diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index a0ec7824d442..c81bbef9c7fd 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -927,6 +927,44 @@ static void dwc3_set_incr_burst_type(struct dwc3 *dwc) dwc3_writel(dwc->regs, DWC3_GSBUSCFG0, cfg); } +static void dwc3_set_power_down_clk_scale(struct dwc3 *dwc) +{ + struct device *dev = dwc->dev; + struct device_node *node = dev->of_node; + struct clk *suspend_clk; + u32 scale; + u32 reg; + + if (dwc->num_clks == 0) + return; + + /* + * The power down scale field specifies how many suspend_clk + * periods fit into a 16KHz clock period. When performing + * the division, round up the remainder. + * + * The power down scale value is calculated using the fastest + * frequency of the suspend_clk. If it isn't fixed (but within + * the accuracy requirement), the driver may not know the max + * rate of the suspend_clk, so only update the power down scale + * if the default is less than the calculated value from + * clk_get_rate() or if the default is questionably high + * (3x or more) to be within the requirement. + */ + suspend_clk = of_clk_get_by_name(node, "suspend"); + if (IS_ERR(suspend_clk)) + return; + + scale = DIV_ROUND_UP(clk_get_rate(suspend_clk), 16000); + reg = dwc3_readl(dwc->regs, DWC3_GCTL); + if ((reg & DWC3_GCTL_PWRDNSCALE_MASK) < DWC3_GCTL_PWRDNSCALE(scale) || + (reg & DWC3_GCTL_PWRDNSCALE_MASK) > DWC3_GCTL_PWRDNSCALE(scale*3)) { + reg &= ~(DWC3_GCTL_PWRDNSCALE_MASK); + reg |= DWC3_GCTL_PWRDNSCALE(scale); + dwc3_writel(dwc->regs, DWC3_GCTL, reg); + } +} + /** * dwc3_core_init - Low-level initialization of DWC3 Core * @dwc: Pointer to our controller context structure @@ -1003,6 +1041,9 @@ static int dwc3_core_init(struct dwc3 *dwc) if (ret) goto err1; + /* Set power down scale of suspend_clk */ + dwc3_set_power_down_clk_scale(dwc); + /* Adjust Frame Length */ dwc3_frame_length_adjustment(dwc); diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index 241bd842f8ef..32a90b147b8b 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -230,6 +230,7 @@ /* Global Configuration Register */ #define DWC3_GCTL_PWRDNSCALE(n) ((n) << 19) +#define DWC3_GCTL_PWRDNSCALE_MASK DWC3_GCTL_PWRDNSCALE(0x1fff) #define DWC3_GCTL_U2RSTECN BIT(16) #define DWC3_GCTL_RAMCLKSEL(x) (((x) & DWC3_GCTL_CLK_MASK) << 6) #define DWC3_GCTL_CLK_BUS (0)