regulator: max8972: Fix setting ramp delay

Current code can set ramp delay to a wrong setting that the return value from .set_voltage_time_sel is not enough for proper delay. Fix the logic in .set_ramp_delay and also remove unused ret_val variable.

---
 drivers/regulator/max8973-regulator.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

index 08d2f13..3958f50 100644
@@ -271,22 +271,18 @@ static int max8973_set_ramp_delay(struct regulator_dev *rdev,
 	struct max8973_chip *max = rdev_get_drvdata(rdev);
 	unsigned int control;
 	int ret;
-	int ret_val;
 
 	/* Set ramp delay */
-	if (ramp_delay < 25000) {
+	if (ramp_delay <= 12000)
 		control = MAX8973_RAMP_12mV_PER_US;
-		ret_val = 12000;
-	} else if (ramp_delay < 50000) {
+	else if (ramp_delay <= 25000)
 		control = MAX8973_RAMP_25mV_PER_US;
-		ret_val = 25000;
-	} else if (ramp_delay < 200000) {
+	else if (ramp_delay <= 50000)
 		control = MAX8973_RAMP_50mV_PER_US;
-		ret_val = 50000;
-	} else {
+	else if (ramp_delay <= 200000)
 		control = MAX8973_RAMP_200mV_PER_US;
-		ret_val = 200000;
-	}
+	else
+		return -EINVAL;
 
 	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
 			MAX8973_RAMP_MASK, control);

2.5.0

I don't understand what yo wanted to say here. What wrong setting is possible? Why do you mention set_voltage_time_sel() here?

Can you elaborate?

The only difference I spotted is how you round up the ramp_delay values.

Best regards,
Krzysztof

2016-05-30 16:48 GMT+08:00 Krzysztof Kozlowski <[email protected]>:

Assume rdev->constraints->ramp_delay is 20000.

Original code will set MAX8973_RAMP_12mV_PER_US.

However, in regulator_set_voltage_time_sel()

        return DIV_ROUND_UP(abs(new_volt - old_volt), ramp_delay);

This return value is not enough if the device is using MAX8973_RAMP_12mV_PER_US setting.

Thanks, now it makes sense but the commit message needs improvements. The problem is that current code for .set_ramp_delay() rounds down the value written to register, while the implementation of .set_voltage_time_sel() works on original constraints (not rounded down).

Please, fix the message.

Best regards,
Krzysztof

The patch

regulator: max8973: Fix setting ramp delay

has been applied to the regulator tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git

All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying to this mail.

Thanks,
Mark

From: Axel Lin <[email protected]>
Date: Sun, 29 May 2016 19:20:03 +0800
Subject: [PATCH] regulator: max8973: Fix setting ramp delay

Current code can set ramp delay to a wrong setting that the return value from .set_voltage_time_sel is not enough for proper delay. Fix the logic in .set_ramp_delay and also remove unused ret_val variable.

---
 drivers/regulator/max8973-regulator.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

index 08d2f13eca00..3958f50c5975 100644
@@ -271,22 +271,18 @@ static int max8973_set_ramp_delay(struct regulator_dev *rdev,
 	struct max8973_chip *max = rdev_get_drvdata(rdev);
 	unsigned int control;
 	int ret;
-	int ret_val;
 
 	/* Set ramp delay */
-	if (ramp_delay < 25000) {
+	if (ramp_delay <= 12000)
 		control = MAX8973_RAMP_12mV_PER_US;
-		ret_val = 12000;
-	} else if (ramp_delay < 50000) {
+	else if (ramp_delay <= 25000)
 		control = MAX8973_RAMP_25mV_PER_US;
-		ret_val = 25000;
-	} else if (ramp_delay < 200000) {
+	else if (ramp_delay <= 50000)
 		control = MAX8973_RAMP_50mV_PER_US;
-		ret_val = 50000;
-	} else {
+	else if (ramp_delay <= 200000)
 		control = MAX8973_RAMP_200mV_PER_US;
-		ret_val = 200000;
-	}
+	else
+		return -EINVAL;
 
 	ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
 			MAX8973_RAMP_MASK, control);

2.8.1