Re:Re: [PATCH v2] clk: sprd: Hold reference returned by of_get_parent()

["Liang He" <windhl@126.com>]

At 2022-07-01 08:15:23, "Orson Zhai" <orsonzhai@gmail.com> wrote:
>Hi Liang,
>
>On Tue, Jun 28, 2022 at 9:54 PM Liang He <windhl@126.com> wrote:
>>
>> We should hold the reference returned by of_get_parent() and use it
>> to call of_node_out() for refcount balance.
>
>typo. s/out/put
>

Thanks, I will correct it in next version.

>>
>> Fixes: f95e8c7923d1 ("clk: sprd: support to get regmap from parent node")
>>
>> Signed-off-by: Liang He <windhl@126.com>
>> ---
>>  changelog:
>>
>>  v2: minimize the effective range of of_get_parent() advised by Orson
>>  v1: hold reference returned by of_get_parent()
>>
>>  v1-link: https://lore.kernel.org/all/20220624103809.4167753-1-windhl@126.com/
>>
>>  Patched file has been compiled test in 5.19rc2.
>>
>>  drivers/clk/sprd/common.c | 37 +++++++++++++++++++++----------------
>>  1 file changed, 21 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/clk/sprd/common.c b/drivers/clk/sprd/common.c
>> index d620bbbcdfc8..d85ba80c5931 100644
>> --- a/drivers/clk/sprd/common.c
>> +++ b/drivers/clk/sprd/common.c
>> @@ -50,23 +50,28 @@ int sprd_clk_regmap_init(struct platform_device *pdev,
>>                         pr_err("%s: failed to get syscon regmap\n", __func__);
>>                         return PTR_ERR(regmap);
>>                 }
>> -       } else if (of_device_is_compatible(of_get_parent(dev->of_node),
>> -                          "syscon")) {
>> -               regmap = device_node_to_regmap(of_get_parent(dev->of_node));
>> -               if (IS_ERR(regmap)) {
>> -                       dev_err(dev, "failed to get regmap from its parent.\n");
>> -                       return PTR_ERR(regmap);
>> -               }
>>         } else {
>> -               base = devm_platform_ioremap_resource(pdev, 0);
>> -               if (IS_ERR(base))
>> -                       return PTR_ERR(base);
>> -
>> -               regmap = devm_regmap_init_mmio(&pdev->dev, base,
>> -                                              &sprdclk_regmap_config);
>> -               if (IS_ERR(regmap)) {
>> -                       pr_err("failed to init regmap\n");
>> -                       return PTR_ERR(regmap);
>> +               struct device_node *np = of_get_parent(dev->of_node);
>
>move the declaration of "np" to the beginning part without assigning any value.
>

OK.

>> +
>> +               if (of_device_is_compatible(np, "syscon")) {
>
>There may be no need to split the origin structure of "if...else if...else".
>How about the following method?
>
>                    else if (of_device_is_compatible(np =
>of_get_parent(dev->of_node), "syscon")
>                        || (of_node_put(np), 0)) {
>
Thanks, I will try it and compile test it before I send next version.

>> +                       regmap = device_node_to_regmap(np);
>> +                       of_node_put(np);
>> +                       if (IS_ERR(regmap)) {
>> +                               dev_err(dev, "failed to get regmap from its parent.\n");
>> +                               return PTR_ERR(regmap);
>> +                       }
>> +               } else {
>> +                       of_node_put(np);
>
>This line would not be necessary then.
>
>-Orson

Thanks, I will remove this line.

Liang

>
>> +                       base = devm_platform_ioremap_resource(pdev, 0);
>> +                       if (IS_ERR(base))
>> +                               return PTR_ERR(base);
>> +
>> +                       regmap = devm_regmap_init_mmio(&pdev->dev, base,
>> +                                                          &sprdclk_regmap_config);
>> +                       if (IS_ERR(regmap)) {
>> +                               pr_err("failed to init regmap\n");
>> +                               return PTR_ERR(regmap);
>> +                       }
>>                 }
>>         }
>>
>> --
>> 2.25.1
>>