drivers: phy: add generic PHY framework

Commit Message

Kishon Vijay Abraham I Sept. 26, 2012, 3:01 p.m. UTC

The PHY framework provides a set of API's for the PHY drivers to
create/destroy a PHY and API's for the PHY users to obtain a reference to the
PHY with or without using phandle. To obtain a reference to the PHY without
using phandle, the platform specfic intialization code (say from board file)
should have already called phy_bind with the binding information. The binding
information consists of phy's device name, phy user device name and an index.
The index is used when the same phy user binds to mulitple phys.

PHY drivers should create the PHY by passing phy_descriptor that has
describes the PHY (label, type etc..) and ops like init, exit, suspend, resume,
poweron, shutdown.

Cc: Felipe Balbi <[e-mail]>
Cc: Marc Kleine-Budde <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>
---
Did testing (phandle path) to some extent by hacking omap-usb2 to use this
new framework. (completely modifying omap-usb2 to use this framework will
take some time mostly because of the OTG stuff). Also perfomed non-dt
testing by moving to a older kernel. Any kind of testing for this patch is
welcome :-)
 MAINTAINERS             |    7 +
 drivers/Kconfig         |    2 +
 drivers/Makefile        |    2 +
 drivers/phy/Kconfig     |   13 ++
 drivers/phy/Makefile    |    5 +
 drivers/phy/phy-core.c  |  445 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/phy/phy.h |  182 +++++++++++++++++++
 7 files changed, 656 insertions(+)
 create mode 100644 drivers/phy/Kconfig
 create mode 100644 drivers/phy/Makefile
 create mode 100644 drivers/phy/phy-core.c
 create mode 100644 include/linux/phy/phy.h

Comments

Joe Perches Sept. 26, 2012, 4:57 p.m. UTC | #1

On Wed, 2012-09-26 at 20:31 +0530, Kishon Vijay Abraham I wrote:
> The PHY framework provides a set of API's for the PHY drivers to
> create/destroy a PHY and API's 

Just some trivial notes.

> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
[]
> @@ -0,0 +1,445 @@
[]
> +static void devm_phy_release(struct device *dev, void *res)
> +{
> +	struct phy *phy = *(struct phy **)res;

That's a bit twisted isn't it?
Perhaps
	struct phy *phy = res;

[]

> +static int devm_phy_match(struct device *dev, void *res, void *match_data)
> +{
> +	return res == match_data;

static bool devm_phy_match(etc...)

[]

> +struct phy *devm_of_phy_get(struct device *dev, const char *phandle, u8 index)
> +{
> +	struct phy *phy = NULL, **ptr;
> +	struct device_node *node;
> +
> +	if (!dev->of_node) {
> +		dev_dbg(dev, "device does not have a device node entry\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	node = of_parse_phandle(dev->of_node, phandle, index);
> +	if (!node) {
> +		dev_dbg(dev, "failed to get %s phandle in %s node\n", phandle,
> +			dev->of_node->full_name);
> +		return ERR_PTR(-ENODEV);
> +	}
> +
> +	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);

Is this the right size?

Because ptr is **, perhaps sizeof(struct phy) is clearer.

> +	if (!ptr) {
> +		dev_dbg(dev, "failed to allocate memory for devres\n");

alloc failures generally don't need specific OOM messages
as the general alloc OOM dumps stack.

> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	mutex_lock(&phy_list_mutex);
> +
> +	phy = of_phy_lookup(dev, node);
> +	if (IS_ERR(phy) || !phy->dev.class ||
> +			!try_module_get(phy->dev.class->owner)) {

I think it's tasteful coding style to align like:

	if (IS_ERR(phy) || !phy->dev.class ||
	    !try_module_get(phy->dev.class->owner)) {
[]

> +struct phy *phy_create(struct device *dev, struct phy_descriptor *desc)
> +{
> +	int ret;
> +	struct phy *phy;
> +	struct phy_bind *phy_bind;
> +	const char *devname = NULL;
> +
> +	if (!dev || !desc) {
> +		dev_err(dev, "no descriptor/device provided for PHY\n");
> +		ret = -EINVAL;
> +		goto err0;
> +	}
> +
> +	if (!desc->ops) {
> +		dev_err(dev, "no PHY ops provided\n");
> +		ret = -EINVAL;
> +		goto err0;
> +	}
> +
> +	phy = kzalloc(sizeof(*phy), GFP_KERNEL);
> +	if (!phy) {
> +		dev_err(dev, "no memory for PHY\n");

No OOM message required...

[]

> +static int __init phy_core_init(void)
> +{
> +	phy_class = class_create(THIS_MODULE, "phy");
> +	if (IS_ERR(phy_class)) {
> +		pr_err("failed to create phy class --> %ld\n",
> +			PTR_ERR(phy_class));

You might add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
before any include so that pr_<levels> are prefixed.

cheers, Joe

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Greg Kroah-Hartman Sept. 26, 2012, 5:04 p.m. UTC | #2

On Wed, Sep 26, 2012 at 08:31:15PM +0530, Kishon Vijay Abraham I wrote:
> The PHY framework provides a set of API's for the PHY drivers to
> create/destroy a PHY and API's for the PHY users to obtain a reference to the
> PHY with or without using phandle. To obtain a reference to the PHY without
> using phandle, the platform specfic intialization code (say from board file)
> should have already called phy_bind with the binding information. The binding
> information consists of phy's device name, phy user device name and an index.
> The index is used when the same phy user binds to mulitple phys.
> 
> PHY drivers should create the PHY by passing phy_descriptor that has
> describes the PHY (label, type etc..) and ops like init, exit, suspend, resume,
> poweron, shutdown.

Do you have an example driver that uses this new framework?

How does it look in sysfs?  You need to add Documentation/ABI/ entries
for the sysfs files you created as well.

greg k-h
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David Miller Sept. 26, 2012, 5:08 p.m. UTC | #3

All networking patches must be submitted to [e-mail]

Thank you.
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Dmitry Torokhov Sept. 26, 2012, 5:41 p.m. UTC | #4

On Wednesday, September 26, 2012 09:57:57 AM Joe Perches wrote:
> On Wed, 2012-09-26 at 20:31 +0530, Kishon Vijay Abraham I wrote:
> > The PHY framework provides a set of API's for the PHY drivers to
> > create/destroy a PHY and API's
> 
> Just some trivial notes.
> 
> > diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> 
> []
> 
> > @@ -0,0 +1,445 @@
> 
> []
> 
> > +static void devm_phy_release(struct device *dev, void *res)
> > +{
> > +	struct phy *phy = *(struct phy **)res;
> 
> That's a bit twisted isn't it?
> Perhaps
> 	struct phy *phy = res;

No, because you really need to dereference ptr, not simply cast.

