[v12,09/13] PCI: imx6: Turn off regulator when system is in suspend mode

Commit Message

Bjorn Helgaas June 15, 2022, 11:15 p.m. UTC

From: Richard Zhu <[e-mail]>

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
[e-mail]
Signed-off-by: Richard Zhu <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>
---
 drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

Comments

Bjorn Helgaas June 15, 2022, 11:30 p.m. UTC | #1

On Wed, Jun 15, 2022 at 06:15:47PM -0500, Bjorn Helgaas wrote:
> From: Richard Zhu <[e-mail]>
> 
> 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
> [e-mail]
> Signed-off-by: Richard Zhu <[e-mail]>
> Signed-off-by: Bjorn Helgaas <[e-mail]>
> ---
>  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 6eddd0b5f628..537b8a2e0e3b 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, err;
>  
> -	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",
> @@ -796,7 +786,7 @@ 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",
> @@ -1023,6 +1013,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
>  		break;
>  	}
>  
> +	if (imx6_pcie->vpcie)
> +		regulator_disable(imx6_pcie->vpcie);

This is a little bit ugly because imx6_pcie_suspend_noirq() and
imx6_pcie_resume_noirq() are not symmetric.

We call regulator_disable() directly here in
imx6_pcie_suspend_noirq(), but the corresponding regulator_enable() is
buried in imx6_pcie_deassert_core_reset().

It would be nicer if the suspend and resume paths looked more similar,
as rockchip_pcie_suspend_noirq() and rockchip_pcie_resume_noirq() do,
for example.

>  	return 0;
>  }
>  
> @@ -1269,6 +1262,8 @@ 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
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> [e-mail]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Hongxing Zhu June 16, 2022, 2:23 a.m. UTC | #2

> -----Original Message-----
> From: Bjorn Helgaas <[e-mail]>
> Sent: 2022年6月16日 7:31
> To: Hongxing Zhu <[e-mail]>; Lucas Stach
> <[e-mail]>; Rob Herring <[e-mail]>; Mark Brown
> <[e-mail]>; Lorenzo Pieralisi <[e-mail]>; Fabio
> Estevam <[e-mail]>; Francesco Dolcini
> <[e-mail]>
> Cc: [e-mail]; [e-mail];
> [e-mail]; [e-mail]; dl-linux-imx
> <[e-mail]>; Bjorn Helgaas <[e-mail]>
> Subject: Re: [PATCH v12 09/13] PCI: imx6: Turn off regulator when system is in
> suspend mode
> 
> On Wed, Jun 15, 2022 at 06:15:47PM -0500, Bjorn Helgaas wrote:
> > From: Richard Zhu <[e-mail]>
> >
> > 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&amp;d
> at
> >
> a=05%7C01%7Chongxing.zhu%40nxp.com%7C8dea46d908d34cb4825808da4
> f270eaf%
> >
> 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379093264156415
> 35%7CUnkn
> >
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> haWwi
> >
> LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=tqzlcCmtSkUNxNzJ0Fr5o
> CR3X2CTH
> > 4dwUJS4NXt5KRc%3D&amp;reserved=0
> > [e-mail]
> > Signed-off-by: Richard Zhu <[e-mail]>
> > Signed-off-by: Bjorn Helgaas <[e-mail]>
> > ---
> >  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 6eddd0b5f628..537b8a2e0e3b 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, err;
> >
> > -	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", @@
> -796,7
> > +786,7 @@ 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", @@
> -1023,6
> > +1013,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> >  		break;
> >  	}
> >
> > +	if (imx6_pcie->vpcie)
> > +		regulator_disable(imx6_pcie->vpcie);
> 
> This is a little bit ugly because imx6_pcie_suspend_noirq() and
> imx6_pcie_resume_noirq() are not symmetric.
> 
> We call regulator_disable() directly here in imx6_pcie_suspend_noirq(), but the
> corresponding regulator_enable() is buried in imx6_pcie_deassert_core_reset().
> 
> It would be nicer if the suspend and resume paths looked more similar, as
> rockchip_pcie_suspend_noirq() and rockchip_pcie_resume_noirq() do, for
> example.
Yes, it is. The regulator_disable()/regulator_enable() are not invoked
 symmetrically.

