I recently upgraded from a 3.4 kernel to a 3.8 kernel and found that the drivers for the functionality provided by the TiWi module on the pandaboard (Bluetooth, WiFI, etc.) could no longer probe the device. After some investigation, it turned out that the TiWi clock is provided by the twl6030 PMIC chip. The clock output of the twl6030 was first enabled via these commits: https://patchwork.kernel.org/patch/546381/ https://patchwork.kernel.org/patch/546401/ Since most of the functionality of the TWL6030 is power regulation and the clock is enabled via a similar mechanism to the power outputs, the clock was added as a 'pseudo-regulator' to drivers/regulator/twl-regulator.c. Some time later, a series of commits removed the clock functionality from twl-regulator.c, apparently due to being out-of-place in the Device Tree listings or something. The first of these is recorded here: https://lkml.org/lkml/2012/6/4/330 The next two just clean up the code that was orphaned by the previous: e76ab829 "regulator: twl: Remove references to the twl4030 regulator" 029dd3ce "regulator: twl: Remove another unused variable warning" Luciano Cuelho, who maintains the driver for the WiFi portion of the TiWi modules, reported the resulting breakage some time later on the LKML: https://lkml.org/lkml/2012/11/15/72 Despite the protestation of Mark Brown that his code removal wasn't the cause of the problem, reverting his changes does indeed enable the clock. However, it also seems to be the case that there ought to be a better home for the clock than twl-regulator.c. At the time of the previous discussion, it wasn't clear if the framework was in place to support a clock driver for the twl6030's clock, but it seems like the support exists now, since there's a clock driver for the twl6030's companion, the twl6040 audio chip. So: Is there any chance of simply reverting the 3 commits that broke the clock? I have done this locally, but I hate to see pandaboard support in the mainstream kernel continue to be broken in this way. If for whatever reason the commits cannot be reverted, would creating a driver like drivers/clk/clk-twl6040.c that enabled the twl6030's clock output be a suitable alternative? I'd be willing to take a stab at writing it if there's not something like that in the works already. --- Levi Pearson -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
