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Subject: Re: [PATCH 4/4] tty: n_gsm: add ioctl to map serial device to mux'ed
 tty
To:     Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.com>, linux-kernel@vger.kernel.org,
        =?UTF-8?Q?Sean_Nyekj=c3=a6r?= <sean@geanix.com>,
        Esben Haabendal <esben@geanix.com>
References: <20190708190252.24628-1-martin@geanix.com>
 <20190708190252.24628-4-martin@geanix.com>
 <20190709162221.623f99ce@alans-desktop>
From:   =?UTF-8?Q?Martin_Hundeb=c3=b8ll?= <martin@geanix.com>
Message-ID: <789b9d92-8110-d9e6-796e-e372d440fe51@geanix.com>
Date:   Wed, 10 Jul 2019 11:51:15 +0200
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On 09/07/2019 17.22, Alan Cox wrote:
>> +	int base;
>>   
>>   	/* open the serial port connected to the modem */
>>   	fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY);
>> @@ -58,6 +61,11 @@ Major parts of the initialization program :
>>   	c.mtu = 127;
>>   	/* set the new configuration */
>>   	ioctl(fd, GSMIOC_SETCONF, &c);
>> +	/* get and print base gsmtty device node */
>> +	ioctl(fd, GSMIOC_GETBASE, &base);
> Can we at least use a specific sized type ? uint32_t or whatever is fine.

Sure.

I am also considering whether returning the base (i.e. the unexposed 
control line) just confuses users. It might be better to use 
GSMIOC_GETFIRST instead, which would then return 1 for the first mux, 
and 65 for the second, and so forth.

// Martin