...

> > +
> > +	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);
> 
> Is this the right size?
> 
> Because ptr is **, perhaps sizeof(struct phy) is clearer.

But incorrect.

Thanks.

Marc Kleine-Budde Sept. 26, 2012, 6:01 p.m. UTC | #5

On 09/26/2012 07:41 PM, Dmitry Torokhov wrote:
> On Wednesday, September 26, 2012 09:57:57 AM Joe Perches wrote:
>> On Wed, 2012-09-26 at 20:31 +0530, Kishon Vijay Abraham I wrote:
>>> The PHY framework provides a set of API's for the PHY drivers to
>>> create/destroy a PHY and API's
>>
>> Just some trivial notes.
>>
>>> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
>>
>> []
>>
>>> @@ -0,0 +1,445 @@
>>
>> []
>>
>>> +static void devm_phy_release(struct device *dev, void *res)
>>> +{
>>> +	struct phy *phy = *(struct phy **)res;
>>
>> That's a bit twisted isn't it?
>> Perhaps
>> 	struct phy *phy = res;
> 
> No, because you really need to dereference ptr, not simply cast.

To avoid this confusion I suggest to create a struct phy_res. For now
its only member will be a pointer to a struct phy.

> 
> ...
> 
>>> +
>>> +	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);
>>
>> Is this the right size?
>>
>> Because ptr is **, perhaps sizeof(struct phy) is clearer.
> 
> But incorrect.

A proper struct will make the code more readable here, too.

Marc

Marc Kleine-Budde Sept. 26, 2012, 8:07 p.m. UTC | #6

On 09/26/2012 05:01 PM, Kishon Vijay Abraham I wrote:
> The PHY framework provides a set of API's for the PHY drivers to
> create/destroy a PHY and API's for the PHY users to obtain a reference to the
> PHY with or without using phandle. To obtain a reference to the PHY without
> using phandle, the platform specfic intialization code (say from board file)
> should have already called phy_bind with the binding information. The binding
> information consists of phy's device name, phy user device name and an index.
> The index is used when the same phy user binds to mulitple phys.
> 
> PHY drivers should create the PHY by passing phy_descriptor that has
> describes the PHY (label, type etc..) and ops like init, exit, suspend, resume,
> poweron, shutdown.
> 
> Cc: Felipe Balbi <[e-mail]>
> Cc: Marc Kleine-Budde <[e-mail]>
> Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

I suggest to talk to someone who is familiar with the linux-bus
abstraction. Adding devices, drivers, matching them and maintaining
binding information should not be reinvented.

See more comments inline.

> ---
> Did testing (phandle path) to some extent by hacking omap-usb2 to use this
> new framework. (completely modifying omap-usb2 to use this framework will
> take some time mostly because of the OTG stuff). Also perfomed non-dt
> testing by moving to a older kernel. Any kind of testing for this patch is
> welcome :-)
>  MAINTAINERS             |    7 +
>  drivers/Kconfig         |    2 +
>  drivers/Makefile        |    2 +
>  drivers/phy/Kconfig     |   13 ++
>  drivers/phy/Makefile    |    5 +
>  drivers/phy/phy-core.c  |  445 +++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/phy/phy.h |  182 +++++++++++++++++++
>  7 files changed, 656 insertions(+)
>  create mode 100644 drivers/phy/Kconfig
>  create mode 100644 drivers/phy/Makefile
>  create mode 100644 drivers/phy/phy-core.c
>  create mode 100644 include/linux/phy/phy.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index ea0519a..48f3cfb 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -3078,6 +3078,13 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git
>  S:	Maintained
>  F:	include/asm-generic
>  
> +GENERIC PHY FRAMEWORK
> +M:	Kishon Vijay Abraham I <[e-mail]>
> +L:	[e-mail]
> +S:	Supported
> +F:	drivers/phy/
> +F:	include/linux/phy/
> +
>  GENERIC UIO DRIVER FOR PCI DEVICES
>  M:	"Michael S. Tsirkin" <[e-mail]>
>  L:	[e-mail]
> diff --git a/drivers/Kconfig b/drivers/Kconfig
> index 324e958..d289df5 100644
> --- a/drivers/Kconfig
> +++ b/drivers/Kconfig
> @@ -154,4 +154,6 @@ source "drivers/vme/Kconfig"
>  
>  source "drivers/pwm/Kconfig"
>  
> +source "drivers/phy/Kconfig"
> +
>  endmenu
> diff --git a/drivers/Makefile b/drivers/Makefile
> index d64a0f7..e39252d 100644
> --- a/drivers/Makefile
> +++ b/drivers/Makefile
> @@ -40,6 +40,8 @@ obj-y				+= char/
>  # gpu/ comes after char for AGP vs DRM startup
>  obj-y				+= gpu/
>  
> +obj-y				+= phy/
> +
>  obj-$(CONFIG_CONNECTOR)		+= connector/
>  
>  # i810fb and intelfb depend on char/agp/
> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> new file mode 100644
> index 0000000..34f7077
> --- /dev/null
> +++ b/drivers/phy/Kconfig
> @@ -0,0 +1,13 @@
> +#
> +# PHY
> +#
> +
> +menuconfig GENERIC_PHY
> +	tristate "Generic PHY Support"
> +	help
> +	  Generic PHY support.
> +
> +	  This framework is designed to provide a generic interface for PHY
> +	  devices present in the kernel. This layer will have the generic
> +	  API by which phy drivers can create PHY using the phy framework and
> +	  phy users can obtain reference to the PHY.
> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
> new file mode 100644
> index 0000000..9e9560f
> --- /dev/null
> +++ b/drivers/phy/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for the phy drivers.
> +#
> +
> +obj-$(CONFIG_GENERIC_PHY)	+= phy-core.o
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> new file mode 100644
> index 0000000..bf47a88
> --- /dev/null
> +++ b/drivers/phy/phy-core.c
> @@ -0,0 +1,445 @@
> +/*
> + * phy-core.c  --  Generic Phy framework.
> + *
> + * Copyright (C) 2012 Texas Instruments
> + *
> + * Author: Kishon Vijay Abraham I <[e-mail]>
> + *
> + * This program is free software; you can redistribute  it and/or modify it
> + * under  the terms of  the GNU General  Public License as published by the
> + * Free Software Foundation;  either version 2 of the  License, or (at your
> + * option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/export.h>
> +#include <linux/module.h>
> +#include <linux/err.h>
> +#include <linux/device.h>
> +#include <linux/slab.h>
> +#include <linux/of.h>
> +#include <linux/phy/phy.h>
> +
> +static struct class *phy_class;
> +static LIST_HEAD(phy_list);
> +static DEFINE_MUTEX(phy_list_mutex);
> +static LIST_HEAD(phy_bind_list);
> +
> +static void devm_phy_release(struct device *dev, void *res)
> +{
> +	struct phy *phy = *(struct phy **)res;
> +
> +	phy_put(phy);
> +}
> +
> +static int devm_phy_match(struct device *dev, void *res, void *match_data)
> +{
> +	return res == match_data;
> +}
> +
> +static struct phy *phy_lookup(struct device *dev, u8 index)
> +{
> +	struct phy_bind *phy_bind = NULL;
> +
> +	list_for_each_entry(phy_bind, &phy_bind_list, list) {
> +		if (!(strcmp(phy_bind->dev_name, dev_name(dev))) &&
> +				phy_bind->index == index)
> +			return phy_bind->phy;
> +	}
> +
> +	return ERR_PTR(-ENODEV);
> +}
> +
> +static struct phy *of_phy_lookup(struct device *dev, struct device_node *node)
> +{
> +	int index = 0;
> +	struct phy *phy;
> +	struct phy_bind *phy_map = NULL;
> +
> +	list_for_each_entry(phy_map, &phy_bind_list, list)
> +		if (!(strcmp(phy_map->dev_name, dev_name(dev))))
> +			index++;

