LinuxLists.cc - [PATCH v14 10/17] PCI: imx6: Turn off regulator when system is in suspend mode

2022-07-01 03:43:25

Subject: [PATCH v14 10/17] PCI: imx6: Turn off regulator when system is in suspend mode

The driver should undo any enables it did itself. The regulator disable
shouldn't be basing decisions on regulator_is_enabled().

Move the regulator_disable to the suspend function, turn off regulator when
the system is in suspend mode.

To keep the balance of the regulator usage counter, disable the regulator
in shutdown.

Link: https://lore.kernel.org/r/1655189942-12678-6-git-send-email-hongxing.z
[email protected]
Signed-off-by: Richard Zhu <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
---
drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 2b42c37f1617..f72eb609769b 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)

static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
{
- struct device *dev = imx6_pcie->pci->dev;
-
switch (imx6_pcie->drvdata->variant) {
case IMX7D:
case IMX8MQ:
@@ -702,14 +700,6 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
break;
}

- if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
- int ret = regulator_disable(imx6_pcie->vpcie);
-
- if (ret)
- dev_err(dev, "failed to disable vpcie regulator: %d\n",
- ret);
- }
-
/* Some boards don't have PCIe reset GPIO. */
if (gpio_is_valid(imx6_pcie->reset_gpio))
gpio_set_value_cansleep(imx6_pcie->reset_gpio,
@@ -722,7 +712,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
struct device *dev = pci->dev;
int ret;

- if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
+ if (imx6_pcie->vpcie) {
ret = regulator_enable(imx6_pcie->vpcie);
if (ret) {
dev_err(dev, "failed to enable vpcie regulator: %d\n",
@@ -795,7 +785,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
return 0;

err_clks:
- if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
+ if (imx6_pcie->vpcie) {
ret = regulator_disable(imx6_pcie->vpcie);
if (ret)
dev_err(dev, "failed to disable vpcie regulator: %d\n",
@@ -1022,6 +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
break;
}

+ if (imx6_pcie->vpcie)
+ regulator_disable(imx6_pcie->vpcie);
+
return 0;
}

@@ -1268,6 +1261,8 @@ static void imx6_pcie_shutdown(struct platform_device *pdev)

/* bring down link, so bootloader gets clean state in case of reboot */
imx6_pcie_assert_core_reset(imx6_pcie);
+ if (imx6_pcie->vpcie)
+ regulator_disable(imx6_pcie->vpcie);
}

static const struct imx6_pcie_drvdata drvdata[] = {
--
2.25.1

2022-07-13 08:52:37

by Lucas Stach

[permalink] [raw]

Subject: Re: [PATCH v14 10/17] PCI: imx6: Turn off regulator when system is in suspend mode

Am Freitag, dem 01.07.2022 um 11:25 +0800 schrieb Richard Zhu:
> The driver should undo any enables it did itself. The regulator disable
> shouldn't be basing decisions on regulator_is_enabled().
>
> Move the regulator_disable to the suspend function, turn off regulator when
> the system is in suspend mode.
>
> To keep the balance of the regulator usage counter, disable the regulator
> in shutdown.
>
> Link: https://lore.kernel.org/r/1655189942-12678-6-git-send-email-hongxing.z
> [email protected]
> Signed-off-by: Richard Zhu <[email protected]>
> Signed-off-by: Bjorn Helgaas <[email protected]>
> ---
> drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
> 1 file changed, 7 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 2b42c37f1617..f72eb609769b 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
>
> static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
> {
> - struct device *dev = imx6_pcie->pci->dev;
> -
> switch (imx6_pcie->drvdata->variant) {
> case IMX7D:
> case IMX8MQ:
> @@ -702,14 +700,6 @@ static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
> break;
> }
>
> - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> - int ret = regulator_disable(imx6_pcie->vpcie);
> -
> - if (ret)
> - dev_err(dev, "failed to disable vpcie regulator: %d\n",
> - ret);
> - }
> -
> /* Some boards don't have PCIe reset GPIO. */
> if (gpio_is_valid(imx6_pcie->reset_gpio))
> gpio_set_value_cansleep(imx6_pcie->reset_gpio,
> @@ -722,7 +712,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> struct device *dev = pci->dev;
> int ret;
>
> - if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
> + if (imx6_pcie->vpcie) {
> ret = regulator_enable(imx6_pcie->vpcie);
> if (ret) {
> dev_err(dev, "failed to enable vpcie regulator: %d\n",

The regulator really has nothing to do with the core reset. Please move
this regulator enable into imx6_pcie_host_init().

