Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [RFC net-next 00/15] net: A socket API for LoRa
From:   =?UTF-8?Q?Andreas_F=c3=a4rber?= <afaerber@suse.de>
To:     Jian-Hong Pan <starnight@g.ncu.edu.tw>
Cc:     netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, Jiri Pirko <jiri@resnulli.us>,
        Marcel Holtmann <marcel@holtmann.org>,
        "David S. Miller" <davem@davemloft.net>,
        Matthias Brugger <mbrugger@suse.com>,
        Janus Piwek <jpiwek@arroweurope.com>,
        =?UTF-8?Q?Michael_R=c3=b6der?= <michael.roeder@avnet.eu>,
        Dollar Chen <dollar.chen@wtmec.com>,
        Ken Yu <ken.yu@rakwireless.com>,
        =?UTF-8?Q?Konstantin_B=c3=b6hm?= <konstantin.boehm@ancud.de>,
        Jan Jongboom <jan.jongboom@arm.com>,
        Jon Ortego <Jon.Ortego@imst.de>, contact@snootlab.com,
        Ben Whitten <ben.whitten@lairdtech.com>,
        Brian Ray <brian.ray@link-labs.com>, lora@globalsat.com.tw,
        Alexander Graf <agraf@suse.de>,
        =?UTF-8?Q?Michal_Kube=c4=8dek?= <mkubecek@suse.cz>,
        Rob Herring <robh@kernel.org>, devicetree@vger.kernel.org,
        Steve deRosier <derosier@gmail.com>,
        Mark Brown <broonie@kernel.org>, linux-spi@vger.kernel.org,
        Pieter Robyns <pieter.robyns@uhasselt.be>,
        Hasnain Virk <Hasnain.Virk@arm.com>,
        Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
        linux-wpan <linux-wpan@vger.kernel.org>,
        Stefan Schmidt <stefan@datenfreihafen.org>,
        Daniele Comel <dcomel@mipot.com>,
        Xue Liu <liuxuenetmail@gmail.com>,
        =?UTF-8?Q?Sebastian_He=c3=9f?= <shess@hessware.de>
References: <20180701110804.32415-1-afaerber@suse.de>
 <CAC=mGzgUCopz2xTOA0R-WD8a1DOaOOUn=YpfdMiJ33y3hnh6kg@mail.gmail.com>
 <92ee4016-1da9-826b-3674-b2d604a64848@suse.de>
Openpgp: preference=signencrypt
Autocrypt: addr=afaerber@suse.de; prefer-encrypt=mutual; keydata=
 xsFNBE6W6ZQBEAC/BIukDnkVenIkK9O14UucicBIVvRB5WSMHC23msS+R2h915mW7/vXfn+V
 0nrr5ECmEg/5OjujKf0x/uhJYrsxcp45nDyYCk+RYoOJmGzzUFya1GvT/c04coZ8VmgFUWGE
 vCfhHJro85dZUL99IoLP21VXEVlCPyIngSstikeuf14SY17LPTN1aIpGQDI2Qt8HHY1zOVWv
 iz53aiFLFeIVhQlBmOABH2Ifr2M9loRC9yOyGcE2GhlzgyHGlQxEVGFn/QptX6iYbtaTBTU0
 c72rpmbe1Nec6hWuzSwu2uE8lF+HYcYi+22ml1XBHNMBeAdSEbSfDbwc///8QKtckUzbDvME
 S8j4KuqQhwvYkSg7dV9rs53WmjO2Wd4eygkC3tBhPM5s38/6CVGl3ABiWJs3kB08asUNy8Wk
 juusU/nRJbXDzxu1d+hv0d+s5NOBy/5+7Pa6HeyBnh1tUmCs5/f1D/cJnuzzYwAmZTHFUsfQ
