linux-kernel - Re: [PATCH v3 14/16] phy: Add notify

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Message-ID: <c16f8b3f-1065-7405-d57d-8d9526417dce@ti.com>
Date:   Tue, 12 Dec 2017 17:13:54 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Manu Gautam <mgautam@...eaurora.org>
CC:     <linux-arm-msm@...r.kernel.org>, <linux-usb@...r.kernel.org>,
        "open list:GENERIC PHY FRAMEWORK" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 14/16] phy: Add notify_speed callback

Hi,

On Tuesday 21 November 2017 02:53 PM, Manu Gautam wrote:
> QCOM USB PHYs can monitor resume/remote-wakeup event in
> suspended state. However PHY driver must know current
> operational speed of PHY in order to set correct polarity of
> wakeup events for detection. E.g. QUSB2 PHY monitors DP/DM
> signals depending on speed is LS or FS/HS to detect resume.
> Similarly QMP USB3 PHY in SS mode should monitor RX
> terminations attach/detach and LFPS events depending on
> SSPHY is active or not.
> 
> Signed-off-by: Manu Gautam <mgautam@...eaurora.org>
> ---
>  drivers/phy/phy-core.c  | 30 ++++++++++++++++++++++++++++++
>  include/linux/phy/phy.h | 26 ++++++++++++++++++++++++++
>  2 files changed, 56 insertions(+)
> 
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index b4964b0..03df2be 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -387,6 +387,36 @@ int phy_calibrate(struct phy *phy)
>  }
>  EXPORT_SYMBOL_GPL(phy_calibrate);
>  
> +int phy_notify_speed(struct phy *phy, enum phy_speed speed)
> +{
> +	int ret;
> +
> +	if (!phy || !phy->ops->notify_speed)
> +		return 0;
> +
> +	mutex_lock(&phy->mutex);
> +	ret = phy->ops->notify_speed(phy, speed);
> +	mutex_unlock(&phy->mutex);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(phy_notify_speed);
> +
> +enum phy_speed phy_get_speed(struct phy *phy)
> +{
> +	enum phy_speed ret;
> +
> +	if (!phy || !phy->ops->get_speed)
> +		return PHY_SPEED_UNKNOWN;
> +
> +	mutex_lock(&phy->mutex);
> +	ret = phy->ops->get_speed(phy);
> +	mutex_unlock(&phy->mutex);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(phy_get_speed);

So this is equivalent to set_speed (why notify?) and get_speed. set_speed will
most likely be invoked by USB driver? who will invoke get_speed?

Thanks
Kishon