[v7,8/8] PCI: imx: Add the imx8mm pcie support

Commit Message

Richard Zhu Dec. 2, 2021, 8:02 a.m. UTC

i.MX8MM PCIe works mostly like the i.MX8MQ one, but has a different PHY
and allows to output the internal PHY reference clock via the refclk pad.
Add the i.MX8MM PCIe support based on the standalone PHY driver.

Signed-off-by: Richard Zhu <[e-mail]>
Tested-by: Marcel Ziswiler <[e-mail]>
Reviewed-by: Tim Harvey <[e-mail]>
Tested-by: Tim Harvey <[e-mail]>
---
 drivers/pci/controller/dwc/pci-imx6.c | 83 ++++++++++++++++++++++++---
 1 file changed, 75 insertions(+), 8 deletions(-)

Comments

Krzysztof Wilczyński Dec. 16, 2021, 4:51 p.m. UTC | #1

Hi Richard,

Apologies for a very late review!  Especially since Lorenzo already took
patches as per:

  https://lore.kernel.org/linux-pci/[e-mail]/

However, perhaps it's not too late.

[...]
> @@ -446,6 +452,13 @@ static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
>  		break;
>  	case IMX7D:
>  		break;
> +	case IMX8MM:
> +		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
> +		if (ret) {
> +			dev_err(dev, "unable to enable pcie_aux clock\n");
> +			break;
> +		}
> +		break;

You can drop the inner break, it wouldn't do much here, unless this was
intended to be a return?

> @@ -538,6 +559,10 @@ static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
>  	case IMX8MQ:
>  		reset_control_deassert(imx6_pcie->pciephy_reset);
>  		break;
> +	case IMX8MM:
> +		if (phy_init(imx6_pcie->phy) != 0)
> +			dev_err(dev, "Waiting for PHY ready timeout!\n");
> +		break;

If the above, you can keep the same style as used throughout the file
already, so it would just simply be:

  if (phy_init(imx6_pcie->phy))

Also, a nitpick: to be consistent with other such messages here, the error
message would be all lower-case letters.

[...]
> @@ -614,6 +639,8 @@ static void imx6_pcie_configure_type(struct imx6_pcie *imx6_pcie)
>  static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
>  {
>  	switch (imx6_pcie->drvdata->variant) {
> +	case IMX8MM:
> +		break;
>  	case IMX8MQ:

Would it warrant a comment that adds a note there to this single bare
break?  Perhaps this version is not support, lack this particular
functionality, etc.

[...]
> @@ -1089,10 +1122,39 @@ static int imx6_pcie_probe(struct platform_device *pdev)
>  			dev_err(dev, "Failed to get PCIE APPS reset control\n");
>  			return PTR_ERR(imx6_pcie->apps_reset);
>  		}
> +		break;
> +	case IMX8MM:
> +		imx6_pcie->pcie_aux = devm_clk_get(dev, "pcie_aux");
> +		if (IS_ERR(imx6_pcie->pcie_aux))
> +			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_aux),
> +					     "pcie_aux clock source missing or invalid\n");
> +		imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
> +									 "apps");
> +		if (IS_ERR(imx6_pcie->apps_reset)) {
> +			dev_err(dev, "Failed to get PCIE APPS reset control\n");
> +			return PTR_ERR(imx6_pcie->apps_reset);
> +		}
> +
> +		imx6_pcie->phy = devm_phy_get(dev, "pcie-phy");
> +		if (IS_ERR(imx6_pcie->phy)) {
> +			if (PTR_ERR(imx6_pcie->phy) == -EPROBE_DEFER)
> +				return -EPROBE_DEFER;
> +			dev_err(dev, "Failed to get PCIE PHY\n");
> +			return PTR_ERR(imx6_pcie->phy);
> +		}

A question about handling of the -EPROBE_DEFER above: why not to use the
dev_err_probe() helper similarly to the code above and below?  Would there
be something different preventing the use of dev_err_probe() here too?

>  		break;
>  	default:
>  		break;
>  	}
> +	/* Don't fetch the pcie_phy clock, if it has abstract PHY driver */
> +	if (imx6_pcie->phy == NULL) {
> +		imx6_pcie->pcie_phy = devm_clk_get(dev, "pcie_phy");
> +		if (IS_ERR(imx6_pcie->pcie_phy))
> +			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_phy),
> +					     "pcie_phy clock source missing or invalid\n");
> +	}

Thank you for another amazing patch!

