[PATCH] net: ethernet: cpsw-phy-sel: prefer phandle for phy sel and update binding

[PATCH] net: ethernet: cpsw-phy-sel: prefer phandle for phy sel and update binding

[Tony Lindgren]

The cpsw-phy-sel device is not a child of the cpsw interconnect target
module. It lives in the system control module.

Let's fix this issue by trying to use cpsw-phy-sel phandle first if it
exists and if not fall back to current usage of trying to find the
cpsw-phy-sel child. That way the phy sel driver can be a child of the
system control module where it belongs in the device tree.

Without this fix, we cannot have a proper interconnect target module
hierarchy in device tree for things like genpd.

For documenting it, looks like the cpsw-phy-sel is used for all cpsw device
tree nodes. It's missing the related binding documentation, so let's also
update the binding documentation accordingly.

Cc: devicetree@vger.kernel.org
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>
Cc: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 Documentation/devicetree/bindings/net/cpsw.txt | 5 +++++
 drivers/net/ethernet/ti/cpsw-phy-sel.c         | 9 ++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/cpsw.txt b/Documentation/devicetree/bindings/net/cpsw.txt
--- a/Documentation/devicetree/bindings/net/cpsw.txt
+++ b/Documentation/devicetree/bindings/net/cpsw.txt
@@ -19,6 +19,9 @@ Required properties:
 - slaves		: Specifies number for slaves
 - active_slave		: Specifies the slave to use for time stamping,
 			  ethtool and SIOCGMIIPHY
+- cpsw-phy-sel		: Specifies the phandle to the CPSW phy mode selection
+			  device. Note that in legacy cases cpsw-phy-sel may be
+			  a child device instead of a phandle.
 
 Optional properties:
 - ti,hwmods		: Must be "cpgmac0"
@@ -75,6 +78,7 @@ Examples:
 		cpts_clock_mult = <0x80000000>;
 		cpts_clock_shift = <29>;
 		syscon = <&cm>;
+		cpsw-phy-sel = <&phy_sel>;
 		cpsw_emac0: slave@0 {
 			phy_id = <&davinci_mdio>, <0>;
 			phy-mode = "rgmii-txid";
@@ -103,6 +107,7 @@ Examples:
 		cpts_clock_mult = <0x80000000>;
 		cpts_clock_shift = <29>;
 		syscon = <&cm>;
+		cpsw-phy-sel = <&phy_sel>;
 		cpsw_emac0: slave@0 {
 			phy_id = <&davinci_mdio>, <0>;
 			phy-mode = "rgmii-txid";
diff --git a/drivers/net/ethernet/ti/cpsw-phy-sel.c b/drivers/net/ethernet/ti/cpsw-phy-sel.c
--- a/drivers/net/ethernet/ti/cpsw-phy-sel.c
+++ b/drivers/net/ethernet/ti/cpsw-phy-sel.c
@@ -170,10 +170,13 @@ void cpsw_phy_sel(struct device *dev, phy_interface_t phy_mode, int slave)
 	struct device_node *node;
 	struct cpsw_phy_sel_priv *priv;
 
-	node = of_get_child_by_name(dev->of_node, "cpsw-phy-sel");
+	node = of_parse_phandle(dev->of_node, "cpsw-phy-sel", 0);
 	if (!node) {
-		dev_err(dev, "Phy mode driver DT not found\n");
-		return;
+		node = of_get_child_by_name(dev->of_node, "cpsw-phy-sel");
+		if (!node) {
+			dev_err(dev, "Phy mode driver DT not found\n");
+			return;
+		}
 	}
 
 	dev = bus_find_device(&platform_bus_type, NULL, node, match);
-- 
2.17.1

Re: [PATCH] net: ethernet: cpsw-phy-sel: prefer phandle for phy sel and update binding

[Andrew Lunn]

> +++ b/Documentation/devicetree/bindings/net/cpsw.txt
> @@ -19,6 +19,9 @@ Required properties:
>  - slaves		: Specifies number for slaves
>  - active_slave		: Specifies the slave to use for time stamping,
>  			  ethtool and SIOCGMIIPHY
> +- cpsw-phy-sel		: Specifies the phandle to the CPSW phy mode selection
> +			  device. Note that in legacy cases cpsw-phy-sel may be
> +			  a child device instead of a phandle.

Hi Tony

It would be good to reference cpsw-phy-sel.txt.

>  Optional properties:
>  - ti,hwmods		: Must be "cpgmac0"
> @@ -75,6 +78,7 @@ Examples:
>  		cpts_clock_mult = <0x80000000>;
>  		cpts_clock_shift = <29>;
>  		syscon = <&cm>;
> +		cpsw-phy-sel = <&phy_sel>;
>  		cpsw_emac0: slave@0 {
>  			phy_id = <&davinci_mdio>, <0>;
>  			phy-mode = "rgmii-txid";
> @@ -103,6 +107,7 @@ Examples:
>  		cpts_clock_mult = <0x80000000>;
>  		cpts_clock_shift = <29>;
>  		syscon = <&cm>;
> +		cpsw-phy-sel = <&phy_sel>;
>  		cpsw_emac0: slave@0 {
>  			phy_id = <&davinci_mdio>, <0>;
>  			phy-mode = "rgmii-txid";
> diff --git a/drivers/net/ethernet/ti/cpsw-phy-sel.c b/drivers/net/ethernet/ti/cpsw-phy-sel.c
> --- a/drivers/net/ethernet/ti/cpsw-phy-sel.c
> +++ b/drivers/net/ethernet/ti/cpsw-phy-sel.c
> @@ -170,10 +170,13 @@ void cpsw_phy_sel(struct device *dev, phy_interface_t phy_mode, int slave)
>  	struct device_node *node;
>  	struct cpsw_phy_sel_priv *priv;
>  
> -	node = of_get_child_by_name(dev->of_node, "cpsw-phy-sel");
> +	node = of_parse_phandle(dev->of_node, "cpsw-phy-sel", 0);
>  	if (!node) {

Do you need to handle EPROBE_DEFER here? The phandle points to a
device which has not yet been loaded? I'm not sure exactly where it
will be returned, maybe it is bus_find_device(), but i expect to see
some handling of it somewhere in this function.

