linux-kernel - Re: [PATCH v4] phy: samsung: Use readl_poll

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Date:   Thu, 16 Jul 2020 11:26:20 +0530
From:   Anand Moon <linux.amoon@...il.com>
To:     Vinod Koul <vkoul@...nel.org>
Cc:     linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Linux USB Mailing List <linux-usb@...r.kernel.org>,
        linux-samsung-soc@...r.kernel.org,
        Linux Kernel <linux-kernel@...r.kernel.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Kukjin Kim <kgene@...nel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH v4] phy: samsung: Use readl_poll_timeout function

Hi Vinod,

On Thu, 16 Jul 2020 at 11:20, Vinod Koul <vkoul@...nel.org> wrote:
>
> On 13-07-20, 07:42, Anand Moon wrote:
> > Instead of a busy waiting while loop using udelay
> > use readl_poll_timeout function to check the condition
> > is met or timeout occurs in crport_handshake function.
> > readl_poll_timeout is called in non atomic context so
> > it safe to sleep until the condition is met.
> >
> > Fixes: d8c80bb3b55b ("phy: exynos5-usbdrd: Calibrate LOS levels for exynos5420/5800")
> > Signed-off-by: Anand Moon <linux.amoon@...il.com>
> > ---
> > Changes v4:
> > Rebased on to of patch [0] https://patchwork.kernel.org/patch/11651673/
> > --Fix the commit message.
> > --Fix the error timeout condition for -ETIMEDOUT
> > ---
> > Changes v3:
> > --Fix the commit message.
> > --Drop the variable, used the value directly.
> > Changes v2:
> > --used the default timeout values.
> > --Added missing Fixed tags.
> > ---
> >  drivers/phy/samsung/phy-exynos5-usbdrd.c | 39 ++++++++----------------
> >  1 file changed, 12 insertions(+), 27 deletions(-)
> >
> > diff --git a/drivers/phy/samsung/phy-exynos5-usbdrd.c b/drivers/phy/samsung/phy-exynos5-usbdrd.c
> > index 7f6279fb4f8f..ad81aa65cdff 100644
> > --- a/drivers/phy/samsung/phy-exynos5-usbdrd.c
> > +++ b/drivers/phy/samsung/phy-exynos5-usbdrd.c
> > @@ -16,6 +16,7 @@
> >  #include <linux/of.h>
> >  #include <linux/of_address.h>
> >  #include <linux/of_device.h>
> > +#include <linux/iopoll.h>
> >  #include <linux/phy/phy.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/mutex.h>
> > @@ -556,41 +557,25 @@ static int exynos5_usbdrd_phy_power_off(struct phy *phy)
> >  static int crport_handshake(struct exynos5_usbdrd_phy *phy_drd,
> >                           u32 val, u32 cmd)
> >  {
> > -     u32 usec = 100;
> >       unsigned int result;
> > +     int err;
> >
> >       writel(val | cmd, phy_drd->reg_phy + EXYNOS5_DRD_PHYREG0);
> >
> > -     do {
> > -             result = readl(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1);
> > -             if (result & PHYREG1_CR_ACK)
> > -                     break;
> > -
> > -             udelay(1);
> > -     } while (usec-- > 0);
> > -
> > -     if (!usec) {
> > -             dev_err(phy_drd->dev,
> > -                     "CRPORT handshake timeout1 (0x%08x)\n", val);
> > -             return -ETIME;
> > +     err = readl_poll_timeout(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1,
> > +                     result, (result & PHYREG1_CR_ACK), 1, 100);
>
> pls align this line to opening brace of preceding line:
>
>         err = readl_poll_timeout(phy_drd->reg_phy + EXYNOS5_DRD_PHYREG1,
>                                  result, (result & PHYREG1_CR_ACK), 1, 100);
>
> This is recommended way of splitting lines, see
> Documentation/process/coding-style.rst and run checkpatch.pl with
> --strict option

Ok, I will do this, just waiting for some more feedback on these changes.
>
> thanks
> --
> ~Vinod

-Anand