Merge tag 'sunxi-drm-for-4.9' of...

Merge tag 'sunxi-drm-for-4.9' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux into drm-next

Allwinner DRM changes for 4.9

This tag adds the support of a new SoC to sun4i-drm (the Allwinner A33),
and the usual few fixes and enhancements

* tag 'sunxi-drm-for-4.9' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux:
  drm/sun4i: add missing header dependencies
  drm/sun4i: Add a DRC driver
  drm/sun4i: backend: Handle the SAT
  drm/sun4i: support A33 tcon
  drm/sun4i: support TCONs without channel 1
  drm/sun4i: Clear encoder->bridge if a bridge is not found
  drm/sun4i: rgb: add missing calls to drm_panel_{prepare,unprepare}
  drm/sun4i: Remove redundant dev_err call in sun4i_tcon_init_regmap()
  drm/sun4i: Add bridge support
  drm/sun4i: Move panel retrieval in RGB connector
  drm/sun4i: Store TCON's device structure pointer

Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt

@@ -26,13 +26,14 @@ TCON
 The TCON acts as a timing controller for RGB, LVDS and TV interfaces.
 
 Required properties:
- - compatible: value should be "allwinner,sun5i-a13-tcon".
+ - compatible: value must be either:
+   * allwinner,sun5i-a13-tcon
+   * allwinner,sun8i-a33-tcon
  - reg: base address and size of memory-mapped region
  - interrupts: interrupt associated to this IP
  - clocks: phandles to the clocks feeding the TCON. Three are needed:
    - 'ahb': the interface clocks
    - 'tcon-ch0': The clock driving the TCON channel 0
-   - 'tcon-ch1': The clock driving the TCON channel 1
  - resets: phandles to the reset controllers driving the encoder
    - "lcd": the reset line for the TCON channel 0
 
@@ -49,6 +50,33 @@ Required properties:
   second the block connected to the TCON channel 1 (usually the TV
   encoder)
 
+On the A13, there is one more clock required:
+   - 'tcon-ch1': The clock driving the TCON channel 1
+
+DRC
+---
+
+The DRC (Dynamic Range Controller), found in the latest Allwinner SoCs
+(A31, A23, A33), allows to dynamically adjust pixel
+brightness/contrast based on histogram measurements for LCD content
+adaptive backlight control.
+
+
+Required properties:
+  - compatible: value must be one of:
+    * allwinner,sun8i-a33-drc
+  - reg: base address and size of the memory-mapped region.
+  - interrupts: interrupt associated to this IP
+  - clocks: phandles to the clocks feeding the DRC
+    * ahb: the DRC interface clock
+    * mod: the DRC module clock
+    * ram: the DRC DRAM clock
+  - clock-names: the clock names mentioned above
+  - resets: phandles to the reset line driving the DRC
+
+- ports: A ports node with endpoint definitions as defined in
+  Documentation/devicetree/bindings/media/video-interfaces.txt. The
+  first port should be the input endpoints, the second one the outputs
 
 Display Engine Backend
 ----------------------
@@ -59,6 +87,7 @@ system.
 Required properties:
   - compatible: value must be one of:
     * allwinner,sun5i-a13-display-backend
+    * allwinner,sun8i-a33-display-backend
   - reg: base address and size of the memory-mapped region.
   - clocks: phandles to the clocks feeding the frontend and backend
     * ahb: the backend interface clock
@@ -71,6 +100,14 @@ Required properties:
   Documentation/devicetree/bindings/media/video-interfaces.txt. The
   first port should be the input endpoints, the second one the output
 
+On the A33, some additional properties are required:
+  - reg needs to have an additional region corresponding to the SAT
+  - reg-names need to be set, with "be" and "sat"
+  - clocks and clock-names need to have a phandle to the SAT bus
+    clocks, whose name will be "sat"
+  - resets and reset-names need to have a phandle to the SAT bus
+    resets, whose name will be "sat"
+
 Display Engine Frontend
 -----------------------
 
