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 <[email protected]> --- Documentation/devicetree/bindings/power/opp.txt | 25 +++++++++ drivers/base/power/opp.c | 65 +++++++++++++++++++++++ include/linux/opp.h | 8 +++ 3 files changed, 98 insertions(+), 0 deletions(-) create mode 100644 Documentation/devicetree/bindings/power/opp.txt diff --git a/Documentation/devicetree/bindings/power/opp.txt b/Documentation/devicetree/bindings/power/opp.txt new file mode 100644 index 0000000..2238520 --- /dev/null +++ b/Documentation/devicetree/bindings/power/opp.txt @@ -0,0 +1,25 @@ +* Generic OPP Interface + +SoCs have a standard set of tuples consisting of frequency and +voltage pairs that the device will support per voltage domain. These +are called Operating Performance Points or OPPs. + +Properties: +- operating-points: An array of 3-tuples items, and each item consists + of frequency and voltage like <freq-kHz vol-uV>. + freq: clock frequency in kHz + vol: voltage in microvolt + +Examples: + +cpu@0 { + compatible = "arm,cortex-a9"; + reg = <0>; + next-level-cache = <&L2>; + operating-points = < + /* kHz uV */ + 792000 1100000 + 396000 950000 + 198000 850000 + >; +}; diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index ac993ea..1bf1be8 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 +675,67 @@ 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) +{ + struct device_node *np = dev->of_node; + const char *propname = "operating-points"; + const struct property *pp; + u32 *opp; + int ret, i, nr; + + pp = of_find_property(np, propname, NULL); + if (!pp) { + dev_err(dev, "%s: Unable to find property", __func__); + return -ENODEV; + } + + opp = kzalloc(pp->length, GFP_KERNEL); + if (!opp) { + dev_err(dev, "%s: Unable to allocate array\n", __func__); + return -ENOMEM; + } + + nr = pp->length / sizeof(u32); + ret = of_property_read_u32_array(np, propname, opp, nr); + if (ret) { + dev_err(dev, "%s: Unable to read OPPs\n", __func__); + goto out; + } + + if (nr % 2) { + dev_err(dev, "%s: Invalid OPP list\n", __func__); + ret = -EINVAL; + goto out; + } + + nr /= 2; + for (i = 0; i < nr; i++) { + /* + * Each OPP is a set of tuples consisting of frequency and + * voltage like <freq-kHz vol-uV>. + */ + u32 *val = opp + i * 2; + + val[0] *= 1000; + ret = opp_add(dev, val[0], val[1]); + if (ret) { + dev_warn(dev, "%s: Failed to add OPP %d: %d\n", + __func__, val[0], ret); + continue; + } + } + + ret = 0; +out: + kfree(opp); + return ret; +} +#endif diff --git a/include/linux/opp.h b/include/linux/opp.h index 2a4e5fa..214e0eb 100644 --- a/include/linux/opp.h +++ b/include/linux/opp.h @@ -48,6 +48,14 @@ int opp_disable(struct device *dev, unsigned long freq); struct srcu_notifier_head *opp_get_notifier(struct device *dev); +#ifdef CONFIG_OF +int of_init_opp_table(struct device *dev); +#else +static inline int of_init_opp_table(struct device *dev) +{ + return -EINVAL; +} +#endif /* CONFIG_OF */ #else static inline unsigned long opp_get_voltage(struct opp *opp) { -- 1.7.5.4 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
