Messages in this thread | | | Date | Mon, 8 Apr 2024 22:26:16 +0200 | From | Christophe JAILLET <> | Subject | Re: [PATCH v1 3/4] usb: dwc3: exynos: Use devm_regulator_bulk_get_enable() helper function |
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Le 08/04/2024 à 12:02, Anand Moon a écrit : > Hi Christophe, > > On Fri, 5 Apr 2024 at 21:42, Christophe JAILLET > <christophe.jaillet@wanadoo.fr> wrote: >> >> Le 05/04/2024 à 08:10, Anand Moon a écrit : >>> Hi Christophe, Krzysztof, >>> >>> On Mon, 4 Mar 2024 at 17:16, Anand Moon <linux.amoon@gmail.com> wrote: >>>> >>>> Hi Christophe, >>>> >>>> On Sun, 3 Mar 2024 at 00:07, Christophe JAILLET >>>> <christophe.jaillet@wanadoo.fr> wrote: >>>>> >>>>> Le 02/03/2024 à 17:48, Anand Moon a écrit : >>>>>> Hi Christophe, >>>>>> >>>>>> On Sat, 2 Mar 2024 at 21:20, Christophe JAILLET >>>>>> <christophe.jaillet@wanadoo.fr> wrote: >>>>>>> >>>>>>> Le 01/03/2024 à 20:38, Anand Moon a écrit : >>>>>>>> Use devm_regulator_bulk_get_enable() instead of open coded >>>>>>>> 'devm_regulator_get(), regulator_enable(), regulator_disable(). >>>>>>>> >>>>>>>> Signed-off-by: Anand Moon <linux.amoon@gmail.com> >>>>>>>> --- >>>>>>>> drivers/usb/dwc3/dwc3-exynos.c | 49 +++------------------------------- >>>>>>>> 1 file changed, 4 insertions(+), 45 deletions(-) >>>>>>>> >>>>>>>> diff --git a/drivers/usb/dwc3/dwc3-exynos.c b/drivers/usb/dwc3/dwc3-exynos.c >>>>>>>> index 5d365ca51771..7c77f3c69825 100644 >>>>>>>> --- a/drivers/usb/dwc3/dwc3-exynos.c >>>>>>>> +++ b/drivers/usb/dwc3/dwc3-exynos.c >>>>>>>> @@ -32,9 +32,6 @@ struct dwc3_exynos { >>>>>>>> struct clk *clks[DWC3_EXYNOS_MAX_CLOCKS]; >>>>>>>> int num_clks; >>>>>>>> int suspend_clk_idx; >>>>>>>> - >>>>>>>> - struct regulator *vdd33; >>>>>>>> - struct regulator *vdd10; >>>>>>>> }; >>>>>>>> >>>>>>>> static int dwc3_exynos_probe(struct platform_device *pdev) >>>>>>>> @@ -44,6 +41,7 @@ static int dwc3_exynos_probe(struct platform_device *pdev) >>>>>>>> struct device_node *node = dev->of_node; >>>>>>>> const struct dwc3_exynos_driverdata *driver_data; >>>>>>>> int i, ret; >>>>>>>> + static const char * const regulators[] = { "vdd33", "vdd10" }; >>>>>>>> >>>>>>>> exynos = devm_kzalloc(dev, sizeof(*exynos), GFP_KERNEL); >>>>>>>> if (!exynos) >>>>>>>> @@ -78,27 +76,9 @@ static int dwc3_exynos_probe(struct platform_device *pdev) >>>>>>>> if (exynos->suspend_clk_idx >= 0) >>>>>>>> clk_prepare_enable(exynos->clks[exynos->suspend_clk_idx]); >>>>>>>> >>>>>>>> - exynos->vdd33 = devm_regulator_get(dev, "vdd33"); >>>>>>>> - if (IS_ERR(exynos->vdd33)) { >>>>>>>> - ret = PTR_ERR(exynos->vdd33); >>>>>>>> - goto vdd33_err; >>>>>>>> - } >>>>>>>> - ret = regulator_enable(exynos->vdd33); >>>>>>>> - if (ret) { >>>>>>>> - dev_err(dev, "Failed to enable VDD33 supply\n"); >>>>>>>> - goto vdd33_err; >>>>>>>> - } >>>>>>>> - >>>>>>>> - exynos->vdd10 = devm_regulator_get(dev, "vdd10"); >>>>>>>> - if (IS_ERR(exynos->vdd10)) { >>>>>>>> - ret = PTR_ERR(exynos->vdd10); >>>>>>>> - goto vdd10_err; >>>>>>>> - } >>>>>>>> - ret = regulator_enable(exynos->vdd10); >>>>>>>> - if (ret) { >>>>>>>> - dev_err(dev, "Failed to enable VDD10 supply\n"); >>>>>>>> - goto vdd10_err; >>>>>>>> - } >>>>>>>> + ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(regulators), regulators); >>>>>>>> + if (ret) >>>>>>>> + return dev_err_probe(dev, ret, "Failed to enable regulators\n"); >>>>>>>> >>>>>>>> if (node) { >>>>>>>> ret = of_platform_populate(node, NULL, NULL, dev); >>>>>>>> @@ -115,10 +95,6 @@ static int dwc3_exynos_probe(struct platform_device *pdev) >>>>>>>> return 0; >>>>>>>> >>>>>>>> populate_err: >>>>>>>> - regulator_disable(exynos->vdd10); >>>>>>>> -vdd10_err: >>>>>>>> - regulator_disable(exynos->vdd33); >>>>>>>> -vdd33_err: >>>>>>>> for (i = exynos->num_clks - 1; i >= 0; i--) >>>>>>>> clk_disable_unprepare(exynos->clks[i]); >>>>>>>> >>>>>>>> @@ -140,9 +116,6 @@ static void dwc3_exynos_remove(struct platform_device *pdev) >>>>>>>> >>>>>>>> if (exynos->suspend_clk_idx >= 