@@ -80,6 +117,7 @@ deinterlacing and color space conversion.
 Required properties:
   - compatible: value must be one of:
     * allwinner,sun5i-a13-display-frontend
+    * allwinner,sun8i-a33-display-frontend
   - reg: base address and size of the memory-mapped region.
   - interrupts: interrupt associated to this IP
   - clocks: phandles to the clocks feeding the frontend and backend
@@ -104,6 +142,7 @@ extra node.
 Required properties:
   - compatible: value must be one of:
     * allwinner,sun5i-a13-display-engine
+    * allwinner,sun8i-a33-display-engine
 
   - allwinner,pipelines: list of phandle to the display engine
     frontends available.

drivers/gpu/drm/sun4i/Makefile

@@ -9,5 +9,5 @@ sun4i-tcon-y += sun4i_dotclock.o
 
 obj-$(CONFIG_DRM_SUN4I)		+= sun4i-drm.o sun4i-tcon.o
 obj-$(CONFIG_DRM_SUN4I)		+= sun4i_backend.o
-
+obj-$(CONFIG_DRM_SUN4I)		+= sun6i_drc.o
 obj-$(CONFIG_DRM_SUN4I)		+= sun4i_tv.o

drivers/gpu/drm/sun4i/sun4i_backend.c

@@ -217,6 +217,51 @@ int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
 }
 EXPORT_SYMBOL(sun4i_backend_update_layer_buffer);
 
+static int sun4i_backend_init_sat(struct device *dev) {
+	struct sun4i_backend *backend = dev_get_drvdata(dev);
+	int ret;
+
+	backend->sat_reset = devm_reset_control_get(dev, "sat");
+	if (IS_ERR(backend->sat_reset)) {
+		dev_err(dev, "Couldn't get the SAT reset line\n");
+		return PTR_ERR(backend->sat_reset);
+	}
+
+	ret = reset_control_deassert(backend->sat_reset);
+	if (ret) {
+		dev_err(dev, "Couldn't deassert the SAT reset line\n");
+		return ret;
+	}
+
+	backend->sat_clk = devm_clk_get(dev, "sat");
+	if (IS_ERR(backend->sat_clk)) {
+		dev_err(dev, "Couldn't get our SAT clock\n");
+		ret = PTR_ERR(backend->sat_clk);
+		goto err_assert_reset;
+	}
+
+	ret = clk_prepare_enable(backend->sat_clk);
+	if (ret) {
+		dev_err(dev, "Couldn't enable the SAT clock\n");
+		return ret;
+	}
+
+	return 0;
+
+err_assert_reset:
+	reset_control_assert(backend->sat_reset);
+	return ret;
+}
+
+static int sun4i_backend_free_sat(struct device *dev) {
+	struct sun4i_backend *backend = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(backend->sat_clk);
+	reset_control_assert(backend->sat_reset);
+
+	return 0;
+}
+
 static struct regmap_config sun4i_backend_regmap_config = {
 	.reg_bits	= 32,
 	.val_bits	= 32,
@@ -291,6 +336,15 @@ static int sun4i_backend_bind(struct device *dev, struct device *master,
 	}
 	clk_prepare_enable(backend->ram_clk);
 
+	if (of_device_is_compatible(dev->of_node,
+				    "allwinner,sun8i-a33-display-backend")) {
+		ret = sun4i_backend_init_sat(dev);
+		if (ret) {
+			dev_err(dev, "Couldn't init SAT resources\n");
+			goto err_disable_ram_clk;
+		}
+	}
+
 	/* Reset the registers */
 	for (i = 0x800; i < 0x1000; i += 4)
 		regmap_write(backend->regs, i, 0);
@@ -306,6 +360,8 @@ static int sun4i_backend_bind(struct device *dev, struct device *master,
 
 	return 0;
 
+err_disable_ram_clk:
+	clk_disable_unprepare(backend->ram_clk);
 err_disable_mod_clk:
 	clk_disable_unprepare(backend->mod_clk);
 err_disable_bus_clk:
@@ -320,6 +376,10 @@ static void sun4i_backend_unbind(struct device *dev, struct device *master,
 {
 	struct sun4i_backend *backend = dev_get_drvdata(dev);
 
