diff mbox series

[v6,02/10] PCI: imx6: Add ref clock for i.MX95 PCIe

Message ID 20241101070610.1267391-3-hongxing.zhu@nxp.com (mailing list archive)
State Superseded
Headers show
Series A bunch of changes to refine i.MX PCIe driver | expand

Commit Message

Richard Zhu Nov. 1, 2024, 7:06 a.m. UTC 
Add "ref" clock to enable reference clock. To avoid the DT
compatibility, i.MX95 REF clock might be optional. Replace the
devm_clk_bulk_get() by devm_clk_bulk_get_optional() to fetch
i.MX95 PCIe optional clocks in driver.

If use external clock, ref clock should point to external reference.

If use internal clock, CREF_EN in LAST_TO_REG controls reference output,
which implement in drivers/clk/imx/clk-imx95-blk-ctl.c.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

Comments

Manivannan Sadhasivam Nov. 15, 2024, 6:38 a.m. UTC | #1 
On Fri, Nov 01, 2024 at 03:06:02PM +0800, Richard Zhu wrote:
> Add "ref" clock to enable reference clock. To avoid the DT
> compatibility, i.MX95 REF clock might be optional.

Your wording is not correct. Perhaps you wanted to say, "To avoid breaking DT
backwards compatibility"?

> Replace the
> devm_clk_bulk_get() by devm_clk_bulk_get_optional() to fetch
> i.MX95 PCIe optional clocks in driver.
> 
> If use external clock, ref clock should point to external reference.
> 
> If use internal clock, CREF_EN in LAST_TO_REG controls reference output,
> which implement in drivers/clk/imx/clk-imx95-blk-ctl.c.
> 
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> ---
>  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index 808d1f105417..bc8567677a67 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -82,6 +82,7 @@ enum imx_pcie_variants {
>  #define IMX_PCIE_FLAG_HAS_SERDES		BIT(6)
>  #define IMX_PCIE_FLAG_SUPPORT_64BIT		BIT(7)
>  #define IMX_PCIE_FLAG_CPU_ADDR_FIXUP		BIT(8)
> +#define IMX_PCIE_FLAG_CUSTOM_PME_TURNOFF	BIT(9)
>  
>  #define imx_check_flag(pci, val)	(pci->drvdata->flags & val)
>  
> @@ -98,6 +99,7 @@ struct imx_pcie_drvdata {
>  	const char *gpr;
>  	const char * const *clk_names;
>  	const u32 clks_cnt;
> +	const u32 clks_optional_cnt;
>  	const u32 ltssm_off;
>  	const u32 ltssm_mask;
>  	const u32 mode_off[IMX_PCIE_MAX_INSTANCES];
> @@ -1278,9 +1280,8 @@ static int imx_pcie_probe(struct platform_device *pdev)
>  	struct device_node *np;
>  	struct resource *dbi_base;
>  	struct device_node *node = dev->of_node;
> -	int ret;
> +	int ret, i, req_cnt;
>  	u16 val;
> -	int i;
>  
>  	imx_pcie = devm_kzalloc(dev, sizeof(*imx_pcie), GFP_KERNEL);
>  	if (!imx_pcie)
> @@ -1330,7 +1331,10 @@ static int imx_pcie_probe(struct platform_device *pdev)
>  		imx_pcie->clks[i].id = imx_pcie->drvdata->clk_names[i];
>  
>  	/* Fetch clocks */
> -	ret = devm_clk_bulk_get(dev, imx_pcie->drvdata->clks_cnt, imx_pcie->clks);
> +	req_cnt = imx_pcie->drvdata->clks_cnt - imx_pcie->drvdata->clks_optional_cnt;
> +	ret = devm_clk_bulk_get(dev, req_cnt, imx_pcie->clks);
> +	ret |= devm_clk_bulk_get_optional(dev, imx_pcie->drvdata->clks_optional_cnt,
> +					  imx_pcie->clks + req_cnt);

Why do you need to use 'clk_bulk' API to get a single reference clock? Just use
devm_clk_get_optional(dev, "ref")

And who is going to supply the reference clock in the absence of this clockn in
DT?

