Hi Jagan, On 15 September 2014 06:33, Simon Glass <s...@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. > > 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 assist with the conversion of other SPI drivers, a README file is > added to walk through the process. > > As always, driver model patches are available at u-boot-dm.git branch > 'working'. > I've decided that the chip select approach is not going to server our purposes for the long term. I'm going to respin this series with a few changes and then send v3. It is currently at u-boot-dm/spi-working. Also this isn't going to go into dm/master yet, except for some of the more minor sandbox changes that you have reviewed. But I would like to get it into dm/next. Regards, Simon
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