+	if (of_device_is_compatible(dev->of_node,
+				    "allwinner,sun8i-a33-display-backend"))
+		sun4i_backend_free_sat(dev);
+
 	clk_disable_unprepare(backend->ram_clk);
 	clk_disable_unprepare(backend->mod_clk);
 	clk_disable_unprepare(backend->bus_clk);
@@ -345,6 +405,7 @@ static int sun4i_backend_remove(struct platform_device *pdev)
 
 static const struct of_device_id sun4i_backend_of_table[] = {
 	{ .compatible = "allwinner,sun5i-a13-display-backend" },
+	{ .compatible = "allwinner,sun8i-a33-display-backend" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, sun4i_backend_of_table);

drivers/gpu/drm/sun4i/sun4i_backend.h

@@ -146,6 +146,9 @@ struct sun4i_backend {
 	struct clk		*bus_clk;
 	struct clk		*mod_clk;
 	struct clk		*ram_clk;
+
+	struct clk		*sat_clk;
+	struct reset_control	*sat_reset;
 };
 
 void sun4i_backend_apply_color_correction(struct sun4i_backend *backend);

drivers/gpu/drm/sun4i/sun4i_dotclock.c

@@ -14,6 +14,7 @@
 #include <linux/regmap.h>
 
 #include "sun4i_tcon.h"
+#include "sun4i_dotclock.h"
 
 struct sun4i_dclk {
 	struct clk_hw	hw;

drivers/gpu/drm/sun4i/sun4i_drv.c

@@ -200,13 +200,14 @@ static const struct component_master_ops sun4i_drv_master_ops = {
 
 static bool sun4i_drv_node_is_frontend(struct device_node *node)
 {
-	return of_device_is_compatible(node,
-				       "allwinner,sun5i-a13-display-frontend");
+	return of_device_is_compatible(node, "allwinner,sun5i-a13-display-frontend") ||
+		of_device_is_compatible(node, "allwinner,sun8i-a33-display-frontend");
 }
 
 static bool sun4i_drv_node_is_tcon(struct device_node *node)
 {
-	return of_device_is_compatible(node, "allwinner,sun5i-a13-tcon");
+	return of_device_is_compatible(node, "allwinner,sun5i-a13-tcon") ||
+		of_device_is_compatible(node, "allwinner,sun8i-a33-tcon");
 }
 
 static int compare_of(struct device *dev, void *data)
@@ -258,8 +259,8 @@ static int sun4i_drv_add_endpoints(struct device *dev,
 		}
 
 		/*
-		 * If the node is our TCON, the first port is used for our
-		 * panel, and will not be part of the
+		 * If the node is our TCON, the first port is used for
+		 * panel or bridges, and will not be part of the
 		 * component framework.
 		 */
 		if (sun4i_drv_node_is_tcon(node)) {
@@ -321,6 +322,7 @@ static int sun4i_drv_remove(struct platform_device *pdev)
 
 static const struct of_device_id sun4i_drv_of_table[] = {
 	{ .compatible = "allwinner,sun5i-a13-display-engine" },
+	{ .compatible = "allwinner,sun8i-a33-display-engine" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, sun4i_drv_of_table);

drivers/gpu/drm/sun4i/sun4i_framebuffer.c

@@ -15,6 +15,7 @@
 #include <drm/drmP.h>
 
 #include "sun4i_drv.h"
+#include "sun4i_framebuffer.h"
 
 static void sun4i_de_output_poll_changed(struct drm_device *drm)
 {

drivers/gpu/drm/sun4i/sun4i_rgb.c

@@ -19,6 +19,7 @@
 
 #include "sun4i_drv.h"
 #include "sun4i_tcon.h"
+#include "sun4i_rgb.h"
 
 struct sun4i_rgb {
 	struct drm_connector	connector;
@@ -151,7 +152,14 @@ static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
 
 	DRM_DEBUG_DRIVER("Enabling RGB output\n");
 
-	drm_panel_enable(tcon->panel);
+	if (!IS_ERR(tcon->panel)) {
+		drm_panel_prepare(tcon->panel);
+		drm_panel_enable(tcon->panel);
+	}
+
+	/* encoder->bridge can be NULL; drm_bridge_enable checks for it */
+	drm_bridge_enable(encoder->bridge);
+
 	sun4i_tcon_channel_enable(tcon, 0);
 }
 