In the original codes, the regulator_disable() is contained in
imx6_pcie_assert_core_reset() and with _eanbled() check.
And regulator_enable() is embedded in imx6_pcie_deassert_core_reset().
Both the regulator disable and enable are invoked in resume before.
I move the regulator_disable to suspend mode refer to Lucas' comments.

Refer to the current situation, how about to move the regulator_disable()
 out of imx6_pcie_deassert_core_reset() too?

Best Regards
Richard Zhu

> 
> >  	return 0;
> >  }
> >
> > @@ -1269,6 +1262,8 @@ 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
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > [e-mail]
> > https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists
> > .infradead.org%2Fmailman%2Flistinfo%2Flinux-arm-kernel&amp;data=05%7
> C0
> >
> 1%7Chongxing.zhu%40nxp.com%7C8dea46d908d34cb4825808da4f270eaf%7
> C686ea1
> >
> d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637909326415641535%7CUnk
> nown%7CTW
> >
> FpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXV
> CI6
> >
> Mn0%3D%7C3000%7C%7C%7C&amp;sdata=xjn3jX7ub9%2BX%2BAJQ7YPecV5
> ujkzLAPXkY
> > hcieKs%2BKqg%3D&amp;reserved=0

Bjorn Helgaas June 16, 2022, 3:56 p.m. UTC | #3

On Thu, Jun 16, 2022 at 02:23:29AM +0000, Hongxing Zhu wrote:
> > -----Original Message-----
> > From: Bjorn Helgaas <[e-mail]>
> > Sent: 2022年6月16日 7:31
> > To: Hongxing Zhu <[e-mail]>; Lucas Stach
> > <[e-mail]>; Rob Herring <[e-mail]>; Mark Brown
> > <[e-mail]>; Lorenzo Pieralisi <[e-mail]>; Fabio
> > Estevam <[e-mail]>; Francesco Dolcini
> > <[e-mail]>
> > Cc: [e-mail]; [e-mail];
> > [e-mail]; [e-mail]; dl-linux-imx
> > <[e-mail]>; Bjorn Helgaas <[e-mail]>
> > Subject: Re: [PATCH v12 09/13] PCI: imx6: Turn off regulator when system is in
> > suspend mode
> > 
> > On Wed, Jun 15, 2022 at 06:15:47PM -0500, Bjorn Helgaas wrote:
> > > From: Richard Zhu <[e-mail]>
> > >
> > > 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&amp;d
> > at
> > >
> > a=05%7C01%7Chongxing.zhu%40nxp.com%7C8dea46d908d34cb4825808da4
> > f270eaf%
> > >
> > 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379093264156415
> > 35%7CUnkn
> > >
> > own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> > haWwi
> > >
> > LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=tqzlcCmtSkUNxNzJ0Fr5o
> > CR3X2CTH
> > > 4dwUJS4NXt5KRc%3D&amp;reserved=0
> > > [e-mail]
> > > Signed-off-by: Richard Zhu <[e-mail]>
> > > Signed-off-by: Bjorn Helgaas <[e-mail]>
> > > ---
> > >  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 6eddd0b5f628..537b8a2e0e3b 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, err;
> > >
> > > -	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", @@
> > -796,7
> > > +786,7 @@ 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", @@
> > -1023,6
> > > +1013,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> > >  		break;
> > >  	}
> > >
> > > +	if (imx6_pcie->vpcie)
> > > +		regulator_disable(imx6_pcie->vpcie);
> > 
> > This is a little bit ugly because imx6_pcie_suspend_noirq() and
> > imx6_pcie_resume_noirq() are not symmetric.
> > 
> > We call regulator_disable() directly here in imx6_pcie_suspend_noirq(), but the
> > corresponding regulator_enable() is buried in imx6_pcie_deassert_core_reset().
> > 
> > It would be nicer if the suspend and resume paths looked more similar, as
> > rockchip_pcie_suspend_noirq() and rockchip_pcie_resume_noirq() do, for
> > example.
> Yes, it is. The regulator_disable()/regulator_enable() are not invoked
>  symmetrically.
> 
> In the original codes, the regulator_disable() is contained in
> imx6_pcie_assert_core_reset() and with _eanbled() check.
> And regulator_enable() is embedded in imx6_pcie_deassert_core_reset().
> Both the regulator disable and enable are invoked in resume before.
> I move the regulator_disable to suspend mode refer to Lucas' comments.
> 
> Refer to the current situation, how about to move the regulator_disable()
>  out of imx6_pcie_deassert_core_reset() too?

