[PATCH v3 03/19] media: venus: pm_helpers: Add kerneldoc to venus_clks_get()

[Konrad Dybcio <konrad.dybcio@linaro.org>]

To make it easier to understand the various clock requirements within
this driver, add kerneldoc to venus_clk_get() explaining the fluff.

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/media/platform/qcom/venus/pm_helpers.c | 28 ++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/media/platform/qcom/venus/pm_helpers.c b/drivers/media/platform/qcom/venus/pm_helpers.c
index ac7c83404c6e..cf91f50a33aa 100644
--- a/drivers/media/platform/qcom/venus/pm_helpers.c
+++ b/drivers/media/platform/qcom/venus/pm_helpers.c
@@ -23,6 +23,34 @@
 
 static bool legacy_binding;
 
+/**
+ * venus_clks_get() - Get Venus clocks that are not bound to a vcodec
+ * @core: A pointer to the venus core resource
+ *
+ * The Venus block (depending on the generation) can be split into a couple
+ * of clock domains: one for main logic and one for each video core (0-2 instances).
+ *
+ * MSM8916 (and possibly other HFIv1 users) only feature the "main logic"
+ * domain, so this function is the only kind if clk_get necessary there.
+ *
+ * MSM8996 (and other HFIv3 users) feature two video cores, with core0 being
+ * statically defined a decoder and core1 an encoder, with both having
+ * their own clock domains.
+ *
+ * SDM845 features two video cores, each one of which may or may not be
+ * subdivided into two encoder/decoder threads.
+ *
+ * Other SoCs either feature a single video core (with its own clock domain)
+ * or one video core and one CVP (Computer Vision Processor) core. In both cases
+ * we treat it the same way (CVP only happens to live near-by Venus on the SoC).
+ *
+ * Due to unfortunate developments in the past, we need to support legacy
+ * bindings (MSM8996, SDM660, SDM845) that require specifying the clocks and
+ * power-domains associated with a video core domain in a bogus sub-node,
+ * which means that additional fluff is necessary..
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
 static int venus_clks_get(struct venus_core *core)
 {
 	const struct venus_resources *res = core->res;

-- 
2.44.0