	Krzysztof

Richard Zhu Dec. 17, 2021, 5:54 a.m. UTC | #2

> -----Original Message-----
> From: Krzysztof Wilczyński <[e-mail]>
> Sent: Friday, December 17, 2021 12:52 AM
> To: Hongxing Zhu <[e-mail]>
> Cc: [e-mail]; [e-mail];
> [e-mail]; Marcel Ziswiler
> <[e-mail]>; [e-mail];
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; dl-linux-imx
> <[e-mail]>
> Subject: Re: [PATCH v7 8/8] PCI: imx: Add the imx8mm pcie support
> 
> Hi Richard,
> 
> Apologies for a very late review!  Especially since Lorenzo already took
> patches as per:
> 
> 
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flor
> e.kernel.org%2Flinux-pci%2F163965080404.20006.52416095516435017
> 49.b4-ty%40arm.com%2F&amp;data=04%7C01%7Chongxing.zhu%40nxp
> .com%7C8afb673348214261883608d9c0b45b1d%7C686ea1d3bc2b4c6fa
> 92cd99c5c301635%7C0%7C0%7C637752703124166805%7CUnknown%7
> CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1ha
> WwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=rfmN1Xojubap2vi3J4Jol3ozy
> N1Q2q7YiBM5bqMm22s%3D&amp;reserved=0
> 
> However, perhaps it's not too late.
[Richard Zhu] Hi Krzysztof: 
Thanks for your review.
But I don't know how to handle this situation.
How about that I add this refine patch into the following bug fix and
 refine patch-set later?
PCI: imx6: refine codes and add compliance tests mode support
" https://patchwork.kernel.org/project/linux-arm-kernel/cover/[e-mail]/"

> 
> [...]
> > @@ -446,6 +452,13 @@ static int imx6_pcie_enable_ref_clk(struct
> imx6_pcie *imx6_pcie)
> >  		break;
> >  	case IMX7D:
> >  		break;
> > +	case IMX8MM:
> > +		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
> > +		if (ret) {
> > +			dev_err(dev, "unable to enable pcie_aux clock\n");
> > +			break;
> > +		}
> > +		break;
> 
> You can drop the inner break, it wouldn't do much here, unless this was
> intended to be a return?
[Richard Zhu] Yes, it is. The inner break can be dropped. The error return
would be handled in the end.

> 
> > @@ -538,6 +559,10 @@ static void
> imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> >  	case IMX8MQ:
> >  		reset_control_deassert(imx6_pcie->pciephy_reset);
> >  		break;
> > +	case IMX8MM:
> > +		if (phy_init(imx6_pcie->phy) != 0)
> > +			dev_err(dev, "Waiting for PHY ready timeout!\n");
> > +		break;
> 
> If the above, you can keep the same style as used throughout the file
> already, so it would just simply be:
> 
>   if (phy_init(imx6_pcie->phy))
> 
> Also, a nitpick: to be consistent with other such messages here, the error
> message would be all lower-case letters.
[Richard Zhu] Yes, it is.
> 
> [...]
> > @@ -614,6 +639,8 @@ static void imx6_pcie_configure_type(struct
> > imx6_pcie *imx6_pcie)  static void imx6_pcie_init_phy(struct
> imx6_pcie
> > *imx6_pcie)  {
> >  	switch (imx6_pcie->drvdata->variant) {
> > +	case IMX8MM:
> > +		break;
> >  	case IMX8MQ:
> 
> Would it warrant a comment that adds a note there to this single bare
> break?  Perhaps this version is not support, lack this particular
> functionality, etc.
[Richard Zhu] Yes, it's easier to understand after add one comment.
> 
> [...]
> > @@ -1089,10 +1122,39 @@ static int imx6_pcie_probe(struct
> platform_device *pdev)
> >  			dev_err(dev, "Failed to get PCIE APPS reset control\n");
> >  			return PTR_ERR(imx6_pcie->apps_reset);
> >  		}
> > +		break;
> > +	case IMX8MM:
> > +		imx6_pcie->pcie_aux = devm_clk_get(dev, "pcie_aux");
> > +		if (IS_ERR(imx6_pcie->pcie_aux))
> > +			return dev_err_probe(dev,
> PTR_ERR(imx6_pcie->pcie_aux),
> > +					     "pcie_aux clock source missing or
> invalid\n");
> > +		imx6_pcie->apps_reset =
> devm_reset_control_get_exclusive(dev,
> > +									 "apps");
> > +		if (IS_ERR(imx6_pcie->apps_reset)) {
> > +			dev_err(dev, "Failed to get PCIE APPS reset control\n");
> > +			return PTR_ERR(imx6_pcie->apps_reset);
> > +		}
> > +
> > +		imx6_pcie->phy = devm_phy_get(dev, "pcie-phy");
> > +		if (IS_ERR(imx6_pcie->phy)) {
> > +			if (PTR_ERR(imx6_pcie->phy) == -EPROBE_DEFER)
> > +				return -EPROBE_DEFER;
> > +			dev_err(dev, "Failed to get PCIE PHY\n");
> > +			return PTR_ERR(imx6_pcie->phy);
> > +		}
> 
> A question about handling of the -EPROBE_DEFER above: why not to use
> the
> dev_err_probe() helper similarly to the code above and below?  Would
> there be something different preventing the use of dev_err_probe() here
> too?
[Richard Zhu] To be aligned, the above one can be replaced totally.
I didn't want to dump the error message when -EPROBE_DEFFER occurs.
Anyway, I can make them aligned later.