 ygGBRRKpAVu0VxCFNPSYKW0ULi5eZV6bcj+NAhtafGsWcv8WPFXgVE8s2YU38D1VtlBvCo5/
 0MPtQORqAQ/Itag1EHHtnfuK3MBtA0fNxQbb2jha+/oMAi5hKpmB/zAlFoRtYHwjFPFldHfv
 Iljpe1S0rDASaF9NsQPfUBEm7dA5UUkyvvi00HZ3e7/uyBGb0QARAQABzSJBbmRyZWFzIEbD
 pHJiZXIgPGFmYWVyYmVyQHN1c2UuZGU+wsF7BBMBAgAlAhsDBgsJCAcDAgYVCAIJCgsEFgID
 AQIeAQIXgAUCTqGJnQIZAQAKCRD6LtEtPn4BPzetD/4rF6k/HF+9U9KqykfJaWdUHJvXpI85
 Roab12rQbiIrL4hVEYKrYwPEKpCf+FthXpgOq+JdTGJ831DMlTx7Ed5/QJ9KAAQuhZlSNjSc
 +FNobJm7EbFv9jWFjQC0JcOl17Ji1ikgRcIRDCul1nQh9jCdfh1b848GerZmzteNdT9afRJm
 7rrvMqXs1Y52/dTlfIW0ygMA2n5Vv3EwykXJOPF6fRimkErKO84sFMNg0eJV9mXs+Zyionfi
 g2sZJfVeKjkDqjxy7sDDBZZR68I9HWq5VJQrXqQkCZUvtr6TBLI+uiDLbGRUDNxA3wgjVdS2
 v9bhjYceSOHpKU+h3H2S8ju9rjhOADT2F5lUQMTSpjlzglh8IatV5rXLGkXEyum4MzMo2sCE
 Cr+GD6i2M3pHCtaIVV3xV0nRGALa6DdF7jBWqM54KHaKsE883kFH2+6ARcPCPrnPm7LX98h2
 4VpG984ysoq6fpzHHG/KCaYCEOe1bpr3Plmmp3sqj0utA6lwzJy0hj5dqug+lqmg7QKAnxl+
 porgluoY56U0X0PIVBc0yO0dWqRxtylJa9kDX/TKwFYNVddMn2NQNjOJXzx2H9hf0We7rG7+
 F/vgwALVVYbiTzvp2L0XATTv/oX4BHagAa/Qc3dIsBYJH+KVhBp+ZX4uguxk4xlc2hm75b1s
 cqeAD87BTQROlumUARAAzd7eu+tw/52FB7xQZWDv5aF+6CAkoz7AuY4s1fo0AQQDqjLOdpQF
 bifdH7B8SnsA4eo0syfs+1tZW6nn9hdy1GHEMbeuvdhNwkhEfYGDYpSue7oVxB4jajKvRHAP
 VcewKZIxvIiZ5aSp5n1Bd7B0c0C443DHiWE/0XWSpvbU7fTzTNvdz+2OZmGtqCn610gBqScv
 1BOiP3OfLly8ghxcJsos23c0mkB/1iWlzh3UMFIGrzsK3sZJ/3uRaLYFimmqqPlSwFqx3b0M
 1gFdHWKfOpvQ4wwP5P10xwvqNXLWC30wB1QmJGD/X8aAoVNnGsmEL7GcWF4cLoOSRidSoccz
 znShE+Ap+FVDD6MRyesNT4D67l792//B38CGJRdELtNacdwazaFgxH9O85Vnd70ZC7fIcwzG
 yg/4ZEf96DlAvrSOnu/kgklofEYdzpZmW+Fqas6cnk6ZaHa35uHuBPesdE13MVz5TeiHGQTW
 xP1jbgWQJGPvJZ+htERT8SZGBQRb1paoRd1KWQ1mlr3CQvXtfA/daq8p/wL48sXrKNwedrLV
 iZOeJOFwfpJgsFU4xLoO/8N0RNFsnelBgWgZE3ZEctEd4BsWFUw+czYCPYfqOcJ556QUGA9y
 DeDcxSitpYrNIvpk4C5CHbvskVLKPIUVXxTNl8hAGo1Ahm1VbNkYlocAEQEAAcLBXwQYAQIA
 CQUCTpbplAIbDAAKCRD6LtEtPn4BPzA6D/9TbSBOPM99SHPX9JiEQAw4ITCBF2oTWeZQ6RJg
 RKpB15lzyPfyFbNSceJp9dCiwDWe+pzKaX6KYOFZ5+YTS0Ph2eCR+uT2l6Mt6esAun8dvER/
 xlPDW7p88dwGUcV8mHEukWdurSEDTj8V3K29vpgvIgRq2lHCn2wqRQBGpiJAt72Vg0HxUlwN
 GAJNvhpeW8Yb43Ek7lWExkUgOfNsDCTvDInF8JTFtEXMnUcPxC0d/GdAuvBilL9SlmzvoDIZ
 5k2k456bkY3+3/ydDvKU5WIgThydyCEQUHlmE6RdA3C1ccIrIvKjVEwSH27Pzy5jKQ78qnhv
 dtLLAavOXyBJnOGlNDOpOyBXfv02x91RoRiyrSIM7dKmMEINKQlAMgB/UU/6B+mvzosbs5d3
 4FPzBLuuRz9WYzXmnC460m2gaEVk1GjpidBWw0yY6kgnAM3KhwCFSecqUQCvwKFDGSXDDbCr
 w08b3GDk40UoCoUq9xrGfhlf05TUSFTg2NlSrK7+wAEsTUgs2ZYLpHyEeftoDDnKpM4ghs/O
 ceCeyZUP1zSgRSjgITQp691Uli5Nd1mIzaaM8RjOE/Rw67FwgblKR6HAhSy/LYw1HVOu+Ees