- Mani

>  	if (ret)
>  		return ret;
>  
> @@ -1480,6 +1484,7 @@ static const char * const imx8mm_clks[] = {"pcie_bus", "pcie", "pcie_aux"};
>  static const char * const imx8mq_clks[] = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux"};
>  static const char * const imx6sx_clks[] = {"pcie_bus", "pcie", "pcie_phy", "pcie_inbound_axi"};
>  static const char * const imx8q_clks[] = {"mstr", "slv", "dbi"};
> +static const char * const imx95_clks[] = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux", "ref"};
>  
>  static const struct imx_pcie_drvdata drvdata[] = {
>  	[IMX6Q] = {
> @@ -1592,9 +1597,11 @@ static const struct imx_pcie_drvdata drvdata[] = {
>  	},
>  	[IMX95] = {
>  		.variant = IMX95,
> -		.flags = IMX_PCIE_FLAG_HAS_SERDES,
> -		.clk_names = imx8mq_clks,
> -		.clks_cnt = ARRAY_SIZE(imx8mq_clks),
> +		.flags = IMX_PCIE_FLAG_HAS_SERDES |
> +			 IMX_PCIE_FLAG_SUPPORTS_SUSPEND,
> +		.clk_names = imx95_clks,
> +		.clks_cnt = ARRAY_SIZE(imx95_clks),
> +		.clks_optional_cnt = 1,
>  		.ltssm_off = IMX95_PE0_GEN_CTRL_3,
>  		.ltssm_mask = IMX95_PCIE_LTSSM_EN,
>  		.mode_off[0]  = IMX95_PE0_GEN_CTRL_1,
> -- 
> 2.37.1
>
Richard Zhu Nov. 18, 2024, 2:59 a.m. UTC | #2 
> -----Original Message-----
> From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Sent: 2024年11月15日 14:38
> To: Hongxing Zhu <hongxing.zhu@nxp.com>
> Cc: l.stach@pengutronix.de; bhelgaas@google.com; lpieralisi@kernel.org;
> kw@linux.com; robh@kernel.org; krzk+dt@kernel.org; conor+dt@kernel.org;
> shawnguo@kernel.org; Frank Li <frank.li@nxp.com>;
> s.hauer@pengutronix.de; festevam@gmail.com; imx@lists.linux.dev;
> kernel@pengutronix.de; linux-pci@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org;
> linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v6 02/10] PCI: imx6: Add ref clock for i.MX95 PCIe
> 
> On Fri, Nov 01, 2024 at 03:06:02PM +0800, Richard Zhu wrote:
> > Add "ref" clock to enable reference clock. To avoid the DT
> > compatibility, i.MX95 REF clock might be optional.
> 
> Your wording is not correct. Perhaps you wanted to say, "To avoid breaking
> DT backwards compatibility"?
> 
Yes, you're right. Thanks.

