Hi, On Fri, Nov 15, 2013 at 11:26 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Friday 15 November 2013, Loc Ho wrote: >> >> +- CTLE0 : PHY override parameters for channel 0 register REG1 >> >> + field CTLE_EQ. First value for Gen1, second value >> >> + for Gen2, and third value for Gen3. Default is 0x2. >> >> +- CTLE1 : PHY override parameters for channel 1 register REG1 >> >> + field CTLE_EQ. First value for Gen1, second value >> >> + for Gen2, and third value for Gen3. Default is 0x2. >> >> +- PQ0 : PHY override parameters for channel 0 register REG125 >> >> + field PQ_REG. First value for Gen1, second value >> >> + for Gen2, and third value for Gen3. Default is 0xA. >> >> +- PQ1 : PHY override parameters for channel 1 register REG125 >> >> + field PQ_REG. First value for Gen1, second value >> >> + for Gen2, and third value for Gen3. Default is 0xA. >> > >> > As mentioned before, I don't think putting register-level information into the binding >> > is the right approach here. >> > >> [Loc Ho] >> I don't want to change the driver for every possible customer or APM >> boards out there. In general, if the board designer follows the board >> design guideline, this isn't necessary. Unfortunately, I can not >> control what customer do. If these setting is NOT driven by DTS, then >> I or others may have to change the driver every time there is an new >> board. Another option is pass them as module parameters. > > Module parameters are certainly not a solution for this, that would make the > problem worse. > > Would it be possible to read out the values that were set by the firmware > at startup and reuse those during run-time? I assume that the devices are > already brought up when the kernel starts. > > If that s not possible, change the properties to be named after what the > setting does and make the values be units that are sensible to a board > designer, e.g. (specifics are totally made up here) > > - polarity: If present, override the polarity of the signal line. > zero for negative polarity, one for positive polarity. > If absent, use the firmware default. > - signal-clock-frequency: If present, override the signal clock frequency. > This value is defined in HZ > - x-y-time: If present, override the timing setting for the X/Y signal > time, in nanoseconds. > > This way, you can reuse the properties for an updated version of the device > that has similar settings but a different register layout. > [Loc Ho] It may be possible from ACPI point of view (hasn't tried yet). But for DTS, there is no such firmware. I will make the entry more friendly for DTS. For ACPI, I am thinking that the BIOS/Firmware will just initialize it. As long as the clock isn't reset, the value will be there. Let's agree on these: 1. DTS - use more friendly name 2. ACPI - handled by the BIOS/Firmware -Loc -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
