[PATCH v3.1 1/2] drm/rockchip: analogix_dp: introduce the pclk for grf

[Yakir Yang]

For RK3399's GRF module, if we want to operate the graphic related grf
registers, we need to enable the pclk_vio_grf which supply power for VIO
GRF IOs, so it's better to introduce an optional grf clock in driver.

Signed-off-by: Yakir Yang <ykk@xxxxxxxxxxxxxx>
---
Hi all,

This is an external patch for analogix_dp misc cleanup thread [0]
[0]: https://patchwork.kernel.org/patch/9175613/

BR,
- Yakir

 drivers/gpu/drm/rockchip/analogix_dp-rockchip.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
index 787dc51..6a83f1a 100644
--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -56,6 +56,7 @@ struct rockchip_dp_device {
 	struct drm_display_mode  mode;
 
 	struct clk               *pclk;
+	struct clk               *grfclk;
 	struct regmap            *grf;
 	struct reset_control     *rst;
 
@@ -151,11 +152,20 @@ static void rockchip_dp_drm_encoder_enable(struct drm_encoder *encoder)
 
 	dev_dbg(dp->dev, "vop %s output to dp\n", (ret) ? "LIT" : "BIG");
 
+	if (dp->grfclk) {
+		ret = clk_prepare_enable(dp->grfclk);
+		if (ret < 0) {
+			dev_err(dp->dev, "failed to enable grfclk %d\n", ret);
+			return;
+		}
+	}
+
 	ret = regmap_write(dp->grf, dp->data->lcdsel_grf_reg, val);
-	if (ret != 0) {
+	if (ret != 0)
 		dev_err(dp->dev, "Could not write to GRF: %d\n", ret);
-		return;
-	}
+
+	if (dp->grfclk)
+		clk_disable_unprepare(dp->grfclk);
 }
 
 static void rockchip_dp_drm_encoder_nop(struct drm_encoder *encoder)
@@ -235,6 +245,10 @@ static int rockchip_dp_init(struct rockchip_dp_device *dp)
 		return PTR_ERR(dp->grf);
 	}
 
+	dp->grfclk = devm_clk_get(dev, "grf");
+	if (IS_ERR(dp->grfclk))
+		dp->grfclk = NULL;
+
 	dp->pclk = devm_clk_get(dev, "pclk");
 	if (IS_ERR(dp->pclk)) {
 		dev_err(dev, "failed to get pclk property\n");
-- 
1.9.1