drm/sun4i: Use lists to track registered display backends and TCONs

To support multiple display pipelines, we need to keep track of the
multiple display backends and TCONs registered with the driver.

Switch to lists to track registered components. Components are only
appended to their respective lists if the bind process was successful.
The TCON bind function now defers if a backend was not registered.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

6 files changed, 30 insertions, 5 deletions

diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
index d660741ba475..95a77c6a9161 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
@@ -19,6 +19,7 @@
 #include <drm/drm_plane_helper.h>
 
 #include <linux/component.h>
+#include <linux/list.h>
 #include <linux/reset.h>
 
 #include "sun4i_backend.h"
@@ -310,7 +311,6 @@ static int sun4i_backend_bind(struct device *dev, struct device *master,
         if (!backend)
                 return -ENOMEM;
         dev_set_drvdata(dev, backend);
-        drv->backend = backend;
 
         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         regs = devm_ioremap_resource(dev, res);
@@ -369,6 +369,8 @@ static int sun4i_backend_bind(struct device *dev, struct device *master,
                 }
         }
 
+        list_add_tail(&backend->list, &drv->backend_list);
+
         /* Reset the registers */
         for (i = 0x800; i < 0x1000; i += 4)
                 regmap_write(backend->regs, i, 0);
@@ -400,6 +402,8 @@ static void sun4i_backend_unbind(struct device *dev, struct device *master,
 {
         struct sun4i_backend *backend = dev_get_drvdata(dev);
 
+        list_del(&backend->list);
+
         if (of_device_is_compatible(dev->of_node,
                                     "allwinner,sun8i-a33-display-backend"))
                 sun4i_backend_free_sat(dev);
diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.h b/drivers/gpu/drm/sun4i/sun4i_backend.h
index 83e63cc702b4..9c8287309c65 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.h
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.h
@@ -14,6 +14,7 @@
 #define _SUN4I_BACKEND_H_
 
 #include <linux/clk.h>
+#include <linux/list.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
 
@@ -149,6 +150,9 @@ struct sun4i_backend {
 
         struct clk              *sat_clk;
         struct reset_control    *sat_reset;
+
+        /* Backend list management */
+        struct list_head        list;
 };
 
 void sun4i_backend_apply_color_correction(struct sun4i_backend *backend);
diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.c b/drivers/gpu/drm/sun4i/sun4i_drv.c
index 8ddd72cd5873..c52f7a9eb045 100644
--- a/drivers/gpu/drm/sun4i/sun4i_drv.c
+++ b/drivers/gpu/drm/sun4i/sun4i_drv.c
@@ -91,6 +91,8 @@ static int sun4i_drv_bind(struct device *dev)
                 goto free_drm;
         }
         drm->dev_private = drv;
+        INIT_LIST_HEAD(&drv->backend_list);
+        INIT_LIST_HEAD(&drv->tcon_list);
 
         ret = of_reserved_mem_device_init(dev);
         if (ret && ret != -ENODEV) {
diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.h b/drivers/gpu/drm/sun4i/sun4i_drv.h
index 5df50126ff52..250c29017ef5 100644
--- a/drivers/gpu/drm/sun4i/sun4i_drv.h
+++ b/drivers/gpu/drm/sun4i/sun4i_drv.h
@@ -14,11 +14,12 @@
 #define _SUN4I_DRV_H_
 
 #include <linux/clk.h>
+#include <linux/list.h>
 #include <linux/regmap.h>
 
 struct sun4i_drv {
-        struct sun4i_backend    *backend;
-        struct sun4i_tcon       *tcon;
+        struct list_head        backend_list;
+        struct list_head        tcon_list;
 
         struct drm_fbdev_cma    *fbdev;
 };
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 9a83a85529ac..5adb643ed41d 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -25,6 +25,7 @@
 #include <linux/regmap.h>
 #include <linux/reset.h>
 
+#include "sun4i_backend.h"
 #include "sun4i_crtc.h"
 #include "sun4i_dotclock.h"
 #include "sun4i_drv.h"
@@ -407,14 +408,18 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
 {
         struct drm_device *drm = data;
         struct sun4i_drv *drv = drm->dev_private;
+        struct sun4i_backend *backend;
         struct sun4i_tcon *tcon;
         int ret;
 
+        /* Wait for a backend to be registered */
+        if (list_empty(&drv->backend_list))
+                return -EPROBE_DEFER;
+
         tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
         if (!tcon)
                 return -ENOMEM;
         dev_set_drvdata(dev, tcon);
-        drv->tcon = tcon;
         tcon->drm = drm;
         tcon->dev = dev;
         tcon->quirks = of_device_get_match_data(dev);
@@ -459,7 +464,9 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
                 goto err_free_dotclock;
         }
 
-        tcon->crtc = sun4i_crtc_init(drm, drv->backend, tcon);
+        backend = list_first_entry(&drv->backend_list,
+                                   struct sun4i_backend, list);
+        tcon->crtc = sun4i_crtc_init(drm, backend, tcon);
         if (IS_ERR(tcon->crtc)) {
                 dev_err(dev, "Couldn't create our CRTC\n");
                 ret = PTR_ERR(tcon->crtc);
@@ -470,6 +477,8 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
         if (ret < 0)
                 goto err_free_clocks;
 
+        list_add_tail(&tcon->list, &drv->tcon_list);
+
         return 0;
 
 err_free_dotclock:
@@ -486,6 +495,7 @@ static void sun4i_tcon_unbind(struct device *dev, struct device *master,
 {
         struct sun4i_tcon *tcon = dev_get_drvdata(dev);
 
+        list_del(&tcon->list);
         sun4i_dclk_free(tcon);
         sun4i_tcon_free_clocks(tcon);
 }
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h
index f636343a935d..1bda4d183eec 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.h
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h
@@ -17,6 +17,7 @@
 #include <drm/drm_crtc.h>
 
 #include <linux/kernel.h>
+#include <linux/list.h>
 #include <linux/reset.h>
 
 #define SUN4I_TCON_GCTL_REG                     0x0
@@ -172,6 +173,9 @@ struct sun4i_tcon {
 
         /* Associated crtc */
         struct sun4i_crtc               *crtc;
+
+        /* TCON list management */
+        struct list_head                list;
 };
 
 struct drm_bridge *sun4i_tcon_find_bridge(struct device_node *node);