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Subject[PATCH v3 3/7] usb: dwc3: Calculate REFCLKPER based on reference clock
Date
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@seco.com>
Reviewed-by: Robert Hancock <robert.hancock@calian.com>
Tested-by: Robert Hancock <robert.hancock@calian.com>
---

Changes in v3:
- Define each variable on its own line

drivers/usb/dwc3/core.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 699ab9abdc47..38fef5c74359 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -347,14 +347,24 @@ static void dwc3_frame_length_adjustment(struct dwc3 *dwc)
*/
static void dwc3_ref_clk_period(struct dwc3 *dwc)
{
+ unsigned long period;
+ unsigned long rate;
u32 reg;

- 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
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