netdev - Re: [PATCHv3 2/4] net: phy: extend fixed driver with fixed_phy_register()

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Message-Id: <20140308042102.9BAE6C41032@trevor.secretlab.ca>
Date:	Sat, 08 Mar 2014 04:21:02 +0000
From:	Grant Likely <grant.likely@...retlab.ca>
To:	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
	devicetree@...r.kernel.org
Cc:	Lior Amsalem <alior@...vell.com>,
	Mark Rutland <mark.rutland@....com>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Christian Gmeiner <christian.gmeiner@...il.com>,
	Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>,
	Gregory Clement <gregory.clement@...e-electrons.com>,
	Florian Fainelli <florian@...nwrt.org>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCHv3 2/4] net: phy: extend fixed driver with fixed_phy_register()

On Tue,  4 Mar 2014 11:58:22 +0100, Thomas Petazzoni <thomas.petazzoni@...e-electrons.com> wrote:
> The existing fixed_phy_add() function has several drawbacks that
> prevents it from being used as is for OF-based declaration of fixed
> PHYs:
> 
>  * The address of the PHY on the fake bus needs to be passed, while a
>    dynamic allocation is desired.
> 
>  * Since the phy_device instantiation is post-poned until the next
>    mdiobus scan, there is no way to associate the fixed PHY with its
>    OF node, which later prevents of_phy_connect() from finding this
>    fixed PHY from a given OF node.
> 
> To solve this, this commit introduces fixed_phy_register(), which will
> allocate an available PHY address, add the PHY using fixed_phy_add()
> and instantiate the phy_device structure associated with the provided
> OF node.

The phy address assignment is a little naive, but that can be fixed in a
follow-up patch (see below for a suggestion)

Acked-by: Grant Likely <grant.likely@...aro.org>

> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
> ---
>  drivers/net/phy/fixed.c   | 61 +++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/phy_fixed.h | 11 +++++++++
>  2 files changed, 72 insertions(+)
> 
> diff --git a/drivers/net/phy/fixed.c b/drivers/net/phy/fixed.c
> index 0f02403..82095cc 100644
> --- a/drivers/net/phy/fixed.c
> +++ b/drivers/net/phy/fixed.c
> @@ -21,6 +21,7 @@
>  #include <linux/phy_fixed.h>
>  #include <linux/err.h>
>  #include <linux/slab.h>
> +#include <linux/of.h>
>  
>  #define MII_REGS_NUM 29
>  
> @@ -203,6 +204,66 @@ err_regs:
>  }
>  EXPORT_SYMBOL_GPL(fixed_phy_add);
>  
> +void fixed_phy_del(int phy_addr)
> +{
> +	struct fixed_mdio_bus *fmb = &platform_fmb;
> +	struct fixed_phy *fp, *tmp;
> +
> +	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
> +		if (fp->addr == phy_addr) {
> +			list_del(&fp->node);
> +			kfree(fp);
> +			return;
> +		}
> +	}
> +}
> +EXPORT_SYMBOL_GPL(fixed_phy_del);
> +
> +static int phy_fixed_addr;
> +static DEFINE_SPINLOCK(phy_fixed_addr_lock);
> +
> +int fixed_phy_register(unsigned int irq,
> +		       struct fixed_phy_status *status,
> +		       struct device_node *np)
> +{
> +	struct fixed_mdio_bus *fmb = &platform_fmb;
> +	struct phy_device *phy;
> +	int phy_addr;
> +	int ret;
> +
> +	/* Get the next available PHY address, up to PHY_MAX_ADDR */
> +	spin_lock(&phy_fixed_addr_lock);
> +	if (phy_fixed_addr == PHY_MAX_ADDR) {
> +		spin_unlock(&phy_fixed_addr_lock);
> +		return -ENOSPC;
> +	}
> +	phy_addr = phy_fixed_addr++;

If this instead looked over the fixed mdio bus list then an unallocated
address could be assigned without the global static.

> +	spin_unlock(&phy_fixed_addr_lock);
> +
> +	ret = fixed_phy_add(PHY_POLL, phy_addr, status);
> +	if (ret < 0)
> +		return ret;
> +
> +	phy = get_phy_device(fmb->mii_bus, phy_addr, false);
> +	if (!phy || IS_ERR(phy)) {
> +		fixed_phy_del(phy_addr);
> +		return -EINVAL;
> +	}
> +
> +	of_node_get(np);
> +	phy->dev.of_node = np;
> +
> +	ret = phy_device_register(phy);
> +	if (ret) {
> +		phy_device_free(phy);
> +		of_node_put(np);
> +		fixed_phy_del(phy_addr);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  static int __init fixed_mdio_bus_init(void)
>  {
>  	struct fixed_mdio_bus *fmb = &platform_fmb;
> diff --git a/include/linux/phy_fixed.h b/include/linux/phy_fixed.h
> index 509d8f5..902e8a1 100644
> --- a/include/linux/phy_fixed.h
> +++ b/include/linux/phy_fixed.h
> @@ -9,15 +9,26 @@ struct fixed_phy_status {
>  	int asym_pause;
>  };
>  
> +struct device_node;
> +
>  #ifdef CONFIG_FIXED_PHY
>  extern int fixed_phy_add(unsigned int irq, int phy_id,
>  			 struct fixed_phy_status *status);
> +extern int fixed_phy_register(unsigned int irq,
> +			      struct fixed_phy_status *status,
> +			      struct device_node *np);
>  #else
>  static inline int fixed_phy_add(unsigned int irq, int phy_id,
>  				struct fixed_phy_status *status)
>  {
>  	return -ENODEV;
>  }
> +extern int fixed_phy_register(unsigned int irq,
> +			      struct fixed_phy_status *status,
> +			      struct device_node *np)
> +{
> +	return -ENODEV;
> +}
>  #endif /* CONFIG_FIXED_PHY */
>  
>  /*
> -- 
> 1.8.3.2
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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