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

From: Sachin Kamat
Date: Wed Aug 01 2012 - 00:38:23 EST


On 1 August 2012 10:00, Jingoo Han <jg1.han@xxxxxxxxxxx> wrote:
> 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().

They are not changed. They still exist. devm_request_and_ioremap() is
an additional function provided for device managed resources.


>
>
> 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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>> > the body of a message to majordomo@xxxxxxxxxxxxxxx
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>> > Please read the FAQ at http://www.tux.org/lkml/
>>
>>
>>
>> --
>> With warm regards,
>> Sachin
>



--
With warm regards,
Sachin
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