From: Mark Brown <broonie@kernel.org>
To: "Andreas Färber" <afaerber@suse.de>
Cc: netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
"Jian-Hong Pan" <starnight@g.ncu.edu.tw>,
"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>,
"Michael Röder" <michael.roeder@avnet.eu>,
"Dollar Chen" <dollar.chen@wtmec.com>,
"Ken Yu" <ken.yu@rakwireless.com>,
"Ben Whitten" <ben.whitten@lairdtech.com>,
"Steve deRosier" <derosier@gmail.com>,
linux-spi@vger.kernel.org, LoRa_Community_Support@semtech.com
Subject: Re: [RFC net-next 15/15] net: lora: Add Semtech SX1301
Date: Tue, 3 Jul 2018 16:31:37 +0100 [thread overview]
Message-ID: <20180703153137.GB13744@sirena.org.uk> (raw)
In-Reply-To: <809fc546-6012-37f3-9485-cfd8eaf99488@suse.de>
[-- Attachment #1: Type: text/plain, Size: 2006 bytes --]
On Tue, Jul 03, 2018 at 05:09:38PM +0200, Andreas Färber wrote:
> Am 03.07.2018 um 16:50 schrieb Mark Brown:
> >> 2) This SPI device is in turn exposing the two SPI masters that you
> >> already found below, and I didn't see a sane way to split that code out
> >> into drivers/spi/, so it's in drivers/net/lora/ here - has there been
> >> any precedence either way?
> > A MFD?
> I know of mfd, but how would the the the net vs. spi pieces interact
> then? Some functions would need to be exported then or is there an
> easier way without needing to set a cross-module API in stone?
It's an in-kernel ABI it's not exactly set in stone but yeah, you'll
need some interface. A lot of devices work by having the children know
that they're part of a MFD and fish things out of the parent device,
either the pdata or (in the common case where the MFD bit mostly just
instantiates subdevices and holds a regmap) with dev_get_regmap().
> > A register map would work just as well here, we already have plenty of
> > devices that abstract at this level (most obviously the I2C/SPI devices
> > that use it to offer both interfaces with a single core driver).
> The address and data registers together form a two-byte SPI message!
> It is transmitted by writing to the CS register.
> The received data is afterwards available in another register.
Right, but it seems from the code that the hardware understands that
it's formatting register I/O and not just shifting in and out a byte
stream which is what a SPI controller does. I'd not be surprised to
learn that the register you're calling a chip select register is a
strobe that initiates the transfer (and that this may be some of the
difficulty you're having with handling it in the way the framework
expects), the pattern with writing 1 followed immediately by 0 is a bit
of a flag here.
I've seen such before hardware where I know it was intentionally
designed that way so it wouldn't be totally surprising.
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next prev parent reply other threads:[~2018-07-03 15:32 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-01 11:07 [RFC net-next 00/15] net: A socket API for LoRa Andreas Färber
2018-07-01 11:07 ` [RFC net-next 01/15] net: Reserve protocol numbers " Andreas Färber
2018-07-01 11:07 ` [RFC net-next 02/15] net: lora: Define sockaddr_lora Andreas Färber
2018-07-01 11:07 ` [RFC net-next 03/15] net: lora: Add protocol numbers Andreas Färber
2018-07-01 11:07 ` [RFC net-next 04/15] net: Add lora subsystem Andreas Färber
2018-07-01 11:07 ` [RFC net-next 05/15] HACK: net: lora: Deal with .poll_mask in 4.18-rc2 Andreas Färber
2018-07-02 16:22 ` Jiri Pirko
2018-07-02 16:59 ` Andreas Färber
2018-07-01 11:07 ` [RFC net-next 06/15] net: lora: Prepare for device drivers Andreas Färber
2018-07-01 11:07 ` [RFC net-next 07/15] net: lora: Add Semtech SX1276 Andreas Färber
2018-07-01 12:02 ` Andreas Färber
2018-07-01 11:07 ` [RFC net-next 08/15] net: lora: sx1276: Add debugfs Andreas Färber
2018-07-02 16:26 ` Jiri Pirko
2018-07-02 17:57 ` Andreas Färber
2018-07-01 11:07 ` [RFC net-next 09/15] net: lora: Prepare EUI helpers Andreas Färber
2018-07-01 11:07 ` [RFC net-next 10/15] net: lora: Add Microchip RN2483 Andreas Färber
2018-07-01 11:08 ` [RFC net-next 11/15] net: lora: Add IMST WiMOD Andreas Färber
2019-01-06 14:57 ` Heinrich Schuchardt
2019-01-07 11:29 ` Andreas Färber
2018-07-01 11:08 ` [RFC net-next 12/15] net: lora: Add USI WM-SG-SM-42 Andreas Färber
2018-07-01 11:08 ` [RFC net-next 13/15] net: lora: Prepare RAK RAK811 Andreas Färber
2018-07-01 11:08 ` [RFC net-next 14/15] net: lora: Prepare Semtech SX1257 Andreas Färber
2018-07-01 11:08 ` [RFC net-next 15/15] net: lora: Add Semtech SX1301 Andreas Färber
2018-07-02 11:51 ` Ben Whitten
2018-07-03 3:01 ` Andreas Färber
2018-07-05 8:59 ` Ben Whitten
2018-07-02 16:12 ` Mark Brown
2018-07-02 17:34 ` Andreas Färber
2018-07-02 20:43 ` Ben Whitten
2018-07-03 3:21 ` Andreas Färber
2018-07-05 8:43 ` Ben Whitten
2018-07-03 14:50 ` Mark Brown
2018-07-03 15:09 ` Andreas Färber
2018-07-03 15:31 ` Mark Brown [this message]
2018-07-03 16:40 ` Andreas Färber
2018-07-04 11:43 ` Mark Brown
2018-07-04 13:41 ` Ben Whitten
2018-07-04 14:32 ` Mark Brown
2018-07-03 15:11 ` [RFC net-next 00/15] net: A socket API for LoRa Jian-Hong Pan
2018-08-05 0:11 ` Andreas Färber
2018-08-08 20:36 ` Alan Cox
2018-08-08 22:42 ` Andreas Färber
2018-08-09 11:59 ` Alan Cox
2018-08-09 15:02 ` Jian-Hong Pan
2018-08-09 15:21 ` Alexander Aring
2018-08-10 15:57 ` Alan Cox
2018-08-11 18:30 ` Stefan Schmidt
2018-08-12 16:49 ` Andreas Färber
2018-08-12 16:37 ` Jian-Hong Pan
2018-08-12 17:59 ` Andreas Färber
2018-08-13 12:36 ` Alan Cox
2018-08-09 15:12 ` Alexander Aring
2018-08-09 0:50 ` Andreas Färber
2018-07-04 18:26 ` Stefan Schmidt
2018-07-05 10:43 ` Helmut Tschemernjak
2018-07-11 2:07 ` Andreas Färber
2018-07-11 11:45 ` Helmut Tschemernjak
2018-07-11 15:21 ` Ben Whitten
2018-07-15 18:13 ` Andreas Färber
2018-07-18 11:28 ` Ben Whitten
2018-08-02 7:52 ` Jian-Hong Pan
2018-08-03 8:44 ` linux-lora.git and LoRaWAN (was: [RFC net-next 00/15] net: A socket API for LoRa) Andreas Färber
2018-08-05 12:49 ` Jian-Hong Pan
2018-08-05 13:49 ` [RFC net-next 00/15] net: A socket API for LoRa Andreas Färber
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