linux-kernel - Re: [PATCH v3] PCI: armada8k: change to use devm_clk_get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ebff7e4c-a561-4c61-a40d-f1905ac3d42a@gmail.com>
Date: Sat, 31 Aug 2024 08:06:26 +0800
From: Wu Bo <wubo.oduw@...il.com>
To: Anand Moon <linux.amoon@...il.com>, Wu Bo <bo.wu@...o.com>
Cc: linux-kernel@...r.kernel.org,
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
 Lorenzo Pieralisi <lpieralisi@...nel.org>,
 Krzysztof Wilczyński <kw@...ux.com>,
 Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
 Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
 linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3] PCI: armada8k: change to use devm_clk_get_enabled()
 helper

On 2024/8/27 14:44, Anand Moon wrote:
> Hi Wu Bo,
>
> On Tue, 27 Aug 2024 at 07:55, Wu Bo <bo.wu@...o.com> wrote:
>> Use devm_clk_get_enabled() instead of devm_clk_get() to make the code
>> cleaner and avoid calling clk_disable_unprepare()
>>
>> Signed-off-by: Wu Bo <bo.wu@...o.com>
>> ---
>>   drivers/pci/controller/dwc/pcie-armada8k.c | 36 ++++++++--------------
>>   1 file changed, 13 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-armada8k.c b/drivers/pci/controller/dwc/pcie-armada8k.c
>> index b5c599ccaacf..e7ef6c2641b8 100644
>> --- a/drivers/pci/controller/dwc/pcie-armada8k.c
>> +++ b/drivers/pci/controller/dwc/pcie-armada8k.c
>> @@ -284,23 +284,17 @@ static int armada8k_pcie_probe(struct platform_device *pdev)
>>
>>          pcie->pci = pci;
>>
>> -       pcie->clk = devm_clk_get(dev, NULL);
>> +       pcie->clk = devm_clk_get_enabled(dev, NULL);
>>          if (IS_ERR(pcie->clk))
>> -               return PTR_ERR(pcie->clk);
>> -
>> -       ret = clk_prepare_enable(pcie->clk);
>> -       if (ret)
>> -               return ret;
>> -
>> -       pcie->clk_reg = devm_clk_get(dev, "reg");
>> -       if (pcie->clk_reg == ERR_PTR(-EPROBE_DEFER)) {
>> -               ret = -EPROBE_DEFER;
>> -               goto fail;
>> -       }

I don't know much about this device. But from the code here, its 
previous logic is that the function will only return when the error code 
is EPROBE_DEFER, and other errors will continue to execute.

So I followed the previous logic, is it correct？

>> -       if (!IS_ERR(pcie->clk_reg)) {
>> -               ret = clk_prepare_enable(pcie->clk_reg);
>> -               if (ret)
>> -                       goto fail_clkreg;
>> +               return dev_err_probe(dev, PTR_ERR(pcie->clk),
>> +                               "could not enable clk\n");
>> +
>> +       pcie->clk_reg = devm_clk_get_enabled(dev, "reg");
>> +       if (IS_ERR(pcie->clk_reg)) {
>> +               ret = dev_err_probe(dev, PTR_ERR(pcie->clk_reg),
>> +                               "could not enable reg clk\n");
>> +               if (ret == -EPROBE_DEFER)
>> +                       goto out;
> You can drop this check as dev_err_probe handle this inside
> It will defer the enabling of clock.
>>          }
>>
>>          /* Get the dw-pcie unit configuration/control registers base. */
>> @@ -308,12 +302,12 @@ static int armada8k_pcie_probe(struct platform_device *pdev)
>>          pci->dbi_base = devm_pci_remap_cfg_resource(dev, base);
>>          if (IS_ERR(pci->dbi_base)) {
>>                  ret = PTR_ERR(pci->dbi_base);
>> -               goto fail_clkreg;
>> +               goto out;
>>          }
>>
>>          ret = armada8k_pcie_setup_phys(pcie);
>>          if (ret)
>> -               goto fail_clkreg;
>> +               goto out;
>>
>>          platform_set_drvdata(pdev, pcie);
>>
>> @@ -325,11 +319,7 @@ static int armada8k_pcie_probe(struct platform_device *pdev)
>>
>>   disable_phy:
>>          armada8k_pcie_disable_phys(pcie);
>> -fail_clkreg:
>> -       clk_disable_unprepare(pcie->clk_reg);
>> -fail:
>> -       clk_disable_unprepare(pcie->clk);
>> -
>> +out:
>>          return ret;
>>   }
>>
> Thanks
> -Anand
>> --
>> 2.25.1
>>
>>