On Fri, May 29, 2015 at 11:32 PM, Ivan T. Ivanov <iiva...@mm-sol.com> wrote: > > On Fri, 2015-05-29 at 19:44 +0900, Chanwoo Choi wrote: >> Hi Ivan, >> >> On 05/28/2015 05:45 PM, Ivan T. Ivanov wrote: >> > Hi Chanwoo, >> > >> > On Wed, 2015-05-27 at 21:15 +0900, Chanwoo Choi wrote: >> > > Previously, I discussed how to inform the changed state of both ID >> > > and VBUS pin for USB connector on patch-set[1]. >> > > [1] https://lkml.org/lkml/2015/4/2/310 >> > > >> > > So, this patch adds the extcon_set_cable_line_state() function to inform >> > > the additional state of external connectors without additional register/ >> > > unregister functions. This function uses the existing notifier chain >> > > which is registered by extcon_register_notifier() / >> > > extcon_register_interest(). >> > > >> > > The extcon_set_cable_line_state() can inform the new state of both >> > > ID and VBUS pin state through extcon_set_cable_line_state(). >> > > >> > > For exmaple: >> > > - On extcon-usb-gpio.c as extcon provider driver as following: >> > > static void usb_extcon_detect_cable(struct work_struct *work) >> > > { >> > > ... >> > > /* check ID and update cable state */ >> > > id = gpiod_get_value_cansleep(info->id_gpiod); >> > > if (id) { >> > > extcon_set_cable_state_(info->edev, >> > > EXTCON_USB_HOST, false); >> > > extcon_set_cable_state_(info->edev, EXTCON_USB, >> > > true); >> > > >> > > extcon_set_cable_line_state(info->edev, >> > > EXTCON_USB, >> > > >> > > EXTCON_USB_ID_HIGH); >> > >> > I am getting more and more confused :-). Why EXTCON_USB is now used for ID >> > notifications? >> > It should be EXTCON_USB_HOST, no? Why we need another function, framework >> > already have >> > required information from the function one line above, do I miss something? >> >> The EXTCON fwk has the follwoing different functions: >> - extcon_set_cable_state() >> : Send whether external connectors is attached or detached to the extcon >> consumer driver in kernel space and to the user-space by using the uevent. >> - extcon_set_cable_line_state() >> : Send the specific line state of both ID and VBUS pin state of USB >> connector to only the extcon consumer driver in kernel space. This function >> don't send the uevent to the user-space because user- >> space process don't consider the h/w pin state. > > My understanding, from discussion several letters back, is that clients > will receive single event per change (EXTCON_USB_ID_HIGH, > EXTCON_USB_ID_LOW...),
There are following constraints between events for EXTCON_USB: - EXTCON_USB_ID_HIGH and EXTCON_USB_ID_LOW are mutually exclusive. - EXTCON_USB_VBUS_HIGH and EXTCON_USB_VBUS_LOW are mutually exclusive. If extcon provider (e.g., extcon-usb-gpio) don't violate the constraints, extcon provider can send the multiple events as following. Namely, extcon consumer/clients will receive the the multiple events. For example: extcon_set_cable_line_state(edev, EXTCON_USB, EXTCON_USB_ID_HIGH | EXTCON_USB_VBUS_LOW); > > My point was, why we need another function (extcon_set_cable_line_state) if > extcon_set_cable_state_ already have required information? Or the plan is to > move extcon_set_cable_state_ to USB drivers and use only > extcon_set_cable_line_state > by extcon drivers? You pointed out appropriately. I worried about adding new extcon_set_cable_line_state(). I'll use extcon_set_cable_state_() without adding extcon_set_cable_line_state() as following but it need the modification of function prototype. - extcon_set_cable_state(struct extcon_dev *edev, enum extcon id, bool state) -> extcon_set_cable_state(struct extcon_dev *edev, enum extcon id, u64 state) And extcon use the bit mask for both attached state and detached state of external connectors instead of boolean. #define EXTCON_DETACHED BIT(0) #define EXTCON_ATTACHED BIT(1) #define EXTCON_USB_ID_LOW BIT(2) #define EXTCON_USB_ID_HIGH BIT(3) #define EXTCON_USB_VBUS_LOW BIT(4) #define EXTCON_USB_VBUS_HIGH BIT(5) After it, extcon_set_cable_state() would send multiple events at time as following: e.g., extcon_set_cable_state(edev, EXTCON_USB, EXTCON_ATTACHED | EXTCON_USB_ID_HIGH | EXTCON_USB_VBUS_HIGH); Thanks, Chanwoo Choi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
