drm/rockchip: dw_hdmi: Simplify clock handling

Make use of devm_clk_get_optional_enabled() to replace devm_clk_get()
and clk_prepare_enable() for ref_clk and drop the now unnecessary calls
to clk_disable_unprepare().

Additionally, use devm_clk_get_optional() helper for grf_clk to replace
the open coding call to devm_clk_get() followed by the -ENOENT test.
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240813-dw-hdmi-rockchip-cleanup-v1-2-b3e73b5f4fd6@collabora.com

drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c

@@ -209,6 +209,7 @@ static const struct dw_hdmi_phy_config rockchip_phy_config[] = {
 static int rockchip_hdmi_parse_dt(struct rockchip_hdmi *hdmi)
 {
 	struct device_node *np = hdmi->dev->of_node;
+	int ret;
 
 	hdmi->regmap = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
 	if (IS_ERR(hdmi->regmap)) {
@@ -216,25 +217,23 @@ static int rockchip_hdmi_parse_dt(struct rockchip_hdmi *hdmi)
 		return PTR_ERR(hdmi->regmap);
 	}
 
-	hdmi->ref_clk = devm_clk_get_optional(hdmi->dev, "ref");
+	hdmi->ref_clk = devm_clk_get_optional_enabled(hdmi->dev, "ref");
 	if (!hdmi->ref_clk)
-		hdmi->ref_clk = devm_clk_get_optional(hdmi->dev, "vpll");
+		hdmi->ref_clk = devm_clk_get_optional_enabled(hdmi->dev, "vpll");
 
-	if (PTR_ERR(hdmi->ref_clk) == -EPROBE_DEFER) {
-		return -EPROBE_DEFER;
-	} else if (IS_ERR(hdmi->ref_clk)) {
-		drm_err(hdmi, "failed to get reference clock\n");
-		return PTR_ERR(hdmi->ref_clk);
+	if (IS_ERR(hdmi->ref_clk)) {
+		ret = PTR_ERR(hdmi->ref_clk);
+		if (ret != -EPROBE_DEFER)
+			drm_err(hdmi, "failed to get reference clock\n");
+		return ret;
 	}
 
-	hdmi->grf_clk = devm_clk_get(hdmi->dev, "grf");
-	if (PTR_ERR(hdmi->grf_clk) == -ENOENT) {
-		hdmi->grf_clk = NULL;
-	} else if (PTR_ERR(hdmi->grf_clk) == -EPROBE_DEFER) {
-		return -EPROBE_DEFER;
-	} else if (IS_ERR(hdmi->grf_clk)) {
-		drm_err(hdmi, "failed to get grf clock\n");
-		return PTR_ERR(hdmi->grf_clk);
+	hdmi->grf_clk = devm_clk_get_optional(hdmi->dev, "grf");
+	if (IS_ERR(hdmi->grf_clk)) {
+		ret = PTR_ERR(hdmi->grf_clk);
+		if (ret != -EPROBE_DEFER)
+			drm_err(hdmi, "failed to get grf clock\n");
+		return ret;
 	}
 
 	hdmi->avdd_0v9 = devm_regulator_get(hdmi->dev, "avdd-0v9");
@@ -615,12 +614,6 @@ static int dw_hdmi_rockchip_bind(struct device *dev, struct device *master,
 		goto err_avdd_1v8;
 	}
 
-	ret = clk_prepare_enable(hdmi->ref_clk);
-	if (ret) {
-		drm_err(hdmi, "Failed to enable HDMI reference 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 |
@@ -649,8 +642,6 @@ static int dw_hdmi_rockchip_bind(struct device *dev, struct device *master,
 
 err_bind:
 	drm_encoder_cleanup(encoder);
-	clk_disable_unprepare(hdmi->ref_clk);
-err_clk:
 	regulator_disable(hdmi->avdd_1v8);
 err_avdd_1v8:
 	regulator_disable(hdmi->avdd_0v9);
@@ -665,7 +656,6 @@ static void dw_hdmi_rockchip_unbind(struct device *dev, struct device *master,
 
 	dw_hdmi_unbind(hdmi->hdmi);
 	drm_encoder_cleanup(&hdmi->encoder.encoder);
-	clk_disable_unprepare(hdmi->ref_clk);
 
 	regulator_disable(hdmi->avdd_1v8);
 	regulator_disable(hdmi->avdd_0v9);