diff mbox

[v9,3/4] phy: Add new Exynos USB 2.0 PHY driver

Message ID 1394033288-5551-4-git-send-email-k.debski@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kamil Debski March 5, 2014, 3:28 p.m. UTC
Add a new driver for the Exynos USB 2.0 PHY. The new driver uses the generic
PHY framework. The driver includes support for the Exynos 4x10 and 4x12
SoC families.

Signed-off-by: Kamil Debski <k.debski@samsung.com>
---
 .../devicetree/bindings/phy/samsung-phy.txt        |   53 ++++
 Documentation/phy/samsung-usb2.txt                 |  134 ++++++++
 drivers/phy/Kconfig                                |   29 ++
 drivers/phy/Makefile                               |    3 +
 drivers/phy/phy-exynos4210-usb2.c                  |  261 ++++++++++++++++
 drivers/phy/phy-exynos4x12-usb2.c                  |  328 ++++++++++++++++++++
 drivers/phy/phy-samsung-usb2.c                     |  222 +++++++++++++
 drivers/phy/phy-samsung-usb2.h                     |   66 ++++
 8 files changed, 1096 insertions(+)
 create mode 100644 Documentation/phy/samsung-usb2.txt
 create mode 100644 drivers/phy/phy-exynos4210-usb2.c
 create mode 100644 drivers/phy/phy-exynos4x12-usb2.c
 create mode 100644 drivers/phy/phy-samsung-usb2.c
 create mode 100644 drivers/phy/phy-samsung-usb2.h

Comments

Tomasz Figa March 5, 2014, 4:04 p.m. UTC | #1
On 05.03.2014 16:28, Kamil Debski wrote:
> Add a new driver for the Exynos USB 2.0 PHY. The new driver uses the generic
> PHY framework. The driver includes support for the Exynos 4x10 and 4x12
> SoC families.
>
> Signed-off-by: Kamil Debski <k.debski@samsung.com>
> ---
>   .../devicetree/bindings/phy/samsung-phy.txt        |   53 ++++
>   Documentation/phy/samsung-usb2.txt                 |  134 ++++++++
>   drivers/phy/Kconfig                                |   29 ++
>   drivers/phy/Makefile                               |    3 +
>   drivers/phy/phy-exynos4210-usb2.c                  |  261 ++++++++++++++++
>   drivers/phy/phy-exynos4x12-usb2.c                  |  328 ++++++++++++++++++++
>   drivers/phy/phy-samsung-usb2.c                     |  222 +++++++++++++
>   drivers/phy/phy-samsung-usb2.h                     |   66 ++++
>   8 files changed, 1096 insertions(+)
>   create mode 100644 Documentation/phy/samsung-usb2.txt
>   create mode 100644 drivers/phy/phy-exynos4210-usb2.c
>   create mode 100644 drivers/phy/phy-exynos4x12-usb2.c
>   create mode 100644 drivers/phy/phy-samsung-usb2.c
>   create mode 100644 drivers/phy/phy-samsung-usb2.h

Reviewed-by: Tomasz Figa <t.figa@samsung.com>

Best regards,
Tomasz
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Anton Tikhomirov March 6, 2014, 8:26 a.m. UTC | #2
Hi Kamil,

...

> +| 3. Supporting SoCs
> ++--------------------
> +
> +To support a new SoC a new file should be added to the drivers/phy
> +directory. Each SoC's configuration is stored in an instance of the
> +struct samsung_usb2_phy_config.
> +
> +struct samsung_usb2_phy_config {
> +	const struct samsung_usb2_common_phy *phys;
> +	unsigned int num_phys;
> +	bool has_mode_switch;

You missed rate_to_clk here.

> +};
> +

...

> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-samsung-
> usb2.c
> new file mode 100644
> index 0000000..c3b7719
> --- /dev/null
> +++ b/drivers/phy/phy-samsung-usb2.c
> @@ -0,0 +1,222 @@
> +/*
> + * Samsung SoC USB 1.1/2.0 PHY driver
> + *
> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
> + * Author: Kamil Debski <k.debski@samsung.com>
> + *
> + * This program is free software; you can redistribute it and/or
> modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +#include "phy-samsung-usb2.h"
> +
> +static int samsung_usb2_phy_power_on(struct phy *phy)
> +{
> +	struct samsung_usb2_phy_instance *inst = phy_get_drvdata(phy);
> +	struct samsung_usb2_phy_driver *drv = inst->drv;
> +	int ret;
> +
> +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
> +		inst->cfg->label);
> +	ret = clk_prepare_enable(drv->clk);

clk_prepare_enable() can sleep, and therefore doesn't allow
samusng_usb2_phy_power_on() to be used in atomic context
(e.g. inside spin_lock-ed area), what sometimes may be desirable.
What about to prepare clock in probe, and just enable it here
(note: clk_enable() doesn't sleep).

> +	if (ret)
> +		goto err_main_clk;
> +	ret = clk_prepare_enable(drv->ref_clk);
> +	if (ret)
> +		goto err_instance_clk;
> +	if (inst->cfg->power_on) {
> +		spin_lock(&drv->lock);
> +		ret = inst->cfg->power_on(inst);
> +		spin_unlock(&drv->lock);
> +	}
> +
> +	return 0;

Thank you

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Kishon Vijay Abraham I March 6, 2014, 8:30 a.m. UTC | #3
On Thursday 06 March 2014 01:56 PM, Anton Tikhomirov wrote:
> Hi Kamil,
>
> ...
>
>> +| 3. Supporting SoCs
>> ++--------------------
>> +
>> +To support a new SoC a new file should be added to the drivers/phy
>> +directory. Each SoC's configuration is stored in an instance of the
>> +struct samsung_usb2_phy_config.
>> +
>> +struct samsung_usb2_phy_config {
>> +	const struct samsung_usb2_common_phy *phys;
>> +	unsigned int num_phys;
>> +	bool has_mode_switch;
>
> You missed rate_to_clk here.
>
>> +};
>> +
>
> ...
>
>> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-samsung-
>> usb2.c
>> new file mode 100644
>> index 0000000..c3b7719
>> --- /dev/null
>> +++ b/drivers/phy/phy-samsung-usb2.c
>> @@ -0,0 +1,222 @@
>> +/*
>> + * Samsung SoC USB 1.1/2.0 PHY driver
>> + *
>> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
>> + * Author: Kamil Debski <k.debski@samsung.com>
>> + *
>> + * This program is free software; you can redistribute it and/or
>> modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/phy/phy.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/spinlock.h>
>> +#include "phy-samsung-usb2.h"
>> +
>> +static int samsung_usb2_phy_power_on(struct phy *phy)
>> +{
>> +	struct samsung_usb2_phy_instance *inst = phy_get_drvdata(phy);
>> +	struct samsung_usb2_phy_driver *drv = inst->drv;
>> +	int ret;
>> +
>> +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
>> +		inst->cfg->label);
>> +	ret = clk_prepare_enable(drv->clk);
>
> clk_prepare_enable() can sleep, and therefore doesn't allow
> samusng_usb2_phy_power_on() to be used in atomic context
> (e.g. inside spin_lock-ed area), what sometimes may be desirable.
> What about to prepare clock in probe, and just enable it here
> (note: clk_enable() doesn't sleep).

The PHY power-on callback is anyway called with mutex held, so I guess 
it's fine to have clk_prepare_enable() here.

Thanks
Kishon
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Anton Tikhomirov March 6, 2014, 8:52 a.m. UTC | #4
Hello,

> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
> 
> 
> 
> On Thursday 06 March 2014 01:56 PM, Anton Tikhomirov wrote:
> > Hi Kamil,
> >
> > ...
> >
> >> +| 3. Supporting SoCs
> >> ++--------------------
> >> +
> >> +To support a new SoC a new file should be added to the drivers/phy
> >> +directory. Each SoC's configuration is stored in an instance of the
> >> +struct samsung_usb2_phy_config.
> >> +
> >> +struct samsung_usb2_phy_config {
> >> +	const struct samsung_usb2_common_phy *phys;
> >> +	unsigned int num_phys;
> >> +	bool has_mode_switch;
> >
> > You missed rate_to_clk here.
> >
> >> +};
> >> +
> >
> > ...
> >
> >> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-
> samsung-
> >> usb2.c
> >> new file mode 100644
> >> index 0000000..c3b7719
> >> --- /dev/null
> >> +++ b/drivers/phy/phy-samsung-usb2.c
> >> @@ -0,0 +1,222 @@
> >> +/*
> >> + * Samsung SoC USB 1.1/2.0 PHY driver
> >> + *
> >> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
> >> + * Author: Kamil Debski <k.debski@samsung.com>
> >> + *
> >> + * This program is free software; you can redistribute it and/or
> >> modify
> >> + * it under the terms of the GNU General Public License version 2
> as
> >> + * published by the Free Software Foundation.
> >> + */
> >> +
> >> +#include <linux/clk.h>
> >> +#include <linux/mfd/syscon.h>
> >> +#include <linux/module.h>
> >> +#include <linux/of.h>
> >> +#include <linux/of_address.h>
> >> +#include <linux/phy/phy.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/spinlock.h>
> >> +#include "phy-samsung-usb2.h"
> >> +
> >> +static int samsung_usb2_phy_power_on(struct phy *phy)
> >> +{
> >> +	struct samsung_usb2_phy_instance *inst = phy_get_drvdata(phy);
> >> +	struct samsung_usb2_phy_driver *drv = inst->drv;
> >> +	int ret;
> >> +
> >> +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
> >> +		inst->cfg->label);
> >> +	ret = clk_prepare_enable(drv->clk);
> >
> > clk_prepare_enable() can sleep, and therefore doesn't allow
> > samusng_usb2_phy_power_on() to be used in atomic context
> > (e.g. inside spin_lock-ed area), what sometimes may be desirable.
> > What about to prepare clock in probe, and just enable it here
> > (note: clk_enable() doesn't sleep).
> 
> The PHY power-on callback is anyway called with mutex held, so I guess
> it's fine to have clk_prepare_enable() here.

If we rely totally on generic PHY functions such as phy_power_on()
and friends, why do we need to use locking in callbacks at all.

