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

From: Jingoo Han
Date: Wed Aug 01 2012 - 00:30:51 EST


On Wednesday, August 01, 2012 1:00 PMSachin Kamat wrote:
>
> On 1 August 2012 04:51, Jingoo Han <jg1.han@xxxxxxxxxxx> wrote:
> > On Wednesday, August 01, 2012 1:39 AM Damien Cassou wrote:
> >>
> >> From: Damien Cassou <damien.cassou@xxxxxxx>
> >>
> >> 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@xxxxxxx>
> >>
> >> ---
> >> 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

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