[PATCH v3 3/4] drm/rockchip/dsi: enable the grf clk before writing grf registers

From: Chris Zhong
Date: Fri Mar 17 2017 - 00:02:58 EST


For RK3399, the grf clk should be enabled before writing grf registers,
otherwise the register value can not be changed.

Signed-off-by: Chris Zhong <zyw@xxxxxxxxxxxxxx>
---

Changes in v3:
- add a DW_MIPI_NEEDS_GRF_CLK for RK3399

Changes in v2:
- check the grf_clk only for RK3399

drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
index 68f48b0..5a18281 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
@@ -252,6 +252,7 @@
#define THS_ZERO_PROGRAM_EN BIT(6)

#define DW_MIPI_NEEDS_PHY_CFG_CLK BIT(0)
+#define DW_MIPI_NEEDS_GRF_CLK BIT(1)

enum {
BANDGAP_97_07,
@@ -294,6 +295,7 @@ struct dw_mipi_dsi {
struct regmap *grf_regmap;
void __iomem *base;

+ struct clk *grf_clk;
struct clk *pllref_clk;
struct clk *pclk;
struct clk *phy_cfg_clk;
@@ -982,6 +984,17 @@ static void dw_mipi_dsi_encoder_enable(struct drm_encoder *encoder)
dw_mipi_dsi_dphy_interface_config(dsi);
dw_mipi_dsi_clear_err(dsi);

+ /*
+ * For the RK3399, the clk of grf must be enabled before writing grf
+ * register. And for RK3288 or other soc, this grf_clk must be NULL,
+ * the clk_prepare_enable return true directly.
+ */
+ ret = clk_prepare_enable(dsi->grf_clk);
+ if (ret) {
+ dev_err(dsi->dev, "Failed to enable grf_clk\n");
+ return;
+ }
+
if (pdata->grf_dsi0_mode_reg)
regmap_write(dsi->grf_regmap, pdata->grf_dsi0_mode_reg,
pdata->grf_dsi0_mode);
@@ -1006,6 +1019,8 @@ static void dw_mipi_dsi_encoder_enable(struct drm_encoder *encoder)
regmap_write(dsi->grf_regmap, pdata->grf_switch_reg, val);
dev_dbg(dsi->dev, "vop %s output to dsi0\n", (mux) ? "LIT" : "BIG");
dsi->dpms_mode = DRM_MODE_DPMS_ON;
+
+ clk_disable_unprepare(dsi->grf_clk);
}

static int
@@ -1139,7 +1154,7 @@ static struct dw_mipi_dsi_plat_data rk3399_mipi_dsi_drv_data = {
.grf_switch_reg = RK3399_GRF_SOC_CON19,
.grf_dsi0_mode = RK3399_GRF_DSI_MODE,
.grf_dsi0_mode_reg = RK3399_GRF_SOC_CON22,
- .flags = DW_MIPI_NEEDS_PHY_CFG_CLK,
+ .flags = DW_MIPI_NEEDS_PHY_CFG_CLK | DW_MIPI_NEEDS_GRF_CLK,
.max_data_lanes = 4,
};

@@ -1240,6 +1255,15 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
}
}

+ if (pdata->flags & DW_MIPI_NEEDS_GRF_CLK) {
+ dsi->grf_clk = devm_clk_get(dev, "grf");
+ if (IS_ERR(dsi->grf_clk)) {
+ ret = PTR_ERR(dsi->grf_clk);
+ dev_err(dev, "Unable to get grf_clk: %d\n", ret);
+ return ret;
+ }
+ }
+
ret = clk_prepare_enable(dsi->pllref_clk);
if (ret) {
dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);
--
2.6.3