[U-Boot] [PATCH 0/25] Introduce driver model support for SPI, SPI flash, cros_ec

[Simon Glass]

Hi,

On 14 July 2014 18:56, Simon Glass <sjg at chromium.org> wrote:
> Up until now driver model has not been used for any type of bus. Buses
> have some unique properties and needs, so we cannot claim that driver
> model can cover all the common cases unless we have converted a bus over
> to driver model.
>
> SPI is a reasonable choice for this next step. It has a fairly simple
> API and not too many dependencies. The main one is SPI flash so we may
> as well convert that also. Since the boards I test with have cros_ec I
> have also included that, for SPI only.
>
> The technique used is make use of driver model's supported data structures
> to hold information currently kept by each subsystem in a private data
> structure. Since 'struct spi_slave' relates to the slave device on the bus
> it is stored in the 'parent' data with each child device of the bus.
> Since 'struct spi_flash' is a standard interface used for each SPI flash
> driver, it is stored in the SPI FLash uclass's private data for each
> device.
>
> New defines are created to enable driver model for each subsystem. These
> are:
>
>    CONFIG_DM_SPI
>    CONFIG_DM_SPI_FLASH
>    CONFIG_DM_CROS_EC
>
> This allows us to move some boards and drivers to driver model, while
> leaving others behind. A 'big bang' conversion of everything to driver
> model, event at a subsystem level, is never going to work.
>
> On the other hand, we change the driver at the same time as the CONFIG
> option is enabled. Keeping both version of the driver around involves a
> flock of #ifdefs, the benefit of which is not apparent to me, since the
> old code is removed anyway.
>
> There is some cost in changing the uclass interface after it is created,
> so if you have limited time, please spend it reviewing the uclass
> interfaces in spi.h and spi_flash.h. These need to be supported by each
> driver, so changing them later may involve changing multiple drivers.
>
> To help with conversion of SPI drivers to driver model, documentation is
> provided which takes the happy camper through the process with an example.
>
> As always, driver model patches are available at u-boot-dm.git branch
> 'working'.
>
> Note: This series is not fully ready - e.g. some header files are missing
> comments. But I wanted to get it out for review early since some SPI work
> is ongoing which might depend on it.

Are there any comments on this series please? I'd like to apply these
to dm/master early next week, excluding the exynos ones.

Regards,
Simon