On 7/2/18 11:05 AM, Tony Lindgren wrote:
> * Maciej Purski <m.purski@xxxxxxxxxxx> [180618 14:11]:
>> If the regulator is not coupled, balance_voltage() should preserve
>> its desired max uV, instead of setting the exact value like in
>> coupled regulators case.
>>
>> Remove debugs, which are not necessary for now.
>
> Sorry for the delay in testing. I gave your series with this one
> a quick boot test on beagleboard-x15 and now the output is
> different. So instead of just hanging it seems to be stuck in
> some eternal loop see below.
Hello guys,
I'm working on the CPUFreq driver for NVIDIA Tegra and it requires the coupled-regulators functionality, hence I'm interested in getting the coupled regulators series finalized ASAP and want to help with it.
It looks to me that the infinite-loop problem is caused by the voltage value that is getting rounded-up by the driver because it isn't aligned to the uV_step. IIUC, uV_step is relevant only for the "linear" regulators and hence we can't simply set the best_delta to uV_step to solve the problem. Other solution could be to bail out of the loop once regulator sets value equal to the "desired".
Tony, could you please give a try to the patch below?
Do the following:
1) git cherry-pick 696861761a58d8c93605b5663824929fb6540f16
2) git cherry-pick 456e7cdf3b1a14e2606b8b687385ab2e3f23a49a
3) Apply this patch:
>From 7928aecb3af9d367dd3c085972349aaa16318c1b Mon Sep 17 00:00:00 2001
From: Dmitry Osipenko <digetx@xxxxxxxxx>
Date: Fri, 28 Sep 2018 21:49:20 +0300
Subject: [PATCH] Fixup regulator_balance_voltage()
---
drivers/regulator/core.c | 39 ++++++++++++++++++++++++---------------
1 file changed, 24 insertions(+), 15 deletions(-)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 282511508698..4a386fe9f26a 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3187,7 +3187,8 @@ static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
return ret;
}
-static int regulator_get_optimal_voltage(struct regulator_dev *rdev)
+static int regulator_get_optimal_voltage(struct regulator_dev *rdev,
+ int *min_uV, int *max_uV)
{
struct coupling_desc *c_desc = &rdev->coupling_desc;
struct regulator_dev **c_rdevs = c_desc->coupled_rdevs;
@@ -3211,7 +3212,9 @@ static int regulator_get_optimal_voltage(struct regulator_dev *rdev)
* by consumers.
*/
if (n_coupled == 1) {
- ret = desired_min_uV;
+ *min_uV = desired_min_uV;
+ *max_uV = desired_max_uV;
+ ret = 1;
goto out;
}
@@ -3285,8 +3288,10 @@ static int regulator_get_optimal_voltage(struct regulator_dev *rdev)
ret = -EINVAL;
goto out;
}
- ret = possible_uV;
+ ret = (possible_uV == desired_min_uV);
+ *min_uV = possible_uV;
+ *max_uV = desired_max_uV;
out:
return ret;
}
@@ -3298,7 +3303,8 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
struct regulator_dev *best_rdev;
struct coupling_desc *c_desc = &rdev->coupling_desc;
int n_coupled;
- int i, best_delta, best_uV, ret = 1;
+ int i, best_delta, best_min_uV, best_max_uV, ret = 1;
+ bool last = false;
c_rdevs = c_desc->coupled_rdevs;
n_coupled = c_desc->n_coupled;
@@ -3314,9 +3320,10 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
* Find the best possible voltage change on each loop. Leave the loop
* if there isn't any possible change.
*/
- while (1) {
+ while (!last) {
best_delta = 0;
- best_uV = 0;
+ best_min_uV = 0;
+ best_max_uV = 0;
best_rdev = NULL;
/*
@@ -3330,24 +3337,26 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
* max_spread constraint in order to balance
* the coupled voltages.
*/
- int optimal_uV, current_uV;
+ int optimal_uV, optimal_max_uV, current_uV;
- optimal_uV = regulator_get_optimal_voltage(c_rdevs[i]);
- if (optimal_uV < 0) {
- ret = optimal_uV;
+ ret = regulator_get_optimal_voltage(c_rdevs[i],
+ &optimal_uV,
+ &optimal_max_uV);
+ if (ret < 0)
goto out;
- }
current_uV = _regulator_get_voltage(c_rdevs[i]);
if (current_uV < 0) {
- ret = optimal_uV;
+ ret = current_uV;
goto out;
}
if (abs(best_delta) < abs(optimal_uV - current_uV)) {
best_delta = optimal_uV - current_uV;
best_rdev = c_rdevs[i];
- best_uV = optimal_uV;
+ best_min_uV = optimal_uV;
+ best_max_uV = optimal_max_uV;
+ last = (best_rdev == rdev && ret > 0);
}
}
@@ -3357,8 +3366,8 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
goto out;
}
- ret = regulator_set_voltage_rdev(best_rdev, best_uV,
- best_uV, state);
+ ret = regulator_set_voltage_rdev(best_rdev, best_min_uV,
+ best_max_uV, state);
if (ret < 0)
goto out;
--
2.19.0