Best Regards
Richard

> 
> >  		break;
> >  	default:
> >  		break;
> >  	}
> > +	/* Don't fetch the pcie_phy clock, if it has abstract PHY driver */
> > +	if (imx6_pcie->phy == NULL) {
> > +		imx6_pcie->pcie_phy = devm_clk_get(dev, "pcie_phy");
> > +		if (IS_ERR(imx6_pcie->pcie_phy))
> > +			return dev_err_probe(dev,
> PTR_ERR(imx6_pcie->pcie_phy),
> > +					     "pcie_phy clock source missing or
> invalid\n");
> > +	}
> 
> Thank you for another amazing patch!
> 
> 	Krzysztof

Lorenzo Pieralisi Dec. 23, 2021, 11:49 a.m. UTC | #3

On Fri, Dec 17, 2021 at 05:54:21AM +0000, Hongxing Zhu wrote:
> > -----Original Message-----
> > From: Krzysztof Wilczyński <[e-mail]>
> > Sent: Friday, December 17, 2021 12:52 AM
> > To: Hongxing Zhu <[e-mail]>
> > Cc: [e-mail]; [e-mail];
> > [e-mail]; Marcel Ziswiler
> > <[e-mail]>; [e-mail];
> > [e-mail]; [e-mail]; [e-mail];
> > [e-mail]; [e-mail];
> > [e-mail]; [e-mail];
> > [e-mail]; [e-mail];
> > [e-mail]; [e-mail]; dl-linux-imx
> > <[e-mail]>
> > Subject: Re: [PATCH v7 8/8] PCI: imx: Add the imx8mm pcie support
> > 
> > Hi Richard,
> > 
> > Apologies for a very late review!  Especially since Lorenzo already took
> > patches as per:
> > 
> > 
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flor
> > e.kernel.org%2Flinux-pci%2F163965080404.20006.52416095516435017
> > 49.b4-ty%40arm.com%2F&amp;data=04%7C01%7Chongxing.zhu%40nxp
> > .com%7C8afb673348214261883608d9c0b45b1d%7C686ea1d3bc2b4c6fa
> > 92cd99c5c301635%7C0%7C0%7C637752703124166805%7CUnknown%7
> > CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1ha
> > WwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=rfmN1Xojubap2vi3J4Jol3ozy
> > N1Q2q7YiBM5bqMm22s%3D&amp;reserved=0
> > 
> > However, perhaps it's not too late.
> [Richard Zhu] Hi Krzysztof: 
> Thanks for your review.
> But I don't know how to handle this situation.
> How about that I add this refine patch into the following bug fix and
>  refine patch-set later?
> PCI: imx6: refine codes and add compliance tests mode support
> " https://patchwork.kernel.org/project/linux-arm-kernel/cover/[e-mail]/"
> 
> > 
> > [...]
> > > @@ -446,6 +452,13 @@ static int imx6_pcie_enable_ref_clk(struct
> > imx6_pcie *imx6_pcie)
> > >  		break;
> > >  	case IMX7D:
> > >  		break;
> > > +	case IMX8MM:
> > > +		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
> > > +		if (ret) {
> > > +			dev_err(dev, "unable to enable pcie_aux clock\n");
> > > +			break;
> > > +		}
> > > +		break;
> > 
> > You can drop the inner break, it wouldn't do much here, unless this was
> > intended to be a return?
> [Richard Zhu] Yes, it is. The inner break can be dropped. The error return
> would be handled in the end.
> 
> > 
> > > @@ -538,6 +559,10 @@ static void
> > imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> > >  	case IMX8MQ:
> > >  		reset_control_deassert(imx6_pcie->pciephy_reset);
> > >  		break;
> > > +	case IMX8MM:
> > > +		if (phy_init(imx6_pcie->phy) != 0)
> > > +			dev_err(dev, "Waiting for PHY ready timeout!\n");
> > > +		break;
> > 
> > If the above, you can keep the same style as used throughout the file
> > already, so it would just simply be:
> > 
> >   if (phy_init(imx6_pcie->phy))
> > 
> > Also, a nitpick: to be consistent with other such messages here, the error
> > message would be all lower-case letters.
> [Richard Zhu] Yes, it is.
> > 
> > [...]
> > > @@ -614,6 +639,8 @@ static void imx6_pcie_configure_type(struct
> > > imx6_pcie *imx6_pcie)  static void imx6_pcie_init_phy(struct
> > imx6_pcie
> > > *imx6_pcie)  {
> > >  	switch (imx6_pcie->drvdata->variant) {
> > > +	case IMX8MM:
> > > +		break;
> > >  	case IMX8MQ:
> > 
> > Would it warrant a comment that adds a note there to this single bare
> > break?  Perhaps this version is not support, lack this particular
> > functionality, etc.
> [Richard Zhu] Yes, it's easier to understand after add one comment.
> > 
> > [...]
> > > @@ -1089,10 +1122,39 @@ static int imx6_pcie_probe(struct
> > platform_device *pdev)
> > >  			dev_err(dev, "Failed to get PCIE APPS reset control\n");
> > >  			return PTR_ERR(imx6_pcie->apps_reset);
> > >  		}
> > > +		break;
> > > +	case IMX8MM:
> > > +		imx6_pcie->pcie_aux = devm_clk_get(dev, "pcie_aux");
> > > +		if (IS_ERR(imx6_pcie->pcie_aux))
> > > +			return dev_err_probe(dev,
> > PTR_ERR(imx6_pcie->pcie_aux),
> > > +					     "pcie_aux clock source missing or
> > invalid\n");
> > > +		imx6_pcie->apps_reset =
> > devm_reset_control_get_exclusive(dev,
> > > +									 "apps");
> > > +		if (IS_ERR(imx6_pcie->apps_reset)) {
> > > +			dev_err(dev, "Failed to get PCIE APPS reset control\n");
> > > +			return PTR_ERR(imx6_pcie->apps_reset);
> > > +		}
> > > +
> > > +		imx6_pcie->phy = devm_phy_get(dev, "pcie-phy");
> > > +		if (IS_ERR(imx6_pcie->phy)) {
> > > +			if (PTR_ERR(imx6_pcie->phy) == -EPROBE_DEFER)
> > > +				return -EPROBE_DEFER;
> > > +			dev_err(dev, "Failed to get PCIE PHY\n");
> > > +			return PTR_ERR(imx6_pcie->phy);
> > > +		}
> > 
> > A question about handling of the -EPROBE_DEFER above: why not to use
> > the
> > dev_err_probe() helper similarly to the code above and below?  Would
> > there be something different preventing the use of dev_err_probe() here
> > too?
> [Richard Zhu] To be aligned, the above one can be replaced totally.
> I didn't want to dump the error message when -EPROBE_DEFFER occurs.
> Anyway, I can make them aligned later.

Can you send me an update for this patch only so that I can update
the corresponding commit according to this review please ?