This automatically index generation looks error prone to me. It might
differ from the "index" in the DT phandle.

> +
> +	list_for_each_entry(phy, &phy_list, head) {
> +		if (node != phy->desc->of_node)
> +			continue;
> +
> +		phy_map = phy_bind(dev_name(dev), index, dev_name(&phy->dev));

Why does a lookup create a phy binding? From my point of view the lookup
function should do the lookup, the *_phy_get should create the binding.

Again - you should really have a look at the linux "bus" subsystem. It's
used all over the kernel to create and maintain bindings of all sort of
driver/devices. I don't know how to integrate this into the phy
infrastructure, but I'm pretty sure it will fit.

> +		if (!IS_ERR(phy_map)) {
> +			phy_map->phy = phy;
> +			phy_map->auto_bind = true;
> +		}
> +
> +		return phy;
> +	}
> +
> +	return ERR_PTR(-ENODEV);
> +}
> +
> +/**
> + * devm_phy_get - lookup and obtain a reference to a phy.
> + * @dev: device that requests this phy
> + * @index: the index of the phy
> + *
> + * Gets the phy using phy_get(), and associates a device with it using
> + * devres. On driver detach, release function is invoked on the devres data,
> + * then, devres data is freed.
> + */
> +struct phy *devm_phy_get(struct device *dev, u8 index)
> +{
> +	struct phy **ptr, *phy;
> +
> +	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);
> +	if (!ptr)
> +		return NULL;
> +
> +	phy = phy_get(dev, index);
> +	if (!IS_ERR(phy)) {
> +		*ptr = phy;
> +		devres_add(dev, ptr);
> +	} else
> +		devres_free(ptr);

Please use { } in else, too.

> +
> +	return phy;
> +}
> +EXPORT_SYMBOL_GPL(devm_phy_get);
> +
> +/**
> + * devm_phy_put - release the PHY
> + * @dev: device that wants to release this phy
> + * @phy: the phy returned by devm_phy_get()
> + *
> + * destroys the devres associated with this phy and invokes phy_put
> + * to release the phy.
> + */
> +void devm_phy_put(struct device *dev, struct phy *phy)
> +{
> +	int r;
> +
> +	r = devres_destroy(dev, devm_phy_release, devm_phy_match, phy);
> +	dev_WARN_ONCE(dev, r, "couldn't find PHY resource\n");
> +}
> +EXPORT_SYMBOL_GPL(devm_phy_put);
> +
> +/**
> + * devm_of_phy_get - lookup and obtain a reference to a phy by phandle
> + * @dev: device that requests this phy
> + * @phandle: name of the property holding the phy phandle value
> + * @index: the index of the phy
> + *
> + * Returns the phy driver associated with the given phandle value,
> + * after getting a refcount to it or -ENODEV if there is no such phy or
> + * -EPROBE_DEFER if there is a phandle to the phy, but the device is
> + * not yet loaded. While at that, it also associates the device with the
> + * phy using devres. On driver detach, release function is invoked on the
> + * devres data, then, devres data is freed.
> + */
> +struct phy *devm_of_phy_get(struct device *dev, const char *phandle, u8 index)
> +{
> +	struct phy *phy = NULL, **ptr;
> +	struct device_node *node;
> +
> +	if (!dev->of_node) {
> +		dev_dbg(dev, "device does not have a device node entry\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	node = of_parse_phandle(dev->of_node, phandle, index);

Where's the corresponding of_node_put()?

> +	if (!node) {
> +		dev_dbg(dev, "failed to get %s phandle in %s node\n", phandle,
> +			dev->of_node->full_name);
> +		return ERR_PTR(-ENODEV);
> +	}
> +
> +	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);
> +	if (!ptr) {
> +		dev_dbg(dev, "failed to allocate memory for devres\n");
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	mutex_lock(&phy_list_mutex);
> +
> +	phy = of_phy_lookup(dev, node);
> +	if (IS_ERR(phy) || !phy->dev.class ||
> +			!try_module_get(phy->dev.class->owner)) {

If I understand the code correctly, you are now locking the phy-core
module itself. Which is not needed, as you cannot unload a module while
someone uses the exported symbols.

I was talking about to lock the module that provides the individual phy
driver implementaton. I'm using this to lock the phy module:

	try_module_get(phy->dev->driver->owner)

> +		phy = ERR_PTR(-EPROBE_DEFER);
> +		devres_free(ptr);
> +		goto err0;
> +	}
> +
> +	*ptr = phy;
> +	devres_add(dev, ptr);
> +
> +	get_device(&phy->dev);
> +
> +err0:
> +	mutex_unlock(&phy_list_mutex);
> +
> +	return phy;
> +}
> +EXPORT_SYMBOL_GPL(devm_of_phy_get);
> +
> +/**
> + * phy_get - lookup and obtain a reference to a phy.
> + * @dev: device that requests this phy
> + * @index: the index of the phy
> + *
> + * Returns the phy driver, after getting a refcount to it; or
> + * -ENODEV if there is no such phy.  The caller is responsible for
> + * calling phy_put() to release that count.
> + */
> +struct phy *phy_get(struct device *dev, u8 index)
> +{
> +	struct phy *phy = NULL;
> +
> +	mutex_lock(&phy_list_mutex);
> +
> +	phy = phy_lookup(dev, index);
> +	if (IS_ERR(phy) || !phy->dev.class ||
> +			!try_module_get(phy->dev.class->owner)) {
> +		dev_dbg(dev, "unable to obtain phy\n");
> +		goto err0;
> +	}
> +
> +	get_device(&phy->dev);
> +
> +err0:
> +	mutex_unlock(&phy_list_mutex);
> +
> +	return phy;
> +}
> +EXPORT_SYMBOL_GPL(phy_get);
> +
> +/**
> + * phy_put - release the PHY
> + * @phy: the phy returned by phy_get()
> + *
> + * Releases a refcount the caller received from phy_get().
> + */
> +void phy_put(struct phy *phy)
> +{
> +	if (phy) {
> +		put_device(&phy->dev);

You are not allowed to deref phy->dev after the put.