> 
> Thanks
> Kishon

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Kishon Vijay Abraham I March 6, 2014, 8:56 a.m. UTC | #5
Hi,

On Thursday 06 March 2014 02:22 PM, Anton Tikhomirov wrote:
> Hello,
>
>> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
>>
>>
>>
>> On Thursday 06 March 2014 01:56 PM, Anton Tikhomirov wrote:
>>> Hi Kamil,
>>>
>>> ...
>>>
>>>> +| 3. Supporting SoCs
>>>> ++--------------------
>>>> +
>>>> +To support a new SoC a new file should be added to the drivers/phy
>>>> +directory. Each SoC's configuration is stored in an instance of the
>>>> +struct samsung_usb2_phy_config.
>>>> +
>>>> +struct samsung_usb2_phy_config {
>>>> +	const struct samsung_usb2_common_phy *phys;
>>>> +	unsigned int num_phys;
>>>> +	bool has_mode_switch;
>>>
>>> You missed rate_to_clk here.
>>>
>>>> +};
>>>> +
>>>
>>> ...
>>>
>>>> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-
>> samsung-
>>>> usb2.c
>>>> new file mode 100644
>>>> index 0000000..c3b7719
>>>> --- /dev/null
>>>> +++ b/drivers/phy/phy-samsung-usb2.c
>>>> @@ -0,0 +1,222 @@
>>>> +/*
>>>> + * Samsung SoC USB 1.1/2.0 PHY driver
>>>> + *
>>>> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
>>>> + * Author: Kamil Debski <k.debski@samsung.com>
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or
>>>> modify
>>>> + * it under the terms of the GNU General Public License version 2
>> as
>>>> + * published by the Free Software Foundation.
>>>> + */
>>>> +
>>>> +#include <linux/clk.h>
>>>> +#include <linux/mfd/syscon.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/of.h>
>>>> +#include <linux/of_address.h>
>>>> +#include <linux/phy/phy.h>
>>>> +#include <linux/platform_device.h>
>>>> +#include <linux/spinlock.h>
>>>> +#include "phy-samsung-usb2.h"
>>>> +
>>>> +static int samsung_usb2_phy_power_on(struct phy *phy)
>>>> +{
>>>> +	struct samsung_usb2_phy_instance *inst = phy_get_drvdata(phy);
>>>> +	struct samsung_usb2_phy_driver *drv = inst->drv;
>>>> +	int ret;
>>>> +
>>>> +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
>>>> +		inst->cfg->label);
>>>> +	ret = clk_prepare_enable(drv->clk);
>>>
>>> clk_prepare_enable() can sleep, and therefore doesn't allow
>>> samusng_usb2_phy_power_on() to be used in atomic context
>>> (e.g. inside spin_lock-ed area), what sometimes may be desirable.
>>> What about to prepare clock in probe, and just enable it here
>>> (note: clk_enable() doesn't sleep).
>>
>> The PHY power-on callback is anyway called with mutex held, so I guess
>> it's fine to have clk_prepare_enable() here.
>
> If we rely totally on generic PHY functions such as phy_power_on()
> and friends, why do we need to use locking in callbacks at all.

Didn't get you.. We don't want to invoke power_on when init is getting 
executed or you don't want power on or power off to get executed 
simultaneously right? So we need to protect it.

Cheers
Kishon
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Anton Tikhomirov March 6, 2014, 9:02 a.m. UTC | #6
Hi,

> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
> 
> Hi,
> 
> On Thursday 06 March 2014 02:22 PM, Anton Tikhomirov wrote:
> > Hello,
> >
> >> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
> >>
> >>
> >>
> >> On Thursday 06 March 2014 01:56 PM, Anton Tikhomirov wrote:
> >>> Hi Kamil,
> >>>
> >>> ...
> >>>
> >>>> +| 3. Supporting SoCs
> >>>> ++--------------------
> >>>> +
> >>>> +To support a new SoC a new file should be added to the
> drivers/phy
> >>>> +directory. Each SoC's configuration is stored in an instance of
> the
> >>>> +struct samsung_usb2_phy_config.
> >>>> +
> >>>> +struct samsung_usb2_phy_config {
> >>>> +	const struct samsung_usb2_common_phy *phys;
> >>>> +	unsigned int num_phys;
> >>>> +	bool has_mode_switch;
> >>>
> >>> You missed rate_to_clk here.
> >>>
> >>>> +};
> >>>> +
> >>>
> >>> ...
> >>>
> >>>> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-
> >> samsung-
> >>>> usb2.c
> >>>> new file mode 100644
> >>>> index 0000000..c3b7719
> >>>> --- /dev/null
> >>>> +++ b/drivers/phy/phy-samsung-usb2.c
> >>>> @@ -0,0 +1,222 @@
> >>>> +/*
> >>>> + * Samsung SoC USB 1.1/2.0 PHY driver
> >>>> + *
> >>>> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
> >>>> + * Author: Kamil Debski <k.debski@samsung.com>
> >>>> + *
> >>>> + * This program is free software; you can redistribute it and/or
> >>>> modify
> >>>> + * it under the terms of the GNU General Public License version 2
> >> as
> >>>> + * published by the Free Software Foundation.
> >>>> + */
> >>>> +
> >>>> +#include <linux/clk.h>
> >>>> +#include <linux/mfd/syscon.h>
> >>>> +#include <linux/module.h>
> >>>> +#include <linux/of.h>
> >>>> +#include <linux/of_address.h>
> >>>> +#include <linux/phy/phy.h>
> >>>> +#include <linux/platform_device.h>
> >>>> +#include <linux/spinlock.h>
> >>>> +#include "phy-samsung-usb2.h"
> >>>> +
> >>>> +static int samsung_usb2_phy_power_on(struct phy *phy)
> >>>> +{
> >>>> +	struct samsung_usb2_phy_instance *inst =
> phy_get_drvdata(phy);
> >>>> +	struct samsung_usb2_phy_driver *drv = inst->drv;
> >>>> +	int ret;
> >>>> +
> >>>> +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
> >>>> +		inst->cfg->label);
> >>>> +	ret = clk_prepare_enable(drv->clk);
> >>>
> >>> clk_prepare_enable() can sleep, and therefore doesn't allow
> >>> samusng_usb2_phy_power_on() to be used in atomic context
> >>> (e.g. inside spin_lock-ed area), what sometimes may be desirable.
> >>> What about to prepare clock in probe, and just enable it here
> >>> (note: clk_enable() doesn't sleep).
> >>
> >> The PHY power-on callback is anyway called with mutex held, so I
> guess
> >> it's fine to have clk_prepare_enable() here.
> >
> > If we rely totally on generic PHY functions such as phy_power_on()
> > and friends, why do we need to use locking in callbacks at all.
> 
> Didn't get you.. We don't want to invoke power_on when init is getting
> executed or you don't want power on or power off to get executed
> simultaneously right? So we need to protect it.

I mean callbacks such as samsung_usb2_phy_power_on() which uses spin_lock.
It's already protected by mutex in phy_power_on().

> 
> Cheers
> Kishon

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Anton Tikhomirov March 6, 2014, 9:19 a.m. UTC | #7
Hi,

> Subject: RE: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
> 
> Hi,
> 
> > Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
> >
> > Hi,
> >
> > On Thursday 06 March 2014 02:22 PM, Anton Tikhomirov wrote:
> > > Hello,
> > >
> > >> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
> > >>
> > >>
> > >>
> > >> On Thursday 06 March 2014 01:56 PM, Anton Tikhomirov wrote:
> > >>> Hi Kamil,
> > >>>
> > >>> ...
> > >>>
> > >>>> +| 3. Supporting SoCs
> > >>>> ++--------------------
> > >>>> +
> > >>>> +To support a new SoC a new file should be added to the
> > drivers/phy
> > >>>> +directory. Each SoC's configuration is stored in an instance of
> > the
> > >>>> +struct samsung_usb2_phy_config.
> > >>>> +
> > >>>> +struct samsung_usb2_phy_config {
> > >>>> +	const struct samsung_usb2_common_phy *phys;
> > >>>> +	unsigned int num_phys;
> > >>>> +	bool has_mode_switch;
> > >>>
> > >>> You missed rate_to_clk here.
> > >>>
> > >>>> +};
> > >>>> +
> > >>>
> > >>> ...
> > >>>
> > >>>> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-
> > >> samsung-
> > >>>> usb2.c
> > >>>> new file mode 100644
> > >>>> index 0000000..c3b7719
> > >>>> --- /dev/null
> > >>>> +++ b/drivers/phy/phy-samsung-usb2.c
> > >>>> @@ -0,0 +1,222 @@
> > >>>> +/*
> > >>>> + * Samsung SoC USB 1.1/2.0 PHY driver
> > >>>> + *
> > >>>> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
> > >>>> + * Author: Kamil Debski <k.debski@samsung.com>
> > >>>> + *
> > >>>> + * This program is free software; you can redistribute it
> and/or
> > >>>> modify
> > >>>> + * it under the terms of the GNU General Public License version
> 2
> > >> as
> > >>>> + * published by the Free Software Foundation.
> > >>>> + */
> > >>>> +
> > >>>> +#include <linux/clk.h>
> > >>>> +#include <linux/mfd/syscon.h>
> > >>>> +#include <linux/module.h>
> > >>>> +#include <linux/of.h>
> > >>>> +#include <linux/of_address.h>
> > >>>> +#include <linux/phy/phy.h>
> > >>>> +#include <linux/platform_device.h>
> > >>>> +#include <linux/spinlock.h>
> > >>>> +#include "phy-samsung-usb2.h"
> > >>>> +
> > >>>> +static int samsung_usb2_phy_power_on(struct phy *phy)
> > >>>> +{
> > >>>> +	struct samsung_usb2_phy_instance *inst =
> > phy_get_drvdata(phy);
> > >>>> +	struct samsung_usb2_phy_driver *drv = inst->drv;
> > >>>> +	int ret;
> > >>>> +
> > >>>> +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
> > >>>> +		inst->cfg->label);
> > >>>> +	ret = clk_prepare_enable(drv->clk);
> > >>>
> > >>> clk_prepare_enable() can sleep, and therefore doesn't allow
> > >>> samusng_usb2_phy_power_on() to be used in atomic context
> > >>> (e.g. inside spin_lock-ed area), what sometimes may be desirable.
> > >>> What about to prepare clock in probe, and just enable it here
> > >>> (note: clk_enable() doesn't sleep).
> > >>
> > >> The PHY power-on callback is anyway called with mutex held, so I
> > guess
> > >> it's fine to have clk_prepare_enable() here.
> > >
> > > If we rely totally on generic PHY functions such as phy_power_on()
> > > and friends, why do we need to use locking in callbacks at all.
> >
> > Didn't get you.. We don't want to invoke power_on when init is
> getting
> > executed or you don't want power on or power off to get executed
> > simultaneously right? So we need to protect it.
> 
> I mean callbacks such as samsung_usb2_phy_power_on() which uses
> spin_lock.
> It's already protected by mutex in phy_power_on().

Well... phy_power_on() uses mutex to protect power_on() callback.
power_on() is samsung_usb2_phy_power_on() in our case.
samsung_usb2_phy_power_on() uses spinlock.
My question is why do we need to use spinlock _inside_ callback
if it is already protected by mutex.



