[PATCH v4 05/10] drm/rockchip: analogix_dp: Enable hclk for RK3588

[Damon Ding]

Acquire and enable the HCLK_VO1 bus clock explicitly for RK3588
eDP controller to guarantee register and datapath access.

The clock was previously enabled implicitly via rockchip,vo-grf
phandle reference, which relies on side effect and is fragile.

Fetch optional "hclk" clock in driver to align with updated device
tree binding and keep consistent with hardware clock dependency.

Fixes: 729f8eefdcad ("drm/rockchip: analogix_dp: Add support for RK3588")
Signed-off-by: Damon Ding <damon.ding at rock-chips.com>

---

Changes in v4:
- Modify the commit msg.
---
 drivers/gpu/drm/rockchip/analogix_dp-rockchip.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
index 41ff44eaf44d..a864bcf8200e 100644
--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -311,6 +311,7 @@ static int rockchip_dp_of_probe(struct rockchip_dp_device *dp)
 {
 	struct device *dev = dp->dev;
 	struct device_node *np = dev->of_node;
+	struct clk *clk;
 
 	dp->grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
 	if (IS_ERR(dp->grf))
@@ -327,6 +328,11 @@ static int rockchip_dp_of_probe(struct rockchip_dp_device *dp)
 		return dev_err_probe(dev, PTR_ERR(dp->pclk),
 				     "failed to get pclk property\n");
 
+	clk = devm_clk_get_optional_enabled(dev, "hclk");
+	if (IS_ERR(clk))
+		return dev_err_probe(dev, PTR_ERR(clk),
+				     "failed to get hclk property\n");
+
 	dp->rst = devm_reset_control_get(dev, "dp");
 	if (IS_ERR(dp->rst))
 		return dev_err_probe(dev, PTR_ERR(dp->rst),
-- 
2.34.1