 RAEdbtRt37A8brlb/ENxbLd9SGC8/j20FQjit7oPNMkTJDs7Uo2eb7WxOt5pSTVVqZkv7Q==
Organization: SUSE Linux GmbH
Message-ID: <f1967750-0a42-0e76-2d7d-da293bc351af@suse.de>
Date:   Thu, 9 Aug 2018 02:50:39 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.9.1
MIME-Version: 1.0
In-Reply-To: <92ee4016-1da9-826b-3674-b2d604a64848@suse.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Am 05.08.2018 um 02:11 schrieb Andreas Färber:
> Am 03.07.2018 um 17:11 schrieb Jian-Hong Pan:
>> 2018-07-01 19:07 GMT+08:00 Andreas Färber <afaerber@suse.de>:
>>> 5) Many of the modules support multiple modes, such as LoRa, LoRaWAN and FSK.
>>>    Lacking a LoRaWAN implementation, I am currently switching them into LoRa
>>>    mode at probe time wherever possible. How do we deal with that properly?
[...]
> Independently of what LoRaWAN does, the
> user needs to be able to send on the physical layer from a selection of
> LoRa, GFSK, FSK, OOK, GMSK and MSK.
> Supposedly Wireless M-Bus and IEEE 802.15.4 can be implemented via those
> according to the SX1276 datasheet.
> 
> This opens a can of worms...
> 
> SX127x has a single channel, so I don't think there should be six
> network interfaces lora0, gfsk0, fsk0, ook0, gmsk0 and msk0 exposed to
> the user.
> Having a lora0 interface speak non-LoRa modulations may be confusing,
> but since the chip is sold as LoRa transceiver it might be acceptable.
> 
> SX130x has 8+2 channels, with IF9 dedicated to GFSK/FSK. It appears to
> use one FIFO for receiving (up to 16 packets) and can only transmit one
> packet at a time. So I think this should be one lora0 interface, too.
> 
> With a view to supporting non-LoRa RF chipsets such as Si4xxx (GFSK,
> FSK, OOK) or nRF905 and nRF24L01+ (both GFSK) at a later date, I don't
> think those modulations should be some netlink option on a PF_LORA
> interface but cleanly distinguished as ETH_P_GFSK or something.
> For example, the Chistera Pi HAT has both an RFM95W and an RFM22 module.

Answering myself here: MSK is a special case of FSK, and GMSK a special
case of GFSK. SX1276 allows to switch between LoRa and FSK/OOK modes,
and in FSK/OOK mode between FSK and OOK modulation types and for FSK
modulation allows to set Gaussian filter values. I assume (G)MSK is
selected indirectly through BitRate and Fdev settings or something.

So we would just need ETH_P_FSK and ETH_P_OOK plus some skb fields for
ETH_P_FSK.

Regards,
Andreas

-- 
SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)