I think it's important to tweak this closer to the pattern of other
drivers like exynos and rockchip.

exynos_pcie_resume_noirq() calls exynos_pcie_host_init().
imx6_pcie_resume_noirq() is VERY similar to imx6_pcie_host_init(), and
I think it should call imx6_pcie_host_init() instead of duplicating
that code.  The only real difference is that imx6_pcie_host_init()
calls imx6_setup_phy_mpll() while imx6_pcie_resume_noirq() does not.
I suspect that's a bug.

I don't think "regulator_enable(imx6_pcie->vpcie)" really has anything
to do with imx6_pcie_deassert_core_reset() and it should be moved out.
The typical pattern is to enable regulators in *_probe() and
*_resume_noirq() and disable them in *_remove() and *_suspend_noirq().
I think you should do the same unless there's some reason you can't.

Can you give this a try, starting with this v12 posting?

Bjorn

Hongxing Zhu June 17, 2022, 5:57 a.m. UTC | #4

> -----Original Message-----
> From: Bjorn Helgaas <[e-mail]>
> Sent: 2022年6月16日 23:56
> To: Hongxing Zhu <[e-mail]>
> Cc: Lucas Stach <[e-mail]>; Rob Herring <[e-mail]>;
> Mark Brown <[e-mail]>; Lorenzo Pieralisi
> <[e-mail]>; Fabio Estevam <[e-mail]>;
> Francesco Dolcini <[e-mail]>; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; dl-linux-imx <[e-mail]>; Bjorn Helgaas
> <[e-mail]>
> Subject: Re: [PATCH v12 09/13] PCI: imx6: Turn off regulator when system is in
> suspend mode
> 
> On Thu, Jun 16, 2022 at 02:23:29AM +0000, Hongxing Zhu wrote:
> > > -----Original Message-----
> > > From: Bjorn Helgaas <[e-mail]>
> > > Sent: 2022年6月16日 7:31
> > > To: Hongxing Zhu <[e-mail]>; Lucas Stach
> > > <[e-mail]>; Rob Herring <[e-mail]>; Mark
> > > Brown <[e-mail]>; Lorenzo Pieralisi
> > > <[e-mail]>; Fabio Estevam <[e-mail]>;
> > > Francesco Dolcini <[e-mail]>
> > > Cc: [e-mail]; [e-mail];
> > > [e-mail]; [e-mail]; dl-linux-imx
> > > <[e-mail]>; Bjorn Helgaas <[e-mail]>
> > > Subject: Re: [PATCH v12 09/13] PCI: imx6: Turn off regulator when
> > > system is in suspend mode
> > >
> > > On Wed, Jun 15, 2022 at 06:15:47PM -0500, Bjorn Helgaas wrote:
> > > > From: Richard Zhu <[e-mail]>
> > > >
> > > > 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&am
> p
> > > > ;d
> > > at
> > > >
> > >
> a=05%7C01%7Chongxing.zhu%40nxp.com%7C8dea46d908d34cb4825808da4
> > > f270eaf%
> > > >
> > >
> 7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6379093264156415
> > > 35%7CUnkn
> > > >
> > >
> own%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1
> > > haWwi
> > > >
> > >
> LCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=tqzlcCmtSkUNxNzJ0Fr5o
> > > CR3X2CTH
> > > > 4dwUJS4NXt5KRc%3D&amp;reserved=0
> > > > [e-mail]
> > > > Signed-off-by: Richard Zhu <[e-mail]>
> > > > Signed-off-by: Bjorn Helgaas <[e-mail]>
> > > > ---
> > > >  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 6eddd0b5f628..537b8a2e0e3b 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, err;
> > > >
> > > > -	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", @@
> > > -796,7
