Den 25.08.2016 15:09, skrev Rob Herring:
> On Mon, Aug 22, 2016 at 3:25 PM, Noralf Trønnes <noralf at tronnes.org>
> wrote:
>> The SimpleDRM driver binds to simple-framebuffer devices and provides a
>> DRM/KMS API. It provides only a single CRTC+encoder+connector combination
>> plus one initial mode.
>>
>> Userspace can create dumb-buffers which can be blit into the real
>> framebuffer similar to UDL. No access to the real framebuffer is allowed
>> (compared to earlier version of this driver) to avoid security issues.
>> Furthermore, this way we can support arbitrary modes as long as we have a
>> conversion-helper.
>>
>> The driver was originally written by David Herrmann in 2014.
>> My main contribution is to make use of drm_simple_kms_helper and
>> rework the probe path to avoid use of the deprecated drm_platform_init()
>> and drm_driver.{load,unload}().
>> Additions have also been made for later changes to the Device Tree binding
>> document, like support for clocks, regulators and having the node under
>> /chosen. This code was lifted verbatim from simplefb.c.
>>
>> Cc: dh.herrmann at gmail.com
>> Cc: libv at skynet.be
>> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
> [...]
>
>> + /* Count the number of regulator supplies */
>> + for_each_property_of_node(np, prop) {
>> + p = strstr(prop->name, SUPPLY_SUFFIX);
>> + if (p && p != prop->name)
>> + count++;
>> + }
> The regulator API should have functions for this rather than open coding it.
I couldn't find anything that matches this usecase. There are regulator
bulk functions, but they require the names to be known in advance.
And I don't know how many regulators there are nor their names.
>From Documentation/devicetree/bindings/display/simple-framebuffer.txt:
- *-supply : Any number of regulators used by the framebuffer. These should
be named according to the names in the device's design.
>> +
>> + if (!count)
>> + return 0;
>> +
>> + sdrm->regulators = devm_kcalloc(&pdev->dev, count,
>> + sizeof(struct regulator *),
>> + GFP_KERNEL);
>> + if (!sdrm->regulators)
>> + return -ENOMEM;
>> +
>> + /* Get all the regulators */
>> + for_each_property_of_node(np, prop) {
>> + char name[32]; /* 32 is max size of property name */
>> +
>> + p = strstr(prop->name, SUPPLY_SUFFIX);
>> + if (!p || p == prop->name)
>> + continue;
> This too.
>
>> +
>> + strlcpy(name, prop->name,
>> + strlen(prop->name) - strlen(SUPPLY_SUFFIX) + 1);
>> + regulator = devm_regulator_get_optional(&pdev->dev, name);
> [...]
>
>> + if (IS_ENABLED(CONFIG_OF_ADDRESS) && of_chosen) {
>> + struct device_node *np;
>> +
>> + for_each_child_of_node(of_chosen, np) {
>> + if (of_device_is_compatible(np,
>> "simple-framebuffer"))
> Rather than exporting of_chosen, this whole chunk can be replaced with
> a of_find_compatible_node call. Yes, that would match if
> simple-framebuffer exists somewhere else in the DT, but it is not the
> kernel's job to do DT validation.
This seems to do the job:
/*
* The binding doc states that simplefb nodes should be sub-nodes of
* chosen and that older devicetree files can have them in a different
* place. of_platform_device_create() just returns NULL if a device
* has already been created for the node.
*/
for_each_compatible_node(np, NULL, "simple-framebuffer")
of_platform_device_create(np, NULL, NULL);
Noralf.
>> + of_platform_device_create(np, NULL, NULL);
>> + }
>> + }
> Rob
>