@@ -164,7 +172,14 @@ static void sun4i_rgb_encoder_disable(struct drm_encoder *encoder)
 	DRM_DEBUG_DRIVER("Disabling RGB output\n");
 
 	sun4i_tcon_channel_disable(tcon, 0);
-	drm_panel_disable(tcon->panel);
+
+	/* encoder->bridge can be NULL; drm_bridge_disable checks for it */
+	drm_bridge_disable(encoder->bridge);
+
+	if (!IS_ERR(tcon->panel)) {
+		drm_panel_disable(tcon->panel);
+		drm_panel_unprepare(tcon->panel);
+	}
 }
 
 static void sun4i_rgb_encoder_mode_set(struct drm_encoder *encoder,
@@ -203,17 +218,22 @@ int sun4i_rgb_init(struct drm_device *drm)
 {
 	struct sun4i_drv *drv = drm->dev_private;
 	struct sun4i_tcon *tcon = drv->tcon;
+	struct drm_encoder *encoder;
 	struct sun4i_rgb *rgb;
 	int ret;
 
-	/* If we don't have a panel, there's no point in going on */
-	if (IS_ERR(tcon->panel))
-		return -ENODEV;
-
 	rgb = devm_kzalloc(drm->dev, sizeof(*rgb), GFP_KERNEL);
 	if (!rgb)
 		return -ENOMEM;
 	rgb->drv = drv;
+	encoder = &rgb->encoder;
+
+	tcon->panel = sun4i_tcon_find_panel(tcon->dev->of_node);
+	encoder->bridge = sun4i_tcon_find_bridge(tcon->dev->of_node);
+	if (IS_ERR(tcon->panel) && IS_ERR(encoder->bridge)) {
+		dev_info(drm->dev, "No panel or bridge found... RGB output disabled\n");
+		return 0;
+	}
 
 	drm_encoder_helper_add(&rgb->encoder,
 			       &sun4i_rgb_enc_helper_funcs);
@@ -230,19 +250,38 @@ int sun4i_rgb_init(struct drm_device *drm)
 	/* The RGB encoder can only work with the TCON channel 0 */
 	rgb->encoder.possible_crtcs = BIT(0);
 
-	drm_connector_helper_add(&rgb->connector,
-				 &sun4i_rgb_con_helper_funcs);
-	ret = drm_connector_init(drm, &rgb->connector,
-				 &sun4i_rgb_con_funcs,
-				 DRM_MODE_CONNECTOR_Unknown);
-	if (ret) {
-		dev_err(drm->dev, "Couldn't initialise the rgb connector\n");
-		goto err_cleanup_connector;
+	if (!IS_ERR(tcon->panel)) {
+		drm_connector_helper_add(&rgb->connector,
+					 &sun4i_rgb_con_helper_funcs);
+		ret = drm_connector_init(drm, &rgb->connector,
+					 &sun4i_rgb_con_funcs,
+					 DRM_MODE_CONNECTOR_Unknown);
+		if (ret) {
+			dev_err(drm->dev, "Couldn't initialise the rgb connector\n");
+			goto err_cleanup_connector;
+		}
+
+		drm_mode_connector_attach_encoder(&rgb->connector,
+						  &rgb->encoder);
+
+		ret = drm_panel_attach(tcon->panel, &rgb->connector);
+		if (ret) {
+			dev_err(drm->dev, "Couldn't attach our panel\n");
+			goto err_cleanup_connector;
+		}
 	}
 
-	drm_mode_connector_attach_encoder(&rgb->connector, &rgb->encoder);
+	if (!IS_ERR(encoder->bridge)) {
+		encoder->bridge->encoder = &rgb->encoder;
 
