lkml.org 
[lkml]   [2015]   [May]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/3 v2] ARM: bcm2835: Add the Raspberry Pi firmware driver

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;
}



\
 
 \ /
  Last update: 2015-05-17 20:41    [W:0.145 / U:0.252 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site