diff options
author | Shawn Guo <shawn.guo@linaro.org> | 2012-09-05 01:09:12 +0200 |
---|---|---|
committer | Rafael J. Wysocki <rjw@sisk.pl> | 2012-09-09 22:06:33 +0200 |
commit | b496dfbc94ab86f970ef0167eaabe51f930aa5fb (patch) | |
tree | 3ce7bdb6847fbcff3f46935ebc5b5c17da23d31d /drivers/base | |
parent | ARM: add cpufreq transiton notifier to adjust loops_per_jiffy for smp (diff) | |
download | linux-b496dfbc94ab86f970ef0167eaabe51f930aa5fb.tar.xz linux-b496dfbc94ab86f970ef0167eaabe51f930aa5fb.zip |
PM / OPP: Initialize OPP table from device tree
With a lot of devices booting from device tree nowadays, it requires
that OPP table can be initialized from device tree. The patch adds
a helper function of_init_opp_table together with a binding doc for
that purpose.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'drivers/base')
-rw-r--r-- | drivers/base/power/opp.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index ac993eafec82..d9468642fc41 100644 --- a/drivers/base/power/opp.c +++ b/drivers/base/power/opp.c @@ -22,6 +22,7 @@ #include <linux/rculist.h> #include <linux/rcupdate.h> #include <linux/opp.h> +#include <linux/of.h> /* * Internal data structure organization with the OPP layer library is as @@ -674,3 +675,49 @@ struct srcu_notifier_head *opp_get_notifier(struct device *dev) return &dev_opp->head; } + +#ifdef CONFIG_OF +/** + * of_init_opp_table() - Initialize opp table from device tree + * @dev: device pointer used to lookup device OPPs. + * + * Register the initial OPP table with the OPP library for given device. + */ +int of_init_opp_table(struct device *dev) +{ + const struct property *prop; + const __be32 *val; + int nr; + + prop = of_find_property(dev->of_node, "operating-points", NULL); + if (!prop) + return -ENODEV; + if (!prop->value) + return -ENODATA; + + /* + * Each OPP is a set of tuples consisting of frequency and + * voltage like <freq-kHz vol-uV>. + */ + nr = prop->length / sizeof(u32); + if (nr % 2) { + dev_err(dev, "%s: Invalid OPP list\n", __func__); + return -EINVAL; + } + + val = prop->value; + while (nr) { + unsigned long freq = be32_to_cpup(val++) * 1000; + unsigned long volt = be32_to_cpup(val++); + + if (opp_add(dev, freq, volt)) { + dev_warn(dev, "%s: Failed to add OPP %ld\n", + __func__, freq); + continue; + } + nr -= 2; + } + + return 0; +} +#endif |