Thanks,
Lorenzo

> Best Regards
> Richard
> 
> > 
> > >  		break;
> > >  	default:
> > >  		break;
> > >  	}
> > > +	/* Don't fetch the pcie_phy clock, if it has abstract PHY driver */
> > > +	if (imx6_pcie->phy == NULL) {
> > > +		imx6_pcie->pcie_phy = devm_clk_get(dev, "pcie_phy");
> > > +		if (IS_ERR(imx6_pcie->pcie_phy))
> > > +			return dev_err_probe(dev,
> > PTR_ERR(imx6_pcie->pcie_phy),
> > > +					     "pcie_phy clock source missing or
> > invalid\n");
> > > +	}
> > 
> > Thank you for another amazing patch!
> > 
> > 	Krzysztof

Richard Zhu Dec. 24, 2021, 2:09 a.m. UTC | #4

> -----Original Message-----
> From: Lorenzo Pieralisi <[e-mail]>
> Sent: Thursday, December 23, 2021 7:50 PM
> To: Hongxing Zhu <[e-mail]>
> Cc: Krzysztof Wilczyński <[e-mail]>; [e-mail];
> [e-mail]; Marcel Ziswiler <[e-mail]>;
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; dl-linux-imx
> <[e-mail]>
> Subject: Re: [PATCH v7 8/8] PCI: imx: Add the imx8mm pcie support
> 
> On Fri, Dec 17, 2021 at 05:54:21AM +0000, Hongxing Zhu wrote:
> > > -----Original Message-----
> > > From: Krzysztof Wilczyński <[e-mail]>
> > > Sent: Friday, December 17, 2021 12:52 AM
> > > To: Hongxing Zhu <[e-mail]>
> > > Cc: [e-mail]; [e-mail];
> > > [e-mail]; Marcel Ziswiler
> > > <[e-mail]>; [e-mail];
> [e-mail];
> > > [e-mail]; [e-mail]; [e-mail];
> > > [e-mail]; [e-mail];
> > > [e-mail]; [e-mail];
> > > [e-mail];
> > > [e-mail]; [e-mail]; dl-linux-imx
> > > <[e-mail]>
> > > Subject: Re: [PATCH v7 8/8] PCI: imx: Add the imx8mm pcie support
> > >
> > > Hi Richard,
> > >
> > > Apologies for a very late review!  Especially since Lorenzo already
> > > took patches as per:
> > >
> > >
> > >
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flo
> > > r
> > >
> e.kernel.org%2Flinux-pci%2F163965080404.20006.52416095516435017
> > >
> 49.b4-ty%40arm.com%2F&amp;data=04%7C01%7Chongxing.zhu%40nxp
> > > .com%7C8afb673348214261883608d9c0b45b1d%7C686ea1d3bc2b4
> c6fa
> > >
> 92cd99c5c301635%7C0%7C0%7C637752703124166805%7CUnknown%7
> > >
> CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1ha
> > >
> WwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=rfmN1Xojubap2vi3J4Jol3ozy
> > > N1Q2q7YiBM5bqMm22s%3D&amp;reserved=0
> > >
> > > However, perhaps it's not too late.
> > [Richard Zhu] Hi Krzysztof:
> > Thanks for your review.
> > But I don't know how to handle this situation.
> > How about that I add this refine patch into the following bug fix and
> > refine patch-set later?
> > PCI: imx6: refine codes and add compliance tests mode support "
> >
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpa
> tchwork.kernel.org%2Fproject%2Flinux-arm-kernel%2Fcover%2F1635747
> 478-25562-1-git-send-email-hongxing.zhu%40nxp.com%2F&amp;data=0
> 4%7C01%7Chongxing.zhu%40nxp.com%7Ce04c6cda020b4f3849bf08d9c
> 60a5da0%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C1%7C6377
> 58570100053598%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwM
> DAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&amp;
> sdata=joTJZcYJhmYlzSTWY%2BhGCFV5ch12HPR4mbbOwZ5vcO0%3D&a
> mp;reserved=0"
> >
> > >
> > > [...]
> > > > @@ -446,6 +452,13 @@ static int imx6_pcie_enable_ref_clk(struct
> > > imx6_pcie *imx6_pcie)
> > > >  		break;
> > > >  	case IMX7D:
> > > >  		break;
> > > > +	case IMX8MM:
> > > > +		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
> > > > +		if (ret) {