0) >>>>>>>> clk_disable_unprepare(exynos->clks[exynos->suspend_clk_idx]); >>>>>>>> - >>>>>>>> - regulator_disable(exynos->vdd33); >>>>>>>> - regulator_disable(exynos->vdd10); >>>>>>>> } >>>>>>>> >>>>>>>> static const struct dwc3_exynos_driverdata exynos5250_drvdata = { >>>>>>>> @@ -196,9 +169,6 @@ static int dwc3_exynos_suspend(struct device *dev) >>>>>>>> for (i = exynos->num_clks - 1; i >= 0; i--) >>>>>>>> clk_disable_unprepare(exynos->clks[i]); >>>>>>>> >>>>>>>> - regulator_disable(exynos->vdd33); >>>>>>>> - regulator_disable(exynos->vdd10); >>>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> Same here, I don't think that removing regulator_[en|dis]able from the >>>>>>> suspend and resume function is correct. >>>>>>> >>>>>>> The goal is to stop some hardware when the system is suspended, in order >>>>>>> to save some power. >>>>>> Ok, >>>>>>> >>>>>>> Why did you removed it? >>>>>> >>>>>> As per the description of the function devm_regulator_bulk_get_enable >>>>>> >>>>>> * This helper function allows drivers to get several regulator >>>>>> * consumers in one operation with management, the regulators will >>>>>> * automatically be freed when the device is unbound. If any of the >>>>>> * regulators cannot be acquired then any regulators that were >>>>>> * allocated will be freed before returning to the caller. >>>>> >>>>> The code in suspend/resume is not about freeing some resources. It is >>>>> about enabling/disabling some hardware to save some power. >>>>> >>>>> Think to the probe/remove functions as the software in the kernel that >>>>> knows how to handle some hardawre, and the suspend/resume as the on/off >>>>> button to power-on and off the electrical chips. >>>>> >>>>> When the system is suspended, the software is still around. But some >>>>> hardware can be set in a low consumption mode to save some power. >>>>> >>>>> IMHO, part of the code you removed changed this behaviour and increase >>>>> the power consumption when the system is suspended. >>>>> >>>> >>>> You are correct, I have changed the regulator API from >>>> devm_regulator_get_enable to devm_regulator_bulk_get_enable >>>> which changes this behavior. >>>> I will fix it in the next version. >>>> >>>>> CJ >>> >>> I could not find any example in the kernel to support >>> devm_regulator_bulk_disable >>> but here is my modified file. >>> >>> If you have any suggestions for this plz let me know. >> >> I don't think that your approach is correct, and I don't think that the >> proposed patch does what you expect it to do. >> >> Calling a devm_ function in suspend/resume functions looks really >> strange to me and is likely broken. >> >> Especially here, devm_regulator_bulk_get_enable() in the resume function >> allocates some memory that is not freed in >> devm_regulator_bulk_disable(), because the API is not designed to work >> like that. So this could generate a kind of memory leak. >> >> >> *I think that the code is good enough as-is*, but if you really want to >> change something, maybe: >> - devm_regulator_get()+regulator_enable() in the probe could be >> changed to devm_regulator_get_enable() >> - the resume/suspend function should be left as-is with >> regulator_disable()/regulator_ensable() >> - remove regulator_disable() from the error handling path of the >> probe and from the remove function. >> >> I *think* it would work. >> > No devm_regulator_get_enable use the same logic as > devm_regulator_bulk_get_enable > to enable the regulator.
Yes, the logic is the same, but you get a pointer to the "struct regulator" which can be used to disable/enable in the suspend/resume functions.
With the bulk version, you can not do that.
See my first reply on your 3/4 patch.
> > [0] https://elixir.bootlin.com/linux/latest/source/drivers/regulator/devres.c#L126 > > So as of now I am dropping the changes on the regulator in this patch series.
I do agree that it is certainly the way to go here.
CJ
> >> CJ >> > Thanks for your inputs. > > Thanks > > -Anand > >
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