> @@ -795,7 +785,7 @@ static int imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> return 0;
>
> err_clks:
> - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> + if (imx6_pcie->vpcie) {
> ret = regulator_disable(imx6_pcie->vpcie);
> if (ret)
> dev_err(dev, "failed to disable vpcie regulator: %d\n",
> @@ -1022,6 +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> break;
> }
>
> + if (imx6_pcie->vpcie)
> + regulator_disable(imx6_pcie->vpcie);
> +
> return 0;
> }
>
> @@ -1268,6 +1261,8 @@ static void imx6_pcie_shutdown(struct platform_device *pdev)
>
> /* bring down link, so bootloader gets clean state in case of reboot */
> imx6_pcie_assert_core_reset(imx6_pcie);
> + if (imx6_pcie->vpcie)
> + regulator_disable(imx6_pcie->vpcie);

This looks like a separate change, not mentioned in the commit message.
I'm not sure if we should do this. Shutdown is supposed to just stop
the device, which is already achieved by
imx6_pcie_assert_core_reset().

If we would want to do a full cleanup here we would also need to
disable clocks and get the reset GPIO into asserted state. I don't
think we want to do all of this here.

Regards,
Lucas
> }
>
> static const struct imx6_pcie_drvdata drvdata[] = {

2022-07-13 11:27:46

by Richard Zhu

[permalink] [raw]

Subject: RE: [PATCH v14 10/17] PCI: imx6: Turn off regulator when system is in suspend mode

> -----Original Message-----
> From: Lucas Stach <[email protected]>
> Sent: 2022??7??13?? 16:34
> To: Hongxing Zhu <[email protected]>; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]; dl-linux-imx
> <[email protected]>
> Subject: Re: [PATCH v14 10/17] PCI: imx6: Turn off regulator when system is in
> suspend mode
>
> Am Freitag, dem 01.07.2022 um 11:25 +0800 schrieb Richard Zhu:
> > The driver should undo any enables it did itself. The regulator
> > disable shouldn't be basing decisions on regulator_is_enabled().
> >
> > Move the regulator_disable to the suspend function, turn off regulator
> > when the system is in suspend mode.
> >
> > To keep the balance of the regulator usage counter, disable the
> > regulator in shutdown.
> >
> > Link:
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore
> > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email-hongxing.z&d
> at
> >
> a=05%7C01%7Chongxing.zhu%40nxp.com%7C361c9bf365b64895482808da6
> 4aa7cca%
> >
> 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379329806385373
> 39%7CUnkn
> >
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> haWwi
> >
> LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=A%2Fw6AFCddC0T%2FA
> ocBT%2F7OJZ
> > ddAeYPTbgeAxpHpPubkw%3D&reserved=0
> > [email protected]
> > Signed-off-by: Richard Zhu <[email protected]>
> > Signed-off-by: Bjorn Helgaas <[email protected]>
> > ---
> > drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
> > 1 file changed, 7 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 2b42c37f1617..f72eb609769b 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct imx6_pcie
> > *imx6_pcie)
> >
> > static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
> > {
> > - struct device *dev = imx6_pcie->pci->dev;
> > -
> > switch (imx6_pcie->drvdata->variant) {
> > case IMX7D:
> > case IMX8MQ:
> > @@ -702,14 +700,6 @@ static void imx6_pcie_assert_core_reset(struct
> imx6_pcie *imx6_pcie)
> > break;
> > }
> >
> > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> > - int ret = regulator_disable(imx6_pcie->vpcie);
> > -
> > - if (ret)
> > - dev_err(dev, "failed to disable vpcie regulator: %d\n",
> > - ret);
> > - }
> > -
> > /* Some boards don't have PCIe reset GPIO. */
> > if (gpio_is_valid(imx6_pcie->reset_gpio))
> > gpio_set_value_cansleep(imx6_pcie->reset_gpio,
> > @@ -722,7 +712,7 @@ static int imx6_pcie_deassert_core_reset(struct
> imx6_pcie *imx6_pcie)
> > struct device *dev = pci->dev;
> > int ret;
> >
> > - if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie->vpcie)) {
> > + if (imx6_pcie->vpcie) {
> > ret = regulator_enable(imx6_pcie->vpcie);
> > if (ret) {
> > dev_err(dev, "failed to enable vpcie regulator: %d\n",
>
> The regulator really has nothing to do with the core reset. Please move this
> regulator enable into imx6_pcie_host_init().
Hi Lucas:
Thanks for your comments.
Got that. Had done it in the 11/17 commit.

