Re: [PATCH 3/4] usb: dwc3: Calculate REFCLKPER based on reference clock

[Sean Anderson <seanga2@gmail.com>]

On 10/30/22 17:09, Marek Vasut wrote:
> From: Sean Anderson <sean.anderson@seco.com>
> 
> 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.
> 
> [ marek: Ported from Linux kernel commit
>           5114c3ee24875 ("usb: dwc3: Calculate REFCLKPER based on reference clock") ]
> 
> Signed-off-by: Sean Anderson <sean.anderson@seco.com>
> Signed-off-by: Marek Vasut <marex@denx.de> # Port from Linux
> ---
> Cc: Angus Ainslie <angus@akkea.ca>
> Cc: Bin Meng <bmeng.cn@gmail.com>
> Cc: Fabio Estevam <festevam@gmail.com>
> Cc: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
> Cc: Michal Simek <michal.simek@xilinx.com>
> Cc: Peng Fan <peng.fan@nxp.com>
> Cc: Sean Anderson <sean.anderson@seco.com>
> Cc: Stefano Babic <sbabic@denx.de>
> ---
>   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 300450100c9..cf66976a088 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -126,14 +126,24 @@ static void dwc3_frame_length_adjustment(struct dwc3 *dwc, u32 fladj)
>    */
>   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);
>   }
>   

Reviewed-by: Sean Anderson <seanga2@gmail.com>