> -		dev_err(dev, "Phy mode driver DT not found\n");
> -		return;
> +		node = of_get_child_by_name(dev->of_node, "cpsw-phy-sel");
> +		if (!node) {
> +			dev_err(dev, "Phy mode driver DT not found\n");
> +			return;
> +		}
>  	}

	Andrew

Re: [PATCH] net: ethernet: cpsw-phy-sel: prefer phandle for phy sel and update binding

[Tony Lindgren]

* Andrew Lunn <andrew@lunn.ch> [180808 12:02]:
> > +++ b/Documentation/devicetree/bindings/net/cpsw.txt
> > @@ -19,6 +19,9 @@ Required properties:
> >  - slaves		: Specifies number for slaves
> >  - active_slave		: Specifies the slave to use for time stamping,
> >  			  ethtool and SIOCGMIIPHY
> > +- cpsw-phy-sel		: Specifies the phandle to the CPSW phy mode selection
> > +			  device. Note that in legacy cases cpsw-phy-sel may be
> > +			  a child device instead of a phandle.
> 
> Hi Tony
> 
> It would be good to reference cpsw-phy-sel.txt.

OK will add.

> > --- a/drivers/net/ethernet/ti/cpsw-phy-sel.c
> > +++ b/drivers/net/ethernet/ti/cpsw-phy-sel.c
> > @@ -170,10 +170,13 @@ void cpsw_phy_sel(struct device *dev, phy_interface_t phy_mode, int slave)
> >  	struct device_node *node;
> >  	struct cpsw_phy_sel_priv *priv;
> >  
> > -	node = of_get_child_by_name(dev->of_node, "cpsw-phy-sel");
> > +	node = of_parse_phandle(dev->of_node, "cpsw-phy-sel", 0);
> >  	if (!node) {
> 
> Do you need to handle EPROBE_DEFER here? The phandle points to a
> device which has not yet been loaded? I'm not sure exactly where it
> will be returned, maybe it is bus_find_device(), but i expect to see
> some handling of it somewhere in this function.

With the proper interconnect hierarchy in the device tree there should be
no EPROBE_DEFER happening here as the interconnects are probed in the
right order with the always on interrupt with system control module first :)

But then again, adding support for EPROBE_DEFER here won't hurt either,
will take a look.

Regards,

Tony

Re: [PATCH] net: ethernet: cpsw-phy-sel: prefer phandle for phy sel and update binding

[Tony Lindgren]

* Tony Lindgren <tony@atomide.com> [180808 13:52]:
> * Andrew Lunn <andrew@lunn.ch> [180808 12:02]:
> > 
> > Do you need to handle EPROBE_DEFER here? The phandle points to a
> > device which has not yet been loaded? I'm not sure exactly where it
> > will be returned, maybe it is bus_find_device(), but i expect to see
> > some handling of it somewhere in this function.

If no device is found the driver just produces a warning currently.
And in that case cpsw attempts to continue with bootloader settings.

And looking at the caller function cpsw_slave_open() it also just
produces warnings for phy_connect() too..

I agree that in general this this whole pile of cpsw related drivers sure
could use some better error handling. Starting with making cpsw_slave_open()
and cpsw_phy_sel() return errors instead of just ignoring them might be a
good start.

Grygorii, care to add that note of things to do into your cpsw maintainer
hat?

> With the proper interconnect hierarchy in the device tree there should be
> no EPROBE_DEFER happening here as the interconnects are probed in the
> right order with the always on interrupt with system control module first :)
>
> But then again, adding support for EPROBE_DEFER here won't hurt either,
> will take a look.

I'll just add some notes about that to the patch description considering
the above.

Regards,

Tony

Re: [PATCH] net: ethernet: cpsw-phy-sel: prefer phandle for phy sel and update binding

[Grygorii Strashko]

On 08/09/2018 05:46 AM, Tony Lindgren wrote:
> * Tony Lindgren <tony@atomide.com> [180808 13:52]:
>> * Andrew Lunn <andrew@lunn.ch> [180808 12:02]:
>>>
>>> Do you need to handle EPROBE_DEFER here? The phandle points to a
>>> device which has not yet been loaded? I'm not sure exactly where it
>>> will be returned, maybe it is bus_find_device(), but i expect to see
>>> some handling of it somewhere in this function.
> 
> If no device is found the driver just produces a warning currently.
> And in that case cpsw attempts to continue with bootloader settings.
> 
> And looking at the caller function cpsw_slave_open() it also just
> produces warnings for phy_connect() too..
> 
> I agree that in general this this whole pile of cpsw related drivers sure
> could use some better error handling. Starting with making cpsw_slave_open()
> and cpsw_phy_sel() return errors instead of just ignoring them might be a
> good start.
> 
> Grygorii, care to add that note of things to do into your cpsw maintainer
> hat?

Right. EPROBE_DEFER not supported for this module as of now.

> 
>> With the proper interconnect hierarchy in the device tree there should be
>> no EPROBE_DEFER happening here as the interconnects are probed in the
>> right order with the always on interrupt with system control module first :)
>>
>> But then again, adding support for EPROBE_DEFER here won't hurt either,
>> will take a look.
> 
> I'll just add some notes about that to the patch description considering
> the above.

thanks Tony.

-- 
regards,
-grygorii