> > > > +786,7 @@ 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", @@
> > > -1023,6
> > > > +1013,9 @@ static int imx6_pcie_suspend_noirq(struct device *dev)
> > > >  		break;
> > > >  	}
> > > >
> > > > +	if (imx6_pcie->vpcie)
> > > > +		regulator_disable(imx6_pcie->vpcie);
> > >
> > > This is a little bit ugly because imx6_pcie_suspend_noirq() and
> > > imx6_pcie_resume_noirq() are not symmetric.
> > >
> > > We call regulator_disable() directly here in
> > > imx6_pcie_suspend_noirq(), but the corresponding regulator_enable() is
> buried in imx6_pcie_deassert_core_reset().
> > >
> > > It would be nicer if the suspend and resume paths looked more
> > > similar, as
> > > rockchip_pcie_suspend_noirq() and rockchip_pcie_resume_noirq() do,
> > > for example.
> > Yes, it is. The regulator_disable()/regulator_enable() are not invoked
> > symmetrically.
> >
> > In the original codes, the regulator_disable() is contained in
> > imx6_pcie_assert_core_reset() and with _eanbled() check.
> > And regulator_enable() is embedded in imx6_pcie_deassert_core_reset().
> > Both the regulator disable and enable are invoked in resume before.
> > I move the regulator_disable to suspend mode refer to Lucas' comments.
> >
> > Refer to the current situation, how about to move the
> > regulator_disable()  out of imx6_pcie_deassert_core_reset() too?
> 
> I think it's important to tweak this closer to the pattern of other drivers like
> exynos and rockchip.
> 
> exynos_pcie_resume_noirq() calls exynos_pcie_host_init().
> imx6_pcie_resume_noirq() is VERY similar to imx6_pcie_host_init(), and I think
> it should call imx6_pcie_host_init() instead of duplicating that code.  The only
> real difference is that imx6_pcie_host_init() calls imx6_setup_phy_mpll() while
> imx6_pcie_resume_noirq() does not.
> I suspect that's a bug.
> 
> I don't think "regulator_enable(imx6_pcie->vpcie)" really has anything to do
> with imx6_pcie_deassert_core_reset() and it should be moved out.
> The typical pattern is to enable regulators in *_probe() and
> *_resume_noirq() and disable them in *_remove() and *_suspend_noirq().
> I think you should do the same unless there's some reason you can't.
> 
> Can you give this a try, starting with this v12 posting?
Thanks a lot for your inspiration.
Exactly, these codes are almost same. The host_init can be invoked directly
 in resume. I would re-change the #12/13 of v12, and send the v13 later.

Best Regards
Richard Zhu

> 
> Bjorn

Patch

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 6eddd0b5f628..537b8a2e0e3b 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, err;
 
-	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",
@@ -796,7 +786,7 @@  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",
@@ -1023,6 +1013,9 @@  static int imx6_pcie_suspend_noirq(struct device *dev)
 		break;
 	}
 
+	if (imx6_pcie->vpcie)
+		regulator_disable(imx6_pcie->vpcie);
+
 	return 0;
 }
 
@@ -1269,6 +1262,8 @@  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[] = {