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Message-Id: <1373247868-21444-1-git-send-email-mturquette@linaro.org> Date: Sun, 7 Jul 2013 18:44:25 -0700 From: Mike Turquette <mturquette@...aro.org> To: linux-kernel@...r.kernel.org Cc: linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org, Mike Turquette <mturquette@...aro.org> Subject: [PATCH RFC 0/3] voltage scaling via clock rate-change notifiers Scaling regulator voltage as a function of clock frequency is a common power saving technique. It is often referred to as dynamic voltage & frequency scaling (DVFS). The common clock framework has clock rate-change notifier (pre & post) which provide a convenient hook for scaling voltage whenever clk_set_rate is called. The first patch in the series provides helper functions for drivers that wish to scale voltage through the clock rate-change notifiers. The approach taken is that the driver does not care about the details of the OPP table, nor does it care about handling the voltage regulator directly. The driver only has a pointer to the struct clk object; the other details are hidden in the helper functions. The second patch provides a CPUfreq-centric helper, built on top of the first one. This is primarly to help with the struct cpufreq_frequency_table bits and latency calculation. The final patch in the series converts the cpufreq-cpu0 driver to use these functions. Other cpufreq drivers can be converted later. There are not many cases of DVFS usage in the kernel; vendors often keep these out-of-tree. By providing a common approach using the clock rate change notifiers this series hopes to consolidate code across drivers and encourage vendors to upstream their DVFS bits. Mike Turquette (3): clk: notifier handler for dynamic voltage scaling clk: cpufreq helper for voltage scaling cpufreq: cpufreq-cpu0: clk rate-change notifiers drivers/clk/Makefile | 1 + drivers/clk/clk-voltage-notifier.c | 206 +++++++++++++++++++++++++++++++++++++ drivers/cpufreq/cpufreq-cpu0.c | 125 ++++------------------ include/linux/clk.h | 13 ++- 4 files changed, 241 insertions(+), 104 deletions(-) create mode 100644 drivers/clk/clk-voltage-notifier.c -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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