Re: [PATCH v1 3/4] usb: dwc3: exynos: Use devm_regulator_bulk_get_enable() helper function

From: Anand Moon
Date: Fri Apr 05 2024 - 02:14:36 EST

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Hi Christophe, Krzysztof,

On Mon, 4 Mar 2024 at 17:16, Anand Moon <linux.amoon@xxxxxxxxx> wrote:
>
> Hi Christophe,
>
> On Sun, 3 Mar 2024 at 00:07, Christophe JAILLET
> <christophe.jaillet@xxxxxxxxxx> 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@xxxxxxxxxx> 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@xxxxxxxxx>
> > >>> ---
> > >>> 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.
-----8<----------8<----------
diff --git a/drivers/usb/dwc3/dwc3-exynos.c b/drivers/usb/dwc3/dwc3-exynos.c
index 6d07592ad022..2f808cb9a006 100644
--- a/drivers/usb/dwc3/dwc3-exynos.c
+++ b/drivers/usb/dwc3/dwc3-exynos.c
@@ -34,6 +34,8 @@ struct dwc3_exynos {
int suspend_clk_idx;
};

+static const char * const regulators[] = { "vdd33", "vdd10" };
+
static int dwc3_exynos_probe(struct platform_device *pdev)
{
struct dwc3_exynos *exynos;
@@ -41,7 +43,6 @@ 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)
@@ -166,6 +167,8 @@ static int __maybe_unused
dwc3_exynos_suspend(struct device *dev)
struct dwc3_exynos *exynos = dev_get_drvdata(dev);
int i;

+ devm_regulator_bulk_disable(dev);
+
for (i = exynos->num_clks - 1; i >= 0; i--)
clk_disable_unprepare(exynos->clks[i]);

@@ -177,6 +180,11 @@ static int __maybe_unused
dwc3_exynos_resume(struct device *dev)
struct dwc3_exynos *exynos = dev_get_drvdata(dev);
int i, ret;

+ ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(regulators),
+ regulators);
+ if (ret)
+ dev_err(dev, "Failed to enable regulators\n");
+
for (i = 0; i < exynos->num_clks; i++) {
ret = clk_prepare_enable(exynos->clks[i]);
if (ret) {

To support these changes we need to export the
devm_regulator_bulk_disable function.
-----8<----------8<----------
diff --git a/drivers/regulator/devres.c b/drivers/regulator/devres.c
index 90bb0d178885..97eed739f929 100644
--- a/drivers/regulator/devres.c
+++ b/drivers/regulator/devres.c
@@ -318,7 +318,7 @@ void devm_regulator_bulk_put(struct
regulator_bulk_data *consumers)
}
EXPORT_SYMBOL_GPL(devm_regulator_bulk_put);

-static void devm_regulator_bulk_disable(void *res)
+void devm_regulator_bulk_disable(void *res)
{
struct regulator_bulk_devres *devres = res;
int i;
@@ -326,6 +326,7 @@ static void devm_regulator_bulk_disable(void *res)
for (i = 0; i < devres->num_consumers; i++)
regulator_disable(devres->consumers[i].consumer);
}
+EXPORT_SYMBOL_GPL(devm_regulator_bulk_disable);

/**
* devm_regulator_bulk_get_enable - managed get'n enable multiple regulators
diff --git a/include/linux/regulator/consumer.h
b/include/linux/regulator/consumer.h
index 4660582a3302..ce7d28306b17 100644
--- a/include/linux/regulator/consumer.h
+++ b/include/linux/regulator/consumer.h
@@ -214,6 +214,7 @@ int __must_check regulator_bulk_enable(int num_consumers,
struct regulator_bulk_data *consumers);
int devm_regulator_bulk_get_enable(struct device *dev, int num_consumers,
const char * const *id);
+void devm_regulator_bulk_disable(void *res);
int regulator_bulk_disable(int num_consumers,
struct regulator_bulk_data *consumers);
int regulator_bulk_force_disable(int num_consumers,
--------------------------------------------------------------------------

Thanks
-Anand

Next message: Kent Overstreet: "Re: [PATCH v6 00/10] block atomic writes"
Previous message: Honggyu Kim: "[RFC PATCH v3 6/7] mm/damon/paddr: introduce DAMOS_MIGRATE_HOT action for promotion"
Next in thread: Christophe JAILLET: "Re: [PATCH v1 3/4] usb: dwc3: exynos: Use devm_regulator_bulk_get_enable() helper function"
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