX(enable_mutex);
-struct timeval last_enabled;
-
 
 static inline struct hisi_pmic *rdev_to_pmic(struct regulator_dev *dev)
 {
@@ -72,27 +69,6 @@ static inline struct hisi_pmic *rdev_to_pmic(struct regulator_dev *dev)
 /* helper function to ensure when it returns it is at least 'delay_us'
  * microseconds after 'since'.
  */
-static void ensured_time_after(struct timeval since, u32 delay_us)
-{
-	struct timeval now;
-	u64 elapsed_ns64, delay_ns64;
-	u32 actual_us32;
-
-	delay_ns64 = delay_us * NSEC_PER_USEC;
-	do_gettimeofday(&now);
-	elapsed_ns64 = timeval_to_ns(&now) - timeval_to_ns(&since);
-	if (delay_ns64 > elapsed_ns64) {
-		actual_us32 = ((u32)(delay_ns64 - elapsed_ns64) /
-							NSEC_PER_USEC);
-		if (actual_us32 >= 1000) {
-			mdelay(actual_us32 / 1000); /*lint !e647 */
-			udelay(actual_us32 % 1000);
-		} else if (actual_us32 > 0) {
-			udelay(actual_us32);
-		}
-	}
-	return;
-}
 
 static int hisi_regulator_is_enabled(struct regulator_dev *dev)
 {
@@ -113,13 +89,16 @@ static int hisi_regulator_enable(struct regulator_dev *dev)
 	struct hisi_pmic *pmic = rdev_to_pmic(dev);
 
 	/* keep a distance of off_on_delay from last time disabled */
-	ensured_time_after(sreg->last_off_time, sreg->off_on_delay);
+	usleep_range(sreg->off_on_delay, sreg->off_on_delay + 1000);
 
 	pr_debug("<[%s]: off_on_delay=%dus>\n", __func__, sreg->off_on_delay);
 
 	/* cannot enable more than one regulator at one time */
 	mutex_lock(&enable_mutex);
-	ensured_time_after(last_enabled, HISI_REGS_ENA_PROTECT_TIME);
+	usleep_range(HISI_REGS_ENA_PROTECT_TIME,
+		     HISI_REGS_ENA_PROTECT_TIME + 1000);
+
+
 
 	/* set enable register */
 	hisi_pmic_rmw(pmic, sreg->register_info.ctrl_reg,
@@ -128,7 +107,6 @@ static int hisi_regulator_enable(struct regulator_dev *dev)
 	pr_debug("<[%s]: ctrl_reg=0x%x,enable_mask=0x%x>\n", __func__, sreg->register_info.ctrl_reg,\
 			sreg->register_info.enable_mask);
 
-	do_gettimeofday(&last_enabled);
 	mutex_unlock(&enable_mutex);
 
 	return 0;
@@ -143,8 +121,6 @@ static int hisi_regulator_disable(struct regulator_dev *dev)
 	hisi_pmic_rmw(pmic, sreg->register_info.ctrl_reg,
 				sreg->register_info.enable_mask, 0);
 
-	do_gettimeofday(&sreg->last_off_time);
-
 	return 0;
 }