> +		module_put(phy->dev.class->owner);
> +	}
> +}
> +EXPORT_SYMBOL_GPL(phy_put);
> +
> +/**
> + * phy_create - create a new phy
> + * @dev: device that is creating the new phy
> + * @desc: descriptor of the phy
> + *
> + * Called to create a phy using phy framework.
> + */
> +struct phy *phy_create(struct device *dev, struct phy_descriptor *desc)
> +{
> +	int ret;
> +	struct phy *phy;
> +	struct phy_bind *phy_bind;
> +	const char *devname = NULL;
> +
> +	if (!dev || !desc) {
> +		dev_err(dev, "no descriptor/device provided for PHY\n");
> +		ret = -EINVAL;
> +		goto err0;
> +	}
> +
> +	if (!desc->ops) {
> +		dev_err(dev, "no PHY ops provided\n");
> +		ret = -EINVAL;
> +		goto err0;
> +	}
> +
> +	phy = kzalloc(sizeof(*phy), GFP_KERNEL);
> +	if (!phy) {
> +		dev_err(dev, "no memory for PHY\n");
> +		ret = -ENOMEM;
> +		goto err0;
> +	}
> +
> +	devname = dev_name(dev);
> +	device_initialize(&phy->dev);
> +	phy->desc = desc;
> +	phy->dev.class = phy_class;
> +	phy->dev.parent = dev;
> +	ret = dev_set_name(&phy->dev, "%s", devname);
> +	if (ret)
> +		goto err1;
> +
> +	mutex_lock(&phy_list_mutex);
> +	list_for_each_entry(phy_bind, &phy_bind_list, list)
> +		if (!(strcmp(phy_bind->phy_dev_name, devname)))
> +			phy_bind->phy = phy;
> +
> +	list_add_tail(&phy->head, &phy_list);
> +
> +	ret = device_add(&phy->dev);
> +	if (ret)
> +		goto err2;
> +
> +	mutex_unlock(&phy_list_mutex);
> +
> +	return phy;
> +
> +err2:
> +	list_del(&phy->head);
> +	phy_bind->phy = NULL;
> +	mutex_unlock(&phy_list_mutex);
> +
> +err1:
> +	put_device(&phy->dev);
> +	kfree(phy);
> +
> +err0:
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_GPL(phy_create);
> +
> +/**
> + * phy_destroy - destroy the phy
> + * @phy: the phy to be destroyed
> + *
> + * Called to destroy the phy.
> + */
> +void phy_destroy(struct phy *phy)
> +{
> +	struct phy_bind *phy_bind;
> +
> +	mutex_lock(&phy_list_mutex);
> +	list_for_each_entry(phy_bind, &phy_bind_list, list) {
> +		if (phy_bind->phy == phy)
> +			phy_bind->phy = NULL;
> +
> +		if (phy_bind->auto_bind) {
> +			list_del(&phy_bind->list);
> +			kfree(phy_bind);
> +		}
> +	}
> +
> +	list_del(&phy->head);
> +	mutex_unlock(&phy_list_mutex);
> +
> +	device_unregister(&phy->dev);
> +}
> +EXPORT_SYMBOL_GPL(phy_destroy);
> +
> +/**
> + * phy_bind - bind the phy and the controller that uses the phy
> + * @dev_name: the device name of the device that will bind to the phy
> + * @index: index to specify the port number
> + * @phy_dev_name: the device name of the phy
> + *
> + * Fills the phy_bind structure with the dev_name and phy_dev_name. This will
> + * be used when the phy driver registers the phy and when the controller
> + * requests this phy.
> + *
> + * To be used by platform specific initialization code.
> + */
> +struct phy_bind *phy_bind(const char *dev_name, u8 index,
> +				const char *phy_dev_name)
> +{
> +	struct phy_bind *phy_bind;
> +
> +	phy_bind = kzalloc(sizeof(*phy_bind), GFP_KERNEL);
> +	if (!phy_bind) {
> +		pr_err("phy_bind(): No memory for phy_bind");
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	phy_bind->dev_name = dev_name;
> +	phy_bind->phy_dev_name = phy_dev_name;
> +	phy_bind->index = index;
> +	phy_bind->auto_bind = false;
> +
> +	list_add_tail(&phy_bind->list, &phy_bind_list);
> +
> +	return phy_bind;
> +}
> +EXPORT_SYMBOL_GPL(phy_bind);

Why does this function return the phy_bind? Is it used outside of this
framework?

> +
> +static ssize_t phy_name_show(struct device *dev,
> +			     struct device_attribute *attr, char *buf)
> +{
> +	struct phy *phy;
> +
> +	phy = container_of(dev, struct phy, dev);
> +
> +	return sprintf(buf, "%s\n", phy->desc->label);
> +}
> +
> +static ssize_t phy_bind_show(struct device *dev,
> +			     struct device_attribute *attr, char *buf)
> +{
> +	struct phy_bind *phy_bind;
> +	struct phy *phy;
> +	char *p = buf;
> +	int len;
> +
> +	phy = container_of(dev, struct phy, dev);
> +
> +	list_for_each_entry(phy_bind, &phy_bind_list, list)
> +		if (phy_bind->phy == phy)
> +			p += sprintf(p, "%s %d\n", phy_bind->dev_name,
> +							phy_bind->index);

What about the one value per sysfs entry policy?