> > > > +			dev_err(dev, "unable to enable pcie_aux clock\n");
> > > > +			break;
> > > > +		}
> > > > +		break;
> > >
> > > You can drop the inner break, it wouldn't do much here, unless this
> > > was intended to be a return?
> > [Richard Zhu] Yes, it is. The inner break can be dropped. The error
> > return would be handled in the end.
> >
> > >
> > > > @@ -538,6 +559,10 @@ static void
> > > imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
> > > >  	case IMX8MQ:
> > > >  		reset_control_deassert(imx6_pcie->pciephy_reset);
> > > >  		break;
> > > > +	case IMX8MM:
> > > > +		if (phy_init(imx6_pcie->phy) != 0)
> > > > +			dev_err(dev, "Waiting for PHY ready timeout!\n");
> > > > +		break;
> > >
> > > If the above, you can keep the same style as used throughout the
> > > file already, so it would just simply be:
> > >
> > >   if (phy_init(imx6_pcie->phy))
> > >
> > > Also, a nitpick: to be consistent with other such messages here, the
> > > error message would be all lower-case letters.
> > [Richard Zhu] Yes, it is.
> > >
> > > [...]
> > > > @@ -614,6 +639,8 @@ static void imx6_pcie_configure_type(struct
> > > > imx6_pcie *imx6_pcie)  static void imx6_pcie_init_phy(struct
> > > imx6_pcie
> > > > *imx6_pcie)  {
> > > >  	switch (imx6_pcie->drvdata->variant) {
> > > > +	case IMX8MM:
> > > > +		break;
> > > >  	case IMX8MQ:
> > >
> > > Would it warrant a comment that adds a note there to this single
> > > bare break?  Perhaps this version is not support, lack this
> > > particular functionality, etc.
> > [Richard Zhu] Yes, it's easier to understand after add one comment.
> > >
> > > [...]
> > > > @@ -1089,10 +1122,39 @@ static int imx6_pcie_probe(struct
> > > platform_device *pdev)
> > > >  			dev_err(dev, "Failed to get PCIE APPS reset
> control\n");
> > > >  			return PTR_ERR(imx6_pcie->apps_reset);
> > > >  		}
> > > > +		break;
> > > > +	case IMX8MM:
> > > > +		imx6_pcie->pcie_aux = devm_clk_get(dev, "pcie_aux");
> > > > +		if (IS_ERR(imx6_pcie->pcie_aux))
> > > > +			return dev_err_probe(dev,
> > > PTR_ERR(imx6_pcie->pcie_aux),
> > > > +					     "pcie_aux clock source missing or
> > > invalid\n");
> > > > +		imx6_pcie->apps_reset =
> > > devm_reset_control_get_exclusive(dev,
> > > > +									 "apps");
> > > > +		if (IS_ERR(imx6_pcie->apps_reset)) {
> > > > +			dev_err(dev, "Failed to get PCIE APPS reset
> control\n");
> > > > +			return PTR_ERR(imx6_pcie->apps_reset);
> > > > +		}
> > > > +
> > > > +		imx6_pcie->phy = devm_phy_get(dev, "pcie-phy");
> > > > +		if (IS_ERR(imx6_pcie->phy)) {
> > > > +			if (PTR_ERR(imx6_pcie->phy) == -EPROBE_DEFER)
> > > > +				return -EPROBE_DEFER;
> > > > +			dev_err(dev, "Failed to get PCIE PHY\n");
> > > > +			return PTR_ERR(imx6_pcie->phy);
> > > > +		}
> > >
> > > A question about handling of the -EPROBE_DEFER above: why not to
> use
> > > the
> > > dev_err_probe() helper similarly to the code above and below?
> Would
> > > there be something different preventing the use of dev_err_probe()
> > > here too?
> > [Richard Zhu] To be aligned, the above one can be replaced totally.
> > I didn't want to dump the error message when -EPROBE_DEFFER
> occurs.
> > Anyway, I can make them aligned later.
> 
> Can you send me an update for this patch only so that I can update the
> corresponding commit according to this review please ?
[Richard Zhu] Sure, thanks a lot for your kindly help.

