As far as I know you have to be in the priviledged mode to change mux value of pins (or you can use PRU to do this) which means you have to write kernel module like this ( https://github.com/chunsj/nxctrl/blob/master/nxpmx/nxpmx.c).
On Wed, Aug 27, 2014 at 12:40 AM, Cristian Mitu <[email protected]> wrote: > Hello guys, > > > I have a pig problem concerning a driver used for communicating with some > MEMS components via SPI. The driver was developed for a Gumstix platform > with OMAP34... processor running a 3.3 kernel. The driver muxes the pins > using "iowrite16" functions. Some sample code can be seen below: > > ###Mux values sample : > #define SPI_OE_MUX_OFFSET (0x48002A1A - OMAP34XX_PADCONF_START) > #define SPI_CLK_MUX_OFFSET (0x480021C8 - OMAP34XX_PADCONF_START) > ................. > ###### > > ### Pin mode sample: > #define OE_ENABLE_MUX 0x010C /* IEN | PTD | EN | M4 */ > #define SPI_ENABLE_MUX 0x0100 /* IEN | PTD | DIS | M0 */ > ###### > > > // Multiplexing the pins code sample: > base = ioremap(OMAP34XX_PADCONF_START, OMAP34XX_PADCONF_SIZE); > > if (!base) > return -ENOMEM; > > old_spi_mux.oe_offset = ioread16(base + SPI_OE_MUX_OFFSET); > iowrite16(OE_ENABLE_MUX, base + SPI_OE_MUX_OFFSET); > ###### > > Now i understand how the offsets are calculated and how the I/O memory is > beeing used. What i want to know is if i can reuse this code for the > BeagleBone Black ( of course i know that i have to modify the mux values > and pin modes to match to the BBB). My BBB is running a 3.8 kernel and as i > know there is the major change with switching to the Device Tree system. > > Also if i use this method will i still need to write a device tree overlay > setting the pins up there or is this done directly by using this code ( i > feel this is a stupid question seeing as the DT is used specifically for > setting up the pins so this code should do that instead but asking just so > i know for sure). I thank you in advance for the response. > > -- > 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. > -- 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.
