Re: [PATCH 5/5] drivers/video/exynos/exynos_dp_core.c: use devm_ functions

[Jingoo Han <jg1.han@samsung.com>]

On Wednesday, August 01, 2012 1:00 PMSachin Kamat wrote:
> 
> On 1 August 2012 04:51, Jingoo Han <jg1.han@samsung.com> wrote:
> > On Wednesday, August 01, 2012 1:39 AM Damien Cassou wrote:
> >>
> >> From: Damien Cassou <damien.cassou@lifl.fr>
> >>
> >> The various devm_ functions allocate memory that is released when a driver
> >> detaches.  This patch uses these functions for data that is allocated in
> >> the probe function of a platform device and is only freed in the remove
> >> function.
> >>
> >> Signed-off-by: Damien Cassou <damien.cassou@lifl.fr>
> >>
> >> ---
> >>  drivers/video/exynos/exynos_dp_core.c |   27 +++++++--------------------
> >>  1 file changed, 7 insertions(+), 20 deletions(-)
> >>
> >> diff --git a/drivers/video/exynos/exynos_dp_core.c b/drivers/video/exynos/exynos_dp_core.c
> >> index c6c016a..00fe4f0 100644
> >> --- a/drivers/video/exynos/exynos_dp_core.c
> >> +++ b/drivers/video/exynos/exynos_dp_core.c
> >> @@ -872,7 +872,7 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)
> >>
> >>       dp->dev = &pdev->dev;
> >>
> >> -     dp->clock = clk_get(&pdev->dev, "dp");
> >> +     dp->clock = devm_clk_get(&pdev->dev, "dp");
> >>       if (IS_ERR(dp->clock)) {
> >>               dev_err(&pdev->dev, "failed to get clock\n");
> >>               return PTR_ERR(dp->clock);
> >> @@ -881,31 +881,24 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)
> >>       clk_enable(dp->clock);
> >>
> >>       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >> -     if (!res) {
> >> -             dev_err(&pdev->dev, "failed to get registers\n");
> >> -             ret = -EINVAL;
> >> -             goto err_clock;
> >> -     }
> >
> > Why do you remove this return check?
> > If there is no reason, please, do it as follows:
> >
> >         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >         if (!res) {
> >                 dev_err(&pdev->dev, "failed to get registers\n");
> > -               ret = -EINVAL;
> > -               goto err_clock;
> > +               return -EINVAL;
> >         }
> >
> >
> 
> devm_request_and_ioremap function checks the validity of res. Hence
> this check above is redundant and can be removed.


I don't think so.
Even though function called next checks the NULL value,
for robustness, the return value of platform_get_resource() should be
checked.

It is possible that devm_request_and_ioremap() can be changed in the future,
as request_mem_region() & ioremap() were changed to devm_request_and_ioremap().


Best regards,
Jingoo Han


> 
> Damien,
> This patch only adds devm_clk_get() function. Hence you could make the
> subject line more specific.
> 
> 
> 
> 
> > Best regards,
> > Jingoo Han
> >
> >
> >>
> >>       dp->reg_base = devm_request_and_ioremap(&pdev->dev, res);
> >>       if (!dp->reg_base) {
> >>               dev_err(&pdev->dev, "failed to ioremap\n");
> >> -             ret = -ENOMEM;
> >> -             goto err_clock;
> >> +             return -ENOMEM;
> >>       }
> >>
> >>       dp->irq = platform_get_irq(pdev, 0);
> >>       if (!dp->irq) {
> >>               dev_err(&pdev->dev, "failed to get irq\n");
> >> -             ret = -ENODEV;
> >> -             goto err_clock;
> >> +             return -ENODEV;
> >>       }
> >>
> >>       ret = devm_request_irq(&pdev->dev, dp->irq, exynos_dp_irq_handler, 0,
> >>                               "exynos-dp", dp);
> >>       if (ret) {
> >>               dev_err(&pdev->dev, "failed to request irq\n");
> >> -             goto err_clock;
> >> +             return ret;
> >>       }
> >>
> >>       dp->video_info = pdata->video_info;
> >> @@ -917,7 +910,7 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)
> >>       ret = exynos_dp_detect_hpd(dp);
> >>       if (ret) {
> >>               dev_err(&pdev->dev, "unable to detect hpd\n");
> >> -             goto err_clock;
> >> +             return ret;
> >>       }
> >>
> >>       exynos_dp_handle_edid(dp);
> >> @@ -926,7 +919,7 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)
> >>                               dp->video_info->link_rate);
> >>       if (ret) {
> >>               dev_err(&pdev->dev, "unable to do link train\n");
> >> -             goto err_clock;
> >> +             return ret;
> >>       }
> >>
> >>       exynos_dp_enable_scramble(dp, 1);
> >> @@ -940,17 +933,12 @@ static int __devinit exynos_dp_probe(struct platform_device *pdev)
> >>       ret = exynos_dp_config_video(dp, dp->video_info);
> >>       if (ret) {
> >>               dev_err(&pdev->dev, "unable to config video\n");
> >> -             goto err_clock;
> >> +             return ret;
> >>       }
> >>
> >>       platform_set_drvdata(pdev, dp);
> >>
> >>       return 0;
> >> -
> >> -err_clock:
> >> -     clk_put(dp->clock);
> >> -
> >> -     return ret;
> >>  }
> >>
> >>  static int __devexit exynos_dp_remove(struct platform_device *pdev)
> >> @@ -962,7 +950,6 @@ static int __devexit exynos_dp_remove(struct platform_device *pdev)
> >>               pdata->phy_exit();
> >>
> >>       clk_disable(dp->clock);
> >> -     clk_put(dp->clock);
> >>
> >>       return 0;
> >>  }
> >
> > --
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> 
> 
> 
> --
> With warm regards,
> Sachin