From: Mark Brown <broonie@kernel.org> To: Michal Suchanek <hramrach@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org Subject: Re: [PATCH v2 2/3] spi: of: allow instantiating slaves without a driver Date: Mon, 27 Jun 2016 22:14:59 +0100 [thread overview] Message-ID: <20160627211459.GJ17217@sirena.org.uk> (raw) In-Reply-To: <a85f91bf364bd6e1681f5973ac92c2bb7f9a8999.1467053363.git.hramrach@gmail.com> [-- Attachment #1: Type: text/plain, Size: 1539 bytes --] On Mon, Jun 27, 2016 at 09:02:31PM +0200, Michal Suchanek wrote: > SPI slave devices are not created when looking up driver for the slave > fails. Create a device anyway so it can be manually bound to a driver. That's not what of_modalias_node() does, of_modalias_node() just mangles a compatible string into a format for consumption by modutils. It makes no effort to find a driver in doing this, it just does a simple string transformation on the compatible. > This allows manually binding a driver to slave devices for which the > driver specified by compatible is not available of for which no driver > is specified at all. Drivers like spidev or m25p80 that require no > configuratiom can be bound to such node. As ever spidev should never appear directly in a DT because it is not a description of hardware, the DT should describe whatever device is there and then we need to work out in Linux how to bind spidev to it if that's what we want to do. m25p80 does represent real hardware and that hardware should be described, for example by using the jedec,spi-nor compatible which says that a non-specific JEDEC enumerable flash is present. > Since this allows slave DT nodes without specifying a slave driver make > speed also optional. It makes no sense to specify speed when the device > is not specified. The value is only advisory anyway and the slave > driver can try to set arbitrary transfer speed. This appears to be at best marginally related to the rest of the patch. That means that it should be a separate patch. [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 473 bytes --]
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From: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> To: Michal Suchanek <hramrach-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Cc: Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Subject: Re: [PATCH v2 2/3] spi: of: allow instantiating slaves without a driver Date: Mon, 27 Jun 2016 22:14:59 +0100 [thread overview] Message-ID: <20160627211459.GJ17217@sirena.org.uk> (raw) In-Reply-To: <a85f91bf364bd6e1681f5973ac92c2bb7f9a8999.1467053363.git.hramrach-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> [-- Attachment #1: Type: text/plain, Size: 1539 bytes --] On Mon, Jun 27, 2016 at 09:02:31PM +0200, Michal Suchanek wrote: > SPI slave devices are not created when looking up driver for the slave > fails. Create a device anyway so it can be manually bound to a driver. That's not what of_modalias_node() does, of_modalias_node() just mangles a compatible string into a format for consumption by modutils. It makes no effort to find a driver in doing this, it just does a simple string transformation on the compatible. > This allows manually binding a driver to slave devices for which the > driver specified by compatible is not available of for which no driver > is specified at all. Drivers like spidev or m25p80 that require no > configuratiom can be bound to such node. As ever spidev should never appear directly in a DT because it is not a description of hardware, the DT should describe whatever device is there and then we need to work out in Linux how to bind spidev to it if that's what we want to do. m25p80 does represent real hardware and that hardware should be described, for example by using the jedec,spi-nor compatible which says that a non-specific JEDEC enumerable flash is present. > Since this allows slave DT nodes without specifying a slave driver make > speed also optional. It makes no sense to specify speed when the device > is not specified. The value is only advisory anyway and the slave > driver can try to set arbitrary transfer speed. This appears to be at best marginally related to the rest of the patch. That means that it should be a separate patch. [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 473 bytes --]
next prev parent reply other threads:[~2016-06-27 21:15 UTC|newest] Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-06-27 19:02 [PATCH v2 0/3] Updated spidev usability patchset Michal Suchanek 2016-06-27 19:02 ` Michal Suchanek 2016-06-27 19:02 ` [PATCH v2 1/3] spi: spidev: fix the check for spidev in dt Michal Suchanek 2016-06-27 20:36 ` Mark Brown 2016-06-27 20:36 ` Mark Brown 2016-06-27 19:02 ` [PATCH v2 2/3] spi: of: allow instantiating slaves without a driver Michal Suchanek 2016-06-27 21:14 ` Mark Brown [this message] 2016-06-27 21:14 ` Mark Brown 2016-06-27 19:02 ` [PATCH v2 3/3] drivers core: allow id match override when manually binding driver Michal Suchanek 2016-06-27 19:02 ` Michal Suchanek 2016-06-27 19:09 ` Greg Kroah-Hartman 2016-06-27 19:09 ` Greg Kroah-Hartman 2016-06-27 19:40 ` Michal Suchanek 2016-06-27 19:40 ` Michal Suchanek 2016-06-27 20:32 ` Mark Brown 2016-06-27 20:32 ` Mark Brown 2016-06-27 22:12 ` Greg Kroah-Hartman 2016-06-27 22:12 ` Greg Kroah-Hartman 2016-06-28 12:40 ` Michal Suchanek 2016-06-28 12:40 ` Michal Suchanek 2016-06-28 15:51 ` Mark Brown 2016-06-28 15:51 ` Mark Brown 2016-06-28 16:24 ` Michal Suchanek 2016-06-28 16:24 ` Michal Suchanek 2016-06-28 18:38 ` Mark Brown 2016-06-28 18:38 ` Mark Brown 2016-06-28 20:02 ` Michal Suchanek 2016-06-28 20:57 ` Mark Brown 2016-06-28 20:57 ` Mark Brown 2016-06-29 3:32 ` Michal Suchanek 2016-06-29 3:32 ` Michal Suchanek 2016-06-29 18:02 ` Mark Brown 2016-06-29 18:02 ` Mark Brown 2016-06-30 7:47 ` Michal Suchanek 2016-06-30 7:47 ` Michal Suchanek 2016-06-30 9:03 ` Dan O'Donovan 2016-06-30 9:03 ` Dan O'Donovan 2016-07-01 9:36 ` Mark Brown 2016-07-01 10:11 ` Michal Suchanek 2016-07-01 10:11 ` Michal Suchanek 2016-07-01 8:25 ` Mark Brown 2016-07-01 8:58 ` Michal Suchanek 2016-07-01 8:58 ` Michal Suchanek 2016-07-01 15:00 ` Mark Brown 2016-07-01 15:37 ` Michal Suchanek 2016-07-01 16:22 ` Mark Brown 2016-07-01 18:56 ` Michal Suchanek 2016-07-01 18:56 ` Michal Suchanek 2016-07-01 19:36 ` Michal Suchanek 2016-07-01 19:36 ` Michal Suchanek
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