>
> > @@ -795,7 +785,7 @@ static int imx6_pcie_deassert_core_reset(struct
> imx6_pcie *imx6_pcie)
> > return 0;
> >
> > err_clks:
> > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie->vpcie) > 0) {
> > + if (imx6_pcie->vpcie) {
> > ret = regulator_disable(imx6_pcie->vpcie);
> > if (ret)
> > dev_err(dev, "failed to disable vpcie regulator: %d\n", @@
> -1022,6
> > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> > break;
> > }
> >
> > + if (imx6_pcie->vpcie)
> > + regulator_disable(imx6_pcie->vpcie);
> > +
> > return 0;
> > }
> >
> > @@ -1268,6 +1261,8 @@ static void imx6_pcie_shutdown(struct
> > platform_device *pdev)
> >
> > /* bring down link, so bootloader gets clean state in case of reboot */
> > imx6_pcie_assert_core_reset(imx6_pcie);
> > + if (imx6_pcie->vpcie)
> > + regulator_disable(imx6_pcie->vpcie);
>
> This looks like a separate change, not mentioned in the commit message.
> I'm not sure if we should do this. Shutdown is supposed to just stop the device,
> which is already achieved by imx6_pcie_assert_core_reset().
>
> If we would want to do a full cleanup here we would also need to disable
> clocks and get the reset GPIO into asserted state. I don't think we want to do
> all of this here.
The regulator_disable() was contained in imx6_pcie_assert_core_reset() before.
When refine the regulator usage, the regulator_disable() is moved out of
imx6_pcie_assert_core_reset().
Based on the discussion [1] with Francesco.
To keep the same behavior, the regulator_disable() is placed behind of
imx6_pcie_assert_core_reset() in imx6_pcie_shutdown() here.
[1]https://patchwork.ozlabs.org/project/linux-pci/patch/[email protected]/

Best Regards
Richard

>
> Regards,
> Lucas
> > }
> >
> > static const struct imx6_pcie_drvdata drvdata[] = {
>

2022-07-13 11:32:31

by Lucas Stach

[permalink] [raw]

Subject: Re: [PATCH v14 10/17] PCI: imx6: Turn off regulator when system is in suspend mode

