Messages in this thread | | | From | "Mahapatra, Amit Kumar" <> | Subject | RE: [RFC PATCH 1/2] spi: Add multiple CS support for a single SPI device | Date | Wed, 27 Jul 2022 13:02:31 +0000 |
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Hello Mark,
> -----Original Message----- > From: Mark Brown <broonie@kernel.org> > Sent: Tuesday, July 19, 2022 11:23 PM > To: Mahapatra, Amit Kumar <amit.kumar-mahapatra@amd.com> > Cc: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>; > p.yadav@ti.com; miquel.raynal@bootlin.com; richard@nod.at; > vigneshr@ti.com; git@xilinx.com; michal.simek@xilinx.com; linux- > spi@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux- > kernel@vger.kernel.org; michael@walle.cc; linux-mtd@lists.infradead.org; > git (AMD-Xilinx) <git@amd.com> > Subject: Re: [RFC PATCH 1/2] spi: Add multiple CS support for a single SPI > device > > On Tue, Jul 19, 2022 at 01:21:41PM +0000, Mahapatra, Amit Kumar wrote: > > > I agree, so for checking the controller multiple chip select > > capability(using more than one chip select at once) we can define a > > new spi controller DT property like "multi-cs-cap"(please suggest a better > name). > > The controller that can support multiple chip selects should have this > > property in the spi controller DT node. The spi core will check > > ctlr->multi-cs-cap to operate multiple chip select in parallel. > > I'm not sure this needs to be a DT property, it's more just something we infer > from the compatible. The name seems fine, as does the flag in the controller > data.
I agree that we can infer this from the compatible and set the flag in the controller data.
> > > > the chip selects are available and that the controller can do > > > something useful with them (and probably have an implementation in > > > the core for doing so via GPIO). > > > Here are you referring to the usecase in which a controller > > implementing multi CS support using GPIO? > > Yes, we probably ought to.
In my next version I will add the implementation in the spi core for multi CS support using GPIO, but I will not be able test it as I don't have the necessary hardware setup .
Regards, Amit
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