regulator: When constraining modes fall back to higher power modes

PATCH Applied Mark Brown 2 participants 4 messages Mar 29, 2011 – Mar 30, 2011 Voltage and current regulator framework

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Mark Brown

author

2011-03-29 21:29 UTC #0 lore raw

PATCH 1/1 regulator: When constraining modes fall back to higher power modes

If a mode requested by a consumer is not allowed by constraints automatically fall back to a higher power mode if possible. This ensures that consumers get at least the output they requested while allowing machine drivers to transparently limit lower power modes if required.

Signed-off-by Mark Brown <[email protected]>

---

I've not actually had a chance to test this but throwing it out there for comment and testing now; someone with an OMAP board can probably test fairly quickly as the OMAP HSMMC driver is using set_mode().

 drivers/regulator/core.c |   24 +++++++++++++++---------
 1 files changed, 15 insertions(+), 9 deletions(-)

drivers/regulator/core.c +15 -9

index 3ffc697..a634946 100644
@@ -197,9 +197,9 @@ static int regulator_check_current_limit(struct regulator_dev *rdev,
 }
 
 /* operating mode constraint check */
-static int regulator_check_mode(struct regulator_dev *rdev, int mode)
+static int regulator_mode_constrain(struct regulator_dev *rdev, int *mode)
 {
-	switch (mode) {
+	switch (*mode) {
 	case REGULATOR_MODE_FAST:
 	case REGULATOR_MODE_NORMAL:
 	case REGULATOR_MODE_IDLE:

@@ -217,11 +217,17 @@ static int regulator_check_mode(struct regulator_dev *rdev, int mode)
 		rdev_err(rdev, "operation not allowed\n");
 		return -EPERM;
 	}
-	if (!(rdev->constraints->valid_modes_mask & mode)) {
-		rdev_err(rdev, "invalid mode %x\n", mode);
-		return -EINVAL;
+
+	/* The modes are bitmasks, the most power hungry modes having
+	 * the lowest values. If the requested mode isn't supported
+	 * try higher modes. */
+	while (*mode) {
+		if (rdev->constraints->valid_modes_mask & *mode)
+			return 0;
+		*mode /= 2;
 	}
-	return 0;
+
+	return -EINVAL;
 }
 
 /* dynamic regulator mode switching constraint check */

@@ -612,7 +618,7 @@ static void drms_uA_update(struct regulator_dev *rdev)
 						  output_uV, current_uA);
 
 	/* check the new mode is allowed */
-	err = regulator_check_mode(rdev, mode);
+	err = regulator_mode_constrain(rdev, &mode);
 	if (err == 0)
 		rdev->desc->ops->set_mode(rdev, mode);
 }

@@ -2005,7 +2011,7 @@ int regulator_set_mode(struct regulator *regulator, unsigned int mode)
 	}
 
 	/* constraints check */
-	ret = regulator_check_mode(rdev, mode);
+	ret = regulator_mode_constrain(rdev, mode);
 	if (ret < 0)
 		goto out;

@@ -2116,7 +2122,7 @@ int regulator_set_optimum_mode(struct regulator *regulator, int uA_load)
 	mode = rdev->desc->ops->get_optimum_mode(rdev,
 						 input_uV, output_uV,
 						 total_uA_load);
-	ret = regulator_check_mode(rdev, mode);
+	ret = regulator_mode_constrain(rdev, &mode);
 	if (ret < 0) {
 		rdev_err(rdev, "failed to get optimum mode @ %d uA %d -> %d uV\n",
 			 total_uA_load, input_uV, output_uV);

Signature · 1 line

1.7.4.1

Liam Girdwood

2011-03-29 23:29 UTC #1 lore raw

Quoted 42 lines · Mark Brown

If a mode requested by a consumer is not allowed by constraints automatically fall back to a higher power mode if possible. This ensures that consumers get at least the output they requested while allowing machine drivers to transparently limit lower power modes if required.
Signed-off-by Mark Brown <[email protected]>
---
I've not actually had a chance to test this but throwing it out there for comment and testing now; someone with an OMAP board can probably test fairly quickly as the OMAP HSMMC driver is using set_mode().
 drivers/regulator/core.c |   24 +++++++++++++++---------
 1 files changed, 15 insertions(+), 9 deletions(-)
drivers/regulator/core.c +5 -5
index 3ffc697..a634946 100644
@@ -197,9 +197,9 @@ static int regulator_check_current_limit(struct regulator_dev *rdev,
 }
 
 /* operating mode constraint check */
-static int regulator_check_mode(struct regulator_dev *rdev, int mode)
+static int regulator_mode_constrain(struct regulator_dev *rdev, int *mode)
 {
-	switch (mode) {
+	switch (*mode) {
 	case REGULATOR_MODE_FAST:
 	case REGULATOR_MODE_NORMAL:
 	case REGULATOR_MODE_IDLE:
@@ -217,11 +217,17 @@ static int regulator_check_mode(struct regulator_dev *rdev, int mode)
 		rdev_err(rdev, "operation not allowed\n");
 		return -EPERM;
 	}
-	if (!(rdev->constraints->valid_modes_mask & mode)) {
-		rdev_err(rdev, "invalid mode %x\n", mode);
-		return -EINVAL;
+
+	/* The modes are bitmasks, the most power hungry modes having
+	 * the lowest values. If the requested mode isn't supported

drivers/regulator/core.c static int regulator_check_mode(struct regulator_dev *rdev, int mode) · line 231

Quoted 10 lines

drivers/regulator/core.c +7 -1

+	 * try higher modes. */
+	while (*mode) {
+		if (rdev->constraints->valid_modes_mask & *mode)
+			return 0;
+		*mode /= 2;
 	}
-	return 0;
+
+	return -EINVAL;
 }

It's late and I'm wondering if it's cleaner here just to :-

if (mask & *mode)

	return 0;

*mode = fls(mask);
if (*mode)

	return 0;

return -EINVAL;

What do you think ?

Liam

Mark Brown

author

2011-03-29 23:39 UTC #2 lore raw

Quoted 8 lines · Liam Girdwood

It's late and I'm wondering if it's cleaner here just to :-
if (mask & *mode)
	return 0;
*mode = fls(mask);
if (*mode)
	return 0;

This will end up selecting the highest mode in mask, even if it's lower than the one asked for, you'd need to recheck against the original mask. There's a few ways I can think of to do that but they're none of them exceptionally pretty.

Liam Girdwood

Applied

2011-03-30 19:14 UTC #3 lore raw

In reply to Mark Brown

Quoted 8 lines · Mark Brown

If a mode requested by a consumer is not allowed by constraints automatically fall back to a higher power mode if possible. This ensures that consumers get at least the output they requested while allowing machine drivers to transparently limit lower power modes if required.
Signed-off-by Mark Brown <[email protected]>
---

Applied.

Thanks

Liam