Am Mittwoch, dem 13.07.2022 um 10:56 +0000 schrieb Hongxing Zhu:
> > -----Original Message-----
> > From: Lucas Stach <[email protected]>
> > Sent: 2022年7月13日 16:34
> > To: Hongxing Zhu <[email protected]>; [email protected];
> > [email protected]; [email protected]; [email protected];
> > [email protected]; [email protected]
> > Cc: [email protected];
> > [email protected];
> > [email protected]; [email protected]; dl-linux-imx
> > <[email protected]>
> > Subject: Re: [PATCH v14 10/17] PCI: imx6: Turn off regulator when
> > system is in
> > suspend mode
> >
> > Am Freitag, dem 01.07.2022 um 11:25 +0800 schrieb Richard Zhu:
> > > The driver should undo any enables it did itself. The regulator
> > > disable shouldn't be basing decisions on regulator_is_enabled().
> > >
> > > Move the regulator_disable to the suspend function, turn off
> > > regulator
> > > when the system is in suspend mode.
> > >
> > > To keep the balance of the regulator usage counter, disable the
> > > regulator in shutdown.
> > >
> > > Link:
> > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore
> > > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email-
> > > hongxing.z&d
> > at
> > >
> > a=05%7C01%7Chongxing.zhu%40nxp.com%7C361c9bf365b64895482808da6
> > 4aa7cca%
> > >
> > 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379329806385373
> > 39%7CUnkn
> > >
> > own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> > haWwi
> > >
> > LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=A%2Fw6AFCddC0T%2FA
> > ocBT%2F7OJZ
> > > ddAeYPTbgeAxpHpPubkw%3D&reserved=0
> > > [email protected]
> > > Signed-off-by: Richard Zhu <[email protected]>
> > > Signed-off-by: Bjorn Helgaas <[email protected]>
> > > ---
> > > drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
> > > 1 file changed, 7 insertions(+), 12 deletions(-)
> > >
> > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > index 2b42c37f1617..f72eb609769b 100644
> > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct
> > > imx6_pcie
> > > *imx6_pcie)
> > >
> > > static void imx6_pcie_assert_core_reset(struct imx6_pcie
> > > *imx6_pcie)
> > > {
> > > - struct device *dev = imx6_pcie->pci->dev;
> > > -
> > > switch (imx6_pcie->drvdata->variant) {
> > > case IMX7D:
> > > case IMX8MQ:
> > > @@ -702,14 +700,6 @@ static void
> > > imx6_pcie_assert_core_reset(struct
> > imx6_pcie *imx6_pcie)
> > > break;
> > > }
> > >
> > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie-
> > > >vpcie) > 0) {
> > > - int ret = regulator_disable(imx6_pcie->vpcie);
> > > -
> > > - if (ret)
> > > - dev_err(dev, "failed to disable vpcie
> > > regulator: %d\n",
> > > - ret);
> > > - }
> > > -
> > > /* Some boards don't have PCIe reset GPIO. */
> > > if (gpio_is_valid(imx6_pcie->reset_gpio))
> > > gpio_set_value_cansleep(imx6_pcie->reset_gpio,
> > > @@ -722,7 +712,7 @@ static int
> > > imx6_pcie_deassert_core_reset(struct
> > imx6_pcie *imx6_pcie)
> > > struct device *dev = pci->dev;
> > > int ret;
> > >
> > > - if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie-
> > > >vpcie)) {
> > > + if (imx6_pcie->vpcie) {
> > > ret = regulator_enable(imx6_pcie->vpcie);
> > > if (ret) {
> > > dev_err(dev, "failed to enable vpcie
> > > regulator: %d\n",
> >
> > The regulator really has nothing to do with the core reset. Please
> > move this
> > regulator enable into imx6_pcie_host_init().
> Hi Lucas:
> Thanks for your comments.
> Got that. Had done it in the 11/17 commit.
>
> >
> > > @@ -795,7 +785,7 @@ static int
> > > imx6_pcie_deassert_core_reset(struct
> > imx6_pcie *imx6_pcie)
> > > return 0;
> > >
> > > err_clks:
> > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie-
> > > >vpcie) > 0) {
> > > + if (imx6_pcie->vpcie) {
> > > ret = regulator_disable(imx6_pcie->vpcie);
> > > if (ret)
> > > dev_err(dev, "failed to disable vpcie
> > > regulator: %d\n", @@
> > -1022,6
> > > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> > > break;
> > > }
> > >
> > > + if (imx6_pcie->vpcie)
> > > + regulator_disable(imx6_pcie->vpcie);
> > > +
> > > return 0;
> > > }
> > >
> > > @@ -1268,6 +1261,8 @@ static void imx6_pcie_shutdown(struct
> > > platform_device *pdev)
> > >
> > > /* bring down link, so bootloader gets clean state in
> > > case of reboot */
> > > imx6_pcie_assert_core_reset(imx6_pcie);
> > > + if (imx6_pcie->vpcie)
> > > + regulator_disable(imx6_pcie->vpcie);
> >
> > This looks like a separate change, not mentioned in the commit
> > message.
> > I'm not sure if we should do this. Shutdown is supposed to just
> > stop the device,
> > which is already achieved by imx6_pcie_assert_core_reset().
> >
> > If we would want to do a full cleanup here we would also need to
> > disable
> > clocks and get the reset GPIO into asserted state. I don't think we
> > want to do
> > all of this here.
> The regulator_disable() was contained in
> imx6_pcie_assert_core_reset() before.
> When refine the regulator usage, the regulator_disable() is moved out
> of
> imx6_pcie_assert_core_reset().
> Based on the discussion [1] with Francesco.
> To keep the same behavior, the regulator_disable() is placed behind
> of
> imx6_pcie_assert_core_reset() in imx6_pcie_shutdown() here.
> [1]
> https://patchwork.ozlabs.org/project/linux-pci/patch/[email protected]/

I disagree with Francesco on this. This kind of half-done cleanup
doesn't help in any way. Either we care about doing a full cleanup
here, which would involve clocks and reset GPIOs, or we just care about
getting the core in a state where it survives a reboot, which frankly
was the original intention when I added the shutdown callback.

