On Saturday, October 25, 2014 4:43:02 PM UTC-7, [email protected] wrote: > > *Background* > > I have a Beagle Bone Black cape with both a Nordic nRF51822 and TI CC2520. > Both of these devices are on the SPI0 bus. I have kernel drivers that work > for each separately on Debian 3.8.13. > > *Goal* > > I would like to be able to load both kernel drivers at the same time and > have them share the SPI bus. > > *Issue* > > While I have figured out how to make each kernel driver take control of > the SPI0 bus when loaded separately, I can't seem to get them to each have > access when loaded together. I'm far from an expert on device tree overlays > and am not sure how to glue everything together so that the kernel drives > are successfully loaded. > > Here is my code so far in the kernel driver that pertains to creating the > SPI device for the nRF51822. I create a struct spi_driver with config > information and then call module_spi_driver() to init, etc. (copied from > /linux/drivers/net/ieee802154/cc2520.c). The probe() function callback > sets up a character device and configures some GPIOs (that code needs to be > updated to work with device tree, but for now it should be fine). > > > static int nrf51822_spi_probe(struct spi_device *spi_device) > { > ERR(KERN_INFO, "Inserting SPI protocol driver.\n"); > nrf51822_spi_device = spi_device; > > // > // Create a buffer to move data over the character device > // > ... > > // > // Setup the interrupt from the nRF51822 > // > ... > > // > // Configure the character device in /dev > // > ... > > return 0; > } > > static int nrf51822_spi_remove(struct spi_device *spi_device) > { > ERR(KERN_INFO, "Removing SPI protocol driver."); > nrf51822_spi_device = NULL; > > // Free memory and close things > } > > > static const struct spi_device_id nrf51822_ids[] = { > {"nrf51822", }, > {}, > }; > MODULE_DEVICE_TABLE(spi, nrf51822_ids); > > > static const struct of_device_id nrf51822_of_ids[] = { > {.compatible = "brad,nrf51822", }, > {}, > }; > MODULE_DEVICE_TABLE(of, nrf51822_of_ids); > > > // Configure SPI > static struct spi_driver nrf51822_spi_driver = { > .driver = { > .name = nrf51822_name, > .owner = THIS_MODULE, > .bus = &spi_bus_type, > .of_match_table = of_match_ptr(nrf51822_of_ids), > }, > .id_table = nrf51822_ids, > .probe = nrf51822_spi_probe, > .remove = nrf51822_spi_remove, > }; > > // This I believe will load this driver correctly > // and cause it to be probed when it is needed. > module_spi_driver(nrf51822_spi_driver); > > MODULE_LICENSE("GPL"); > MODULE_AUTHOR(DRIVER_AUTHOR); > MODULE_DESCRIPTION(DRIVER_DESC); > > And here is my attempt at a device overlay. I'm only claiming a single > GPIO which I use as an interrupt from the nRF51822 back to the beagle bone. > > /dts-v1/; > /plugin/; > > / { > compatible = "ti,beaglebone", "ti,beaglebone-black"; > > /* identification */ > part-number = "BB-BONE-NRF51822"; > version = "00A0"; > > /* state the resources this cape uses */ > exclusive-use = > /* the pin header uses */ > > /* GPIO */ > "P9.16", /* Interrupt from NRF51822 */ > > /* the hardware ip uses */ > "gpio1_19"; > > > fragment@0 { > target = <&am33xx_pinmux>; > __overlay__ { > bb_cc2520_gpio_pins: pinmux_bb_2520_gpio_pins { > compatible = "nrf51822"; > pinctrl-single,pins = < > /* GPIO */ > 0x04C 0x2F /* ehrpwm1b.gpio1_19, > INPUT | MODE7 */ > >; > }; > }; > }; > > fragment@1 { > target = <&ocp>; > __overlay__ { > nrf51822 { > compatible = "brad,nrf51822"; > > /* the power control gpio */ > interrupt-gpio = <&gpio1 19 0x0>; > > /* the muxing */ > pinctrl-names = "default"; > pinctrl-0 = <&nrf51822_pins>; > }; > }; > }; > }; > > The end effect is that my probe() function in the kernel driver is never > called, even after loading the overlay and kernel module. > > How do I set things up so that two kernel modules can both use SPI0? Has > anyone tried this? Everything I've looked at appears to assume only one > device is attached to the SPI bus so it can specify the SPI pins in its > .dts file (but I could be wrong about that). > > Thanks for any help or direction. >
You don't say where your got the drivers, I couldn't find either in linux-3.16.1. Under normal use spi0 will be controlled by spi/spi-omap2-mcspi.c, as indicated by its inclusion of the compatible entry "ti,omap4-mcspi". See am33xx.dtsi for the definition of this term. By using modprobe, etc. you are bypassing this logic. I believe you may need a master driver that will control the bus, and slave drivers that can manage each device. They could communicate using some kind of message passing. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
