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drm/vc4: hdmi: Move audio structure offset checks

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The HDMI driver unbind hook doesn't have any ALSA-related code anymore, so
let's move the ALSA sanity checks and comments we have to some other part
of the driver dedicated to ALSA.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220711173939.1132294-47-maxime@cerno.tech
This commit is contained in:
Maxime Ripard
2022-07-11 19:39:16 +02:00
parent af8a3b125b
commit 0c9d0ddd9c
1 changed files with 20 additions and 20 deletions
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40
drivers/gpu/drm/vc4/vc4_hdmi.c
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@@ -2076,6 +2076,26 @@ static int vc4_hdmi_audio_init(struct vc4_hdmi *vc4_hdmi)
int index, len;
int ret;
/*
* ASoC makes it a bit hard to retrieve a pointer to the
* vc4_hdmi structure. Registering the card will overwrite our
* device drvdata with a pointer to the snd_soc_card structure,
* which can then be used to retrieve whatever drvdata we want
* to associate.
*
* However, that doesn't fly in the case where we wouldn't
* register an ASoC card (because of an old DT that is missing
* the dmas properties for example), then the card isn't
* registered and the device drvdata wouldn't be set.
*
* We can deal with both cases by making sure a snd_soc_card
* pointer and a vc4_hdmi structure are pointing to the same
* memory address, so we can treat them indistinctly without any
* issue.
*/
BUILD_BUG_ON(offsetof(struct vc4_hdmi_audio, card) != 0);
BUILD_BUG_ON(offsetof(struct vc4_hdmi, audio) != 0);
if (!of_find_property(dev->of_node, "dmas", &len) || !len) {
dev_warn(dev,
"'dmas' DT property is missing or empty, no HDMI audio\n");
@@ -3082,26 +3102,6 @@ err_disable_runtime_pm:
static void vc4_hdmi_unbind(struct device *dev, struct device *master,
void *data)
{
/*
* ASoC makes it a bit hard to retrieve a pointer to the
* vc4_hdmi structure. Registering the card will overwrite our
* device drvdata with a pointer to the snd_soc_card structure,
* which can then be used to retrieve whatever drvdata we want
* to associate.
*
* However, that doesn't fly in the case where we wouldn't
* register an ASoC card (because of an old DT that is missing
* the dmas properties for example), then the card isn't
* registered and the device drvdata wouldn't be set.
*
* We can deal with both cases by making sure a snd_soc_card
* pointer and a vc4_hdmi structure are pointing to the same
* memory address, so we can treat them indistinctly without any
* issue.
*/
BUILD_BUG_ON(offsetof(struct vc4_hdmi_audio, card) != 0);
BUILD_BUG_ON(offsetof(struct vc4_hdmi, audio) != 0);
pm_runtime_disable(dev);
}