linux-kernel - Re: [PATCH] usb: gadget: bdc: use readl_poll

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Date:   Fri, 10 Jul 2020 16:37:02 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Felipe Balbi <balbi@...nel.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, YueHaibing <yuehaibing@...wei.com>,
        linux-kernel@...r.kernel.org,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        linux-mediatek@...ts.infradead.org,
        Matthias Brugger <matthias.bgg@...il.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] usb: gadget: bdc: use readl_poll_timeout() to simplify code

Quoting Chunfeng Yun (2020-07-09 20:30:56)
> diff --git a/drivers/usb/gadget/udc/bdc/bdc_core.c b/drivers/usb/gadget/udc/bdc/bdc_core.c
> index 02a3a77..fa173de 100644
> --- a/drivers/usb/gadget/udc/bdc/bdc_core.c
> +++ b/drivers/usb/gadget/udc/bdc/bdc_core.c
> @@ -32,21 +33,14 @@
>  static int poll_oip(struct bdc *bdc, int usec)

Can we change usec to unsigned? Not sure why negative time is important.

>  {
>         u32 status;
> -       /* Poll till STS!= OIP */
> -       while (usec) {
> -               status = bdc_readl(bdc->regs, BDC_BDCSC);
> -               if (BDC_CSTS(status) != BDC_OIP) {
> -                       dev_dbg(bdc->dev,
> -                               "poll_oip complete status=%d",
> -                               BDC_CSTS(status));

This debug message was lost in the conversion. Any reason?

> -                       return 0;
> -               }
> -               udelay(10);
> -               usec -= 10;
> -       }
> -       dev_err(bdc->dev, "Err: operation timedout BDCSC: 0x%08x\n", status);
> +       int ret;
>  
> -       return -ETIMEDOUT;
> +       ret = readl_poll_timeout(bdc->regs + BDC_BDCSC, status,
> +               (BDC_CSTS(status) != BDC_OIP), 10, usec);
> +       if (ret)
> +               dev_err(bdc->dev, "Err: operation timedout BDCSC: 0x%08x\n", status);

Please drop "Err:" as we have kernel log levels (i.e. dev_err() used
here) for that.

> +
> +       return ret;
>  }