On Sun, Aug 10, 2014 at 2:59 AM, Simon Glass <[email protected]> wrote: > Hi, > > On 14 July 2014 18:56, Simon Glass <[email protected]> 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.
I will be busy in next full week, give me 2 more weeks. Probably I will give my comments on next to next weekend. thanks! -- Jagan. _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