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Kishon Vijay Abraham I March 6, 2014, 9:27 a.m. UTC | #8
Hi,

On Thursday 06 March 2014 02:49 PM, Anton Tikhomirov wrote:
> Hi,
>
>> Subject: RE: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
>>
>> Hi,
>>
>>> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
>>>
>>> Hi,
>>>
>>> On Thursday 06 March 2014 02:22 PM, Anton Tikhomirov wrote:
>>>> Hello,
>>>>
>>>>> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
>>>>>
>>>>>
>>>>>
>>>>> On Thursday 06 March 2014 01:56 PM, Anton Tikhomirov wrote:
>>>>>> Hi Kamil,
>>>>>>
>>>>>> ...
>>>>>>
>>>>>>> +| 3. Supporting SoCs
>>>>>>> ++--------------------
>>>>>>> +
>>>>>>> +To support a new SoC a new file should be added to the
>>> drivers/phy
>>>>>>> +directory. Each SoC's configuration is stored in an instance of
>>> the
>>>>>>> +struct samsung_usb2_phy_config.
>>>>>>> +
>>>>>>> +struct samsung_usb2_phy_config {
>>>>>>> +	const struct samsung_usb2_common_phy *phys;
>>>>>>> +	unsigned int num_phys;
>>>>>>> +	bool has_mode_switch;
>>>>>>
>>>>>> You missed rate_to_clk here.
>>>>>>
>>>>>>> +};
>>>>>>> +
>>>>>>
>>>>>> ...
>>>>>>
>>>>>>> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-
>>>>> samsung-
>>>>>>> usb2.c
>>>>>>> new file mode 100644
>>>>>>> index 0000000..c3b7719
>>>>>>> --- /dev/null
>>>>>>> +++ b/drivers/phy/phy-samsung-usb2.c
>>>>>>> @@ -0,0 +1,222 @@
>>>>>>> +/*
>>>>>>> + * Samsung SoC USB 1.1/2.0 PHY driver
>>>>>>> + *
>>>>>>> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
>>>>>>> + * Author: Kamil Debski <k.debski@samsung.com>
>>>>>>> + *
>>>>>>> + * This program is free software; you can redistribute it
>> and/or
>>>>>>> modify
>>>>>>> + * it under the terms of the GNU General Public License version
>> 2
>>>>> as
>>>>>>> + * published by the Free Software Foundation.
>>>>>>> + */
>>>>>>> +
>>>>>>> +#include <linux/clk.h>
>>>>>>> +#include <linux/mfd/syscon.h>
>>>>>>> +#include <linux/module.h>
>>>>>>> +#include <linux/of.h>
>>>>>>> +#include <linux/of_address.h>
>>>>>>> +#include <linux/phy/phy.h>
>>>>>>> +#include <linux/platform_device.h>
>>>>>>> +#include <linux/spinlock.h>
>>>>>>> +#include "phy-samsung-usb2.h"
>>>>>>> +
>>>>>>> +static int samsung_usb2_phy_power_on(struct phy *phy)
>>>>>>> +{
>>>>>>> +	struct samsung_usb2_phy_instance *inst =
>>> phy_get_drvdata(phy);
>>>>>>> +	struct samsung_usb2_phy_driver *drv = inst->drv;
>>>>>>> +	int ret;
>>>>>>> +
>>>>>>> +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
>>>>>>> +		inst->cfg->label);
>>>>>>> +	ret = clk_prepare_enable(drv->clk);
>>>>>>
>>>>>> clk_prepare_enable() can sleep, and therefore doesn't allow
>>>>>> samusng_usb2_phy_power_on() to be used in atomic context
>>>>>> (e.g. inside spin_lock-ed area), what sometimes may be desirable.
>>>>>> What about to prepare clock in probe, and just enable it here
>>>>>> (note: clk_enable() doesn't sleep).
>>>>>
>>>>> The PHY power-on callback is anyway called with mutex held, so I
>>> guess
>>>>> it's fine to have clk_prepare_enable() here.
>>>>
>>>> If we rely totally on generic PHY functions such as phy_power_on()
>>>> and friends, why do we need to use locking in callbacks at all.
>>>
>>> Didn't get you.. We don't want to invoke power_on when init is
>> getting
>>> executed or you don't want power on or power off to get executed
>>> simultaneously right? So we need to protect it.
>>
>> I mean callbacks such as samsung_usb2_phy_power_on() which uses
>> spin_lock.
>> It's already protected by mutex in phy_power_on().
>
> Well... phy_power_on() uses mutex to protect power_on() callback.
> power_on() is samsung_usb2_phy_power_on() in our case.
> samsung_usb2_phy_power_on() uses spinlock.
> My question is why do we need to use spinlock _inside_ callback
> if it is already protected by mutex.

It is needed when the same PHY provider implements multiple PHYs. 
phy-core can protect phy-ops of same PHY. However if the PHY provider 
implements multiple PHYs, phy-core won't be able to protect.

Cheers
Kishon
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Kamil Debski March 6, 2014, 10:24 a.m. UTC | #9
Hi Anton, Kishon,

> From: Anton Tikhomirov [mailto:av.tikhomirov@samsung.com]
> Sent: Thursday, March 06, 2014 9:26 AM
> 
> Hi Kamil,
> 
> ...
> 
> > +| 3. Supporting SoCs
> > ++--------------------
> > +
> > +To support a new SoC a new file should be added to the drivers/phy
> > +directory. Each SoC's configuration is stored in an instance of the
> > +struct samsung_usb2_phy_config.
> > +
> > +struct samsung_usb2_phy_config {
> > +	const struct samsung_usb2_common_phy *phys;
> > +	unsigned int num_phys;
> > +	bool has_mode_switch;
> 
> You missed rate_to_clk here.

Thank you for spotting this.

Kishon: I am sorry that this omission was made. I am happy to send an
updated patchset. However, I want to give some time for any additional
comments. Do you think that we have for this? Is today evening ok with you?
> 
> > +};
> > +
> 
> ...
> 
> > diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-
> samsung-
> > usb2.c new file mode 100644 index 0000000..c3b7719
> > --- /dev/null
> > +++ b/drivers/phy/phy-samsung-usb2.c
> > @@ -0,0 +1,222 @@
> > +/*
> > + * Samsung SoC USB 1.1/2.0 PHY driver
> > + *
> > + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
> > + * Author: Kamil Debski <k.debski@samsung.com>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/phy/phy.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/spinlock.h>
> > +#include "phy-samsung-usb2.h"
> > +
> > +static int samsung_usb2_phy_power_on(struct phy *phy) {
> > +	struct samsung_usb2_phy_instance *inst = phy_get_drvdata(phy);
> > +	struct samsung_usb2_phy_driver *drv = inst->drv;
> > +	int ret;
> > +
> > +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
> > +		inst->cfg->label);
> > +	ret = clk_prepare_enable(drv->clk);
> 
> clk_prepare_enable() can sleep, and therefore doesn't allow
> samusng_usb2_phy_power_on() to be used in atomic context (e.g. inside
> spin_lock-ed area), what sometimes may be desirable.
> What about to prepare clock in probe, and just enable it here
> (note: clk_enable() doesn't sleep).

From the onward discussion between you and Kishon, I draw the conclusion
that this change is not necessary. Right?

> 
> > +	if (ret)
> > +		goto err_main_clk;
> > +	ret = clk_prepare_enable(drv->ref_clk);
> > +	if (ret)
> > +		goto err_instance_clk;
> > +	if (inst->cfg->power_on) {
> > +		spin_lock(&drv->lock);
> > +		ret = inst->cfg->power_on(inst);
> > +		spin_unlock(&drv->lock);
> > +	}
> > +
> > +	return 0;
> 
> Thank you

Best wishes,
Kishon Vijay Abraham I March 6, 2014, 10:44 a.m. UTC | #10
Hi,

On Thursday 06 March 2014 03:54 PM, Kamil Debski wrote:
> Hi Anton, Kishon,
>
>> From: Anton Tikhomirov [mailto:av.tikhomirov@samsung.com]
>> Sent: Thursday, March 06, 2014 9:26 AM
>>
>> Hi Kamil,
>>
>> ...
>>
>>> +| 3. Supporting SoCs
>>> ++--------------------
>>> +
>>> +To support a new SoC a new file should be added to the drivers/phy
>>> +directory. Each SoC's configuration is stored in an instance of the
>>> +struct samsung_usb2_phy_config.
>>> +
>>> +struct samsung_usb2_phy_config {
>>> +	const struct samsung_usb2_common_phy *phys;
>>> +	unsigned int num_phys;
>>> +	bool has_mode_switch;
>>
>> You missed rate_to_clk here.
>
> Thank you for spotting this.
>
> Kishon: I am sorry that this omission was made. I am happy to send an
> updated patchset. However, I want to give some time for any additional
> comments. Do you think that we have for this? Is today evening ok with you?

Would be great if you can send the patch in 2-3 hrs.. I'd like to give 
enough time for auto build to detect any errors.

>>
>>> +};
>>> +
>>
>> ...
>>
>>> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-
>> samsung-
>>> usb2.c new file mode 100644 index 0000000..c3b7719
>>> --- /dev/null
>>> +++ b/drivers/phy/phy-samsung-usb2.c
>>> @@ -0,0 +1,222 @@
>>> +/*
>>> + * Samsung SoC USB 1.1/2.0 PHY driver
>>> + *
>>> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
>>> + * Author: Kamil Debski <k.debski@samsung.com>
>>> + *
>>> + * This program is free software; you can redistribute it and/or
>>> modify
>>> + * it under the terms of the GNU General Public License version 2 as
>>> + * published by the Free Software Foundation.
>>> + */
>>> +
>>> +#include <linux/clk.h>
>>> +#include <linux/mfd/syscon.h>
>>> +#include <linux/module.h>
>>> +#include <linux/of.h>
>>> +#include <linux/of_address.h>
>>> +#include <linux/phy/phy.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/spinlock.h>
>>> +#include "phy-samsung-usb2.h"
>>> +
>>> +static int samsung_usb2_phy_power_on(struct phy *phy) {
>>> +	struct samsung_usb2_phy_instance *inst = phy_get_drvdata(phy);
>>> +	struct samsung_usb2_phy_driver *drv = inst->drv;
>>> +	int ret;
>>> +
>>> +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
>>> +		inst->cfg->label);
>>> +	ret = clk_prepare_enable(drv->clk);
>>
>> clk_prepare_enable() can sleep, and therefore doesn't allow
>> samusng_usb2_phy_power_on() to be used in atomic context (e.g. inside
>> spin_lock-ed area), what sometimes may be desirable.
>> What about to prepare clock in probe, and just enable it here
>> (note: clk_enable() doesn't sleep).
>
>  From the onward discussion between you and Kishon, I draw the conclusion
> that this change is not necessary. Right?

right.

