[v2,1/3] gadget: Support for the usb charger framework

The usb charger framework is based on usb gadget, and each usb gadget
can be one usb charger to set the current limitation.

This patch adds a notifier mechanism for usb charger to report to usb
charger when the usb gadget state is changed.

Also we introduce a callback 'get_charger_type' which will implemented
by user for usb gadget operations to get the usb charger type.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
 drivers/usb/gadget/udc/udc-core.c |   38 +++++++++++++++++++++++++++++++++++++
 include/linux/usb/gadget.h        |   20 +++++++++++++++++++
 2 files changed, 58 insertions(+)

On 17 August 2015 at 08:40, Peter Chen <peter.chen@freescale.com> wrote:
> On Fri, Aug 14, 2015 at 05:47:44PM +0800, Baolin Wang wrote:
>> The usb charger framework is based on usb gadget, and each usb gadget
>> can be one usb charger to set the current limitation.
>>
>> This patch adds a notifier mechanism for usb charger to report to usb
>> charger when the usb gadget state is changed.
>>
>> Also we introduce a callback 'get_charger_type' which will implemented
>> by user for usb gadget operations to get the usb charger type.
>>
>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
>> ---
>>  drivers/usb/gadget/udc/udc-core.c |   38 +++++++++++++++++++++++++++++++++++++
>>  include/linux/usb/gadget.h        |   20 +++++++++++++++++++
>>  2 files changed, 58 insertions(+)
>>
>> diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c
>> index f660afb..47b231c 100644
>> --- a/drivers/usb/gadget/udc/udc-core.c
>> +++ b/drivers/usb/gadget/udc/udc-core.c
>> @@ -28,6 +28,7 @@
>>  #include <linux/usb/ch9.h>
>>  #include <linux/usb/gadget.h>
>>  #include <linux/usb.h>
>> +#include <linux/usb/usb_charger.h>
>>
>>  /**
>>   * struct usb_udc - describes one usb device controller
>> @@ -129,6 +130,32 @@ void usb_gadget_giveback_request(struct usb_ep *ep,
>>  }
>>  EXPORT_SYMBOL_GPL(usb_gadget_giveback_request);
>>
>> +int usb_gadget_register_notify(struct usb_gadget *gadget,
>> +                            struct notifier_block *nb)
>> +{
>> +     int ret;
>> +
>> +     mutex_lock(&gadget->lock);
>> +     ret = raw_notifier_chain_register(&gadget->nh, nb);
>> +     mutex_unlock(&gadget->lock);
>> +
>> +     return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(usb_gadget_register_notify);
>> +
>> +int usb_gadget_unregister_notify(struct usb_gadget *gadget,
>> +                              struct notifier_block *nb)
>> +{
>> +     int ret;
>> +
>> +     mutex_lock(&gadget->lock);
>> +     ret = raw_notifier_chain_unregister(&gadget->nh, nb);
>> +     mutex_unlock(&gadget->lock);
>> +
>> +     return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(usb_gadget_unregister_notify);
>> +
>>  /* ------------------------------------------------------------------------- */
>>
>>  /**
>> @@ -226,6 +253,10 @@ static void usb_gadget_state_work(struct work_struct *work)
>>       struct usb_gadget *gadget = work_to_gadget(work);
>>       struct usb_udc *udc = gadget->udc;
>>
>> +     mutex_lock(&gadget->lock);
>> +     raw_notifier_call_chain(&gadget->nh, gadget->state, gadget);
>> +     mutex_unlock(&gadget->lock);
>> +
>>       if (udc)
>>               sysfs_notify(&udc->dev.kobj, NULL, "state");
>>  }
>> @@ -364,6 +395,8 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
>>
>>       dev_set_name(&gadget->dev, "gadget");
>>       INIT_WORK(&gadget->work, usb_gadget_state_work);
>> +     RAW_INIT_NOTIFIER_HEAD(&gadget->nh);
>> +     mutex_init(&gadget->lock);
>>       gadget->dev.parent = parent;
>>
>>  #ifdef       CONFIG_HAS_DMA
>> @@ -405,6 +438,10 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
>>
>>       mutex_unlock(&udc_lock);
>>
>> +     ret = usb_charger_init(gadget);
>> +     if (ret)
>> +             goto err4;
>> +
>
> If the charger's initialization fails, you may need to
> call device_del(&udc->dev).
>

Yes, I missed that. Thanks for your comments.

> Peter
>
>>       return 0;
>>
>>  err4:
>> @@ -481,6 +518,7 @@ void usb_del_gadget_udc(struct usb_gadget *gadget)
>>       kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
>>       flush_work(&gadget->work);
>>       device_unregister(&udc->dev);
>> +     usb_charger_exit(gadget);
>>       device_unregister(&gadget->dev);
>>  }
>>  EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
>> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
>> index c14a69b..78cc862 100644
>> --- a/include/linux/usb/gadget.h
>> +++ b/include/linux/usb/gadget.h
>> @@ -537,6 +537,7 @@ struct usb_gadget_ops {
>>       struct usb_ep *(*match_ep)(struct usb_gadget *,
>>                       struct usb_endpoint_descriptor *,
>>                       struct usb_ss_ep_comp_descriptor *);
>> +     enum usb_charger_type   (*get_charger_type)(struct usb_gadget *);
>>  };
>>
>>  /**
>> @@ -609,6 +610,9 @@ struct usb_gadget {
>>       unsigned                        out_epnum;
>>       unsigned                        in_epnum;
>>       struct usb_otg_caps             *otg_caps;
>> +     struct raw_notifier_head        nh;
>> +     struct usb_charger              *uchger;
>> +     struct mutex                    lock;
>>
>>       unsigned                        sg_supported:1;
>>       unsigned                        is_otg:1;
>> @@ -1183,6 +1187,22 @@ extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
>>
>>  /*-------------------------------------------------------------------------*/
>>
>> +/**
>> + * Register a notifiee to get notified by any attach status changes from
>> + * the usb gadget
>> + */
>> +int usb_gadget_register_notify(struct usb_gadget *gadget,
>> +                            struct notifier_block *nb);
>> +
>> +/*-------------------------------------------------------------------------*/
>> +
>> +
>> +/* Unregister a notifiee from the usb gadget */
>> +int usb_gadget_unregister_notify(struct usb_gadget *gadget,
>> +                              struct notifier_block *nb);
>> +
>> +/*-------------------------------------------------------------------------*/
>> +
>>  /* utility to set gadget state properly */
>>
>>  extern void usb_gadget_set_state(struct usb_gadget *gadget,
>> --
>> 1.7.9.5
>>
>
> --
>
> Best Regards,
> Peter Chen