Re: [PATCH 03/11] mux: consumer.h: Add MUX_USB_* state constant defines

[Hans de Goede]

Hi,

On 02-09-17 16:59, Guenter Roeck wrote:
> On 09/01/2017 02:48 PM, Hans de Goede wrote:
> > Add MUX_USB_* state constant defines, which can be used by USB
> > device/host and Type-C polarity/role/altmode mux drivers and consumers
> > to ensure that they agree on the meaning of the mux_control_select()
> > state argument.
> >
> > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> > ---
> >   include/linux/mux/consumer.h | 16 ++++++++++++++++
> >   1 file changed, 16 insertions(+)
> >
> > diff --git a/include/linux/mux/consumer.h b/include/linux/mux/consumer.h
> > index 912dd48a3a5d..e3ec9b4db962 100644
> > --- a/include/linux/mux/consumer.h
> > +++ b/include/linux/mux/consumer.h
> > @@ -15,6 +15,22 @@
> >   #include <linux/compiler.h>
> > +/*
> > + * Mux state values for USB muxes, used for both USB device/host role muxes
> > + * as well as for Type-C polarity/role/altmode muxes.
> > + *
> > + * MUX_USB_POLARITY_INV may be or-ed together with any other mux-state as
> > + * inverted-polarity (Type-C plugged in upside down) can happen with any
> > + * other mux-state.
> > + */
> > +#define MUX_USB_POLARITY_INV    BIT(0)   /* Polarity inverted bit */
> > +#define MUX_USB_NONE        (1 << 1) /* Mux open / not connected */
>
>
> Why BIT(0) but (1 << 1) and so on ?

Because the polarity can be or-ed together with any of the other options.
Each option can be selected normal and inverted polarity (connector
inserted upside down).

Regards,

Hans

> > +#define MUX_USB_DEVICE        (2 << 1) /* USB device mode */
> > +#define MUX_USB_HOST        (3 << 1) /* USB host mode */
> > +#define MUX_USB_HOST_AND_DP_SRC    (4 << 1) /* USB host + 2 lanes Display Port */
> > +#define MUX_USB_DP_SRC        (5 << 1) /* 4 lanes Display Port source */
> > +#define MUX_USB_STATES        (6 << 1)
> > +
> >   struct device;
> >   struct mux_control;