drm/rockchip: Don't change hdmi reference clock rate

The code that changes hdmi->ref_clk was accidentally copied from
downstream code that sets a different clock. We don't actually
want to set any clock here at all.

Setting this clock incorrectly leads to incorrect timings for
DDC, CEC, and HDCP signal generation.

No Fixes listed, as the theoretical timing error in DDC appears to
still be within tolerances and harmless - and HDCP and CEC are not
yet supported.

Signed-off-by: Derek Foreman <derek.foreman@collabora.com>
Reviewed-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20241217201708.3320673-1-derek.foreman@collabora.com

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

@@ -89,7 +89,6 @@ struct rockchip_hdmi_qp {
 	struct regmap *regmap;
 	struct regmap *vo_regmap;
 	struct rockchip_encoder encoder;
-	struct clk *ref_clk;
 	struct dw_hdmi_qp *hdmi;
 	struct phy *phy;
 	struct gpio_desc *enable_gpio;
@@ -122,7 +121,6 @@ static void dw_hdmi_qp_rockchip_encoder_enable(struct drm_encoder *encoder)
 	if (crtc && crtc->state) {
 		rate = drm_hdmi_compute_mode_clock(&crtc->state->adjusted_mode,
 						   8, HDMI_COLORSPACE_RGB);
-		clk_set_rate(hdmi->ref_clk, rate);
 		/*
 		 * FIXME: Temporary workaround to pass pixel clock rate
 		 * to the PHY driver until phy_configure_opts_hdmi
@@ -515,17 +513,6 @@ static int dw_hdmi_qp_rockchip_bind(struct device *dev, struct device *master,
 		return ret;
 	}
 
-	for (i = 0; i < ret; i++) {
-		if (!strcmp(clks[i].id, "ref")) {
-			hdmi->ref_clk = clks[1].clk;
-			break;
-		}
-	}
-	if (!hdmi->ref_clk) {
-		drm_err(hdmi, "Missing ref clock\n");
-		return -EINVAL;
-	}
-
 	hdmi->enable_gpio = devm_gpiod_get_optional(hdmi->dev, "enable",
 						    GPIOD_OUT_HIGH);
 	if (IS_ERR(hdmi->enable_gpio)) {