> +	len = (p - buf);
> +
> +	return len;
> +}
> +
> +static struct device_attribute phy_dev_attrs[] = {
> +	__ATTR(label, 0444, phy_name_show, NULL),
> +	__ATTR(bind, 0444, phy_bind_show, NULL),
> +	__ATTR_NULL,
> +};
> +
> +/**
> + * phy_release - release the phy
> + * @dev: the dev member within phy
> + *
> + * when the last reference to the device is removed; it is called
> + * from the embedded kobject as release method.
> + */
> +static void phy_release(struct device *dev)
> +{
> +	struct phy *phy;
> +
> +	phy = container_of(dev, struct phy, dev);
> +	dev_dbg(dev, "releasing '%s'\n", dev_name(dev));
> +	kfree(phy);
> +}
> +
> +static int __init phy_core_init(void)
> +{
> +	phy_class = class_create(THIS_MODULE, "phy");
> +	if (IS_ERR(phy_class)) {
> +		pr_err("failed to create phy class --> %ld\n",
> +			PTR_ERR(phy_class));
> +		return PTR_ERR(phy_class);
> +	}
> +
> +	phy_class->dev_release = phy_release;
> +	phy_class->dev_attrs = phy_dev_attrs;
> +	phy_class->owner = THIS_MODULE;
> +
> +	return 0;
> +}
> +subsys_initcall(phy_core_init);
> +
> +static void __exit phy_core_exit(void)
> +{
> +	class_destroy(phy_class);
> +}
> +module_exit(phy_core_exit);
> +
> +MODULE_DESCRIPTION("Generic Phy Framework");
> +MODULE_AUTHOR("Kishon Vijay Abraham I <[e-mail]>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
> new file mode 100644
> index 0000000..6fc3f0a
> --- /dev/null
> +++ b/include/linux/phy/phy.h
> @@ -0,0 +1,182 @@
> +/*
> + * phy.h -- generic phy header file
> + *
> + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * Author: Kishon Vijay Abraham I <[e-mail]>
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef __DRIVERS_PHY_H
> +#define __DRIVERS_PHY_H
> +
> +struct phy;
> +
> +/**
> + * struct phy_descriptor - structure that describes the PHY
> + * @label: label given to phy
> + * @type: specifies the phy type
> + * @of_node: device node of the phy
> + * @ops: function pointers for performing phy operations
> + */
> +struct phy_descriptor {
> +	const char		*label;

The label is only used to print in sysfs. Does it have another purpose?

> +	int			type;

What means type here? It seems to be unused in this code.

> +	struct device_node	*of_node;

Why do you need the *of_node here? The device that creates a phy already
has a of_node pointer.

> +	struct phy_ops		*ops;
> +};
> +
> +/**
> + * struct phy_ops - set of function pointers for performing phy operations
> + * @init: operation to be performed for initializing phy
> + * @exit: operation to be performed while exiting
> + * @suspend: suspending the phy
> + * @resume: resuming the phy
> + * @poweron: powering on the phy
> + * @shutdown: shutting down the phy
> + */
> +struct phy_ops {
> +	int	(*init)(struct phy_descriptor *desc);
> +	int	(*exit)(struct phy_descriptor *desc);
> +	int	(*suspend)(struct phy_descriptor *desc);
> +	int	(*resume)(struct phy_descriptor *desc);
> +	int	(*poweron)(struct phy_descriptor *desc);
> +	int	(*shutdown)(struct phy_descriptor *desc);
> +};
> +
> +/**
> + * struct phy - represent the phy device
> + * @desc: descriptor for the phy
> + * @head: to support multiple transceivers
> + */
> +struct phy {
> +	struct device		dev;
> +	struct phy_descriptor	*desc;
> +	struct list_head	head;
> +};
> +
> +/**
> + * struct phy_bind - represent the binding for the phy
> + * @dev_name: the device name of the device that will bind to the phy
> + * @phy_dev_name: the device name of the phy
> + * @index: used if a single controller uses multiple phys
> + * @auto_bind: tells if the binding is done explicitly from board file or not
> + * @phy: reference to the phy
> + * @list: to maintain a linked list of the binding information
> + */
> +struct phy_bind {
> +	const char	*dev_name;
> +	const char	*phy_dev_name;
> +	u8		index;
> +	int		auto_bind:1;
> +	struct phy	*phy;
> +	struct list_head list;
> +};
> +
> +#if defined(CONFIG_GENERIC_PHY) || defined(CONFIG_GENERIC_PHY_MODULE)
> +extern struct phy *devm_phy_get(struct device *dev, u8 index);
> +extern void devm_phy_put(struct device *dev, struct phy *phy);
> +extern struct phy *devm_of_phy_get(struct device *dev, const char *phandle,
> +	u8 index);
> +extern struct phy *phy_get(struct device *dev, u8 index);
> +extern void phy_put(struct phy *phy);
> +extern struct phy *phy_create(struct device *dev, struct phy_descriptor *desc);
> +extern void phy_destroy(struct phy *phy);
> +extern struct phy_bind *phy_bind(const char *dev_name, u8 index,
> +				const char *phy_dev_name);
> +#else
> +static inline struct phy *devm_phy_get(struct device *dev, u8 index)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +static inline void devm_phy_put(struct device *dev, struct phy *phy)
> +{
> +}
> +
> +static inline struct phy *devm_of_phy_get(struct device *dev,
> +		const char *phandle, u8 index)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +static inline struct phy *phy_get(struct device *dev, u8 index)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +static inline void phy_put(struct phy *phy)
> +{
> +}
> +
> +static inline struct phy *phy_create(struct device *dev,
> +	struct phy_descriptor *desc)
> +{
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +static inline void phy_destroy(struct phy *phy)
> +{
> +}
> +
> +static inline struct phy_bind *phy_bind(const char *dev_name, u8 index,
> +				const char *phy_dev_name)
> +{
> +}
> +#endif
> +
> +static inline int phy_init(struct phy *phy)
> +{
> +	if (phy->desc->ops->init)
> +		return phy->desc->ops->init(phy->desc);
> +
> +	return -EINVAL;
> +}
> +
> +static inline int phy_exit(struct phy *phy)
> +{
> +	if (phy->desc->ops->exit)
> +		return phy->desc->ops->exit(phy->desc);
> +
> +	return -EINVAL;
> +}
> +
> +static inline int phy_suspend(struct phy *phy)
> +{
> +	if (phy->desc->ops->suspend)
> +		return phy->desc->ops->suspend(phy->desc);
> +
> +	return -EINVAL;
> +}
> +
> +static inline int phy_resume(struct phy *phy)
> +{
> +	if (phy->desc->ops->resume)
> +		return phy->desc->ops->resume(phy->desc);
> +
> +	return -EINVAL;
> +}
> +
> +static inline int phy_poweron(struct phy *phy)
> +{
> +	if (phy->desc->ops->poweron)
> +		return phy->desc->ops->poweron(phy->desc);
> +
> +	return -EINVAL;
> +}
> +
> +static inline int phy_shutdown(struct phy *phy)
> +{
> +	if (phy->desc->ops->shutdown)
> +		return phy->desc->ops->shutdown(phy->desc);
> +}
> +#endif /* __DRIVERS_PHY_H */
> 

