[PATCH v6 09/23] drm/rockchip: dw_hdmi: Add support for hclk

[Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>]

The rk3568 HDMI has an additional clock that needs to be enabled for the
HDMI controller to work. The purpose of that clock is not clear. It is
named "hclk" in the downstream driver, so use the same name.

Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---

Notes:
    Changes since v5:
    - Use devm_clk_get_optional rather than devm_clk_get

 drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
index 11acd4668ebef..45f66fd613a6d 100644
--- a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
@@ -76,6 +76,7 @@ struct rockchip_hdmi {
 	const struct rockchip_hdmi_chip_data *chip_data;
 	struct clk *ref_clk;
 	struct clk *grf_clk;
+	struct clk *hclk_clk;
 	struct dw_hdmi *hdmi;
 	struct regulator *avdd_0v9;
 	struct regulator *avdd_1v8;
@@ -231,6 +232,14 @@ static int rockchip_hdmi_parse_dt(struct rockchip_hdmi *hdmi)
 		return PTR_ERR(hdmi->grf_clk);
 	}
 
+	hdmi->hclk_clk = devm_clk_get_optional(hdmi->dev, "hclk");
+	if (PTR_ERR(hdmi->hclk_clk) == -EPROBE_DEFER) {
+		return -EPROBE_DEFER;
+	} else if (IS_ERR(hdmi->hclk_clk)) {
+		DRM_DEV_ERROR(hdmi->dev, "failed to get hclk_clk clock\n");
+		return PTR_ERR(hdmi->hclk_clk);
+	}
+
 	hdmi->avdd_0v9 = devm_regulator_get(hdmi->dev, "avdd-0v9");
 	if (IS_ERR(hdmi->avdd_0v9))
 		return PTR_ERR(hdmi->avdd_0v9);
@@ -598,6 +607,13 @@ static int dw_hdmi_rockchip_bind(struct device *dev, struct device *master,
 		goto err_clk;
 	}
 
+	ret = clk_prepare_enable(hdmi->hclk_clk);
+	if (ret) {
+		DRM_DEV_ERROR(hdmi->dev, "Failed to enable HDMI hclk clock: %d\n",
+			      ret);
+		goto err_clk;
+	}
+
 	if (hdmi->chip_data == &rk3568_chip_data) {
 		regmap_write(hdmi->regmap, RK3568_GRF_VO_CON1,
 			     HIWORD_UPDATE(RK3568_HDMI_SDAIN_MSK |
-- 
2.30.2