linux-kernel - Re: [PATCH 03/11] mux: consumer.h: Add MUX_USB

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Message-ID: <3e777501-aa94-70ae-3dc5-f64a15fd9704@redhat.com>
Date:   Sat, 2 Sep 2017 17:59:14 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Guenter Roeck <linux@...ck-us.net>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...radead.org>,
        Peter Rosin <peda@...ntia.se>,
        Mathias Nyman <mathias.nyman@...el.com>
Cc:     platform-driver-x86@...r.kernel.org, devel@...verdev.osuosl.org,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        Sathyanarayanan Kuppuswamy Natarajan <sathyaosid@...il.com>,
        linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org
Subject: Re: [PATCH 03/11] mux: consumer.h: Add MUX_USB_* state constant
 defines

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@...hat.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).

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;
>>
>