On Tue, Sep 26, 2017 at 5:56 PM, Maxime Ripard
[off-list ref] wrote:

Hi,

On Tue, Sep 26, 2017 at 06:59:09AM +0000, Chen-Yu Tsai wrote:

quoted

On systems with 2 TCONs such as the A31, it is possible to demux the
output of the TCONs to one encoder.

Add support for this for the A31.

Signed-off-by: Chen-Yu Tsai <redacted>
---
 drivers/gpu/drm/sun4i/sun4i_tcon.c | 61 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index e853dfe51389..770b843a6fa9 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c

@@ -14,9 +14,12 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_encoder.h>
 #include <drm/drm_modes.h>
 #include <drm/drm_of.h>

+#include <uapi/drm/drm_mode.h>
+
 #include <linux/component.h>
 #include <linux/ioport.h>
 #include <linux/of_address.h>

@@ -109,11 +112,69 @@ void sun4i_tcon_enable_vblank(struct sun4i_tcon *tcon, bool enable)
 }
 EXPORT_SYMBOL(sun4i_tcon_enable_vblank);

+static struct sun4i_tcon *sun4i_get_first_tcon(struct drm_device *drm)
+{
+     struct sun4i_drv *drv = drm->dev_private;
+     struct sun4i_tcon *tcon;
+
+     list_for_each_entry(tcon, &drv->tcon_list, list)
+             if (tcon->id == 0)
+                     return tcon;
+
+     dev_warn(drm->dev,
+              "TCON0 not found, display output muxing may not work\n");
+
+     return tcon;
+}
+
+static int _sun6i_tcon_set_mux(struct drm_encoder *encoder)
+{
+     struct sun4i_tcon *tcon = sun4i_get_first_tcon(encoder->dev);
+     int tcon_id = drm_crtc_to_sun4i_crtc(encoder->crtc)->tcon->id;
+     u32 shift;
+
+     DRM_DEBUG_DRIVER("Muxing encoder %s to CRTC %s (TCON %d)\n",
+                      encoder->name, encoder->crtc->name, tcon_id);
+
+     /* Only 2 TCONs */
+     if (tcon_id >= 2)
+             return -EINVAL;
+
+     switch (encoder->encoder_type) {
+     case DRM_MODE_ENCODER_TMDS:
+             /* HDMI */
+             shift = 8;
+             break;
+     case DRM_MODE_ENCODER_DSI:
+             /* No MIPI DSI on A31s */
+             if (of_device_is_compatible(tcon->dev->of_node,
+                                         "allwinner,sun6i-a31s-tcon"))

I'm not sure that test is needed.

We won't end up in that case if we don't have a connected DSI block,
which isn't going to be the case on the A31. And I guess we can tackle
DSI later (when I'll send my patches...).

OK. I'll leave a comment instead.

quoted

+                     return -EINVAL;
+             shift = 0;
+             break;
+     default:
+             return -EINVAL;
+     }
+
+     regmap_update_bits(tcon->regs, SUN4I_TCON_MUX_CTRL_REG,
+                        0x3 << shift, tcon_id << shift);
+
+     return 0;
+}
+
 void sun4i_tcon_set_mux(struct sun4i_tcon *tcon, int channel,
                      struct drm_encoder *encoder)
 {
+     /* Get the device node of the display engine */
+     struct device_node *node = encoder->dev->dev->of_node;
      u32 val;

+     if (of_device_is_compatible(node, "allwinner,sun6i-a31-display-engine") ||
+         of_device_is_compatible(node, "allwinner,sun6i-a31s-display-engine")) {
+             _sun6i_tcon_set_mux(encoder);
+             return;
+     }
+

I'd really like to avoid mix and matching the structure defined
behaviour and those of_device_is_compatible calls spread out
everywhere.

You can either add a flag or a function pointer.

Function pointer it is!

ChenYu