Hello Jiada, On Tue, Apr 25, 2017 at 12:56:23AM -0700, Jiada Wang wrote: > the use case of > "A (master) <=> B (slave)", "B (master) <=> C(slave)", do share MISO and > MOSI lines, > but there is no SS line between A and C. so for each SPI slave device, there > is only one > master device.
So you need a mutex to make A not use the bus while B communicates to C. Otherwise you have two drivers on MOSI (A and B) and MISO (B and C). Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