Best Regards
Richard Zhu

> 
> Thanks,
> Lorenzo
> 
> > Best Regards
> > Richard
> >
> > >
> > > >  		break;
> > > >  	default:
> > > >  		break;
> > > >  	}
> > > > +	/* Don't fetch the pcie_phy clock, if it has abstract PHY driver */
> > > > +	if (imx6_pcie->phy == NULL) {
> > > > +		imx6_pcie->pcie_phy = devm_clk_get(dev, "pcie_phy");
> > > > +		if (IS_ERR(imx6_pcie->pcie_phy))
> > > > +			return dev_err_probe(dev,
> > > PTR_ERR(imx6_pcie->pcie_phy),
> > > > +					     "pcie_phy clock source missing or
> > > invalid\n");
> > > > +	}
> > >
> > > Thank you for another amazing patch!
> > >
> > > 	Krzysztof

Patch

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 26f49f797b0f..2ac081510632 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -29,6 +29,7 @@ 
 #include <linux/types.h>
 #include <linux/interrupt.h>
 #include <linux/reset.h>
+#include <linux/phy/phy.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 
@@ -49,6 +50,7 @@  enum imx6_pcie_variants {
 	IMX6QP,
 	IMX7D,
 	IMX8MQ,
+	IMX8MM,
 };
 
 #define IMX6_PCIE_FLAG_IMX6_PHY			BIT(0)
@@ -88,6 +90,7 @@  struct imx6_pcie {
 	struct device		*pd_pcie;
 	/* power domain for pcie phy */
 	struct device		*pd_pcie_phy;
+	struct phy		*phy;
 	const struct imx6_pcie_drvdata *drvdata;
 };
 
@@ -372,6 +375,8 @@  static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 	case IMX7D:
 	case IMX8MQ:
 		reset_control_assert(imx6_pcie->pciephy_reset);
+		fallthrough;
+	case IMX8MM:
 		reset_control_assert(imx6_pcie->apps_reset);
 		break;
 	case IMX6SX:
@@ -407,7 +412,8 @@  static void imx6_pcie_assert_core_reset(struct imx6_pcie *imx6_pcie)
 
 static unsigned int imx6_pcie_grp_offset(const struct imx6_pcie *imx6_pcie)
 {
-	WARN_ON(imx6_pcie->drvdata->variant != IMX8MQ);
+	WARN_ON(imx6_pcie->drvdata->variant != IMX8MQ &&
+		imx6_pcie->drvdata->variant != IMX8MM);
 	return imx6_pcie->controller_id == 1 ? IOMUXC_GPR16 : IOMUXC_GPR14;
 }
 
@@ -446,6 +452,13 @@  static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 		break;
 	case IMX7D:
 		break;
+	case IMX8MM:
+		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
+		if (ret) {
+			dev_err(dev, "unable to enable pcie_aux clock\n");
+			break;
+		}
+		break;
 	case IMX8MQ:
 		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
 		if (ret) {
@@ -522,6 +535,14 @@  static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 		goto err_ref_clk;
 	}
 
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MM:
+		if (phy_power_on(imx6_pcie->phy))
+			dev_err(dev, "unable to power on PHY\n");
+		break;
+	default:
+		break;
+	}
 	/* allow the clocks to stabilize */
 	usleep_range(200, 500);
 
@@ -538,6 +559,10 @@  static void imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie)
 	case IMX8MQ:
 		reset_control_deassert(imx6_pcie->pciephy_reset);
 		break;
+	case IMX8MM:
+		if (phy_init(imx6_pcie->phy) != 0)
+			dev_err(dev, "Waiting for PHY ready timeout!\n");
+		break;
 	case IMX7D:
 		reset_control_deassert(imx6_pcie->pciephy_reset);
 
@@ -614,6 +639,8 @@  static void imx6_pcie_configure_type(struct imx6_pcie *imx6_pcie)
 static void imx6_pcie_init_phy(struct imx6_pcie *imx6_pcie)
 {
 	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MM:
+		break;
 	case IMX8MQ:
 		/*
 		 * TODO: Currently this code assumes external
@@ -753,6 +780,7 @@  static void imx6_pcie_ltssm_enable(struct device *dev)
 		break;
 	case IMX7D:
 	case IMX8MQ:
+	case IMX8MM:
 		reset_control_deassert(imx6_pcie->apps_reset);
 		break;
 	}
@@ -871,6 +899,7 @@  static void imx6_pcie_ltssm_disable(struct device *dev)
 				   IMX6Q_GPR12_PCIE_CTL_2, 0);
 		break;
 	case IMX7D:
+	case IMX8MM:
 		reset_control_assert(imx6_pcie->apps_reset);
 		break;
 	default:
@@ -930,6 +959,7 @@  static void imx6_pcie_clk_disable(struct imx6_pcie *imx6_pcie)
 				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
 		break;
 	case IMX8MQ:
+	case IMX8MM:
 		clk_disable_unprepare(imx6_pcie->pcie_aux);
 		break;
 	default:
@@ -945,8 +975,16 @@  static int imx6_pcie_suspend_noirq(struct device *dev)
 		return 0;
 