Marc

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index ea0519a..48f3cfb 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3078,6 +3078,13 @@  T:	git git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git
 S:	Maintained
 F:	include/asm-generic
 
+GENERIC PHY FRAMEWORK
+M:	Kishon Vijay Abraham I <[e-mail]>
+L:	[e-mail]
+S:	Supported
+F:	drivers/phy/
+F:	include/linux/phy/
+
 GENERIC UIO DRIVER FOR PCI DEVICES
 M:	"Michael S. Tsirkin" <[e-mail]>
 L:	[e-mail]
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 324e958..d289df5 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -154,4 +154,6 @@  source "drivers/vme/Kconfig"
 
 source "drivers/pwm/Kconfig"
 
+source "drivers/phy/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index d64a0f7..e39252d 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -40,6 +40,8 @@  obj-y				+= char/
 # gpu/ comes after char for AGP vs DRM startup
 obj-y				+= gpu/
 
+obj-y				+= phy/
+
 obj-$(CONFIG_CONNECTOR)		+= connector/
 
 # i810fb and intelfb depend on char/agp/
diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
new file mode 100644
index 0000000..34f7077
--- /dev/null
+++ b/drivers/phy/Kconfig
@@ -0,0 +1,13 @@ 
+#
+# PHY
+#
+
+menuconfig GENERIC_PHY
+	tristate "Generic PHY Support"
+	help
+	  Generic PHY support.
+
+	  This framework is designed to provide a generic interface for PHY
+	  devices present in the kernel. This layer will have the generic
+	  API by which phy drivers can create PHY using the phy framework and
+	  phy users can obtain reference to the PHY.
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
new file mode 100644
index 0000000..9e9560f
--- /dev/null
+++ b/drivers/phy/Makefile
@@ -0,0 +1,5 @@ 
+#
+# Makefile for the phy drivers.
+#
+
+obj-$(CONFIG_GENERIC_PHY)	+= phy-core.o
diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
new file mode 100644
index 0000000..bf47a88
--- /dev/null
+++ b/drivers/phy/phy-core.c
@@ -0,0 +1,445 @@ 
+/*
+ * phy-core.c  --  Generic Phy framework.
+ *
+ * Copyright (C) 2012 Texas Instruments
+ *
+ * Author: Kishon Vijay Abraham I <[e-mail]>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+
+static struct class *phy_class;
+static LIST_HEAD(phy_list);
+static DEFINE_MUTEX(phy_list_mutex);
+static LIST_HEAD(phy_bind_list);
+
+static void devm_phy_release(struct device *dev, void *res)
+{
+	struct phy *phy = *(struct phy **)res;
+
+	phy_put(phy);
+}
+
+static int devm_phy_match(struct device *dev, void *res, void *match_data)
+{
+	return res == match_data;
+}
+
+static struct phy *phy_lookup(struct device *dev, u8 index)
+{
+	struct phy_bind *phy_bind = NULL;
+
+	list_for_each_entry(phy_bind, &phy_bind_list, list) {
+		if (!(strcmp(phy_bind->dev_name, dev_name(dev))) &&
+				phy_bind->index == index)
+			return phy_bind->phy;
+	}
+
+	return ERR_PTR(-ENODEV);
+}
+
+static struct phy *of_phy_lookup(struct device *dev, struct device_node *node)
+{
+	int index = 0;
+	struct phy *phy;
+	struct phy_bind *phy_map = NULL;
+
+	list_for_each_entry(phy_map, &phy_bind_list, list)
+		if (!(strcmp(phy_map->dev_name, dev_name(dev))))
+			index++;
+
+	list_for_each_entry(phy, &phy_list, head) {
+		if (node != phy->desc->of_node)
+			continue;
+
+		phy_map = phy_bind(dev_name(dev), index, dev_name(&phy->dev));
+		if (!IS_ERR(phy_map)) {
+			phy_map->phy = phy;
+			phy_map->auto_bind = true;
+		}
+
+		return phy;
+	}
+
+	return ERR_PTR(-ENODEV);
+}
+
+/**
+ * devm_phy_get - lookup and obtain a reference to a phy.
+ * @dev: device that requests this phy
+ * @index: the index of the phy
+ *
+ * Gets the phy using phy_get(), and associates a device with it using
+ * devres. On driver detach, release function is invoked on the devres data,
+ * then, devres data is freed.
+ */
+struct phy *devm_phy_get(struct device *dev, u8 index)
+{
+	struct phy **ptr, *phy;
+
+	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	phy = phy_get(dev, index);
+	if (!IS_ERR(phy)) {
+		*ptr = phy;
+		devres_add(dev, ptr);
+	} else
+		devres_free(ptr);
+
+	return phy;
+}
+EXPORT_SYMBOL_GPL(devm_phy_get);
+
+/**
+ * devm_phy_put - release the PHY
+ * @dev: device that wants to release this phy
+ * @phy: the phy returned by devm_phy_get()
+ *
+ * destroys the devres associated with this phy and invokes phy_put
+ * to release the phy.
+ */
+void devm_phy_put(struct device *dev, struct phy *phy)
+{
+	int r;
+
+	r = devres_destroy(dev, devm_phy_release, devm_phy_match, phy);
+	dev_WARN_ONCE(dev, r, "couldn't find PHY resource\n");
+}
+EXPORT_SYMBOL_GPL(devm_phy_put);
+
+/**
+ * devm_of_phy_get - lookup and obtain a reference to a phy by phandle
+ * @dev: device that requests this phy
+ * @phandle: name of the property holding the phy phandle value
+ * @index: the index of the phy
+ *
+ * Returns the phy driver associated with the given phandle value,
+ * after getting a refcount to it or -ENODEV if there is no such phy or
+ * -EPROBE_DEFER if there is a phandle to the phy, but the device is
+ * not yet loaded. While at that, it also associates the device with the
+ * phy using devres. On driver detach, release function is invoked on the
+ * devres data, then, devres data is freed.
+ */
+struct phy *devm_of_phy_get(struct device *dev, const char *phandle, u8 index)
+{
+	struct phy *phy = NULL, **ptr;
+	struct device_node *node;
+
+	if (!dev->of_node) {
+		dev_dbg(dev, "device does not have a device node entry\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	node = of_parse_phandle(dev->of_node, phandle, index);
