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

Guenter Roeck
2017-09-02T19:06:33Z

On Sat, Sep 02, 2017 at 05:59:14PM +0200, Hans de Goede wrote:
> 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@redhat.com>
> >>---
> >> 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).
>
Ah yes, it is (2 << 1), not (1 << 2). But then why don't the options start
with (0 << 1) ?

I'll have to look into the series more closely; so far the polarity was
a separate parameter to tcpm_mux_set() and the low level API.

Guenter

> 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;
> >>
> >