From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleksij Rempel Subject: Re: propper support of 5 wire SPI (SPI_READY signal) Date: Mon, 22 Feb 2016 12:42:59 +0100 Message-ID: <56CAF443.8010705@rempel-privat.de> References: <56C6DB9E.5080905@rempel-privat.de> <20160220195641.GE18327@sirena.org.uk> <56C8DD64.1070700@rempel-privat.de> <20160222110948.GE18327@sirena.org.uk> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="HkT7i6kCCnDuWiNLXAvgBETgdN7CHlo1k" Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dirk.behme-V5te9oGctAVWk0Htik3J/w@public.gmane.org, "EXTERNAL Rempel Oleksij (Brunel, CM-AI/ECO3)" To: Mark Brown Return-path: In-Reply-To: <20160222110948.GE18327-GFdadSzt00ze9xe1eoZjHA@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --HkT7i6kCCnDuWiNLXAvgBETgdN7CHlo1k Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Am 22.02.2016 um 12:09 schrieb Mark Brown: > On Sat, Feb 20, 2016 at 10:40:52PM +0100, Oleksij Rempel wrote: >=20 >> I would need some naming suggestions (we call our protokol SSI). It >> looks like the protocol used by us has some differences with Davinci. >> The Dav. using SPI_READY line only >> to allow or pause transmission (fix me if i'm wrong) >> We call it Request line and use it to: Ready to Receive; Receive >> Finished; and Request data shift by slave. >=20 > Oh, so this isn't SPI_READY? Not 100%. According to TI documentation, transfer initiated by master looks like: 1. Master: SPIx_CS (on) 2. Slave: SPIx_READY (on) 3. Master: Date transfer 4. Slave: SPIx_READY (off) 5. Master: SPIx_CS (off) Bosch version of 5-wire transfer initiated by master: 1. Master: SPIx_CS (on) 2. Slave: SPIx_REQUEST (on) 3. Master: Date transfer 4. Master: SPIx_CS (off) <----- different order. 5. Slave: SPIx_REQUEST (on) <----- >=20 >> In this case probably spi framework need to be extended with kind of >> request call back. If data is currently not transmitted and Req line i= s >> not used for flow control, then call driver specific function to >> initiate data shift. >=20 > This is sounding awfully like SPI slave support? Not completely. Transfer initiated by Slave has only one difference to Master transfer. Bosch version of 5-wire transfer initiated by slave: 1. Slave: SPIx_REQUEST (on) <----- different order. 2. Master: SPIx_CS (on) <---- 3. Master: Date transfer 4. Master: SPIx_CS (off) 5. Slave: SPIx_REQUEST (off) --=20 Regards, Oleksij --HkT7i6kCCnDuWiNLXAvgBETgdN7CHlo1k Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iF4EAREIAAYFAlbK9EcACgkQHwImuRkmbWkmHwD+PRz7D+zVQouk70MmJZXal7qO ttq7dVTnU4sNZythDdcA/AnvkMmsnK3HwU4VCh+0fYqckIVDjrsyV2pgWR8FZhRH =1MQl -----END PGP SIGNATURE----- --HkT7i6kCCnDuWiNLXAvgBETgdN7CHlo1k-- -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html