Cheers
Kishon
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Anton Tikhomirov March 7, 2014, 5:16 a.m. UTC | #11
Hi,

> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
> 
> Hi,
> 
> On Thursday 06 March 2014 02:49 PM, Anton Tikhomirov wrote:
> > Hi,
> >
> >> Subject: RE: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
> >>
> >> Hi,
> >>
> >>> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY driver
> >>>
> >>> Hi,
> >>>
> >>> On Thursday 06 March 2014 02:22 PM, Anton Tikhomirov wrote:
> >>>> Hello,
> >>>>
> >>>>> Subject: Re: [PATCH v9 3/4] phy: Add new Exynos USB 2.0 PHY
> driver
> >>>>>
> >>>>>
> >>>>>
> >>>>> On Thursday 06 March 2014 01:56 PM, Anton Tikhomirov wrote:
> >>>>>> Hi Kamil,
> >>>>>>
> >>>>>> ...
> >>>>>>
> >>>>>>> +| 3. Supporting SoCs
> >>>>>>> ++--------------------
> >>>>>>> +
> >>>>>>> +To support a new SoC a new file should be added to the
> >>> drivers/phy
> >>>>>>> +directory. Each SoC's configuration is stored in an instance
> of
> >>> the
> >>>>>>> +struct samsung_usb2_phy_config.
> >>>>>>> +
> >>>>>>> +struct samsung_usb2_phy_config {
> >>>>>>> +	const struct samsung_usb2_common_phy *phys;
> >>>>>>> +	unsigned int num_phys;
> >>>>>>> +	bool has_mode_switch;
> >>>>>>
> >>>>>> You missed rate_to_clk here.
> >>>>>>
> >>>>>>> +};
> >>>>>>> +
> >>>>>>
> >>>>>> ...
> >>>>>>
> >>>>>>> diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-
> >>>>> samsung-
> >>>>>>> usb2.c
> >>>>>>> new file mode 100644
> >>>>>>> index 0000000..c3b7719
> >>>>>>> --- /dev/null
> >>>>>>> +++ b/drivers/phy/phy-samsung-usb2.c
> >>>>>>> @@ -0,0 +1,222 @@
> >>>>>>> +/*
> >>>>>>> + * Samsung SoC USB 1.1/2.0 PHY driver
> >>>>>>> + *
> >>>>>>> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
> >>>>>>> + * Author: Kamil Debski <k.debski@samsung.com>
> >>>>>>> + *
> >>>>>>> + * This program is free software; you can redistribute it
> >> and/or
> >>>>>>> modify
> >>>>>>> + * it under the terms of the GNU General Public License
> version
> >> 2
> >>>>> as
> >>>>>>> + * published by the Free Software Foundation.
> >>>>>>> + */
> >>>>>>> +
> >>>>>>> +#include <linux/clk.h>
> >>>>>>> +#include <linux/mfd/syscon.h>
> >>>>>>> +#include <linux/module.h>
> >>>>>>> +#include <linux/of.h>
> >>>>>>> +#include <linux/of_address.h>
> >>>>>>> +#include <linux/phy/phy.h>
> >>>>>>> +#include <linux/platform_device.h>
> >>>>>>> +#include <linux/spinlock.h>
> >>>>>>> +#include "phy-samsung-usb2.h"
> >>>>>>> +
> >>>>>>> +static int samsung_usb2_phy_power_on(struct phy *phy)
> >>>>>>> +{
> >>>>>>> +	struct samsung_usb2_phy_instance *inst =
> >>> phy_get_drvdata(phy);
> >>>>>>> +	struct samsung_usb2_phy_driver *drv = inst->drv;
> >>>>>>> +	int ret;
> >>>>>>> +
> >>>>>>> +	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
> >>>>>>> +		inst->cfg->label);
> >>>>>>> +	ret = clk_prepare_enable(drv->clk);
> >>>>>>
> >>>>>> clk_prepare_enable() can sleep, and therefore doesn't allow
> >>>>>> samusng_usb2_phy_power_on() to be used in atomic context
> >>>>>> (e.g. inside spin_lock-ed area), what sometimes may be desirable.
> >>>>>> What about to prepare clock in probe, and just enable it here
> >>>>>> (note: clk_enable() doesn't sleep).
> >>>>>
> >>>>> The PHY power-on callback is anyway called with mutex held, so I
> >>> guess
> >>>>> it's fine to have clk_prepare_enable() here.
> >>>>
> >>>> If we rely totally on generic PHY functions such as phy_power_on()
> >>>> and friends, why do we need to use locking in callbacks at all.
> >>>
> >>> Didn't get you.. We don't want to invoke power_on when init is
> >> getting
> >>> executed or you don't want power on or power off to get executed
> >>> simultaneously right? So we need to protect it.
> >>
> >> I mean callbacks such as samsung_usb2_phy_power_on() which uses
> >> spin_lock.
> >> It's already protected by mutex in phy_power_on().
> >
> > Well... phy_power_on() uses mutex to protect power_on() callback.
> > power_on() is samsung_usb2_phy_power_on() in our case.
> > samsung_usb2_phy_power_on() uses spinlock.
> > My question is why do we need to use spinlock _inside_ callback
> > if it is already protected by mutex.
> 
> It is needed when the same PHY provider implements multiple PHYs.
> phy-core can protect phy-ops of same PHY. However if the PHY provider
> implements multiple PHYs, phy-core won't be able to protect.

Thank you Kishon. Now it's clear.

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diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/phy/samsung-phy.txt b/Documentation/devicetree/bindings/phy/samsung-phy.txt
index c0fccaa..bf955ab 100644
--- a/Documentation/devicetree/bindings/phy/samsung-phy.txt
+++ b/Documentation/devicetree/bindings/phy/samsung-phy.txt
@@ -20,3 +20,56 @@  Required properties:
 - compatible : should be "samsung,exynos5250-dp-video-phy";
 - reg : offset and length of the Display Port PHY register set;
 - #phy-cells : from the generic PHY bindings, must be 0;
+
+Samsung S5P/EXYNOS SoC series USB PHY
+-------------------------------------------------
+
+Required properties:
+- compatible : should be one of the listed compatibles:
+	- "samsung,exynos4210-usb2-phy"
+	- "samsung,exynos4x12-usb2-phy"
+- reg : a list of registers used by phy driver
+	- first and obligatory is the location of phy modules registers
+- samsung,sysreg-phandle - handle to syscon used to control the system registers
+- samsung,pmureg-phandle - handle to syscon used to control PMU registers
+- #phy-cells : from the generic phy bindings, must be 1;
+- clocks and clock-names:
+	- the "phy" clock is required by the phy module, used as a gate
+	- the "ref" clock is used to get the rate of the clock provided to the
+	  PHY module
+
+The first phandle argument in the PHY specifier identifies the PHY, its
+meaning is compatible dependent. For the currently supported SoCs (Exynos 4210
+and Exynos 4212) it is as follows:
+  0 - USB device ("device"),
+  1 - USB host ("host"),
+  2 - HSIC0 ("hsic0"),
+  3 - HSIC1 ("hsic1"),
+
+Exynos 4210 and Exynos 4212 use mode switching and require that mode switch
+register is supplied.
+
+Example:
+
+For Exynos 4412 (compatible with Exynos 4212):
+
+usbphy: phy@125b0000 {
+	compatible = "samsung,exynos4x12-usb2-phy";
+	reg = <0x125b0000 0x100>;
+	clocks = <&clock 305>, <&clock 2>;
+	clock-names = "phy", "ref";
+	status = "okay";
+	#phy-cells = <1>;
+	samsung,sysreg-phandle = <&sys_reg>;
+	samsung,pmureg-phandle = <&pmu_reg>;
+};
+
+Then the PHY can be used in other nodes such as:
+
+phy-consumer@12340000 {
+	phys = <&usbphy 2>;
+	phy-names = "phy";
+};
+
+Refer to DT bindings documentation of particular PHY consumer devices for more
+information about required PHYs and the way of specification.
diff --git a/Documentation/phy/samsung-usb2.txt b/Documentation/phy/samsung-usb2.txt
new file mode 100644
index 0000000..0c8e260
--- /dev/null
+++ b/Documentation/phy/samsung-usb2.txt
@@ -0,0 +1,134 @@ 
+.------------------------------------------------------------------------------+
+|			Samsung USB 2.0 PHY adaptation layer		       |
++-----------------------------------------------------------------------------+'
+
+| 1. Description
++----------------
+
+The architecture of the USB 2.0 PHY module in Samsung SoCs is similar
+among many SoCs. In spite of the similarities it proved difficult to
+create a one driver that would fit all these PHY controllers. Often
+the differences were minor and were found in particular bits of the
+registers of the PHY. In some rare cases the order of register writes or
+the PHY powering up process had to be altered. This adaptation layer is
+a compromise between having separate drivers and having a single driver
+with added support for many special cases.
+
+| 2. Files description
++----------------------
+
+- phy-samsung-usb2.c
+   This is the main file of the adaptation layer. This file contains
+   the probe function and provides two callbacks to the Generic PHY
+   Framework. This two callbacks are used to power on and power off the
+   phy. They carry out the common work that has to be done on all version
+   of the PHY module. Depending on which SoC was chosen they execute SoC
+   specific callbacks. The specific SoC version is selected by choosing
+   the appropriate compatible string. In addition, this file contains
+   struct of_device_id definitions for particular SoCs.
+
+- phy-samsung-usb2.h
+   This is the include file. It declares the structures used by this
+   driver. In addition it should contain extern declarations for
+   structures that describe particular SoCs.
+
+| 3. Supporting SoCs
++--------------------
+
+To support a new SoC a new file should be added to the drivers/phy
+directory. Each SoC's configuration is stored in an instance of the
+struct samsung_usb2_phy_config.
+
+struct samsung_usb2_phy_config {
+	const struct samsung_usb2_common_phy *phys;
+	unsigned int num_phys;
+	bool has_mode_switch;
+};
+
+The num_phys is the number of phys handled by the driver. *phys is an
+array that contains the configuration for each phy. The has_mode_switch
+property is a boolean flag that determines whether the SoC has USB host
+and device on a single pair of pins. If so, a special register has to
+be modified to change the internal routing of these pins between a USB
+device or host module.
+
+For example the configuration for Exynos 4210 is following:
+
+const struct samsung_usb2_phy_config exynos4210_usb2_phy_config = {
+	.has_mode_switch        = 0,
+	.num_phys		= EXYNOS4210_NUM_PHYS,
+	.phys			= exynos4210_phys,
+	.rate_to_clk		= exynos4210_rate_to_clk,
+}
+
+- int (*rate_to_clk)(unsigned long, u32 *)
+	The rate_to_clk callback is to convert the rate of the clock
+	used as the reference clock for the PHY module to the value
+	that should be written in the hardware register.
+
+The exynos4210_phys configuration array is as follows:
+
+static const struct samsung_usb2_common_phy exynos4210_phys[] = {
+	{
+		.label		= "device",
+		.id		= EXYNOS4210_DEVICE,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{
+		.label		= "host",
+		.id		= EXYNOS4210_HOST,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{
+		.label		= "hsic0",
+		.id		= EXYNOS4210_HSIC0,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{
+		.label		= "hsic1",
+		.id		= EXYNOS4210_HSIC1,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{},
+};
+
+- int (*power_on)(struct samsung_usb2_phy_instance *);
+- int (*power_off)(struct samsung_usb2_phy_instance *);
+	These two callbacks are used to power on and power off the phy
+	by modifying appropriate registers.
+
+Final change to the driver is adding appropriate compatible value to the
+phy-samsung-usb2.c file. In case of Exynos 4210 the following lines were
+added to the struct of_device_id samsung_usb2_phy_of_match[] array:
+
+#ifdef CONFIG_PHY_EXYNOS4210_USB2
+	{
+		.compatible = "samsung,exynos4210-usb2-phy",
+		.data = &exynos4210_usb2_phy_config,
+	},
+#endif
+
+To add further flexibility to the driver the Kconfig file enables to
+include support for selected SoCs in the compiled driver. The Kconfig
+entry for Exynos 4210 is following:
+
+config PHY_EXYNOS4210_USB2
+	bool "Support for Exynos 4210"
+	depends on PHY_SAMSUNG_USB2
+	depends on CPU_EXYNOS4210
+	help
+	  Enable USB PHY support for Exynos 4210. This option requires that
+	  Samsung USB 2.0 PHY driver is enabled and means that support for this
+	  particular SoC is compiled in the driver. In case of Exynos 4210 four
+	  phys are available - device, host, HSCI0 and HSCI1.
+
+The newly created file that supports the new SoC has to be also added to the
+Makefile. In case of Exynos 4210 the added line is following:
+
+obj-$(CONFIG_PHY_EXYNOS4210_USB2)       += phy-exynos4210-usb2.o
+
+After completing these steps the support for the new SoC should be ready.
diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index dc1756c..fc5a44a 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -96,4 +96,33 @@  config PHY_SUN4I_USB
 	  This driver controls the entire USB PHY block, both the USB OTG
 	  parts, as well as the 2 regular USB 2 host PHYs.
 
