drm/rockchip: analogix_dp: introduce the pclk for grf

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@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Tomasz Figa <tomasz.figa@chromium.com>

1 files changed, 20 insertions, 3 deletions

diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
index 850edc4d99c8..e81e19a660ad 100644
--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -64,6 +64,7 @@ struct rockchip_dp_device {
         struct drm_display_mode  mode;
 
         struct clk               *pclk;
+        struct clk               *grfclk;
         struct regmap            *grf;
         struct reset_control     *rst;
 
@@ -160,11 +161,17 @@ static void rockchip_dp_drm_encoder_enable(struct drm_encoder *encoder)
 
         dev_dbg(dp->dev, "vop %s output to dp\n", (ret) ? "LIT" : "BIG");
 
-        ret = regmap_write(dp->grf, dp->data->lcdsel_grf_reg, val);
-        if (ret != 0) {
-                dev_err(dp->dev, "Could not write to GRF: %d\n", ret);
+        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)
+                dev_err(dp->dev, "Could not write to GRF: %d\n", ret);
+
+        clk_disable_unprepare(dp->grfclk);
 }
 
 static void rockchip_dp_drm_encoder_nop(struct drm_encoder *encoder)
@@ -234,6 +241,16 @@ static int rockchip_dp_init(struct rockchip_dp_device *dp)
                 return PTR_ERR(dp->grf);
         }
 
+        dp->grfclk = devm_clk_get(dev, "grf");
+        if (PTR_ERR(dp->grfclk) == -ENOENT) {
+                dp->grfclk = NULL;
+        } else if (PTR_ERR(dp->grfclk) == -EPROBE_DEFER) {
+                return -EPROBE_DEFER;
+        } else if (IS_ERR(dp->grfclk)) {
+                dev_err(dev, "failed to get grf clock\n");
+                return PTR_ERR(dp->grfclk);
+        }
+
         dp->pclk = devm_clk_get(dev, "pclk");
         if (IS_ERR(dp->pclk)) {
                 dev_err(dev, "failed to get pclk property\n");