> > Replace the
> > devm_clk_bulk_get() by devm_clk_bulk_get_optional() to fetch
> > i.MX95 PCIe optional clocks in driver.
> >
> > If use external clock, ref clock should point to external reference.
> >
> > If use internal clock, CREF_EN in LAST_TO_REG controls reference
> > output, which implement in drivers/clk/imx/clk-imx95-blk-ctl.c.
> >
> > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > Reviewed-by: Frank Li <Frank.Li@nxp.com>
> > ---
> >  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++++++++------
> >  1 file changed, 13 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > b/drivers/pci/controller/dwc/pci-imx6.c
> > index 808d1f105417..bc8567677a67 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -82,6 +82,7 @@ enum imx_pcie_variants {
> >  #define IMX_PCIE_FLAG_HAS_SERDES		BIT(6)
> >  #define IMX_PCIE_FLAG_SUPPORT_64BIT		BIT(7)
> >  #define IMX_PCIE_FLAG_CPU_ADDR_FIXUP		BIT(8)
> > +#define IMX_PCIE_FLAG_CUSTOM_PME_TURNOFF	BIT(9)
> >
> >  #define imx_check_flag(pci, val)	(pci->drvdata->flags & val)
> >
> > @@ -98,6 +99,7 @@ struct imx_pcie_drvdata {
> >  	const char *gpr;
> >  	const char * const *clk_names;
> >  	const u32 clks_cnt;
> > +	const u32 clks_optional_cnt;
> >  	const u32 ltssm_off;
> >  	const u32 ltssm_mask;
> >  	const u32 mode_off[IMX_PCIE_MAX_INSTANCES]; @@ -1278,9 +1280,8
> @@
> > static int imx_pcie_probe(struct platform_device *pdev)
> >  	struct device_node *np;
> >  	struct resource *dbi_base;
> >  	struct device_node *node = dev->of_node;
> > -	int ret;
> > +	int ret, i, req_cnt;
> >  	u16 val;
> > -	int i;
> >
> >  	imx_pcie = devm_kzalloc(dev, sizeof(*imx_pcie), GFP_KERNEL);
> >  	if (!imx_pcie)
> > @@ -1330,7 +1331,10 @@ static int imx_pcie_probe(struct
> platform_device *pdev)
> >  		imx_pcie->clks[i].id = imx_pcie->drvdata->clk_names[i];
> >
> >  	/* Fetch clocks */
> > -	ret = devm_clk_bulk_get(dev, imx_pcie->drvdata->clks_cnt,
> imx_pcie->clks);
> > +	req_cnt = imx_pcie->drvdata->clks_cnt -
> imx_pcie->drvdata->clks_optional_cnt;
> > +	ret = devm_clk_bulk_get(dev, req_cnt, imx_pcie->clks);
> > +	ret |= devm_clk_bulk_get_optional(dev,
> imx_pcie->drvdata->clks_optional_cnt,
> > +					  imx_pcie->clks + req_cnt);
> 
> Why do you need to use 'clk_bulk' API to get a single reference clock? Just
> use devm_clk_get_optional(dev, "ref")
It's easier to add more optional clks in future. I can change to use
devm_clk_get_optional(dev, "ref") here if you insistent.

> 
> And who is going to supply the reference clock in the absence of this clockn in
> DT?
When the "preview" version firmware is used, this clock is gated on in default.
In this case, hiso-blk-ctrl would gated on this clock in default state.