+config PHY_SAMSUNG_USB2
+	tristate "Samsung USB 2.0 PHY driver"
+	select GENERIC_PHY
+	select MFD_SYSCON
+	help
+	  Enable this to support the Samsung USB 2.0 PHY driver for Samsung
+	  SoCs. This driver provides the interface for USB 2.0 PHY. Support for
+	  particular SoCs has to be enabled in addition to this driver. Number
+	  and type of supported phys depends on the SoC.
+
+config PHY_EXYNOS4210_USB2
+	bool "Support for Exynos 4210"
+	depends on PHY_SAMSUNG_USB2
+	depends on CPU_EXYNOS4210
+	help
+	  Enable USB PHY support for Exynos 4210. This option requires that
+	  Samsung USB 2.0 PHY driver is enabled and means that support for this
+	  particular SoC is compiled in the driver. In case of Exynos 4210 four
+	  phys are available - device, host, HSIC0 and HSIC1.
+
+config PHY_EXYNOS4X12_USB2
+	bool "Support for Exynos 4x12"
+	depends on PHY_SAMSUNG_USB2
+	depends on (SOC_EXYNOS4212 || SOC_EXYNOS4412)
+	help
+	  Enable USB PHY support for Exynos 4x12. This option requires that
+	  Samsung USB 2.0 PHY driver is enabled and means that support for this
+	  particular SoC is compiled in the driver. In case of Exynos 4x12 four
+	  phys are available - device, host, HSIC0 and HSIC1.
 endmenu
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index 5d0b59e..0ea36ff 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -11,3 +11,6 @@  obj-$(CONFIG_OMAP_USB2)			+= phy-omap-usb2.o
 obj-$(CONFIG_TWL4030_USB)		+= phy-twl4030-usb.o
 obj-$(CONFIG_PHY_EXYNOS5250_SATA)	+= phy-exynos5250-sata.o
 obj-$(CONFIG_PHY_SUN4I_USB)		+= phy-sun4i-usb.o
+obj-$(CONFIG_PHY_SAMSUNG_USB2)		+= phy-samsung-usb2.o
+obj-$(CONFIG_PHY_EXYNOS4210_USB2)	+= phy-exynos4210-usb2.o
+obj-$(CONFIG_PHY_EXYNOS4X12_USB2)	+= phy-exynos4x12-usb2.o
diff --git a/drivers/phy/phy-exynos4210-usb2.c b/drivers/phy/phy-exynos4210-usb2.c
new file mode 100644
index 0000000..236a52a
--- /dev/null
+++ b/drivers/phy/phy-exynos4210-usb2.c
@@ -0,0 +1,261 @@ 
+/*
+ * Samsung SoC USB 1.1/2.0 PHY driver - Exynos 4210 support
+ *
+ * Copyright (C) 2013 Samsung Electronics Co., Ltd.
+ * Author: Kamil Debski <k.debski@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/phy/phy.h>
+#include <linux/regmap.h>
+#include "phy-samsung-usb2.h"
+
+/* Exynos USB PHY registers */
+
+/* PHY power control */
+#define EXYNOS_4210_UPHYPWR			0x0
+
+#define EXYNOS_4210_UPHYPWR_PHY0_SUSPEND	BIT(0)
+#define EXYNOS_4210_UPHYPWR_PHY0_PWR		BIT(3)
+#define EXYNOS_4210_UPHYPWR_PHY0_OTG_PWR	BIT(4)
+#define EXYNOS_4210_UPHYPWR_PHY0_SLEEP		BIT(5)
+#define EXYNOS_4210_UPHYPWR_PHY0	( \
+	EXYNOS_4210_UPHYPWR_PHY0_SUSPEND | \
+	EXYNOS_4210_UPHYPWR_PHY0_PWR | \
+	EXYNOS_4210_UPHYPWR_PHY0_OTG_PWR | \
+	EXYNOS_4210_UPHYPWR_PHY0_SLEEP)
+
+#define EXYNOS_4210_UPHYPWR_PHY1_SUSPEND	BIT(6)
+#define EXYNOS_4210_UPHYPWR_PHY1_PWR		BIT(7)
+#define EXYNOS_4210_UPHYPWR_PHY1_SLEEP		BIT(8)
+#define EXYNOS_4210_UPHYPWR_PHY1 ( \
+	EXYNOS_4210_UPHYPWR_PHY1_SUSPEND | \
+	EXYNOS_4210_UPHYPWR_PHY1_PWR | \
+	EXYNOS_4210_UPHYPWR_PHY1_SLEEP)
+
+#define EXYNOS_4210_UPHYPWR_HSIC0_SUSPEND	BIT(9)
+#define EXYNOS_4210_UPHYPWR_HSIC0_SLEEP		BIT(10)
+#define EXYNOS_4210_UPHYPWR_HSIC0 ( \
+	EXYNOS_4210_UPHYPWR_HSIC0_SUSPEND | \
+	EXYNOS_4210_UPHYPWR_HSIC0_SLEEP)
+
+#define EXYNOS_4210_UPHYPWR_HSIC1_SUSPEND	BIT(11)
+#define EXYNOS_4210_UPHYPWR_HSIC1_SLEEP		BIT(12)
+#define EXYNOS_4210_UPHYPWR_HSIC1 ( \
+	EXYNOS_4210_UPHYPWR_HSIC1_SUSPEND | \
+	EXYNOS_4210_UPHYPWR_HSIC1_SLEEP)
+
+/* PHY clock control */
+#define EXYNOS_4210_UPHYCLK			0x4
+
+#define EXYNOS_4210_UPHYCLK_PHYFSEL_MASK	(0x3 << 0)
+#define EXYNOS_4210_UPHYCLK_PHYFSEL_OFFSET	0
+#define EXYNOS_4210_UPHYCLK_PHYFSEL_48MHZ	(0x0 << 0)
+#define EXYNOS_4210_UPHYCLK_PHYFSEL_24MHZ	(0x3 << 0)
+#define EXYNOS_4210_UPHYCLK_PHYFSEL_12MHZ	(0x2 << 0)
+
+#define EXYNOS_4210_UPHYCLK_PHY0_ID_PULLUP	BIT(2)
+#define EXYNOS_4210_UPHYCLK_PHY0_COMMON_ON	BIT(4)
+#define EXYNOS_4210_UPHYCLK_PHY1_COMMON_ON	BIT(7)
+
+/* PHY reset control */
+#define EXYNOS_4210_UPHYRST			0x8
+
+#define EXYNOS_4210_URSTCON_PHY0		BIT(0)
+#define EXYNOS_4210_URSTCON_OTG_HLINK		BIT(1)
+#define EXYNOS_4210_URSTCON_OTG_PHYLINK		BIT(2)
+#define EXYNOS_4210_URSTCON_PHY1_ALL		BIT(3)
+#define EXYNOS_4210_URSTCON_PHY1_P0		BIT(4)
+#define EXYNOS_4210_URSTCON_PHY1_P1P2		BIT(5)
+#define EXYNOS_4210_URSTCON_HOST_LINK_ALL	BIT(6)
+#define EXYNOS_4210_URSTCON_HOST_LINK_P0	BIT(7)
+#define EXYNOS_4210_URSTCON_HOST_LINK_P1	BIT(8)
+#define EXYNOS_4210_URSTCON_HOST_LINK_P2	BIT(9)
+
+/* Isolation, configured in the power management unit */
+#define EXYNOS_4210_USB_ISOL_DEVICE_OFFSET	0x704
+#define EXYNOS_4210_USB_ISOL_DEVICE		BIT(0)
+#define EXYNOS_4210_USB_ISOL_HOST_OFFSET	0x708
+#define EXYNOS_4210_USB_ISOL_HOST		BIT(0)
+
+/* USBYPHY1 Floating prevention */
+#define EXYNOS_4210_UPHY1CON			0x34
+#define EXYNOS_4210_UPHY1CON_FLOAT_PREVENTION	0x1
+
+/* Mode switching SUB Device <-> Host */
+#define EXYNOS_4210_MODE_SWITCH_OFFSET		0x21c
+#define EXYNOS_4210_MODE_SWITCH_MASK		1
+#define EXYNOS_4210_MODE_SWITCH_DEVICE		0
+#define EXYNOS_4210_MODE_SWITCH_HOST		1
+
+enum exynos4210_phy_id {
+	EXYNOS4210_DEVICE,
+	EXYNOS4210_HOST,
+	EXYNOS4210_HSIC0,
+	EXYNOS4210_HSIC1,
+	EXYNOS4210_NUM_PHYS,
+};
+
+/*
+ * exynos4210_rate_to_clk() converts the supplied clock rate to the value that
+ * can be written to the phy register.
+ */
+static int exynos4210_rate_to_clk(unsigned long rate, u32 *reg)
+{
+	switch (rate) {
+	case 12 * MHZ:
+		*reg = EXYNOS_4210_UPHYCLK_PHYFSEL_12MHZ;
+		break;
+	case 24 * MHZ:
+		*reg = EXYNOS_4210_UPHYCLK_PHYFSEL_24MHZ;
+		break;
+	case 48 * MHZ:
+		*reg = EXYNOS_4210_UPHYCLK_PHYFSEL_48MHZ;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void exynos4210_isol(struct samsung_usb2_phy_instance *inst, bool on)
+{
+	struct samsung_usb2_phy_driver *drv = inst->drv;
+	u32 offset;
+	u32 mask;
+
+	switch (inst->cfg->id) {
+	case EXYNOS4210_DEVICE:
+		offset = EXYNOS_4210_USB_ISOL_DEVICE_OFFSET;
+		mask = EXYNOS_4210_USB_ISOL_DEVICE;
+		break;
+	case EXYNOS4210_HOST:
+		offset = EXYNOS_4210_USB_ISOL_HOST_OFFSET;
+		mask = EXYNOS_4210_USB_ISOL_HOST;
+		break;
+	default:
+		return;
+	};
+
+	regmap_update_bits(drv->reg_pmu, offset, mask, on ? 0 : mask);
+}
+
+static void exynos4210_phy_pwr(struct samsung_usb2_phy_instance *inst, bool on)
+{
+	struct samsung_usb2_phy_driver *drv = inst->drv;
+	u32 rstbits = 0;
+	u32 phypwr = 0;
+	u32 rst;
+	u32 pwr;
+	u32 clk;
+
+	switch (inst->cfg->id) {
+	case EXYNOS4210_DEVICE:
+		phypwr =	EXYNOS_4210_UPHYPWR_PHY0;
+		rstbits =	EXYNOS_4210_URSTCON_PHY0;
+		break;
+	case EXYNOS4210_HOST:
