Messages in this thread | | | Date | Sun, 17 May 2015 20:26:08 +0200 | From | Noralf Trønnes <> | Subject | Re: [PATCH 2/3 v2] ARM: bcm2835: Add the Raspberry Pi firmware driver |
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Den 13.05.2015 21:00, skrev Eric Anholt: > This gives us a function for making mailbox property channel requests > of the firmware, which is most notable in that it will let us get and > set clock rates. > > Signed-off-by: Eric Anholt <eric@anholt.net> > ---
[...]
> +/* > + * Submits a single tag to the VPU firmware through the mailbox > + * property interface. > + * > + * This is a convenience wrapper around > + * rpi_firmware_property_list() to avoid some of the > + * boilerplate in property calls. > + */ > +int rpi_firmware_property(struct device_node *of_node, > + u32 tag, void *tag_data, size_t buf_size)
To use the firmware property functions, I need a DT node pointer. Since Device Tree is dynamic now, should I fetch the firmware node each time, or should I do that in probe and store the node pointer?
Device Tree: firmware: firmware { compatible = "raspberrypi,firmware"; };
thermal { compatible = "brcm,bcm2835-thermal"; firmware = <&firmware>; };
Rewritten (not tested) function from downstream bcm2835-thermal driver:
static int bcm2835_get_temp_or_max(struct thermal_zone_device *thermal_dev, unsigned long *temp, unsigned tag_id) { struct device *dev = <get device somehow>; struct device_node *np; struct { u32 id; u32 val; } tag_buf;
np = of_parse_phandle(dev->of_node, "firmware", 0); if (!np) return -EINVAL;
ret = rpi_firmware_property(np, tag_id, &tag_buf, sizeof(tag_buf)); if (ret) return ret;
*temp = val;
return 0; }
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