[PATCH 3/6] usb: dwc3: Calculate REFCLKPER based on reference clock

From: Sean Anderson
Date: Fri Jan 14 2022 - 18:39:38 EST


Instead of using a special property to determine the reference clock
period, use the rate of the reference clock. When we have a legacy
snps,ref-clock-period-ns property and no reference clock, use it
instead. Fractional clocks are not currently supported, and will be
dealt with in the next commit.

Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx>
---

drivers/usb/dwc3/core.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 699ab9abdc47..5214daceda86 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -348,13 +348,22 @@ static void dwc3_frame_length_adjustment(struct dwc3 *dwc)
static void dwc3_ref_clk_period(struct dwc3 *dwc)
{
u32 reg;
+ unsigned long rate, period;

- if (dwc->ref_clk_per == 0)
+ if (dwc->ref_clk) {
+ rate = clk_get_rate(dwc->ref_clk);
+ if (!rate)
+ return;
+ period = NSEC_PER_SEC / rate;
+ } else if (dwc->ref_clk_per) {
+ period = dwc->ref_clk_per;
+ } else {
return;
+ }

reg = dwc3_readl(dwc->regs, DWC3_GUCTL);
reg &= ~DWC3_GUCTL_REFCLKPER_MASK;
- reg |= FIELD_PREP(DWC3_GUCTL_REFCLKPER_MASK, dwc->ref_clk_per);
+ reg |= FIELD_PREP(DWC3_GUCTL_REFCLKPER_MASK, period);
dwc3_writel(dwc->regs, DWC3_GUCTL, reg);
}

--
2.25.1