+		phypwr =	EXYNOS_4210_UPHYPWR_PHY1;
+		rstbits =	EXYNOS_4210_URSTCON_PHY1_ALL |
+				EXYNOS_4210_URSTCON_PHY1_P0 |
+				EXYNOS_4210_URSTCON_PHY1_P1P2 |
+				EXYNOS_4210_URSTCON_HOST_LINK_ALL |
+				EXYNOS_4210_URSTCON_HOST_LINK_P0;
+		writel(on, drv->reg_phy + EXYNOS_4210_UPHY1CON);
+		break;
+	case EXYNOS4210_HSIC0:
+		phypwr =	EXYNOS_4210_UPHYPWR_HSIC0;
+		rstbits =	EXYNOS_4210_URSTCON_PHY1_P1P2 |
+				EXYNOS_4210_URSTCON_HOST_LINK_P1;
+		break;
+	case EXYNOS4210_HSIC1:
+		phypwr =	EXYNOS_4210_UPHYPWR_HSIC1;
+		rstbits =	EXYNOS_4210_URSTCON_PHY1_P1P2 |
+				EXYNOS_4210_URSTCON_HOST_LINK_P2;
+		break;
+	};
+
+	if (on) {
+		clk = readl(drv->reg_phy + EXYNOS_4210_UPHYCLK);
+		clk &= ~EXYNOS_4210_UPHYCLK_PHYFSEL_MASK;
+		clk |= drv->ref_reg_val << EXYNOS_4210_UPHYCLK_PHYFSEL_OFFSET;
+		writel(clk, drv->reg_phy + EXYNOS_4210_UPHYCLK);
+
+		pwr = readl(drv->reg_phy + EXYNOS_4210_UPHYPWR);
+		pwr &= ~phypwr;
+		writel(pwr, drv->reg_phy + EXYNOS_4210_UPHYPWR);
+
+		rst = readl(drv->reg_phy + EXYNOS_4210_UPHYRST);
+		rst |= rstbits;
+		writel(rst, drv->reg_phy + EXYNOS_4210_UPHYRST);
+		udelay(10);
+		rst &= ~rstbits;
+		writel(rst, drv->reg_phy + EXYNOS_4210_UPHYRST);
+		/* The following delay is necessary for the reset sequence to be
+		 * completed */
+		udelay(80);
+	} else {
+		pwr = readl(drv->reg_phy + EXYNOS_4210_UPHYPWR);
+		pwr |= phypwr;
+		writel(pwr, drv->reg_phy + EXYNOS_4210_UPHYPWR);
+	}
+}
+
+static int exynos4210_power_on(struct samsung_usb2_phy_instance *inst)
+{
+	/* Order of initialisation is important - first power then isolation */
+	exynos4210_phy_pwr(inst, 1);
+	exynos4210_isol(inst, 0);
+
+	return 0;
+}
+
+static int exynos4210_power_off(struct samsung_usb2_phy_instance *inst)
+{
+	exynos4210_isol(inst, 1);
+	exynos4210_phy_pwr(inst, 0);
+
+	return 0;
+}
+
+
+static const struct samsung_usb2_common_phy exynos4210_phys[] = {
+	{
+		.label		= "device",
+		.id		= EXYNOS4210_DEVICE,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{
+		.label		= "host",
+		.id		= EXYNOS4210_HOST,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{
+		.label		= "hsic0",
+		.id		= EXYNOS4210_HSIC0,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{
+		.label		= "hsic1",
+		.id		= EXYNOS4210_HSIC1,
+		.power_on	= exynos4210_power_on,
+		.power_off	= exynos4210_power_off,
+	},
+	{},
+};
+
+const struct samsung_usb2_phy_config exynos4210_usb2_phy_config = {
+	.has_mode_switch	= 0,
+	.num_phys		= EXYNOS4210_NUM_PHYS,
+	.phys			= exynos4210_phys,
+	.rate_to_clk		= exynos4210_rate_to_clk,
+};
diff --git a/drivers/phy/phy-exynos4x12-usb2.c b/drivers/phy/phy-exynos4x12-usb2.c
new file mode 100644
index 0000000..d92a7cc
--- /dev/null
+++ b/drivers/phy/phy-exynos4x12-usb2.c
@@ -0,0 +1,328 @@ 
+/*
+ * Samsung SoC USB 1.1/2.0 PHY driver - Exynos 4x12 support
+ *
+ * Copyright (C) 2013 Samsung Electronics Co., Ltd.
+ * Author: Kamil Debski <k.debski@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/phy/phy.h>
+#include <linux/regmap.h>
+#include "phy-samsung-usb2.h"
+
+/* Exynos USB PHY registers */
+
+/* PHY power control */
+#define EXYNOS_4x12_UPHYPWR			0x0
+
+#define EXYNOS_4x12_UPHYPWR_PHY0_SUSPEND	BIT(0)
+#define EXYNOS_4x12_UPHYPWR_PHY0_PWR		BIT(3)
+#define EXYNOS_4x12_UPHYPWR_PHY0_OTG_PWR	BIT(4)
+#define EXYNOS_4x12_UPHYPWR_PHY0_SLEEP		BIT(5)
+#define EXYNOS_4x12_UPHYPWR_PHY0 ( \
+	EXYNOS_4x12_UPHYPWR_PHY0_SUSPEND | \
+	EXYNOS_4x12_UPHYPWR_PHY0_PWR | \
+	EXYNOS_4x12_UPHYPWR_PHY0_OTG_PWR | \
+	EXYNOS_4x12_UPHYPWR_PHY0_SLEEP)
+
+#define EXYNOS_4x12_UPHYPWR_PHY1_SUSPEND	BIT(6)
+#define EXYNOS_4x12_UPHYPWR_PHY1_PWR		BIT(7)
+#define EXYNOS_4x12_UPHYPWR_PHY1_SLEEP		BIT(8)
+#define EXYNOS_4x12_UPHYPWR_PHY1 ( \
+	EXYNOS_4x12_UPHYPWR_PHY1_SUSPEND | \
+	EXYNOS_4x12_UPHYPWR_PHY1_PWR | \
+	EXYNOS_4x12_UPHYPWR_PHY1_SLEEP)
+
+#define EXYNOS_4x12_UPHYPWR_HSIC0_SUSPEND	BIT(9)
+#define EXYNOS_4x12_UPHYPWR_HSIC0_PWR		BIT(10)
+#define EXYNOS_4x12_UPHYPWR_HSIC0_SLEEP		BIT(11)
+#define EXYNOS_4x12_UPHYPWR_HSIC0 ( \
+	EXYNOS_4x12_UPHYPWR_HSIC0_SUSPEND | \
+	EXYNOS_4x12_UPHYPWR_HSIC0_PWR | \
+	EXYNOS_4x12_UPHYPWR_HSIC0_SLEEP)
+
+#define EXYNOS_4x12_UPHYPWR_HSIC1_SUSPEND	BIT(12)
+#define EXYNOS_4x12_UPHYPWR_HSIC1_PWR		BIT(13)
+#define EXYNOS_4x12_UPHYPWR_HSIC1_SLEEP		BIT(14)
+#define EXYNOS_4x12_UPHYPWR_HSIC1 ( \
+	EXYNOS_4x12_UPHYPWR_HSIC1_SUSPEND | \
+	EXYNOS_4x12_UPHYPWR_HSIC1_PWR | \
+	EXYNOS_4x12_UPHYPWR_HSIC1_SLEEP)
+
+/* PHY clock control */
+#define EXYNOS_4x12_UPHYCLK			0x4
+
+#define EXYNOS_4x12_UPHYCLK_PHYFSEL_MASK	(0x7 << 0)
+#define EXYNOS_4x12_UPHYCLK_PHYFSEL_OFFSET	0
+#define EXYNOS_4x12_UPHYCLK_PHYFSEL_9MHZ6	(0x0 << 0)
+#define EXYNOS_4x12_UPHYCLK_PHYFSEL_10MHZ	(0x1 << 0)
+#define EXYNOS_4x12_UPHYCLK_PHYFSEL_12MHZ	(0x2 << 0)
+#define EXYNOS_4x12_UPHYCLK_PHYFSEL_19MHZ2	(0x3 << 0)
+#define EXYNOS_4x12_UPHYCLK_PHYFSEL_20MHZ	(0x4 << 0)
+#define EXYNOS_4x12_UPHYCLK_PHYFSEL_24MHZ	(0x5 << 0)
+#define EXYNOS_4x12_UPHYCLK_PHYFSEL_50MHZ	(0x7 << 0)
+
+#define EXYNOS_4x12_UPHYCLK_PHY0_ID_PULLUP	BIT(3)
+#define EXYNOS_4x12_UPHYCLK_PHY0_COMMON_ON	BIT(4)
+#define EXYNOS_4x12_UPHYCLK_PHY1_COMMON_ON	BIT(7)
+
+#define EXYNOS_4x12_UPHYCLK_HSIC_REFCLK_MASK	(0x7f << 10)
+#define EXYNOS_4x12_UPHYCLK_HSIC_REFCLK_OFFSET  10
+#define EXYNOS_4x12_UPHYCLK_HSIC_REFCLK_12MHZ	(0x24 << 10)
+#define EXYNOS_4x12_UPHYCLK_HSIC_REFCLK_15MHZ	(0x1c << 10)
+#define EXYNOS_4x12_UPHYCLK_HSIC_REFCLK_16MHZ	(0x1a << 10)
+#define EXYNOS_4x12_UPHYCLK_HSIC_REFCLK_19MHZ2	(0x15 << 10)
+#define EXYNOS_4x12_UPHYCLK_HSIC_REFCLK_20MHZ	(0x14 << 10)
+
+/* PHY reset control */
+#define EXYNOS_4x12_UPHYRST			0x8
+
+#define EXYNOS_4x12_URSTCON_PHY0		BIT(0)
+#define EXYNOS_4x12_URSTCON_OTG_HLINK		BIT(1)
+#define EXYNOS_4x12_URSTCON_OTG_PHYLINK		BIT(2)
+#define EXYNOS_4x12_URSTCON_HOST_PHY		BIT(3)
+#define EXYNOS_4x12_URSTCON_PHY1		BIT(4)
+#define EXYNOS_4x12_URSTCON_HSIC0		BIT(5)
+#define EXYNOS_4x12_URSTCON_HSIC1		BIT(6)
+#define EXYNOS_4x12_URSTCON_HOST_LINK_ALL	BIT(7)
+#define EXYNOS_4x12_URSTCON_HOST_LINK_P0	BIT(8)
+#define EXYNOS_4x12_URSTCON_HOST_LINK_P1	BIT(9)
+#define EXYNOS_4x12_URSTCON_HOST_LINK_P2	BIT(10)
+
+/* Isolation, configured in the power management unit */
+#define EXYNOS_4x12_USB_ISOL_OFFSET		0x704
+#define EXYNOS_4x12_USB_ISOL_OTG		BIT(0)
+#define EXYNOS_4x12_USB_ISOL_HSIC0_OFFSET	0x708
+#define EXYNOS_4x12_USB_ISOL_HSIC0		BIT(0)
+#define EXYNOS_4x12_USB_ISOL_HSIC1_OFFSET	0x70c
+#define EXYNOS_4x12_USB_ISOL_HSIC1		BIT(0)
+
+/* Mode switching SUB Device <-> Host */
+#define EXYNOS_4x12_MODE_SWITCH_OFFSET		0x21c
+#define EXYNOS_4x12_MODE_SWITCH_MASK		1
