Messages in this thread | | | Subject | Re: [PATCH v2 1/2] extcon: Add extcon_set_cable_line_state() to inform the additional state of external connectors | From | "Ivan T. Ivanov" <> | Date | Thu, 28 May 2015 12:37:25 +0300 |
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Hi,
On Thu, 2015-05-28 at 18:17 +0900, Chanwoo Choi wrote: > > > 2015년 5월 28일 목요일, Ivan T. Ivanov<iivanov@mm-sol.com>님이 작성한 메시지: > > Hi Chanwoo, > > > > On Thu, 2015-05-28 at 00:06 +0900, Chanwoo Choi wrote: > > > On Wed, May 27, 2015 at 11:38 PM, Roger Quadros <rogerq@ti.com> wrote: > > > > Chanwoo, > > > > > > > > On 27/05/15 15:15, Chanwoo Choi wrote: > > > > > This patch adds the extcon_set_cable_line_state() function to inform > > > > > the additional state of each external connector and 'enum > > > > > extcon_line_state' > > > > > enumeration which include the specific states of each external connector. > > > > > > > > > > The each external connector might need the different line state. So, > > > > > current > > > > > 'extcon_line_state' enumeration contains the specific state for USB as > > > > > following: > > > > > > > > > > - Following the state mean the state of both ID and VBUS line for USB: > > > > > enum extcon_line_state { > > > > > EXTCON_USB_ID_LOW = BIT(1), /* ID line is low. */ > > > > > EXTCON_USB_ID_HIGH = BIT(2), /* ID line is high. */ > > > > > > > > > > > > ID_LOW and ID_HIGH cannot happen simultaneously so they can use the same bit > > > > position. > > > > if the bit is set means it is high, if it is cleared means it is low. > > > > > > These are the notifier event. So, extcon_line_state have to include > > > each event for both low or high state of ID. > > > because the extcon consumer driver using the > > > extcon_register_notifier() need the each event to distinguish the type > > > of event. > > > > > > > > EXTCON_USB_VBUS_LOW = BIT(3), /* VBUS line is low. */ > > > > > EXTCON_USB_VBUS_HIGH = BIT(4), /* VBUS line is high. */ > > > > > > > > > > > > same here. > > > > > > ditto. > > > > > > > enum doesn't look like the right type for extcon_line_state as it is more of > > > > a bitmask. > > > > > > Why? I prefer to use the enum if there are no problem. > > > If you insist your opinion, you shoud suggest the reason. Could you tell me the reason?
It looks unreadable. There is no need to mix interface API (enum extcon_line_state) with implementation details. You can use plain enum at interface level and hide shifting inside implementation.
> > > > > > > > > > > > +enum extcon_line_state { > > > > > + /* Following two definition are used for whether external > > > > > connectors > > > > > + * is attached or detached. */ > > > > > + EXTCON_DETACHED = 0x0, > > > > > + EXTCON_ATTACHED = 0x1, > > > > > + > > > > > + /* Following states are only used for EXTCON_USB. */ > > > > > + EXTCON_USB_ID_LOW = BIT(1), /* ID line is low. */ > > > > > + EXTCON_USB_ID_HIGH = BIT(2), /* ID line is high. */ > > > > > + EXTCON_USB_VBUS_LOW = BIT(3), /* VBUS line is low. */ > > > > > + EXTCON_USB_VBUS_HIGH = BIT(4), /* VBUS line is high. */ > > > > > +}; > > > > > > > > > > > > Why do you use enum? How about the following bit definitions for line state. > > > > > > > > #define EXTCON_ATTACHED_DETACHED_BIT BIT(0) > > > > #define EXTCON_USB_ID_BIT BIT(1) > > > > #define EXTCON_USB_VBUS_BIT BIT(2) > > > > ... > > > > > > > > code must check if appropriate bit is set or cleared to get the high/low > > > > state. > > > > > > I answer about it on upper. > > > > > > > Funny. We can use the one bit for DETACHED/ATTACHED, but we > hmm. Did you read my answer about low/high? > > But, I'm considering again about using the detached/attached value.
Ok, but consumers will receive one event at time, right?
Regards, Ivan
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