[PATCH 4/4] drm/tidss: Fix sampling edge configuration

[Louis Chauvet]

As stated in the AM62x Technical Reference Manual (SPRUIV7B), the data
sampling edge needs to be configured in two distinct registers: one in the
TIDSS IP and another in the memory-mapped control register modules. Since
the latter is not within the same address range, a phandle to a syscon
device is used to access the regmap.

Fixes: 32a1795f57ee ("drm/tidss: New driver for TI Keystone platform Display 
SubSystem")
Signed-off-by: Louis Chauvet <louis.chau...@bootlin.com>

---

Cc: sta...@vger.kernel.org
---
 drivers/gpu/drm/tidss/tidss_dispc.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c 
b/drivers/gpu/drm/tidss/tidss_dispc.c
index 
c0277fa36425ee1f966dccecf2b69a2d01794899..65ca7629a2e75437023bf58f8a1bddc24db5e3da
 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.c
+++ b/drivers/gpu/drm/tidss/tidss_dispc.c
@@ -498,6 +498,7 @@ struct dispc_device {
        const struct dispc_features *feat;
 
        struct clk *fclk;
+       struct regmap *clk_ctrl;
 
        bool is_enabled;
 
@@ -1267,6 +1268,11 @@ void dispc_vp_enable(struct dispc_device *dispc, u32 
hw_videoport,
                       FLD_VAL(mode->vdisplay - 1, 27, 16));
 
        VP_REG_FLD_MOD(dispc, hw_videoport, DISPC_VP_CONTROL, 1, 0, 0);
+
+       if (dispc->clk_ctrl) {
+               regmap_update_bits(dispc->clk_ctrl, 0, 0x100, ipc ? 0x100 : 
0x000);
+               regmap_update_bits(dispc->clk_ctrl, 0, 0x200, rf ? 0x200 : 
0x000);
+       }
 }
 
 void dispc_vp_disable(struct dispc_device *dispc, u32 hw_videoport)
@@ -3012,6 +3018,14 @@ int dispc_init(struct tidss_device *tidss)
 
        dispc_init_errata(dispc);
 
+       dispc->clk_ctrl = 
syscon_regmap_lookup_by_phandle_optional(tidss->dev->of_node,
+                                                                  
"ti,clk-ctrl");
+       if (IS_ERR(dispc->clk_ctrl)) {
+               r = dev_err_probe(dispc->dev, PTR_ERR(dispc->clk_ctrl),
+                                 "DISPC: syscon_regmap_lookup_by_phandle 
failed.\n");
+               return r;
+       }
+
        dispc->fourccs = devm_kcalloc(dev, ARRAY_SIZE(dispc_color_formats),
                                      sizeof(*dispc->fourccs), GFP_KERNEL);
        if (!dispc->fourccs)

-- 
2.50.1