+#define EXYNOS_4x12_MODE_SWITCH_DEVICE		0
+#define EXYNOS_4x12_MODE_SWITCH_HOST		1
+
+enum exynos4x12_phy_id {
+	EXYNOS4x12_DEVICE,
+	EXYNOS4x12_HOST,
+	EXYNOS4x12_HSIC0,
+	EXYNOS4x12_HSIC1,
+	EXYNOS4x12_NUM_PHYS,
+};
+
+/*
+ * exynos4x12_rate_to_clk() converts the supplied clock rate to the value that
+ * can be written to the phy register.
+ */
+static int exynos4x12_rate_to_clk(unsigned long rate, u32 *reg)
+{
+	/* EXYNOS_4x12_UPHYCLK_PHYFSEL_MASK */
+
+	switch (rate) {
+	case 9600 * KHZ:
+		*reg = EXYNOS_4x12_UPHYCLK_PHYFSEL_9MHZ6;
+		break;
+	case 10 * MHZ:
+		*reg = EXYNOS_4x12_UPHYCLK_PHYFSEL_10MHZ;
+		break;
+	case 12 * MHZ:
+		*reg = EXYNOS_4x12_UPHYCLK_PHYFSEL_12MHZ;
+		break;
+	case 19200 * KHZ:
+		*reg = EXYNOS_4x12_UPHYCLK_PHYFSEL_19MHZ2;
+		break;
+	case 20 * MHZ:
+		*reg = EXYNOS_4x12_UPHYCLK_PHYFSEL_20MHZ;
+		break;
+	case 24 * MHZ:
+		*reg = EXYNOS_4x12_UPHYCLK_PHYFSEL_24MHZ;
+		break;
+	case 50 * MHZ:
+		*reg = EXYNOS_4x12_UPHYCLK_PHYFSEL_50MHZ;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void exynos4x12_isol(struct samsung_usb2_phy_instance *inst, bool on)
+{
+	struct samsung_usb2_phy_driver *drv = inst->drv;
+	u32 offset;
+	u32 mask;
+
+	switch (inst->cfg->id) {
+	case EXYNOS4x12_DEVICE:
+	case EXYNOS4x12_HOST:
+		offset = EXYNOS_4x12_USB_ISOL_OFFSET;
+		mask = EXYNOS_4x12_USB_ISOL_OTG;
+		break;
+	case EXYNOS4x12_HSIC0:
+		offset = EXYNOS_4x12_USB_ISOL_HSIC0_OFFSET;
+		mask = EXYNOS_4x12_USB_ISOL_HSIC0;
+		break;
+	case EXYNOS4x12_HSIC1:
+		offset = EXYNOS_4x12_USB_ISOL_HSIC1_OFFSET;
+		mask = EXYNOS_4x12_USB_ISOL_HSIC1;
+		break;
+	default:
+		return;
+	};
+
+	regmap_update_bits(drv->reg_pmu, offset, mask, on ? 0 : mask);
+}
+
+static void exynos4x12_setup_clk(struct samsung_usb2_phy_instance *inst)
+{
+	struct samsung_usb2_phy_driver *drv = inst->drv;
+	u32 clk;
+
+	clk = readl(drv->reg_phy + EXYNOS_4x12_UPHYCLK);
+	clk &= ~EXYNOS_4x12_UPHYCLK_PHYFSEL_MASK;
+	clk |= drv->ref_reg_val << EXYNOS_4x12_UPHYCLK_PHYFSEL_OFFSET;
+	writel(clk, drv->reg_phy + EXYNOS_4x12_UPHYCLK);
+}
+
+static void exynos4x12_phy_pwr(struct samsung_usb2_phy_instance *inst, bool on)
+{
+	struct samsung_usb2_phy_driver *drv = inst->drv;
+	u32 rstbits = 0;
+	u32 phypwr = 0;
+	u32 rst;
+	u32 pwr;
+	u32 mode = 0;
+	u32 switch_mode = 0;
+
+	switch (inst->cfg->id) {
+	case EXYNOS4x12_DEVICE:
+		phypwr =	EXYNOS_4x12_UPHYPWR_PHY0;
+		rstbits =	EXYNOS_4x12_URSTCON_PHY0;
+		mode =		EXYNOS_4x12_MODE_SWITCH_DEVICE;
+		switch_mode =	1;
+		break;
+	case EXYNOS4x12_HOST:
+		phypwr =	EXYNOS_4x12_UPHYPWR_PHY1;
+		rstbits =	EXYNOS_4x12_URSTCON_HOST_PHY;
+		mode =		EXYNOS_4x12_MODE_SWITCH_HOST;
+		switch_mode =	1;
+		break;
+	case EXYNOS4x12_HSIC0:
+		phypwr =	EXYNOS_4x12_UPHYPWR_HSIC0;
+		rstbits =	EXYNOS_4x12_URSTCON_HSIC1 |
+				EXYNOS_4x12_URSTCON_HOST_LINK_P0 |
+				EXYNOS_4x12_URSTCON_HOST_PHY;
+		break;
+	case EXYNOS4x12_HSIC1:
+		phypwr =	EXYNOS_4x12_UPHYPWR_HSIC1;
+		rstbits =	EXYNOS_4x12_URSTCON_HSIC1 |
+				EXYNOS_4x12_URSTCON_HOST_LINK_P1;
+		break;
+	};
+
+	if (on) {
+		if (switch_mode)
+			regmap_update_bits(drv->reg_sys,
+					   EXYNOS_4x12_MODE_SWITCH_OFFSET,
+					   EXYNOS_4x12_MODE_SWITCH_MASK, mode);
+
+		pwr = readl(drv->reg_phy + EXYNOS_4x12_UPHYPWR);
+		pwr &= ~phypwr;
+		writel(pwr, drv->reg_phy + EXYNOS_4x12_UPHYPWR);
+
+		rst = readl(drv->reg_phy + EXYNOS_4x12_UPHYRST);
+		rst |= rstbits;
+		writel(rst, drv->reg_phy + EXYNOS_4x12_UPHYRST);
+		udelay(10);
+		rst &= ~rstbits;
+		writel(rst, drv->reg_phy + EXYNOS_4x12_UPHYRST);
+		/* The following delay is necessary for the reset sequence to be
+		 * completed */
+		udelay(80);
+	} else {
+		pwr = readl(drv->reg_phy + EXYNOS_4x12_UPHYPWR);
+		pwr |= phypwr;
+		writel(pwr, drv->reg_phy + EXYNOS_4x12_UPHYPWR);
+	}
+}
+
+static int exynos4x12_power_on(struct samsung_usb2_phy_instance *inst)
+{
+	struct samsung_usb2_phy_driver *drv = inst->drv;
+
+	inst->enabled = 1;
+	exynos4x12_setup_clk(inst);
+	exynos4x12_phy_pwr(inst, 1);
+	exynos4x12_isol(inst, 0);
+
+	/* Power on the device, as it is necessary for HSIC to work */
+	if (inst->cfg->id == EXYNOS4x12_HSIC0) {
+		struct samsung_usb2_phy_instance *device =
+					&drv->instances[EXYNOS4x12_DEVICE];
+		exynos4x12_phy_pwr(device, 1);
+		exynos4x12_isol(device, 0);
+	}
+
+	return 0;
+}
+
+static int exynos4x12_power_off(struct samsung_usb2_phy_instance *inst)
+{
+	struct samsung_usb2_phy_driver *drv = inst->drv;
+	struct samsung_usb2_phy_instance *device =
+					&drv->instances[EXYNOS4x12_DEVICE];
+
+	inst->enabled = 0;
+	exynos4x12_isol(inst, 1);
+	exynos4x12_phy_pwr(inst, 0);
+
+	if (inst->cfg->id == EXYNOS4x12_HSIC0 && !device->enabled) {
+		exynos4x12_isol(device, 1);
+		exynos4x12_phy_pwr(device, 0);
+	}
+
+	return 0;
+}
+
+
+static const struct samsung_usb2_common_phy exynos4x12_phys[] = {
+	{
+		.label		= "device",
+		.id		= EXYNOS4x12_DEVICE,
+		.power_on	= exynos4x12_power_on,
+		.power_off	= exynos4x12_power_off,
+	},
+	{
+		.label		= "host",
+		.id		= EXYNOS4x12_HOST,
+		.power_on	= exynos4x12_power_on,
+		.power_off	= exynos4x12_power_off,
+	},
+	{
+		.label		= "hsic0",
+		.id		= EXYNOS4x12_HSIC0,
+		.power_on	= exynos4x12_power_on,
+		.power_off	= exynos4x12_power_off,
+	},
+	{
+		.label		= "hsic1",
+		.id		= EXYNOS4x12_HSIC1,
+		.power_on	= exynos4x12_power_on,
+		.power_off	= exynos4x12_power_off,
+	},
+	{},
+};
+
+const struct samsung_usb2_phy_config exynos4x12_usb2_phy_config = {
+	.has_mode_switch	= 1,
+	.num_phys		= EXYNOS4x12_NUM_PHYS,
+	.phys			= exynos4x12_phys,
+	.rate_to_clk		= exynos4x12_rate_to_clk,
+};
diff --git a/drivers/phy/phy-samsung-usb2.c b/drivers/phy/phy-samsung-usb2.c
new file mode 100644
index 0000000..c3b7719
--- /dev/null
+++ b/drivers/phy/phy-samsung-usb2.c
@@ -0,0 +1,222 @@ 
+/*
+ * Samsung SoC USB 1.1/2.0 PHY driver
+ *
+ * Copyright (C) 2013 Samsung Electronics Co., Ltd.
+ * Author: Kamil Debski <k.debski@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include "phy-samsung-usb2.h"
+
+static int samsung_usb2_phy_power_on(struct phy *phy)
+{
+	struct samsung_usb2_phy_instance *inst = phy_get_drvdata(phy);
+	struct samsung_usb2_phy_driver *drv = inst->drv;
+	int ret;
+
+	dev_dbg(drv->dev, "Request to power_on \"%s\" usb phy\n",
+		inst->cfg->label);
+	ret = clk_prepare_enable(drv->clk);
+	if (ret)
+		goto err_main_clk;
+	ret = clk_prepare_enable(drv->ref_clk);
+	if (ret)
+		goto err_instance_clk;
+	if (inst->cfg->power_on) {
+		spin_lock(&drv->lock);
+		ret = inst->cfg->power_on(inst);
+		spin_unlock(&drv->lock);
+	}
+
+	return 0;
+
