On Friday, August 10, 2012, Shawn Guo wrote:
> 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@xxxxxxxxxx>
I need an ACK from whoever maintains the DT bindings for that.
Thanks,
Rafael
> ---
> Documentation/devicetree/bindings/power/opp.txt | 25 ++++++++++++
> drivers/base/power/opp.c | 47 +++++++++++++++++++++++
> include/linux/opp.h | 8 ++++
> 3 files changed, 80 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..74499e5
> --- /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 2-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..d946864 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
> 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)
> {
>
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