+	if (!node) {
+		dev_dbg(dev, "failed to get %s phandle in %s node\n", phandle,
+			dev->of_node->full_name);
+		return ERR_PTR(-ENODEV);
+	}
+
+	ptr = devres_alloc(devm_phy_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr) {
+		dev_dbg(dev, "failed to allocate memory for devres\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	mutex_lock(&phy_list_mutex);
+
+	phy = of_phy_lookup(dev, node);
+	if (IS_ERR(phy) || !phy->dev.class ||
+			!try_module_get(phy->dev.class->owner)) {
+		phy = ERR_PTR(-EPROBE_DEFER);
+		devres_free(ptr);
+		goto err0;
+	}
+
+	*ptr = phy;
+	devres_add(dev, ptr);
+
+	get_device(&phy->dev);
+
+err0:
+	mutex_unlock(&phy_list_mutex);
+
+	return phy;
+}
+EXPORT_SYMBOL_GPL(devm_of_phy_get);
+
+/**
+ * phy_get - lookup and obtain a reference to a phy.
+ * @dev: device that requests this phy
+ * @index: the index of the phy
+ *
+ * Returns the phy driver, after getting a refcount to it; or
+ * -ENODEV if there is no such phy.  The caller is responsible for
+ * calling phy_put() to release that count.
+ */
+struct phy *phy_get(struct device *dev, u8 index)
+{
+	struct phy *phy = NULL;
+
+	mutex_lock(&phy_list_mutex);
+
+	phy = phy_lookup(dev, index);
+	if (IS_ERR(phy) || !phy->dev.class ||
+			!try_module_get(phy->dev.class->owner)) {
+		dev_dbg(dev, "unable to obtain phy\n");
+		goto err0;
+	}
+
+	get_device(&phy->dev);
+
+err0:
+	mutex_unlock(&phy_list_mutex);
+
+	return phy;
+}
+EXPORT_SYMBOL_GPL(phy_get);
+
+/**
+ * phy_put - release the PHY
+ * @phy: the phy returned by phy_get()
+ *
+ * Releases a refcount the caller received from phy_get().
+ */
+void phy_put(struct phy *phy)
+{
+	if (phy) {
+		put_device(&phy->dev);
+		module_put(phy->dev.class->owner);
+	}
+}
+EXPORT_SYMBOL_GPL(phy_put);
+
+/**
+ * phy_create - create a new phy
+ * @dev: device that is creating the new phy
+ * @desc: descriptor of the phy
+ *
+ * Called to create a phy using phy framework.
+ */
+struct phy *phy_create(struct device *dev, struct phy_descriptor *desc)
+{
+	int ret;
+	struct phy *phy;
+	struct phy_bind *phy_bind;
+	const char *devname = NULL;
+
+	if (!dev || !desc) {
+		dev_err(dev, "no descriptor/device provided for PHY\n");
+		ret = -EINVAL;
+		goto err0;
+	}
+
+	if (!desc->ops) {
+		dev_err(dev, "no PHY ops provided\n");
+		ret = -EINVAL;
+		goto err0;
+	}
+
+	phy = kzalloc(sizeof(*phy), GFP_KERNEL);
+	if (!phy) {
+		dev_err(dev, "no memory for PHY\n");
+		ret = -ENOMEM;
+		goto err0;
+	}
+
+	devname = dev_name(dev);
+	device_initialize(&phy->dev);
+	phy->desc = desc;
+	phy->dev.class = phy_class;
+	phy->dev.parent = dev;
+	ret = dev_set_name(&phy->dev, "%s", devname);
+	if (ret)
+		goto err1;
+
+	mutex_lock(&phy_list_mutex);
+	list_for_each_entry(phy_bind, &phy_bind_list, list)
+		if (!(strcmp(phy_bind->phy_dev_name, devname)))
+			phy_bind->phy = phy;
+
+	list_add_tail(&phy->head, &phy_list);
+
+	ret = device_add(&phy->dev);
+	if (ret)
+		goto err2;
+
+	mutex_unlock(&phy_list_mutex);
+
+	return phy;
+
+err2:
+	list_del(&phy->head);
+	phy_bind->phy = NULL;
+	mutex_unlock(&phy_list_mutex);
+
+err1:
+	put_device(&phy->dev);
+	kfree(phy);
+
+err0:
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(phy_create);
+
+/**
+ * phy_destroy - destroy the phy
+ * @phy: the phy to be destroyed
+ *
+ * Called to destroy the phy.
+ */
+void phy_destroy(struct phy *phy)
+{
+	struct phy_bind *phy_bind;
+
+	mutex_lock(&phy_list_mutex);
+	list_for_each_entry(phy_bind, &phy_bind_list, list) {
+		if (phy_bind->phy == phy)
+			phy_bind->phy = NULL;
+
+		if (phy_bind->auto_bind) {
+			list_del(&phy_bind->list);
+			kfree(phy_bind);
+		}
+	}
+
+	list_del(&phy->head);
+	mutex_unlock(&phy_list_mutex);
+
+	device_unregister(&phy->dev);
+}
+EXPORT_SYMBOL_GPL(phy_destroy);
+
+/**
+ * phy_bind - bind the phy and the controller that uses the phy
+ * @dev_name: the device name of the device that will bind to the phy
+ * @index: index to specify the port number
+ * @phy_dev_name: the device name of the phy
+ *
+ * Fills the phy_bind structure with the dev_name and phy_dev_name. This will
+ * be used when the phy driver registers the phy and when the controller
+ * requests this phy.
+ *
+ * To be used by platform specific initialization code.
+ */
+struct phy_bind *phy_bind(const char *dev_name, u8 index,
+				const char *phy_dev_name)
+{
+	struct phy_bind *phy_bind;
+
+	phy_bind = kzalloc(sizeof(*phy_bind), GFP_KERNEL);
+	if (!phy_bind) {
+		pr_err("phy_bind(): No memory for phy_bind");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	phy_bind->dev_name = dev_name;
+	phy_bind->phy_dev_name = phy_dev_name;
+	phy_bind->index = index;
+	phy_bind->auto_bind = false;
+
+	list_add_tail(&phy_bind->list, &phy_bind_list);
+
+	return phy_bind;
+}
+EXPORT_SYMBOL_GPL(phy_bind);
+
+static ssize_t phy_name_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct phy *phy;
+
+	phy = container_of(dev, struct phy, dev);
+
+	return sprintf(buf, "%s\n", phy->desc->label);
+}
+
+static ssize_t phy_bind_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct phy_bind *phy_bind;
+	struct phy *phy;
+	char *p = buf;
+	int len;
+
+	phy = container_of(dev, struct phy, dev);
+
+	list_for_each_entry(phy_bind, &phy_bind_list, list)
+		if (phy_bind->phy == phy)
+			p += sprintf(p, "%s %d\n", phy_bind->dev_name,
+							phy_bind->index);
+	len = (p - buf);
+
+	return len;
+}
+
+static struct device_attribute phy_dev_attrs[] = {
+	__ATTR(label, 0444, phy_name_show, NULL),
+	__ATTR(bind, 0444, phy_bind_show, NULL),
+	__ATTR_NULL,
