Hi, On 2010-12-10 10:12, Marek Szyprowski wrote: > Hello, > > On Friday, December 10, 2010 6:14 AM Kukjin Kim wrote: > >> Sylwester Nawrocki wrote: >>> >>> MIPI DPHY control register requires special handling since it is shared >>> between CSI (camera serial interface) and DSI (display serial interface). >>> By creating this clock a serialized interface is provided for mipi-csis >>> and mipi-dsim drivers, so DPHYs may be safely controlled by both drivers. >>> Similarly dsim_dphy clock could be added for mipi-dsim. >>> >>> --- >>> >>> I am not quite sure about_"dphy_clock", perhaps power domain >>> handling code would be better place for it. >>> >> Yeah, it is MIPI DPHY enable/disable control register not clock control. >> So its proper position is not here... >> >> Hmm...how about driver's probe/open or some kind of setup in machine >> directory? > > I'm not sure that this is the best way of handling this phy controller. Please > notice that mipi phy controller has different register location on S5PC110 and > S5PC210. Please also notice that S5PC210 has 2 mipi csci controllers and phy > interfaces, while s5pc110 has only one. Hiding all the logic and register > specific writes behind this 'csi_dphy' clock easily resolves all these issues > on all different samsung platforms and makes it easy to use it from the driver. > Similar patch has been proposed some time ago for usb_phy interface and imho > this is the right way to go. > More importantly S5P_MIPI_DPHY_CONTROL* register is shared between two devices - MIPI-CSIS and MIPI-DSIM. It means some kind of serialization mechanism need to be employed while accessing this register, a spinlock seems to fit best here. It also means that if we decided to create the platform callback such a code would have to be placed in a common compilation unit which would be built when either mipi-csis or mipi-dsim is selected. And this callback would have to account the differences between various SoC flavours or it would have to be repeated for each mach-s5pvXXX. So if the platform callback is the preferred way, where do we put an implementation of it? Regards, Sylwester -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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