-	drm_panel_attach(tcon->panel, &rgb->connector);
+		ret = drm_bridge_attach(drm, encoder->bridge);
+		if (ret) {
+			dev_err(drm->dev, "Couldn't attach our bridge\n");
+			goto err_cleanup_connector;
+		}
+	} else {
+		encoder->bridge = NULL;
+	}
 
 	return 0;
 

drivers/gpu/drm/sun4i/sun4i_tcon.c

@@ -59,11 +59,13 @@ void sun4i_tcon_channel_disable(struct sun4i_tcon *tcon, int channel)
 		regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
 				   SUN4I_TCON0_CTL_TCON_ENABLE, 0);
 		clk_disable_unprepare(tcon->dclk);
-	} else if (channel == 1) {
-		regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
-				   SUN4I_TCON1_CTL_TCON_ENABLE, 0);
-		clk_disable_unprepare(tcon->sclk1);
+		return;
 	}
+
+	WARN_ON(!tcon->has_channel_1);
+	regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
+			   SUN4I_TCON1_CTL_TCON_ENABLE, 0);
+	clk_disable_unprepare(tcon->sclk1);
 }
 EXPORT_SYMBOL(sun4i_tcon_channel_disable);
 
@@ -75,12 +77,14 @@ void sun4i_tcon_channel_enable(struct sun4i_tcon *tcon, int channel)
 				   SUN4I_TCON0_CTL_TCON_ENABLE,
 				   SUN4I_TCON0_CTL_TCON_ENABLE);
 		clk_prepare_enable(tcon->dclk);
-	} else if (channel == 1) {
-		regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
-				   SUN4I_TCON1_CTL_TCON_ENABLE,
-				   SUN4I_TCON1_CTL_TCON_ENABLE);
-		clk_prepare_enable(tcon->sclk1);
+		return;
 	}
+
+	WARN_ON(!tcon->has_channel_1);
+	regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
+			   SUN4I_TCON1_CTL_TCON_ENABLE,
+			   SUN4I_TCON1_CTL_TCON_ENABLE);
+	clk_prepare_enable(tcon->sclk1);
 }
 EXPORT_SYMBOL(sun4i_tcon_channel_enable);
 
@@ -198,6 +202,8 @@ void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon,
 	u8 clk_delay;
 	u32 val;
 
+	WARN_ON(!tcon->has_channel_1);
+
 	/* Adjust clock delay */
 	clk_delay = sun4i_tcon_get_clk_delay(mode, 1);
 	regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
@@ -321,10 +327,12 @@ static int sun4i_tcon_init_clocks(struct device *dev,
 		return PTR_ERR(tcon->sclk0);
 	}
 
-	tcon->sclk1 = devm_clk_get(dev, "tcon-ch1");
-	if (IS_ERR(tcon->sclk1)) {
-		dev_err(dev, "Couldn't get the TCON channel 1 clock\n");
-		return PTR_ERR(tcon->sclk1);
+	if (tcon->has_channel_1) {
+		tcon->sclk1 = devm_clk_get(dev, "tcon-ch1");
+		if (IS_ERR(tcon->sclk1)) {
+			dev_err(dev, "Couldn't get the TCON channel 1 clock\n");
+			return PTR_ERR(tcon->sclk1);
+		}
 	}
 
 	return sun4i_dclk_create(dev, tcon);
@@ -374,10 +382,8 @@ static int sun4i_tcon_init_regmap(struct device *dev,
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	regs = devm_ioremap_resource(dev, res);
-	if (IS_ERR(regs)) {
-		dev_err(dev, "Couldn't map the TCON registers\n");
+	if (IS_ERR(regs))
 		return PTR_ERR(regs);
-	}
 
 	tcon->regs = devm_regmap_init_mmio(dev, regs,
 					   &sun4i_tcon_regmap_config);
@@ -398,7 +404,7 @@ static int sun4i_tcon_init_regmap(struct device *dev,
 	return 0;
 }
 
-static struct drm_panel *sun4i_tcon_find_panel(struct device_node *node)
+struct drm_panel *sun4i_tcon_find_panel(struct device_node *node)
 {
 	struct device_node *port, *remote, *child;
 	struct device_node *end_node = NULL;
@@ -432,6 +438,40 @@ static struct drm_panel *sun4i_tcon_find_panel(struct device_node *node)
 	return of_drm_find_panel(remote) ?: ERR_PTR(-EPROBE_DEFER);
 }
 
