Subject: Re: [RFC PATCH 1/6] usb: otg: Add an API to bind the USB controller and PHY

From: Roger Quadros <[email-masked]>
Date: Thu, 17 Jan 2013 11:37:07 +0200

On 01/16/2013 05:00 PM, Kishon Vijay Abraham I wrote:
> New platforms are added which has multiple PHY's (of same type) and
> which has multiple USB controllers. The binding information has to be
> present in the PHY library (otg.c) in order for it to return the
> appropriate PHY whenever the USB controller request for the PHY. So
> added a new API to pass the binding information. This API should be
> called by platform specific initialization code.
> 
> Signed-off-by: Kishon Vijay Abraham I <[email-masked]>
> ---
>  drivers/usb/otg/otg.c   |   37 +++++++++++++++++++++++++++++++++++++
>  include/linux/usb/phy.h |   22 ++++++++++++++++++++++
>  2 files changed, 59 insertions(+)
> 
> diff --git a/drivers/usb/otg/otg.c b/drivers/usb/otg/otg.c
> index a30c041..492ba2f 100644
> --- a/drivers/usb/otg/otg.c
> +++ b/drivers/usb/otg/otg.c
> @@ -18,6 +18,7 @@
>  #include <linux/usb/otg.h>
>  
>  static LIST_HEAD(phy_list);
> +static LIST_HEAD(phy_bind_list);
>  static DEFINE_SPINLOCK(phy_lock);
>  
>  static struct usb_phy *__usb_find_phy(struct list_head *list,
> @@ -201,6 +202,42 @@ void usb_remove_phy(struct usb_phy *x)
>  }
>  EXPORT_SYMBOL(usb_remove_phy);
>  
> +/**
> + * usb_bind_phy - 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 usb_phy_bind __init *usb_bind_phy(const char *dev_name, u8 index,
> +				const char *phy_dev_name)
> +{
> +	struct usb_phy_bind *phy_bind;
> +	unsigned long flags;
> +
> +	phy_bind = kzalloc(sizeof(*phy_bind), GFP_KERNEL);
> +	if (!phy_bind) {
> +		pr_err("phy_bind(): No memory for phy_bind");

Function name in comment doesn't match the actual.
Instead, you could use
	pr_err("%s ...", __func__);

> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	phy_bind->dev_name = dev_name;
> +	phy_bind->phy_dev_name = phy_dev_name;
> +	phy_bind->index = index;
> +
> +	spin_lock_irqsave(&phy_lock, flags);
> +	list_add_tail(&phy_bind->list, &phy_bind_list);
> +	spin_unlock_irqrestore(&phy_lock, flags);
> +
> +	return phy_bind;
> +}
> +EXPORT_SYMBOL_GPL(usb_bind_phy);
> +
>  const char *otg_state_string(enum usb_otg_state state)
>  {
>  	switch (state) {
> diff --git a/include/linux/usb/phy.h b/include/linux/usb/phy.h
> index a29ae1e..fbeab1a 100644
> --- a/include/linux/usb/phy.h
> +++ b/include/linux/usb/phy.h
> @@ -106,6 +106,21 @@ struct usb_phy {
>  			enum usb_device_speed speed);
>  };
>  
> +/**
> + * struct usb_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
> + * @phy: reference to the phy
> + * @list: to maintain a linked list of the binding information
> + */
> +struct usb_phy_bind {
> +	const char	*dev_name;
> +	const char	*phy_dev_name;
> +	u8		index;
> +	struct usb_phy	*phy;
> +	struct list_head list;
> +};
>  
>  /* for board-specific init logic */
>  extern int usb_add_phy(struct usb_phy *, enum usb_phy_type type);
> @@ -151,6 +166,8 @@ extern struct usb_phy *devm_usb_get_phy(struct device *dev,
>  	enum usb_phy_type type);
>  extern void usb_put_phy(struct usb_phy *);
>  extern void devm_usb_put_phy(struct device *dev, struct usb_phy *x);
> +extern struct usb_phy_bind *usb_bind_phy(const char *dev_name, u8 index,
> +				const char *phy_dev_name);
>  #else
>  static inline struct usb_phy *usb_get_phy(enum usb_phy_type type)
>  {
> @@ -171,6 +188,11 @@ static inline void devm_usb_put_phy(struct device *dev, struct usb_phy *x)
>  {
>  }
>  
> +static inline struct usb_phy_bind *usb_bind_phy(const char *dev_name, u8 index,
> +				const char *phy_dev_name)
> +{
> +	return NULL;
> +}
>  #endif
>  
>  static inline int
> 

Controllers like ehci-omap which don't need OTG functionality would
benefit from this API. Can we make these PHY APIs not dependent on OTG /
OTG_UTILS?

cheers,
-roger