This patch builds on "clk: notifier handler for dynamic voltage scaling" by adding a CPUfreq-specific helper function for registering a clock rate-change notifier to scale regulator voltage as a function of clock rate.
In particular this patch creates an instance of struct cpufreq_frequency_table and also calculate the voltage scaling latency, both of which are returned to the caller for use in the CPUfreq driver. Signed-off-by: Mike Turquette <[email protected]> --- drivers/clk/clk-voltage-notifier.c | 71 ++++++++++++++++++++++++++++++++++++++ include/linux/clk.h | 6 ++++ 2 files changed, 77 insertions(+) diff --git a/drivers/clk/clk-voltage-notifier.c b/drivers/clk/clk-voltage-notifier.c index cb6b85f..8e1707f 100644 --- a/drivers/clk/clk-voltage-notifier.c +++ b/drivers/clk/clk-voltage-notifier.c @@ -10,6 +10,7 @@ */ #include <linux/clk.h> +#include <linux/cpufreq.h> #include <linux/device.h> #include <linux/module.h> #include <linux/notifier.h> @@ -133,3 +134,73 @@ void of_clk_volt_notifier_unregister(struct notifier_block *nb) kfree(vsd); } EXPORT_SYMBOL_GPL(of_clk_volt_notifier_unregister); + +void of_clk_cpufreq_notifier_unregister(struct notifier_block *nb, + struct cpufreq_frequency_table *freq_table) +{ + struct volt_scale_data *data = to_volt_scale_data(nb); + struct device *dev = data->dev; + + opp_free_cpufreq_table(dev, &freq_table); + of_clk_volt_notifier_unregister(nb); +} +EXPORT_SYMBOL_GPL(of_clk_cpufreq_notifier_unregister); + +/** + * of_clk_cpufreq_notifer_register - register clock notifier to scale voltage + * @dev: device that owns this scaling operation + * @np: pointer to device's DT node + * @clk: clock whose rate-change notifier triggers voltage scaling + * @supply: regulator id string + * @freq_table: pointer to uninitialized CPUfreq frequency scaling table + * @voltage_latency: worst case voltage scaling latency + */ +struct notifier_block *of_clk_cpufreq_notifier_register(struct device *dev, + struct device_node *np, struct clk *clk, const char *supply, + struct cpufreq_frequency_table **table, + unsigned int *voltage_latency) +{ + struct notifier_block *nb; + struct volt_scale_data *vsd; + struct opp *opp; + unsigned long min, max; + int ret, i; + + nb = of_clk_volt_notifier_register(dev, np, clk, supply, + voltage_latency); + if (IS_ERR(nb)) + return nb; + + vsd = to_volt_scale_data(nb); + + ret = opp_init_cpufreq_table(dev, table); + if (ret) { + pr_err("failed to init cpufreq table: %d\n", ret); + goto err_unregister; + } + + /* find the min and max voltages and compute worst-case latency */ + for (i = 0; table[0][i].frequency != CPUFREQ_TABLE_END; i++) + ; + + rcu_read_lock(); + opp = opp_find_freq_exact(dev, + table[0][0].frequency * 1000, true); + min = opp_get_voltage(opp); + opp = opp_find_freq_exact(dev, + table[0][i-1].frequency * 1000, true); + max = opp_get_voltage(opp); + rcu_read_unlock(); + + *voltage_latency = regulator_set_voltage_time(vsd->reg, min, max); + if (*voltage_latency < 0) + pr_warn("%s: failed to calculate voltage latency, %d\n", + __func__, ret); + + return nb; + +err_unregister: + of_clk_volt_notifier_unregister(nb); + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(of_clk_cpufreq_notifier_register); diff --git a/include/linux/clk.h b/include/linux/clk.h index 85ea520..3104883 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -86,6 +86,12 @@ struct notifier_block *of_clk_volt_notifier_register(struct device *dev, struct device_node *np, struct clk *clk, const char *supply, int *voltage_latency); void of_clk_volt_notifier_unregister(struct notifier_block *nb); +struct notifier_block *of_clk_cpufreq_notifier_register(struct device *dev, + struct device_node *np, struct clk *clk, const char *supply, + struct cpufreq_frequency_table **table, + unsigned int *voltage_latency); +void of_clk_cpufreq_notifier_unregister(struct notifier_block *nb, + struct cpufreq_frequency_table *freq_table); #endif -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