As the devices on the bus will see a full PERST reset via the reset
GPIO anyways, there is no harm in keeping them powered across the
reboot.

Regards,
Lucas

2022-07-13 13:18:14

by Richard Zhu

[permalink] [raw]

Subject: RE: [PATCH v14 10/17] PCI: imx6: Turn off regulator when system is in suspend mode

> -----Original Message-----
> From: Lucas Stach <[email protected]>
> Sent: 2022年7月13日 19:23
> To: Hongxing Zhu <[email protected]>; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]; dl-linux-imx
> <[email protected]>
> Subject: Re: [PATCH v14 10/17] PCI: imx6: Turn off regulator when system is in
> suspend mode
>
> Am Mittwoch, dem 13.07.2022 um 10:56 +0000 schrieb Hongxing Zhu:
> > > -----Original Message-----
> > > From: Lucas Stach <[email protected]>
> > > Sent: 2022年7月13日 16:34
> > > To: Hongxing Zhu <[email protected]>; [email protected];
> > > [email protected]; [email protected]; [email protected];
> > > [email protected]; [email protected]
> > > Cc: [email protected];
> > > [email protected];
> > > [email protected]; [email protected]; dl-linux-imx
> > > <[email protected]>
> > > Subject: Re: [PATCH v14 10/17] PCI: imx6: Turn off regulator when
> > > system is in suspend mode
> > >
> > > Am Freitag, dem 01.07.2022 um 11:25 +0800 schrieb Richard Zhu:
> > > > The driver should undo any enables it did itself. The regulator
> > > > disable shouldn't be basing decisions on regulator_is_enabled().
> > > >
> > > > Move the regulator_disable to the suspend function, turn off
> > > > regulator when the system is in suspend mode.
> > > >
> > > > To keep the balance of the regulator usage counter, disable the
> > > > regulator in shutdown.
> > > >
> > > > Link:
> > > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2F
> > > > lore
> > > > .kernel.org%2Fr%2F1655189942-12678-6-git-send-email-
> > > > hongxing.z&d
> > > at
> > > >
> > >
> a=05%7C01%7Chongxing.zhu%40nxp.com%7C361c9bf365b64895482808da6
> > > 4aa7cca%
> > > >
> > >
> 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379329806385373
> > > 39%7CUnkn
> > > >
> > >
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> > > haWwi
> > > >
> > >
> LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=A%2Fw6AFCddC0T%2FA
> > > ocBT%2F7OJZ
> > > > ddAeYPTbgeAxpHpPubkw%3D&reserved=0
> > > > [email protected]
> > > > Signed-off-by: Richard Zhu <[email protected]>
> > > > Signed-off-by: Bjorn Helgaas <[email protected]>
> > > > ---
> > > > drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
> > > > 1 file changed, 7 insertions(+), 12 deletions(-)
> > > >
> > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > > index 2b42c37f1617..f72eb609769b 100644
> > > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > > @@ -670,8 +670,6 @@ static void imx6_pcie_clk_disable(struct
> > > > imx6_pcie
> > > > *imx6_pcie)
> > > >
> > > > static void imx6_pcie_assert_core_reset(struct imx6_pcie
> > > > *imx6_pcie)
> > > > {
> > > > - struct device *dev = imx6_pcie->pci->dev;
> > > > -
> > > > switch (imx6_pcie->drvdata->variant) {
> > > > case IMX7D:
> > > > case IMX8MQ:
> > > > @@ -702,14 +700,6 @@ static void
> > > > imx6_pcie_assert_core_reset(struct
> > > imx6_pcie *imx6_pcie)
> > > > break;
> > > > }
> > > >
> > > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie-
> > > > >vpcie) > 0) {
> > > > - int ret = regulator_disable(imx6_pcie->vpcie);
> > > > -
> > > > - if (ret)
> > > > - dev_err(dev, "failed to disable vpcie
> > > > regulator: %d\n",
> > > > - ret);
> > > > - }
> > > > -
> > > > /* Some boards don't have PCIe reset GPIO. */
> > > > if (gpio_is_valid(imx6_pcie->reset_gpio))
> > > > gpio_set_value_cansleep(imx6_pcie->reset_gpio,
