Hi Wu Bo,
On Sat, 31 Aug 2024 at 05:36, Wu Bo <wubo.oduw@xxxxxxxxx> wrote:
>
> On 2024/8/27 14:44, Anand Moon wrote:
> > Hi Wu Bo,
> >
> > On Tue, 27 Aug 2024 at 07:55, Wu Bo <bo.wu@xxxxxxxx> 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@xxxxxxxx>
> >> ---
> >> 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？
We probably get -EPROBE_DEFER since the clk is not getting enabled during probe.
and we defer the initialization by returning the error. using
dev_err_probe function.
.
We don't need to recheck for EPROBE_DEFER, again it's handled in
dev_err_probe see below.
[1] https://elixir.bootlin.com/linux/v6.10.7/source/drivers/base/core.c#L5018
Thanks
-Anand
>
> >> - 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
> >>
> >>