 	imx6_pcie_pm_turnoff(imx6_pcie);
-	imx6_pcie_clk_disable(imx6_pcie);
 	imx6_pcie_ltssm_disable(dev);
+	imx6_pcie_clk_disable(imx6_pcie);
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX8MM:
+		if (phy_power_off(imx6_pcie->phy))
+			dev_err(dev, "unable to power on PHY\n");
+		break;
+	default:
+		break;
+	}
 
 	return 0;
 }
@@ -1043,11 +1081,6 @@  static int imx6_pcie_probe(struct platform_device *pdev)
 	}
 
 	/* Fetch clocks */
-	imx6_pcie->pcie_phy = devm_clk_get(dev, "pcie_phy");
-	if (IS_ERR(imx6_pcie->pcie_phy))
-		return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_phy),
-				     "pcie_phy clock source missing or invalid\n");
-
 	imx6_pcie->pcie_bus = devm_clk_get(dev, "pcie_bus");
 	if (IS_ERR(imx6_pcie->pcie_bus))
 		return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_bus),
@@ -1089,10 +1122,39 @@  static int imx6_pcie_probe(struct platform_device *pdev)
 			dev_err(dev, "Failed to get PCIE APPS reset control\n");
 			return PTR_ERR(imx6_pcie->apps_reset);
 		}
+		break;
+	case IMX8MM:
+		imx6_pcie->pcie_aux = devm_clk_get(dev, "pcie_aux");
+		if (IS_ERR(imx6_pcie->pcie_aux))
+			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_aux),
+					     "pcie_aux clock source missing or invalid\n");
+		imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
+									 "apps");
+		if (IS_ERR(imx6_pcie->apps_reset)) {
+			dev_err(dev, "Failed to get PCIE APPS reset control\n");
+			return PTR_ERR(imx6_pcie->apps_reset);
+		}
+
+		imx6_pcie->phy = devm_phy_get(dev, "pcie-phy");
+		if (IS_ERR(imx6_pcie->phy)) {
+			if (PTR_ERR(imx6_pcie->phy) == -EPROBE_DEFER)
+				return -EPROBE_DEFER;
+			dev_err(dev, "Failed to get PCIE PHY\n");
+			return PTR_ERR(imx6_pcie->phy);
+		}
+
 		break;
 	default:
 		break;
 	}
+	/* Don't fetch the pcie_phy clock, if it has abstract PHY driver */
+	if (imx6_pcie->phy == NULL) {
+		imx6_pcie->pcie_phy = devm_clk_get(dev, "pcie_phy");
+		if (IS_ERR(imx6_pcie->pcie_phy))
+			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_phy),
+					     "pcie_phy clock source missing or invalid\n");
+	}
+
 
 	/* Grab turnoff reset */
 	imx6_pcie->turnoff_reset = devm_reset_control_get_optional_exclusive(dev, "turnoff");
@@ -1202,6 +1264,10 @@  static const struct imx6_pcie_drvdata drvdata[] = {
 	[IMX8MQ] = {
 		.variant = IMX8MQ,
 	},
+	[IMX8MM] = {
+		.variant = IMX8MM,
+		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND,
+	},
 };
 
 static const struct of_device_id imx6_pcie_of_match[] = {
@@ -1209,7 +1275,8 @@  static const struct of_device_id imx6_pcie_of_match[] = {
 	{ .compatible = "fsl,imx6sx-pcie", .data = &drvdata[IMX6SX], },
 	{ .compatible = "fsl,imx6qp-pcie", .data = &drvdata[IMX6QP], },
 	{ .compatible = "fsl,imx7d-pcie",  .data = &drvdata[IMX7D],  },
-	{ .compatible = "fsl,imx8mq-pcie", .data = &drvdata[IMX8MQ], } ,
+	{ .compatible = "fsl,imx8mq-pcie", .data = &drvdata[IMX8MQ], },
+	{ .compatible = "fsl,imx8mm-pcie", .data = &drvdata[IMX8MM], },
 	{},
 };