On Thursday 07 October 2010 19:36:18 Grant Likely wrote: > On Wed, Oct 6, 2010 at 7:49 AM, Sergii Kovalchuk > > <[email protected]> wrote: > > Hi, > > > > I'm implementing an SPI protocol driver for TI WL12xx combo chip. > > According to the spec, for write transaction I should complete the > > following sequence: > > > > 1. Assert CS > > 2. Wait until chip will trigger IRQ > > 3. Write data > > > > Looking at spi_transfer structure I wondering, how I can implement such > > logic - there is no explicit ways to implement "wait for an event" > > within single spi_message processing. > > > > As current workarround I use a simple delay in 5 us, but for sleep states > > it might be not sufficient, since wake-up time are ususally greater. > > Wow. That's nasty. The SPI layer really doesn't have a mechanism for > handling that. What you *could* do is lock the spi bus; assert CS > manually; wait for the irq, and then issue the transfer. Not exactly > pretty, but it would work within the existing infrastructure. > > g.
Yes, seems to be nasty. This is what I'm doing now - locking the bus and waiting for IRQ, but this is really ugly. Just wondered, if there is some hidden way. Not sure, if it more or less common situation. If so, may be it will be worth to extend spi_tranfer to handle "timed wait for IRQ/event" in some kind of busy loop or completion - depending of context? Of course, any modifications to generic SPI subsystem are hard to push, but this is simple extending and will not break existing functionality. Controller drivers may or may not support this initially. If it will be useful for others and worth implementing. -- Best regards, Sergii ------------------------------------------------------------------------------ Beautiful is writing same markup. Internet Explorer 9 supports standards for HTML5, CSS3, SVG 1.1, ECMAScript5, and DOM L2 & L3. Spend less time writing and rewriting code and more time creating great experiences on the web. Be a part of the beta today. http://p.sf.net/sfu/beautyoftheweb _______________________________________________ spi-devel-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/spi-devel-general
