On 7/16/08, Grant Likely <[EMAIL PROTECTED]> wrote: > On Wed, Jul 16, 2008 at 10:24:22AM -0400, Jon Smirl wrote: > > On 7/16/08, Wolfgang Grandegger <[EMAIL PROTECTED]> wrote: > > > Jon Smirl wrote: > > > > > > > On 7/16/08, Wolfgang Grandegger <[EMAIL PROTECTED]> wrote: > > > > > > > > > Currently, the I2C buses are probed for HWMON I2C devices, which > might > > > > > not be acceptable in same cases. This patch makes device probing > > > > > configurable through the property "probe" of the FDT I2C device > node: > > > > > > > > > > > > > All this patch seems to be doing is removing class I2C_CLASS_HWMON via > > > > a device tree flag, PROBE. > > > > If this is implemented it shouldn't be a device tree option, it should > > be a compile time option in the Kconfig system. We don't want to > > pollute a platform independent device tree with Linux clutter. > > > I'm not sure about this. It is somewhat describing the hardware. It > sounds like it is saying "hey, I've got an i2c bus here, but I don't > know what is on it; so instead of providing a set of child nodes, you > should probe this bus to find out what it has".
Probing an i2c bus does not necessarily come to a good conclusion. The probes for some chips can alter the states in others. People have accidentally changed voltage settings and fried CPU chips. The process is not well defined. I'm not saying remove i2c probing altogether, some things require probing like EDID data from a monitor. Since these are embedded system I just think it is pretty unlikely that stuff like that is going to get hooked to an i2c-mpc bus. That was behind the idea to push it back to a compile time option. > > I don't see any problem specifying it in the device tree. > > Making it a Kconfig option forces *all* i2c busses on supported > platforms into either probe or no-probe mode. Not a multiplatform > friendly solution. Heck, we've got multiple i2c busses on some chips and > it is conceivable that only one would need to be probed. > > Cheers, > > g. > -- Jon Smirl [EMAIL PROTECTED] _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev