On 04/11/2016 05:57 AM, Chanwoo Choi wrote: > This patch adds the new passive governor for DEVFREQ framework. The following > governors are already present and used for DVFS (Dynamic Voltage and Frequency > Scaling) drivers. The following governors are independently used for one device > driver which don't give the influence to other device drviers and also don't > receive the effect from other device drivers. > - ondemand / performance / powersave / userspace > > The passive governor depends on operation of parent driver with specific > governos extremely and is not able to decide the new frequency by oneself. > According to the decided new frequency of parent driver with governor, > the passive governor uses it to decide the appropriate frequency for own > device driver. The passive governor must need the following information > from device tree: > - the source clock and OPP tables > - the instance of parent device > > For exameple, > there are one more devfreq device drivers which need to change their source > clock according to their utilization on runtime. But, they share the same > power line (e.g., regulator). So, specific device driver is operated as parent > with ondemand governor and then the rest device driver with passive governor > is influenced by parent device. > > Suggested-by: Myungjoo Ham <myungjoo.ham@xxxxxxxxxxx> > Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx> > [tjakobi: Reported RCU locking issue and cw00.choi fix it] > Reported-by: Tobias Jakobi <tjakobi@xxxxxxxxxxxxxxxxxxxxx> > [linux.amoon: Reported possible recursive locking and cw00.choi fix it] > Reported-by: Anand Moon <linux.amoon@xxxxxxxxx> > Signed-off-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx> > --- > drivers/devfreq/Kconfig | 8 ++ > drivers/devfreq/Makefile | 1 + > drivers/devfreq/governor_passive.c | 207 +++++++++++++++++++++++++++++++++++++ > include/linux/devfreq.h | 33 ++++++ > 4 files changed, 249 insertions(+) > create mode 100644 drivers/devfreq/governor_passive.c > Acked-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> Best regards, Krzysztof -- 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
