On 24 September 2014 19:17, Simon Glass <s...@chromium.org> wrote: > 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.
In fact I couldn't like vast change on chip select logic yet, it's better to have the dm-spi will compatible with the current implementation. But anyway we need to discuss more on this. thanks! -- Jagan. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