Best Regards
Richard Zhu
> 
> - Mani
> 
> >  	if (ret)
> >  		return ret;
> >
> > @@ -1480,6 +1484,7 @@ static const char * const imx8mm_clks[] =
> > {"pcie_bus", "pcie", "pcie_aux"};  static const char * const
> > imx8mq_clks[] = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux"};  static
> > const char * const imx6sx_clks[] = {"pcie_bus", "pcie", "pcie_phy",
> > "pcie_inbound_axi"};  static const char * const imx8q_clks[] =
> > {"mstr", "slv", "dbi"};
> > +static const char * const imx95_clks[] = {"pcie_bus", "pcie",
> > +"pcie_phy", "pcie_aux", "ref"};
> >
> >  static const struct imx_pcie_drvdata drvdata[] = {
> >  	[IMX6Q] = {
> > @@ -1592,9 +1597,11 @@ static const struct imx_pcie_drvdata drvdata[] =
> {
> >  	},
> >  	[IMX95] = {
> >  		.variant = IMX95,
> > -		.flags = IMX_PCIE_FLAG_HAS_SERDES,
> > -		.clk_names = imx8mq_clks,
> > -		.clks_cnt = ARRAY_SIZE(imx8mq_clks),
> > +		.flags = IMX_PCIE_FLAG_HAS_SERDES |
> > +			 IMX_PCIE_FLAG_SUPPORTS_SUSPEND,
> > +		.clk_names = imx95_clks,
> > +		.clks_cnt = ARRAY_SIZE(imx95_clks),
> > +		.clks_optional_cnt = 1,
> >  		.ltssm_off = IMX95_PE0_GEN_CTRL_3,
> >  		.ltssm_mask = IMX95_PCIE_LTSSM_EN,
> >  		.mode_off[0]  = IMX95_PE0_GEN_CTRL_1,
> > --
> > 2.37.1
> >
> 
> --
> மணிவண்ணன் சதாசிவம்
Richard Zhu Nov. 19, 2024, 5:38 a.m. UTC | #3 
> -----Original Message-----
> From: Hongxing Zhu
> Sent: 2024年11月18日 10:59
> To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Cc: l.stach@pengutronix.de; bhelgaas@google.com; lpieralisi@kernel.org;
> kw@linux.com; robh@kernel.org; krzk+dt@kernel.org; conor+dt@kernel.org;
> shawnguo@kernel.org; Frank Li <frank.li@nxp.com>; s.hauer@pengutronix.de;
> festevam@gmail.com; imx@lists.linux.dev; kernel@pengutronix.de;
> linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> devicetree@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: RE: [PATCH v6 02/10] PCI: imx6: Add ref clock for i.MX95 PCIe
> 
> > -----Original Message-----
> > From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > Sent: 2024年11月15日 14:38
> > To: Hongxing Zhu <hongxing.zhu@nxp.com>
> > Cc: l.stach@pengutronix.de; bhelgaas@google.com;
> > lpieralisi@kernel.org; kw@linux.com; robh@kernel.org;
> > krzk+dt@kernel.org; conor+dt@kernel.org; shawnguo@kernel.org; Frank Li
> > <frank.li@nxp.com>; s.hauer@pengutronix.de; festevam@gmail.com;
> > imx@lists.linux.dev; kernel@pengutronix.de; linux-pci@vger.kernel.org;
> > linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org;
> > linux-kernel@vger.kernel.org
> > Subject: Re: [PATCH v6 02/10] PCI: imx6: Add ref clock for i.MX95 PCIe
> >
> > On Fri, Nov 01, 2024 at 03:06:02PM +0800, Richard Zhu wrote:
> > > Add "ref" clock to enable reference clock. To avoid the DT
> > > compatibility, i.MX95 REF clock might be optional.
> >
> > Your wording is not correct. Perhaps you wanted to say, "To avoid
> > breaking DT backwards compatibility"?
> >
> Yes, you're right. Thanks.
> 
> > > Replace the
> > > devm_clk_bulk_get() by devm_clk_bulk_get_optional() to fetch
> > > i.MX95 PCIe optional clocks in driver.
> > >