> > > > @@ -722,7 +712,7 @@ static int
> > > > imx6_pcie_deassert_core_reset(struct
> > > imx6_pcie *imx6_pcie)
> > > > struct device *dev = pci->dev;
> > > > int ret;
> > > >
> > > > - if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie-
> > > > >vpcie)) {
> > > > + if (imx6_pcie->vpcie) {
> > > > ret = regulator_enable(imx6_pcie->vpcie);
> > > > if (ret) {
> > > > dev_err(dev, "failed to enable vpcie
> > > > regulator: %d\n",
> > >
> > > The regulator really has nothing to do with the core reset. Please
> > > move this regulator enable into imx6_pcie_host_init().
> > Hi Lucas:
> > Thanks for your comments.
> > Got that. Had done it in the 11/17 commit.
> >
> > >
> > > > @@ -795,7 +785,7 @@ static int
> > > > imx6_pcie_deassert_core_reset(struct
> > > imx6_pcie *imx6_pcie)
> > > > return 0;
> > > >
> > > > err_clks:
> > > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie-
> > > > >vpcie) > 0) {
> > > > + if (imx6_pcie->vpcie) {
> > > > ret = regulator_disable(imx6_pcie->vpcie);
> > > > if (ret)
> > > > dev_err(dev, "failed to disable vpcie
> > > > regulator: %d\n", @@
> > > -1022,6
> > > > +1012,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> > > > break;
> > > > }
> > > >
> > > > + if (imx6_pcie->vpcie)
> > > > + regulator_disable(imx6_pcie->vpcie);
> > > > +
> > > > return 0;
> > > > }
> > > >
> > > > @@ -1268,6 +1261,8 @@ static void imx6_pcie_shutdown(struct
> > > > platform_device *pdev)
> > > >
> > > > /* bring down link, so bootloader gets clean state in case of
> > > > reboot */
> > > > imx6_pcie_assert_core_reset(imx6_pcie);
> > > > + if (imx6_pcie->vpcie)
> > > > + regulator_disable(imx6_pcie->vpcie);
> > >
> > > This looks like a separate change, not mentioned in the commit
> > > message.
> > > I'm not sure if we should do this. Shutdown is supposed to just stop
> > > the device, which is already achieved by
> > > imx6_pcie_assert_core_reset().
> > >
> > > If we would want to do a full cleanup here we would also need to
> > > disable clocks and get the reset GPIO into asserted state. I don't
> > > think we want to do all of this here.
> > The regulator_disable() was contained in
> > imx6_pcie_assert_core_reset() before.
> > When refine the regulator usage, the regulator_disable() is moved out
> > of
> > imx6_pcie_assert_core_reset().
> > Based on the discussion [1] with Francesco.
> > To keep the same behavior, the regulator_disable() is placed behind of
> > imx6_pcie_assert_core_reset() in imx6_pcie_shutdown() here.
> > [1]
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatc
> >
> hwork.ozlabs.org%2Fproject%2Flinux-pci%2Fpatch%2F1644290735-3797-6-gi
> t
> >
> -send-email-hongxing.zhu%40nxp.com%2F&data=05%7C01%7Chongxing.
> zhu%
> >
> 40nxp.com%7C88b4bedd17e84c440c5608da64c20698%7C686ea1d3bc2b4c6
> fa92cd99
> >
> c5c301635%7C0%7C0%7C637933081743458707%7CUnknown%7CTWFpbGZ
> sb3d8eyJWIjo
> >
> iMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C300
> 0%7C%
> >
> 7C%7C&sdata=NHl4prCMrfR4KAZgIaCuJX%2FOrMJW3Up31NX%2FzMMY
> pag%3D&amp
> > ;reserved=0
>
> I disagree with Francesco on this. This kind of half-done cleanup doesn't help
> in any way. Either we care about doing a full cleanup here, which would
> involve clocks and reset GPIOs, or we just care about getting the core in a state
> where it survives a reboot, which frankly was the original intention when I
> added the shutdown callback.
>
> As the devices on the bus will see a full PERST reset via the reset GPIO anyways,
> there is no harm in keeping them powered across the reboot.
Okay, I see.
Thanks for your comment.
I can remove it if you insist.

Best Regards
Richard Zhu

>
> Regards,
> Lucas