+err_instance_clk:
+	clk_disable_unprepare(drv->clk);
+err_main_clk:
+	return ret;
+}
+
+static int samsung_usb2_phy_power_off(struct phy *phy)
+{
+	struct samsung_usb2_phy_instance *inst = phy_get_drvdata(phy);
+	struct samsung_usb2_phy_driver *drv = inst->drv;
+	int ret = 0;
+
+	dev_dbg(drv->dev, "Request to power_off \"%s\" usb phy\n",
+		inst->cfg->label);
+	if (inst->cfg->power_off) {
+		spin_lock(&drv->lock);
+		ret = inst->cfg->power_off(inst);
+		spin_unlock(&drv->lock);
+	}
+	clk_disable_unprepare(drv->ref_clk);
+	clk_disable_unprepare(drv->clk);
+	return ret;
+}
+
+static struct phy_ops samsung_usb2_phy_ops = {
+	.power_on	= samsung_usb2_phy_power_on,
+	.power_off	= samsung_usb2_phy_power_off,
+	.owner		= THIS_MODULE,
+};
+
+static struct phy *samsung_usb2_phy_xlate(struct device *dev,
+					struct of_phandle_args *args)
+{
+	struct samsung_usb2_phy_driver *drv;
+
+	drv = dev_get_drvdata(dev);
+	if (!drv)
+		return ERR_PTR(-EINVAL);
+
+	if (WARN_ON(args->args[0] >= drv->cfg->num_phys))
+		return ERR_PTR(-ENODEV);
+
+	return drv->instances[args->args[0]].phy;
+}
+
+static const struct of_device_id samsung_usb2_phy_of_match[] = {
+#ifdef CONFIG_PHY_EXYNOS4210_USB2
+	{
+		.compatible = "samsung,exynos4210-usb2-phy",
+		.data = &exynos4210_usb2_phy_config,
+	},
+#endif
+#ifdef CONFIG_PHY_EXYNOS4X12_USB2
+	{
+		.compatible = "samsung,exynos4x12-usb2-phy",
+		.data = &exynos4x12_usb2_phy_config,
+	},
+#endif
+	{ },
+};
+
+static int samsung_usb2_phy_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *match;
+	const struct samsung_usb2_phy_config *cfg;
+	struct device *dev = &pdev->dev;
+	struct phy_provider *phy_provider;
+	struct resource *mem;
+	struct samsung_usb2_phy_driver *drv;
+	int i, ret;
+
+	if (!pdev->dev.of_node) {
+		dev_err(dev, "This driver is required to be instantiated from device tree\n");
+		return -EINVAL;
+	}
+
+	match = of_match_node(samsung_usb2_phy_of_match, pdev->dev.of_node);
+	if (!match) {
+		dev_err(dev, "of_match_node() failed\n");
+		return -EINVAL;
+	}
+	cfg = match->data;
+
+	drv = devm_kzalloc(dev, sizeof(struct samsung_usb2_phy_driver) +
+		cfg->num_phys * sizeof(struct samsung_usb2_phy_instance),
+								GFP_KERNEL);
+	if (!drv)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, drv);
+	spin_lock_init(&drv->lock);
+
+	drv->cfg = cfg;
+	drv->dev = dev;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	drv->reg_phy = devm_ioremap_resource(dev, mem);
+	if (IS_ERR(drv->reg_phy)) {
+		dev_err(dev, "Failed to map register memory (phy)\n");
+		return PTR_ERR(drv->reg_phy);
+	}
+
+	drv->reg_pmu = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+		"samsung,pmureg-phandle");
+	if (IS_ERR(drv->reg_pmu)) {
+		dev_err(dev, "Failed to map PMU registers (via syscon)\n");
+		return PTR_ERR(drv->reg_pmu);
+	}
+
+	if (drv->cfg->has_mode_switch) {
+		drv->reg_sys = syscon_regmap_lookup_by_phandle(
+				pdev->dev.of_node, "samsung,sysreg-phandle");
+		if (IS_ERR(drv->reg_sys)) {
+			dev_err(dev, "Failed to map system registers (via syscon)\n");
+			return PTR_ERR(drv->reg_sys);
+		}
+	}
+
+	drv->clk = devm_clk_get(dev, "phy");
+	if (IS_ERR(drv->clk)) {
+		dev_err(dev, "Failed to get clock of phy controller\n");
+		return PTR_ERR(drv->clk);
+	}
+
+	drv->ref_clk = devm_clk_get(dev, "ref");
+	if (IS_ERR(drv->ref_clk)) {
+		dev_err(dev, "Failed to get reference clock for the phy controller\n");
+		return PTR_ERR(drv->ref_clk);
+	}
+
+	drv->ref_rate = clk_get_rate(drv->ref_clk);
+	if (drv->cfg->rate_to_clk) {
+		ret = drv->cfg->rate_to_clk(drv->ref_rate, &drv->ref_reg_val);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < drv->cfg->num_phys; i++) {
+		char *label = drv->cfg->phys[i].label;
+		struct samsung_usb2_phy_instance *p = &drv->instances[i];
+
+		dev_dbg(dev, "Creating phy \"%s\"\n", label);
+		p->phy = devm_phy_create(dev, &samsung_usb2_phy_ops, NULL);
+		if (IS_ERR(p->phy)) {
+			dev_err(drv->dev, "Failed to create usb2_phy \"%s\"\n",
+				label);
+			return PTR_ERR(p->phy);
+		}
+
+		p->cfg = &drv->cfg->phys[i];
+		p->drv = drv;
+		phy_set_bus_width(p->phy, 8);
+		phy_set_drvdata(p->phy, p);
+	}
+
+	phy_provider = devm_of_phy_provider_register(dev,
+							samsung_usb2_phy_xlate);
+	if (IS_ERR(phy_provider)) {
+		dev_err(drv->dev, "Failed to register phy provider\n");
+		return PTR_ERR(phy_provider);
+	}
+
+	return 0;
+}
+
+static struct platform_driver samsung_usb2_phy_driver = {
+	.probe	= samsung_usb2_phy_probe,
+	.driver = {
+		.of_match_table	= samsung_usb2_phy_of_match,
+		.name		= "samsung-usb2-phy",
+		.owner		= THIS_MODULE,
+	}
+};
+
+module_platform_driver(samsung_usb2_phy_driver);
+MODULE_DESCRIPTION("Samsung S5P/EXYNOS SoC USB PHY driver");
+MODULE_AUTHOR("Kamil Debski <k.debski@samsung.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:samsung-usb2-phy");
diff --git a/drivers/phy/phy-samsung-usb2.h b/drivers/phy/phy-samsung-usb2.h
new file mode 100644
index 0000000..51a1601
--- /dev/null
+++ b/drivers/phy/phy-samsung-usb2.h
@@ -0,0 +1,66 @@ 
+/*
+ * Samsung SoC USB 1.1/2.0 PHY driver
+ *
+ * Copyright (C) 2013 Samsung Electronics Co., Ltd.
+ * Author: Kamil Debski <k.debski@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _PHY_EXYNOS_USB2_H
+#define _PHY_EXYNOS_USB2_H
+
+#include <linux/clk.h>
+#include <linux/phy/phy.h>
+#include <linux/device.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+
+#define KHZ 1000
+#define MHZ (KHZ * KHZ)
+
+struct samsung_usb2_phy_driver;
+struct samsung_usb2_phy_instance;
+struct samsung_usb2_phy_config;
+
+struct samsung_usb2_phy_instance {
+	const struct samsung_usb2_common_phy *cfg;
+	struct phy *phy;
+	struct samsung_usb2_phy_driver *drv;
+	bool enabled;
+};
+
+struct samsung_usb2_phy_driver {
+	const struct samsung_usb2_phy_config *cfg;
+	struct clk *clk;
+	struct clk *ref_clk;
+	unsigned long ref_rate;
+	u32 ref_reg_val;
+	struct device *dev;
+	void __iomem *reg_phy;
+	struct regmap *reg_pmu;
+	struct regmap *reg_sys;
+	spinlock_t lock;
+	struct samsung_usb2_phy_instance instances[0];
+};
+
+struct samsung_usb2_common_phy {
+	int (*power_on)(struct samsung_usb2_phy_instance *);
+	int (*power_off)(struct samsung_usb2_phy_instance *);
+	unsigned int id;
+	char *label;
+};
+
+
+struct samsung_usb2_phy_config {
+	const struct samsung_usb2_common_phy *phys;
+	int (*rate_to_clk)(unsigned long, u32 *);
+	unsigned int num_phys;
+	bool has_mode_switch;
+};
+
+extern const struct samsung_usb2_phy_config exynos4210_usb2_phy_config;
+extern const struct samsung_usb2_phy_config exynos4x12_usb2_phy_config;
+#endif