linux-kernel - Re: [PATCH v7 3/5] phy: Add set

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Message-ID: <58871CF8.8080109@ti.com>
Date:   Tue, 24 Jan 2017 14:53:04 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Stephen Boyd <stephen.boyd@...aro.org>,
        Peter Chen <peter.chen@....com>
CC:     <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        Andy Gross <andy.gross@...aro.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Neil Armstrong <narmstrong@...libre.com>,
        Arnd Bergmann <arnd@...db.de>, Felipe Balbi <balbi@...nel.org>,
        <linux-usb@...r.kernel.org>
Subject: Re: [PATCH v7 3/5] phy: Add set_vbus callback

Hi,

On Tuesday 24 January 2017 01:28 AM, Stephen Boyd wrote:
> Quoting Kishon Vijay Abraham I (2017-01-22 00:46:21)
>> Hi,
>>
>> On Saturday 21 January 2017 12:20 AM, Stephen Boyd wrote:
>>> Some USB PHYs need to be told about vbus changing state
>>> explicitly. For example the qcom USB HS PHY needs to toggle a bit
>>> when vbus goes from low to high (VBUSVLDEXT) to cause the
>>> "session valid" signal to toggle. This signal will pull up D+
>>> when the phy starts running. If the vbus signal isn't routed to
>>> the PHY this "session valid" signal won't ever toggle, so we have
>>> to toggle it explicitly. This callback is used to do that.
>>>
>>> Cc: Peter Chen <peter.chen@....com>
>>> Signed-off-by: Stephen Boyd <stephen.boyd@...aro.org>
>>> ---
>>>
>>> New patch
>>>
>>>  drivers/phy/phy-core.c  | 15 +++++++++++++++
>>>  include/linux/phy/phy.h | 10 ++++++++++
>>>  2 files changed, 25 insertions(+)
>>>
>>> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
>>> index a268f4d6f3e9..8b1a6bfa5133 100644
>>> --- a/drivers/phy/phy-core.c
>>> +++ b/drivers/phy/phy-core.c
>>> @@ -357,6 +357,21 @@ int phy_set_mode(struct phy *phy, enum phy_mode mode)
>>>  }
>>>  EXPORT_SYMBOL_GPL(phy_set_mode);
>>>  
>>> +int phy_set_vbus(struct phy *phy, int on)
>>> +{
>>> +     int ret;
>>> +
>>> +     if (!phy || !phy->ops->set_vbus)
>>> +             return 0;
>>> +
>>> +     mutex_lock(&phy->mutex);
>>> +     ret = phy->ops->set_vbus(phy, on);
>>> +     mutex_unlock(&phy->mutex);
>>> +
>>> +     return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(phy_set_vbus);
>>> +
>>>  int phy_reset(struct phy *phy)
>>>  {
>>>       int ret;
>>> diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
>>> index 78bb0d7f6b11..4d1ebde7fb14 100644
>>> --- a/include/linux/phy/phy.h
>>> +++ b/include/linux/phy/phy.h
>>> @@ -36,6 +36,7 @@ enum phy_mode {
>>>   * @power_on: powering on the phy
>>>   * @power_off: powering off the phy
>>>   * @set_mode: set the mode of the phy
>>> + * @set_vbus: enable/disable vbus in the phy (USB)
>>>   * @reset: resetting the phy
>>>   * @owner: the module owner containing the ops
>>>   */
>>> @@ -45,6 +46,7 @@ struct phy_ops {
>>>       int     (*power_on)(struct phy *phy);
>>>       int     (*power_off)(struct phy *phy);
>>>       int     (*set_mode)(struct phy *phy, enum phy_mode mode);
>>> +     int     (*set_vbus)(struct phy *phy, int on);
>>
>> please avoid adding usb specific ops in generic phy ops.
>>
> 
> Is there any alternative? Something has to happen here.
> 
> The only other thing I can think of is putting back the vbus extcon in
> the phy driver so it can be notified when vbus is present or not. I can

I think extcon should be used here to get vbus notification.

Thanks
Kishon