[PATCH] regulator: core: resolve supply voltage deferral silently

[Brian Norris <briannorris@chromium.org>]

Voltage-controlled regulators depend on their supply regulator for
retrieving their voltage, and so they might return -EPROBE_DEFER at this
stage. Our caller already attempts to resolve supplies and retry, so we
shouldn't be printing this error to logs.

Quiets log messages like this, on Rockchip RK3399 Gru/Kevin boards:

[    1.033057] ppvar_bigcpu: failed to get the current voltage: -EPROBE_DEFER
...
[    1.036735] ppvar_litcpu: failed to get the current voltage: -EPROBE_DEFER
...
[    1.040366] ppvar_gpu: failed to get the current voltage: -EPROBE_DEFER
...
[    1.044086] ppvar_centerlogic: failed to get the current voltage: -EPROBE_DEFER

Fixes: 21e39809fd7c ("regulator: vctrl: Avoid lockdep warning in enable/disable ops")
Cc: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Brian Norris <briannorris@chromium.org>
---

 drivers/regulator/core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index ca6caba8a191..85783fb3aadf 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1151,9 +1151,10 @@ static int machine_constraints_voltage(struct regulator_dev *rdev,
 		}
 
 		if (current_uV < 0) {
-			rdev_err(rdev,
-				 "failed to get the current voltage: %pe\n",
-				 ERR_PTR(current_uV));
+			if (current_uV != -EPROBE_DEFER)
+				rdev_err(rdev,
+					 "failed to get the current voltage: %pe\n",
+					 ERR_PTR(current_uV));
 			return current_uV;
 		}
 
-- 
2.33.0.259.gc128427fd7-goog