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Subject[PATCH v2 4/4] drm/rockchip: dw_hdmi: introduce the pclk for grf
Date
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>
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>

Changes in v2: describe grf on Documentation.
---

.../bindings/display/rockchip/dw_hdmi-rockchip.txt | 1 +
drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c | 18 ++++++++++++++++++
2 files changed, 19 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt b/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt
index b76b7ee..b4ef61a 100644
--- a/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt
+++ b/Documentation/devicetree/bindings/display/rockchip/dw_hdmi-rockchip.txt
@@ -30,6 +30,7 @@ Optional properties
I2C master controller.
- clock-names: See dw_hdmi.txt. The "cec" clock is optional.
- clock-names: May contain "cec" as defined in dw_hdmi.txt.
+- clock-names: May contain "grf", power for grf io.
- clock-names: May contain "vpll", external clock for some hdmi phy.

Example:
diff --git a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
index 69256cf..a090fc6 100644
--- a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
@@ -47,6 +47,7 @@ struct rockchip_hdmi {
struct drm_encoder encoder;
const struct rockchip_hdmi_chip_data *chip_data;
struct clk *vpll_clk;
+ struct clk *grf_clk;
};

#define to_rockchip_hdmi(x) container_of(x, struct rockchip_hdmi, x)
@@ -181,6 +182,16 @@ static int rockchip_hdmi_parse_dt(struct rockchip_hdmi *hdmi)
return PTR_ERR(hdmi->vpll_clk);
}

+ 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)) {
+ dev_err(hdmi->dev, "failed to get grf clock\n");
+ return PTR_ERR(hdmi->grf_clk);
+ }
+
ret = clk_prepare_enable(hdmi->vpll_clk);
if (ret) {
dev_err(hdmi->dev, "Failed to enable HDMI vpll: %d\n", ret);
@@ -246,10 +257,17 @@ static void dw_hdmi_rockchip_encoder_enable(struct drm_encoder *encoder)
else
val = hdmi->chip_data->lcdsel_big;

+ ret = clk_prepare_enable(hdmi->grf_clk);
+ if (ret < 0) {
+ dev_err(hdmi->dev, "failed to enable grfclk %d\n", ret);
+ return;
+ }
+
ret = regmap_write(hdmi->regmap, hdmi->chip_data->lcdsel_grf_reg, val);
if (ret != 0)
dev_err(hdmi->dev, "Could not write to GRF: %d\n", ret);

+ clk_disable_unprepare(hdmi->grf_clk);
dev_dbg(hdmi->dev, "vop %s output to hdmi\n",
ret ? "LIT" : "BIG");
}
--
1.9.1

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