| Message ID | 1264191502.2224.2@antares (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Grant Likely |
| Headers | show |
Albrecht Dreß wrote: > Make the I2C adapter timeout configurable through a Device Tree property > which gives the timeout in microseconds. My understanding is that software properties should not be defined via the device tree. I think a sysfs entry is more appropriate. Wolfgang.
Am 25.01.10 08:55 schrieb(en) Wolfgang Grandegger: > Albrecht Dreß wrote: >> Make the I2C adapter timeout configurable through a Device Tree property which gives the timeout in microseconds. > > My understanding is that software properties should not be defined via the device tree. I think a sysfs entry is more appropriate. Is the timeout really a /software/ property? My feeling is that the timeout basically depends upon the bus clock and the chips attached to the bus. Therefore, it is linked closer to the composition of the board's hardware as described in the device tree, than to any userland software. Or am I totally wrong here? Thanks, Albrecht.
Albrecht Dreß wrote: > Am 25.01.10 08:55 schrieb(en) Wolfgang Grandegger: >> Albrecht Dreß wrote: >>> Make the I2C adapter timeout configurable through a Device Tree >>> property which gives the timeout in microseconds. >> >> My understanding is that software properties should not be defined via >> the device tree. I think a sysfs entry is more appropriate. > > Is the timeout really a /software/ property? My feeling is that the > timeout basically depends upon the bus clock and the chips attached to > the bus. Therefore, it is linked closer to the composition of the > board's hardware as described in the device tree, than to any userland > software. Or am I totally wrong here? Well, yes, it seems to be a border case. Wolfgang.
On Fri, Jan 22, 2010 at 1:18 PM, Albrecht Dreß <albrecht.dress@arcor.de> wrote: > Make the I2C adapter timeout configurable through a Device Tree property > which gives the timeout in microseconds. > > Signed-off-by: Albrecht Dreß <albrecht.dress@arcor.de> > > --- > > --- linux-2.6.32-orig/Documentation/powerpc/dts-bindings/fsl/i2c.txt 2009-12-03 04:51:21.000000000 +0100 > +++ linux-2.6.32/Documentation/powerpc/dts-bindings/fsl/i2c.txt 2010-01-22 16:04:56.000000000 +0100 > @@ -21,6 +21,7 @@ > - fsl,preserve-clocking : boolean; if defined, the clock settings > from the bootloader are preserved (not touched). > - clock-frequency : desired I2C bus clock frequency in Hz. > + - timeout : I2C timeout in microseconds. fsl,timeout to avoid namespace collisions please (ie. if a common i2c 'timeout' property is ever defined for all i2c busses) g.
--- linux-2.6.32-orig/Documentation/powerpc/dts-bindings/fsl/i2c.txt 2009-12-03 04:51:21.000000000 +0100 +++ linux-2.6.32/Documentation/powerpc/dts-bindings/fsl/i2c.txt 2010-01-22 16:04:56.000000000 +0100 @@ -21,6 +21,7 @@ - fsl,preserve-clocking : boolean; if defined, the clock settings from the bootloader are preserved (not touched). - clock-frequency : desired I2C bus clock frequency in Hz. + - timeout : I2C timeout in microseconds. Examples :
Make the I2C adapter timeout configurable through a Device Tree property which gives the timeout in microseconds. Signed-off-by: Albrecht Dreß <albrecht.dress@arcor.de> ---