To ensure a good balancing of regulators, force PLL disable either by
reset or by clearing the PLLEN bit.
If waiting the powerdown pulse delay isn't enough, return -EPROBE_DEFER
instead of polling the PLLEN bit, which will be low at the next probe.
Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx>
---
drivers/phy/st/phy-stm32-usbphyc.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/phy/st/phy-stm32-usbphyc.c b/drivers/phy/st/phy-stm32-usbphyc.c
index 8ef97c8806ff..33367a325612 100644
--- a/drivers/phy/st/phy-stm32-usbphyc.c
+++ b/drivers/phy/st/phy-stm32-usbphyc.c
@@ -8,7 +8,7 @@
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/delay.h>
-#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_platform.h>
@@ -334,7 +334,7 @@ static int stm32_usbphyc_probe(struct platform_device *pdev)
struct device *dev = &pdev->dev;
struct device_node *child, *np = dev->of_node;
struct phy_provider *phy_provider;
- u32 version;
+ u32 pllen, version;
int ret, port = 0;
usbphyc = devm_kzalloc(dev, sizeof(*usbphyc), GFP_KERNEL);
@@ -366,6 +366,19 @@ static int stm32_usbphyc_probe(struct platform_device *pdev)
ret = PTR_ERR(usbphyc->rst);
if (ret == -EPROBE_DEFER)
goto clk_disable;
+
+ stm32_usbphyc_clr_bits(usbphyc->base + STM32_USBPHYC_PLL, PLLEN);
+ }
+
+ /*
+ * Wait for minimum width of powerdown pulse (ENABLE = Low):
+ * we have to ensure the PLL is disabled before phys initialization.
+ */
+ if (readl_relaxed_poll_timeout(usbphyc->base + STM32_USBPHYC_PLL,
+ pllen, !(pllen & PLLEN), 5, 50)) {
+ dev_warn(usbphyc->dev, "PLL not reset\n");
+ ret = -EPROBE_DEFER;
+ goto clk_disable;
}
usbphyc->switch_setup = -EINVAL;
--
2.17.1