> > > If use external clock, ref clock should point to external reference.
> > >
> > > If use internal clock, CREF_EN in LAST_TO_REG controls reference
> > > output, which implement in drivers/clk/imx/clk-imx95-blk-ctl.c.
> > >
> > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > Reviewed-by: Frank Li <Frank.Li@nxp.com>
> > > ---
> > >  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++++++++------
> > >  1 file changed, 13 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > index 808d1f105417..bc8567677a67 100644
> > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > @@ -82,6 +82,7 @@ enum imx_pcie_variants {
> > >  #define IMX_PCIE_FLAG_HAS_SERDES		BIT(6)
> > >  #define IMX_PCIE_FLAG_SUPPORT_64BIT		BIT(7)
> > >  #define IMX_PCIE_FLAG_CPU_ADDR_FIXUP		BIT(8)
> > > +#define IMX_PCIE_FLAG_CUSTOM_PME_TURNOFF	BIT(9)
> > >
> > >  #define imx_check_flag(pci, val)	(pci->drvdata->flags & val)
> > >
> > > @@ -98,6 +99,7 @@ struct imx_pcie_drvdata {
> > >  	const char *gpr;
> > >  	const char * const *clk_names;
> > >  	const u32 clks_cnt;
> > > +	const u32 clks_optional_cnt;
> > >  	const u32 ltssm_off;
> > >  	const u32 ltssm_mask;
> > >  	const u32 mode_off[IMX_PCIE_MAX_INSTANCES]; @@ -1278,9
> +1280,8
> > @@
> > > static int imx_pcie_probe(struct platform_device *pdev)
> > >  	struct device_node *np;
> > >  	struct resource *dbi_base;
> > >  	struct device_node *node = dev->of_node;
> > > -	int ret;
> > > +	int ret, i, req_cnt;
> > >  	u16 val;
> > > -	int i;
> > >
> > >  	imx_pcie = devm_kzalloc(dev, sizeof(*imx_pcie), GFP_KERNEL);
> > >  	if (!imx_pcie)
> > > @@ -1330,7 +1331,10 @@ static int imx_pcie_probe(struct
> > platform_device *pdev)
> > >  		imx_pcie->clks[i].id = imx_pcie->drvdata->clk_names[i];
> > >
> > >  	/* Fetch clocks */
> > > -	ret = devm_clk_bulk_get(dev, imx_pcie->drvdata->clks_cnt,
> > imx_pcie->clks);
> > > +	req_cnt = imx_pcie->drvdata->clks_cnt -
> > imx_pcie->drvdata->clks_optional_cnt;
> > > +	ret = devm_clk_bulk_get(dev, req_cnt, imx_pcie->clks);
> > > +	ret |= devm_clk_bulk_get_optional(dev,
> > imx_pcie->drvdata->clks_optional_cnt,
> > > +					  imx_pcie->clks + req_cnt);
> >
> > Why do you need to use 'clk_bulk' API to get a single reference clock?
> > Just use devm_clk_get_optional(dev, "ref")
> It's easier to add more optional clks in future. I can change to use
> devm_clk_get_optional(dev, "ref") here if you insistent.
Since the clock fetch is not distinguished by platforms explicitly.
devm_clk_get_optional(dev, "ref") can be used only when i.MX95 specification
 is added.
-       ret |= devm_clk_bulk_get_optional(dev, imx_pcie->drvdata->clks_optional_cnt,
-                                         imx_pcie->clks + req_cnt);
        if (ret)
                return ret;
+       for (i = 0; i < imx_pcie->drvdata->clks_optional_cnt; i++) {
+               imx_pcie->clks[req_cnt + i].clk = devm_clk_get_optional(dev,
+                               imx_pcie->drvdata->clk_names[req_cnt + i]);
+               if (IS_ERR(imx_pcie->clks[req_cnt + i].clk))
+                       return PTR_ERR(imx_pcie->clks[req_cnt + i].clk);
+       }

