On Saturday, April 26, 2014 at 05:10:13 AM, Huang Shijie wrote: > On Sat, Apr 26, 2014 at 12:12:24AM +0200, Marek Vasut wrote: > > > > > the drivers may fills this hook itself, so the code should like this: > > > > > -------------------------------------------------- > > > > > > > > > > if ((info->flags & USE_FSR) && > > > > > > > > > > nor->wait_till_ready == spi_nor_wait_till_fsr_ready) > > > > > > > > > > nor->wait_till_ready = spi_nor_wait_till_fsr_ready; > > > > > > > > > > -------------------------------------------------- > > > > > > > > I sense a misdesign of the SPI NOR subsystem here. The subsystem and > > > > the driver compete for a function pointer here ? I guess one should > > > > have precedence in some way then ... and also, they should be two > > > > different pointers, where the subsystem decides which to use. > > > > > > the subsystem do not decides which one to use, the driver decides which > > > one to use. > > > > > > If driver has its own @wait_till_ready , it means the driver knows the > > > feature, and has implemented it in its own @wait_till_ready. > > > > > > If the driver does not fill any wait_till_ready, it means the driver > > > will use the default @wait_till_ready. We can treat the > > > spi_nor_wait_till_fsr_ready as a default hook too. > > > > I see the driver overwriting a hook previously set by the subsystem. This > > not sure ;) > > The driver set the hooks before the subsystem set these hooks. > > If the driver has already set the @wait_till_ready hook before it calls > the spi_nor_scan, the subsystem will not set the hook anymore. > > Please see the spi_nor_check().
Two things competing over the same pointer looks misdesigned to me. I will need to dig into this one more time ... Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
