[PATCH 5.12 038/677] soc/tegra: regulators: Fix locking up when voltage-spread is out of range

[Greg Kroah-Hartman]

From: Dmitry Osipenko <digetx@xxxxxxxxx>

commit ef85bb582c41524e9e68dfdbde48e519dac4ab3d upstream.

Fix voltage coupler lockup which happens when voltage-spread is out
of range due to a bug in the code. The max-spread requirement shall be
accounted when CPU regulator doesn't have consumers. This problem is
observed on Tegra30 Ouya game console once system-wide DVFS is enabled
in a device-tree.

Fixes: 783807436f36 ("soc/tegra: regulators: Add regulators coupler for Tegra30")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Peter Geis <pgwipeout@xxxxxxxxx>
Tested-by: Peter Geis <pgwipeout@xxxxxxxxx> # Ouya T30
Tested-by: Matt Merhar <mattmerhar@xxxxxxxxxxxxxx> # Ouya T30
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/soc/tegra/regulators-tegra30.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/soc/tegra/regulators-tegra30.c
+++ b/drivers/soc/tegra/regulators-tegra30.c
@@ -178,7 +178,7 @@ static int tegra30_voltage_update(struct
 	 * survive the voltage drop if it's running on a higher frequency.
 	 */
 	if (!cpu_min_uV_consumers)
-		cpu_min_uV = cpu_uV;
+		cpu_min_uV = max(cpu_uV, cpu_min_uV);
 
 	/*
 	 * Bootloader shall set up voltages correctly, but if it