Or
-       ret |= devm_clk_bulk_get_optional(dev, imx_pcie->drvdata->clks_optional_cnt,
-                                         imx_pcie->clks + req_cnt);
        if (ret)
                return ret;
+       if (imx_pcie->drvdata->variant == IMX95) {
+               imx_pcie->clks[req_cnt].clk = devm_clk_get_optional(dev, "ref");
+               if (IS_ERR(imx_pcie->clks[req_cnt].clk))
+                       return PTR_ERR(imx_pcie->clks[req_cnt].clk);
+       }

Which one is better of these two changes?
Or
To keep codes simple and aligned, how about to keep the original one?

Best Regards
Richard Zhu

> 
> >
> > And who is going to supply the reference clock in the absence of this
> > clockn in DT?
> When the "preview" version firmware is used, this clock is gated on in default.
> In this case, hiso-blk-ctrl would gated on this clock in default state.
> 
> Best Regards
> Richard Zhu
> >
> > - Mani
> >
> > >  	if (ret)
> > >  		return ret;
> > >
> > > @@ -1480,6 +1484,7 @@ static const char * const imx8mm_clks[] =
> > > {"pcie_bus", "pcie", "pcie_aux"};  static const char * const
> > > imx8mq_clks[] = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux"};
> > > static const char * const imx6sx_clks[] = {"pcie_bus", "pcie",
> > > "pcie_phy", "pcie_inbound_axi"};  static const char * const
> > > imx8q_clks[] = {"mstr", "slv", "dbi"};
> > > +static const char * const imx95_clks[] = {"pcie_bus", "pcie",
> > > +"pcie_phy", "pcie_aux", "ref"};
> > >
> > >  static const struct imx_pcie_drvdata drvdata[] = {
> > >  	[IMX6Q] = {
> > > @@ -1592,9 +1597,11 @@ static const struct imx_pcie_drvdata
> > > drvdata[] =
> > {
> > >  	},
> > >  	[IMX95] = {
> > >  		.variant = IMX95,
> > > -		.flags = IMX_PCIE_FLAG_HAS_SERDES,
> > > -		.clk_names = imx8mq_clks,
> > > -		.clks_cnt = ARRAY_SIZE(imx8mq_clks),
> > > +		.flags = IMX_PCIE_FLAG_HAS_SERDES |
> > > +			 IMX_PCIE_FLAG_SUPPORTS_SUSPEND,
> > > +		.clk_names = imx95_clks,
> > > +		.clks_cnt = ARRAY_SIZE(imx95_clks),
> > > +		.clks_optional_cnt = 1,
> > >  		.ltssm_off = IMX95_PE0_GEN_CTRL_3,
> > >  		.ltssm_mask = IMX95_PCIE_LTSSM_EN,
> > >  		.mode_off[0]  = IMX95_PE0_GEN_CTRL_1,
> > > --
> > > 2.37.1
> > >
> >
> > --
> > மணிவண்ணன் சதாசிவம்
Manivannan Sadhasivam Nov. 22, 2024, 4:44 p.m. UTC | #4 
On Tue, Nov 19, 2024 at 05:38:30AM +0000, Hongxing Zhu wrote:
> > -----Original Message-----
> > From: Hongxing Zhu
> > Sent: 2024年11月18日 10:59
> > To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > Cc: l.stach@pengutronix.de; bhelgaas@google.com; lpieralisi@kernel.org;
> > kw@linux.com; robh@kernel.org; krzk+dt@kernel.org; conor+dt@kernel.org;
> > shawnguo@kernel.org; Frank Li <frank.li@nxp.com>; s.hauer@pengutronix.de;
> > festevam@gmail.com; imx@lists.linux.dev; kernel@pengutronix.de;
> > linux-pci@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> > devicetree@vger.kernel.org; linux-kernel@vger.kernel.org
> > Subject: RE: [PATCH v6 02/10] PCI: imx6: Add ref clock for i.MX95 PCIe
> > 
> > > -----Original Message-----
> > > From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > Sent: 2024年11月15日 14:38
> > > To: Hongxing Zhu <hongxing.zhu@nxp.com>
> > > Cc: l.stach@pengutronix.de; bhelgaas@google.com;
> > > lpieralisi@kernel.org; kw@linux.com; robh@kernel.org;
> > > krzk+dt@kernel.org; conor+dt@kernel.org; shawnguo@kernel.org; Frank Li
> > > <frank.li@nxp.com>; s.hauer@pengutronix.de; festevam@gmail.com;
> > > imx@lists.linux.dev; kernel@pengutronix.de; linux-pci@vger.kernel.org;
> > > linux-arm-kernel@lists.infradead.org; devicetree@vger.kernel.org;
> > > linux-kernel@vger.kernel.org
> > > Subject: Re: [PATCH v6 02/10] PCI: imx6: Add ref clock for i.MX95 PCIe
> > >
> > > On Fri, Nov 01, 2024 at 03:06:02PM +0800, Richard Zhu wrote:
> > > > Add "ref" clock to enable reference clock. To avoid the DT
> > > > compatibility, i.MX95 REF clock might be optional.
> > >
