netdev - Re: [PATCH V2 net-next 4/5] net: mdio: of: Register discovered MII time stampers.

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Date:   Sun, 7 Oct 2018 11:14:38 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Richard Cochran <richardcochran@...il.com>, netdev@...r.kernel.org
Cc:     devicetree@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
        David Miller <davem@...emloft.net>,
        Jacob Keller <jacob.e.keller@...el.com>,
        Mark Rutland <mark.rutland@....com>,
        Miroslav Lichvar <mlichvar@...hat.com>,
        Rob Herring <robh+dt@...nel.org>,
        Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH V2 net-next 4/5] net: mdio: of: Register discovered MII
 time stampers.



On 10/07/18 10:38, Richard Cochran wrote:
> When parsing a PHY node, register its time stamper, if any, and attach
> the instance to the PHY device.
> 
> Signed-off-by: Richard Cochran <richardcochran@...il.com>
> ---
>  drivers/net/phy/phy_device.c |  3 +++
>  drivers/of/of_mdio.c         | 26 ++++++++++++++++++++++++++
>  2 files changed, 29 insertions(+)
> 
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index a454432d166f..c24bce9b7270 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -833,6 +833,9 @@ EXPORT_SYMBOL(phy_device_register);
>   */
>  void phy_device_remove(struct phy_device *phydev)
>  {
> +	if (phydev->mii_ts)
> +		unregister_mii_timestamper(phydev->mii_ts);
> +
>  	device_del(&phydev->mdio.dev);
>  
>  	/* Assert the reset signal */
> diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
> index f76c10ecc616..7699f167e4a9 100644
> --- a/drivers/of/of_mdio.c
> +++ b/drivers/of/of_mdio.c
> @@ -44,14 +44,38 @@ static int of_get_phy_id(struct device_node *device, u32 *phy_id)
>  	return -EINVAL;
>  }
>  
> +struct mii_timestamper *of_find_mii_timestamper(struct device_node *node)
> +{
> +	struct of_phandle_args args;
> +	unsigned int port = 0;
> +	int err;
> +
> +	err = of_parse_phandle_with_args(node, "timestamper",
> +					 "#phandle-cells", 0, &args);

There appears to be a binding document missing to describe what a
timerstamper provider is. Using a more specific name than
"#phandle-cells" is preferred when dealing with specific devices, e.g:

interrupt-controller/#interrupt-cells
clocks/#clock-cells

etc.

So I would go with #timestamp-cells here, and define what the cell sie
and format should be in a separate "dt-bindings" prefixed patch that the
Device Tree folks can also comment on.

> +	if (err == -ENOENT)
> +		return NULL;
> +	else if (err)
> +		return ERR_PTR(err);
> +
> +	if (args.args_count >= 1)
> +		port = args.args[0];

If it's greater than one, than it is an error, and it should be flagged
as such.

The idea looks good though, should of_find_mii_timestamper() somehow be
made conditional to CONFIG_PTP and we should have a stub for when it is
disabled?

> +
> +	return register_mii_timestamper(args.np, port);
> +}
> +
>  static int of_mdiobus_register_phy(struct mii_bus *mdio,
>  				    struct device_node *child, u32 addr)
>  {
> +	struct mii_timestamper *mii_ts;
>  	struct phy_device *phy;
>  	bool is_c45;
>  	int rc;
>  	u32 phy_id;
>  
> +	mii_ts = of_find_mii_timestamper(child);
> +	if (IS_ERR(mii_ts))
> +		return PTR_ERR(mii_ts);
> +
>  	is_c45 = of_device_is_compatible(child,
>  					 "ethernet-phy-ieee802.3-c45");
>  
> @@ -97,6 +121,8 @@ static int of_mdiobus_register_phy(struct mii_bus *mdio,
>  		return rc;
>  	}
>  
> +	phy->mii_ts = mii_ts;
> +
>  	dev_dbg(&mdio->dev, "registered phy %s at address %i\n",
>  		child->name, addr);
>  	return 0;
> 

-- 
Florian