+};
+
+/**
+ * phy_release - release the phy
+ * @dev: the dev member within phy
+ *
+ * when the last reference to the device is removed; it is called
+ * from the embedded kobject as release method.
+ */
+static void phy_release(struct device *dev)
+{
+	struct phy *phy;
+
+	phy = container_of(dev, struct phy, dev);
+	dev_dbg(dev, "releasing '%s'\n", dev_name(dev));
+	kfree(phy);
+}
+
+static int __init phy_core_init(void)
+{
+	phy_class = class_create(THIS_MODULE, "phy");
+	if (IS_ERR(phy_class)) {
+		pr_err("failed to create phy class --> %ld\n",
+			PTR_ERR(phy_class));
+		return PTR_ERR(phy_class);
+	}
+
+	phy_class->dev_release = phy_release;
+	phy_class->dev_attrs = phy_dev_attrs;
+	phy_class->owner = THIS_MODULE;
+
+	return 0;
+}
+subsys_initcall(phy_core_init);
+
+static void __exit phy_core_exit(void)
+{
+	class_destroy(phy_class);
+}
+module_exit(phy_core_exit);
+
+MODULE_DESCRIPTION("Generic Phy Framework");
+MODULE_AUTHOR("Kishon Vijay Abraham I <[e-mail]>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
new file mode 100644
index 0000000..6fc3f0a
--- /dev/null
+++ b/include/linux/phy/phy.h
@@ -0,0 +1,182 @@ 
+/*
+ * phy.h -- generic phy header file
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Author: Kishon Vijay Abraham I <[e-mail]>
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __DRIVERS_PHY_H
+#define __DRIVERS_PHY_H
+
+struct phy;
+
+/**
+ * struct phy_descriptor - structure that describes the PHY
+ * @label: label given to phy
+ * @type: specifies the phy type
+ * @of_node: device node of the phy
+ * @ops: function pointers for performing phy operations
+ */
+struct phy_descriptor {
+	const char		*label;
+	int			type;
+	struct device_node	*of_node;
+	struct phy_ops		*ops;
+};
+
+/**
+ * struct phy_ops - set of function pointers for performing phy operations
+ * @init: operation to be performed for initializing phy
+ * @exit: operation to be performed while exiting
+ * @suspend: suspending the phy
+ * @resume: resuming the phy
+ * @poweron: powering on the phy
+ * @shutdown: shutting down the phy
+ */
+struct phy_ops {
+	int	(*init)(struct phy_descriptor *desc);
+	int	(*exit)(struct phy_descriptor *desc);
+	int	(*suspend)(struct phy_descriptor *desc);
+	int	(*resume)(struct phy_descriptor *desc);
+	int	(*poweron)(struct phy_descriptor *desc);
+	int	(*shutdown)(struct phy_descriptor *desc);
+};
+
+/**
+ * struct phy - represent the phy device
+ * @desc: descriptor for the phy
+ * @head: to support multiple transceivers
+ */
+struct phy {
+	struct device		dev;
+	struct phy_descriptor	*desc;
+	struct list_head	head;
+};
+
+/**
+ * struct phy_bind - represent the binding for the phy
+ * @dev_name: the device name of the device that will bind to the phy
+ * @phy_dev_name: the device name of the phy
+ * @index: used if a single controller uses multiple phys
+ * @auto_bind: tells if the binding is done explicitly from board file or not
+ * @phy: reference to the phy
+ * @list: to maintain a linked list of the binding information
+ */
+struct phy_bind {
+	const char	*dev_name;
+	const char	*phy_dev_name;
+	u8		index;
+	int		auto_bind:1;
+	struct phy	*phy;
+	struct list_head list;
+};
+
+#if defined(CONFIG_GENERIC_PHY) || defined(CONFIG_GENERIC_PHY_MODULE)
+extern struct phy *devm_phy_get(struct device *dev, u8 index);
+extern void devm_phy_put(struct device *dev, struct phy *phy);
+extern struct phy *devm_of_phy_get(struct device *dev, const char *phandle,
+	u8 index);
+extern struct phy *phy_get(struct device *dev, u8 index);
+extern void phy_put(struct phy *phy);
+extern struct phy *phy_create(struct device *dev, struct phy_descriptor *desc);
+extern void phy_destroy(struct phy *phy);
+extern struct phy_bind *phy_bind(const char *dev_name, u8 index,
+				const char *phy_dev_name);
+#else
+static inline struct phy *devm_phy_get(struct device *dev, u8 index)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline void devm_phy_put(struct device *dev, struct phy *phy)
+{
+}
+
+static inline struct phy *devm_of_phy_get(struct device *dev,
+		const char *phandle, u8 index)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline struct phy *phy_get(struct device *dev, u8 index)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline void phy_put(struct phy *phy)
+{
+}
+
+static inline struct phy *phy_create(struct device *dev,
+	struct phy_descriptor *desc)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline void phy_destroy(struct phy *phy)
+{
+}
+
+static inline struct phy_bind *phy_bind(const char *dev_name, u8 index,
+				const char *phy_dev_name)
+{
+}
+#endif
+
+static inline int phy_init(struct phy *phy)
+{
+	if (phy->desc->ops->init)
+		return phy->desc->ops->init(phy->desc);
+
+	return -EINVAL;
+}
+
+static inline int phy_exit(struct phy *phy)
+{
+	if (phy->desc->ops->exit)
+		return phy->desc->ops->exit(phy->desc);
+
+	return -EINVAL;
+}
+
+static inline int phy_suspend(struct phy *phy)
+{
+	if (phy->desc->ops->suspend)
+		return phy->desc->ops->suspend(phy->desc);
+
+	return -EINVAL;
+}
+
+static inline int phy_resume(struct phy *phy)
+{
+	if (phy->desc->ops->resume)
+		return phy->desc->ops->resume(phy->desc);
+
+	return -EINVAL;
+}
+
+static inline int phy_poweron(struct phy *phy)
+{
+	if (phy->desc->ops->poweron)
+		return phy->desc->ops->poweron(phy->desc);
+
+	return -EINVAL;
+}
+
+static inline int phy_shutdown(struct phy *phy)
+{
+	if (phy->desc->ops->shutdown)
+		return phy->desc->ops->shutdown(phy->desc);
+}
+#endif /* __DRIVERS_PHY_H */