> > > Your wording is not correct. Perhaps you wanted to say, "To avoid
> > > breaking DT backwards compatibility"?
> > >
> > Yes, you're right. Thanks.
> > 
> > > > Replace the
> > > > devm_clk_bulk_get() by devm_clk_bulk_get_optional() to fetch
> > > > i.MX95 PCIe optional clocks in driver.
> > > >
> > > > If use external clock, ref clock should point to external reference.
> > > >
> > > > If use internal clock, CREF_EN in LAST_TO_REG controls reference
> > > > output, which implement in drivers/clk/imx/clk-imx95-blk-ctl.c.
> > > >
> > > > Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> > > > Reviewed-by: Frank Li <Frank.Li@nxp.com>
> > > > ---
> > > >  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++++++++------
> > > >  1 file changed, 13 insertions(+), 6 deletions(-)
> > > >
> > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c
> > > > b/drivers/pci/controller/dwc/pci-imx6.c
> > > > index 808d1f105417..bc8567677a67 100644
> > > > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > > > @@ -82,6 +82,7 @@ enum imx_pcie_variants {
> > > >  #define IMX_PCIE_FLAG_HAS_SERDES		BIT(6)
> > > >  #define IMX_PCIE_FLAG_SUPPORT_64BIT		BIT(7)
> > > >  #define IMX_PCIE_FLAG_CPU_ADDR_FIXUP		BIT(8)
> > > > +#define IMX_PCIE_FLAG_CUSTOM_PME_TURNOFF	BIT(9)
> > > >
> > > >  #define imx_check_flag(pci, val)	(pci->drvdata->flags & val)
> > > >
> > > > @@ -98,6 +99,7 @@ struct imx_pcie_drvdata {
> > > >  	const char *gpr;
> > > >  	const char * const *clk_names;
> > > >  	const u32 clks_cnt;
> > > > +	const u32 clks_optional_cnt;
> > > >  	const u32 ltssm_off;
> > > >  	const u32 ltssm_mask;
> > > >  	const u32 mode_off[IMX_PCIE_MAX_INSTANCES]; @@ -1278,9
> > +1280,8
> > > @@
> > > > static int imx_pcie_probe(struct platform_device *pdev)
> > > >  	struct device_node *np;
> > > >  	struct resource *dbi_base;
> > > >  	struct device_node *node = dev->of_node;
> > > > -	int ret;
> > > > +	int ret, i, req_cnt;
> > > >  	u16 val;
> > > > -	int i;
> > > >
> > > >  	imx_pcie = devm_kzalloc(dev, sizeof(*imx_pcie), GFP_KERNEL);
> > > >  	if (!imx_pcie)
> > > > @@ -1330,7 +1331,10 @@ static int imx_pcie_probe(struct
> > > platform_device *pdev)
> > > >  		imx_pcie->clks[i].id = imx_pcie->drvdata->clk_names[i];
> > > >
> > > >  	/* Fetch clocks */
> > > > -	ret = devm_clk_bulk_get(dev, imx_pcie->drvdata->clks_cnt,
> > > imx_pcie->clks);
> > > > +	req_cnt = imx_pcie->drvdata->clks_cnt -
> > > imx_pcie->drvdata->clks_optional_cnt;
> > > > +	ret = devm_clk_bulk_get(dev, req_cnt, imx_pcie->clks);
> > > > +	ret |= devm_clk_bulk_get_optional(dev,
> > > imx_pcie->drvdata->clks_optional_cnt,
> > > > +					  imx_pcie->clks + req_cnt);
> > >
> > > Why do you need to use 'clk_bulk' API to get a single reference clock?
> > > Just use devm_clk_get_optional(dev, "ref")
> > It's easier to add more optional clks in future. I can change to use
> > devm_clk_get_optional(dev, "ref") here if you insistent.
> Since the clock fetch is not distinguished by platforms explicitly.
> devm_clk_get_optional(dev, "ref") can be used only when i.MX95 specification
>  is added.
> -       ret |= devm_clk_bulk_get_optional(dev, imx_pcie->drvdata->clks_optional_cnt,
> -                                         imx_pcie->clks + req_cnt);
>         if (ret)
>                 return ret;
> +       for (i = 0; i < imx_pcie->drvdata->clks_optional_cnt; i++) {
> +               imx_pcie->clks[req_cnt + i].clk = devm_clk_get_optional(dev,
> +                               imx_pcie->drvdata->clk_names[req_cnt + i]);
> +               if (IS_ERR(imx_pcie->clks[req_cnt + i].clk))
> +                       return PTR_ERR(imx_pcie->clks[req_cnt + i].clk);
> +       }
> 
> Or
> -       ret |= devm_clk_bulk_get_optional(dev, imx_pcie->drvdata->clks_optional_cnt,
> -                                         imx_pcie->clks + req_cnt);
>         if (ret)
>                 return ret;
> +       if (imx_pcie->drvdata->variant == IMX95) {

