On the STM32MP1, shutting down barebox can result in a
ERROR: phy1: phy exit failed --> -22
message printed to the console. This is because the regulator is disabled
more often than it was enabled, because stm32_usbphyc_pll_disable
is called twice:
- Once from stm32_usbphyc_remove calling stm32_usbphyc_phy_exit
- Once from dwc2_remove calling phy_exit -> stm32_usbphyc_phy_exit
The code is taken from Linux and likely causes no issues there, because
devices are removed in reverse probe order, which barebox doesn't
enforce. Properly solving this would be a larger endeavour, so for now
just fix the stm32-usbphyc driver to ignore reference count dropping
below zero and only call __stm32_usbphyc_pll_disable once.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
drivers/phy/phy-stm32-usbphyc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/phy/phy-stm32-usbphyc.c b/drivers/phy/phy-stm32-usbphyc.c
index ac82b019f44c..91f4e7f7e08d 100644
--- a/drivers/phy/phy-stm32-usbphyc.c
+++ b/drivers/phy/phy-stm32-usbphyc.c
@@ -277,7 +277,7 @@ static int __stm32_usbphyc_pll_disable(struct stm32_usbphyc *usbphyc)
static int stm32_usbphyc_pll_disable(struct stm32_usbphyc *usbphyc)
{
/* Check if a phy port is still active or clk48 in use */
- if (atomic_dec_return(&usbphyc->n_pll_cons) > 0)
+ if (atomic_dec_return(&usbphyc->n_pll_cons) != 1)
return 0;
return __stm32_usbphyc_pll_disable(usbphyc);
--
2.39.2
