Alfred, On Fri, Aug 14, 2009 at 04:09:21PM -0500, alfred steele wrote: > In my userspace driver for a temp sensor on a i2c bus, i am using the > /dev interface. When i use plain read/write syscalls , they seem to > work just fine. But when i use a combined read/write using the IOCTL > "I2C_RDWR", i get a return of invalid argument i.e EINVAL from the > kernel space i2c dev/bus driver. > > int rest = ioctl(_fd, I2C_RDWR, trans ); > > So basically res gets a value<1 on execution. I am putting in the > correct slave address. i have double checked on it. What could be the > other obvious reasons? Could endian ness be an issue as well although > the userspace is really invisible and if that had been the case i > would not have got acks from the slave for a i2c scan on the bus. > i checked the kernel bus driver code for the reason, but cannot figure > out just by reading the code at this point as i have a broken h/w. > iam using the freescale mxc i2c bus driver on the kernel side. Can you elaborate: - which kernel version is that - which i.MX derivate are you using? rsc -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
