[PATCH v2 4/7] drm/rockchip: dsi: Support optional AHB clock

[Alex Bee <knaerzche@xxxxxxxxx>]

Some integrations of the IP additionally have an AHB clock which has to be
enabled before accessing the registers is possible.

Add support for it as an optional clock.

Signed-off-by: Alex Bee <knaerzche@xxxxxxxxx>
---
changes since v1:
 - new patch

 .../gpu/drm/rockchip/dw-mipi-dsi-rockchip.c   | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
index 4cc8ed8f4fbd..6ed64cc35275 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
@@ -265,6 +265,7 @@ struct dw_mipi_dsi_rockchip {
 	struct clk *pllref_clk;
 	struct clk *grf_clk;
 	struct clk *phy_cfg_clk;
+	struct clk *ahb_clk;
 
 	/* dual-channel */
 	bool is_slave;
@@ -1153,7 +1154,15 @@ static int dw_mipi_dsi_dphy_init(struct phy *phy)
 			goto err_init;
 		}
 
+		ret = clk_prepare_enable(dsi->ahb_clk);
+		if (ret) {
+			clk_disable_unprepare(dsi->grf_clk);
+			clk_disable_unprepare(dsi->pclk);
+			goto err_init;
+		}
+
 		ret = dsi->cdata->dphy_rx_init(phy);
+		clk_disable_unprepare(dsi->ahb_clk);
 		clk_disable_unprepare(dsi->grf_clk);
 		clk_disable_unprepare(dsi->pclk);
 		if (ret < 0)
@@ -1240,6 +1249,12 @@ static int dw_mipi_dsi_dphy_power_on(struct phy *phy)
 		goto err_phy_cfg_clk;
 	}
 
+	ret = clk_prepare_enable(dsi->ahb_clk);
+	if (ret) {
+		DRM_DEV_ERROR(dsi->dev, "Failed to enable ahb_clk: %d\n", ret);
+		goto err_ahb_clk;
+	}
+
 	/* do soc-variant specific init */
 	if (dsi->cdata->dphy_rx_power_on) {
 		ret = dsi->cdata->dphy_rx_power_on(phy);
@@ -1269,6 +1284,8 @@ static int dw_mipi_dsi_dphy_power_on(struct phy *phy)
 	return ret;
 
 err_pwr_on:
+	clk_disable_unprepare(dsi->ahb_clk);
+err_ahb_clk:
 	clk_disable_unprepare(dsi->phy_cfg_clk);
 err_phy_cfg_clk:
 	clk_disable_unprepare(dsi->grf_clk);
@@ -1296,6 +1313,7 @@ static int dw_mipi_dsi_dphy_power_off(struct phy *phy)
 			DRM_DEV_ERROR(dsi->dev, "hardware-specific phy shutdown failed: %d\n", ret);
 	}
 
+	clk_disable_unprepare(dsi->ahb_clk);
 	clk_disable_unprepare(dsi->grf_clk);
 	clk_disable_unprepare(dsi->pclk);
 
@@ -1429,6 +1447,13 @@ static int dw_mipi_dsi_rockchip_probe(struct platform_device *pdev)
 		}
 	}
 
+	dsi->ahb_clk = devm_clk_get_optional(dev, "ahb");
+	if (IS_ERR(dsi->ahb_clk)) {
+		ret = PTR_ERR(dsi->ahb_clk);
+		DRM_DEV_ERROR(dev, "Unable to get ahb_clk: %d\n", ret);
+		return ret;
+	}
+
 	dsi->grf_regmap = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
 	if (IS_ERR(dsi->grf_regmap)) {
 		DRM_DEV_ERROR(dev, "Unable to get rockchip,grf\n");
-- 
2.43.2