Why do you need this check? If there is no clock, devm_clk_get_optional() will
return NULL, so you can just do IS_ERR() without any checks.

- Mani
diff mbox series

Patch

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 808d1f105417..bc8567677a67 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -82,6 +82,7 @@  enum imx_pcie_variants {
 #define IMX_PCIE_FLAG_HAS_SERDES		BIT(6)
 #define IMX_PCIE_FLAG_SUPPORT_64BIT		BIT(7)
 #define IMX_PCIE_FLAG_CPU_ADDR_FIXUP		BIT(8)
+#define IMX_PCIE_FLAG_CUSTOM_PME_TURNOFF	BIT(9)
 
 #define imx_check_flag(pci, val)	(pci->drvdata->flags & val)
 
@@ -98,6 +99,7 @@  struct imx_pcie_drvdata {
 	const char *gpr;
 	const char * const *clk_names;
 	const u32 clks_cnt;
+	const u32 clks_optional_cnt;
 	const u32 ltssm_off;
 	const u32 ltssm_mask;
 	const u32 mode_off[IMX_PCIE_MAX_INSTANCES];
@@ -1278,9 +1280,8 @@  static int imx_pcie_probe(struct platform_device *pdev)
 	struct device_node *np;
 	struct resource *dbi_base;
 	struct device_node *node = dev->of_node;
-	int ret;
+	int ret, i, req_cnt;
 	u16 val;
-	int i;
 
 	imx_pcie = devm_kzalloc(dev, sizeof(*imx_pcie), GFP_KERNEL);
 	if (!imx_pcie)
@@ -1330,7 +1331,10 @@  static int imx_pcie_probe(struct platform_device *pdev)
 		imx_pcie->clks[i].id = imx_pcie->drvdata->clk_names[i];
 
 	/* Fetch clocks */
-	ret = devm_clk_bulk_get(dev, imx_pcie->drvdata->clks_cnt, imx_pcie->clks);
+	req_cnt = imx_pcie->drvdata->clks_cnt - imx_pcie->drvdata->clks_optional_cnt;
+	ret = devm_clk_bulk_get(dev, req_cnt, imx_pcie->clks);
+	ret |= devm_clk_bulk_get_optional(dev, imx_pcie->drvdata->clks_optional_cnt,
+					  imx_pcie->clks + req_cnt);
 	if (ret)
 		return ret;
 
@@ -1480,6 +1484,7 @@  static const char * const imx8mm_clks[] = {"pcie_bus", "pcie", "pcie_aux"};
 static const char * const imx8mq_clks[] = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux"};
 static const char * const imx6sx_clks[] = {"pcie_bus", "pcie", "pcie_phy", "pcie_inbound_axi"};
 static const char * const imx8q_clks[] = {"mstr", "slv", "dbi"};
+static const char * const imx95_clks[] = {"pcie_bus", "pcie", "pcie_phy", "pcie_aux", "ref"};
 
 static const struct imx_pcie_drvdata drvdata[] = {
 	[IMX6Q] = {
@@ -1592,9 +1597,11 @@  static const struct imx_pcie_drvdata drvdata[] = {
 	},
 	[IMX95] = {
 		.variant = IMX95,
-		.flags = IMX_PCIE_FLAG_HAS_SERDES,
-		.clk_names = imx8mq_clks,
-		.clks_cnt = ARRAY_SIZE(imx8mq_clks),
+		.flags = IMX_PCIE_FLAG_HAS_SERDES |
+			 IMX_PCIE_FLAG_SUPPORTS_SUSPEND,
+		.clk_names = imx95_clks,
+		.clks_cnt = ARRAY_SIZE(imx95_clks),
+		.clks_optional_cnt = 1,
 		.ltssm_off = IMX95_PE0_GEN_CTRL_3,
 		.ltssm_mask = IMX95_PCIE_LTSSM_EN,
 		.mode_off[0]  = IMX95_PE0_GEN_CTRL_1,