+struct drm_bridge *sun4i_tcon_find_bridge(struct device_node *node)
+{
+	struct device_node *port, *remote, *child;
+	struct device_node *end_node = NULL;
+
+	/* Inputs are listed first, then outputs */
+	port = of_graph_get_port_by_id(node, 1);
+
+	/*
+	 * Our first output is the RGB interface where the panel will
+	 * be connected.
+	 */
+	for_each_child_of_node(port, child) {
+		u32 reg;
+
+		of_property_read_u32(child, "reg", &reg);
+		if (reg == 0)
+			end_node = child;
+	}
+
+	if (!end_node) {
+		DRM_DEBUG_DRIVER("Missing bridge endpoint\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	remote = of_graph_get_remote_port_parent(end_node);
+	if (!remote) {
+		DRM_DEBUG_DRIVER("Enable to parse remote node\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	return of_drm_find_bridge(remote) ?: ERR_PTR(-EPROBE_DEFER);
+}
+
 static int sun4i_tcon_bind(struct device *dev, struct device *master,
 			   void *data)
 {
@@ -446,9 +486,15 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
 	dev_set_drvdata(dev, tcon);
 	drv->tcon = tcon;
 	tcon->drm = drm;
+	tcon->dev = dev;
 
-	if (of_device_is_compatible(dev->of_node, "allwinner,sun5i-a13-tcon"))
+	if (of_device_is_compatible(dev->of_node, "allwinner,sun5i-a13-tcon")) {
 		tcon->has_mux = true;
+		tcon->has_channel_1 = true;
+	} else {
+		tcon->has_mux = false;
+		tcon->has_channel_1 = false;
+	}
 
 	tcon->lcd_rst = devm_reset_control_get(dev, "lcd");
 	if (IS_ERR(tcon->lcd_rst)) {
@@ -484,12 +530,6 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
 		goto err_free_clocks;
 	}
 
-	tcon->panel = sun4i_tcon_find_panel(dev->of_node);
-	if (IS_ERR(tcon->panel)) {
-		dev_info(dev, "No panel found... RGB output disabled\n");
-		return 0;
-	}
-
 	ret = sun4i_rgb_init(drm);
 	if (ret < 0)
 		goto err_free_clocks;
@@ -519,19 +559,22 @@ static struct component_ops sun4i_tcon_ops = {
 static int sun4i_tcon_probe(struct platform_device *pdev)
 {
 	struct device_node *node = pdev->dev.of_node;
+	struct drm_bridge *bridge;
 	struct drm_panel *panel;
 
 	/*
-	 * The panel is not ready.
+	 * Neither the bridge or the panel is ready.
 	 * Defer the probe.
 	 */
 	panel = sun4i_tcon_find_panel(node);
+	bridge = sun4i_tcon_find_bridge(node);
 
 	/*
 	 * If we don't have a panel endpoint, just go on
 	 */
-	if (PTR_ERR(panel) == -EPROBE_DEFER) {
-		DRM_DEBUG_DRIVER("Still waiting for our panel. Deferring...\n");
+	if ((PTR_ERR(panel) == -EPROBE_DEFER) &&
+	    (PTR_ERR(bridge) == -EPROBE_DEFER)) {
+		DRM_DEBUG_DRIVER("Still waiting for our panel/bridge. Deferring...\n");
 		return -EPROBE_DEFER;
 	}
 
@@ -547,6 +590,7 @@ static int sun4i_tcon_remove(struct platform_device *pdev)
 
 static const struct of_device_id sun4i_tcon_of_table[] = {
 	{ .compatible = "allwinner,sun5i-a13-tcon" },
+	{ .compatible = "allwinner,sun8i-a33-tcon" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, sun4i_tcon_of_table);

drivers/gpu/drm/sun4i/sun4i_tcon.h

@@ -143,6 +143,7 @@
 #define SUN4I_TCON_MAX_CHANNELS		2
 
 struct sun4i_tcon {
+	struct device			*dev;
 	struct drm_device		*drm;
 	struct regmap			*regs;
 
@@ -163,8 +164,13 @@ struct sun4i_tcon {
 	bool				has_mux;
 
 	struct drm_panel		*panel;
+
+	bool				has_channel_1;
 };
 
+struct drm_bridge *sun4i_tcon_find_bridge(struct device_node *node);
+struct drm_panel *sun4i_tcon_find_panel(struct device_node *node);
+
 /* Global Control */
 void sun4i_tcon_disable(struct sun4i_tcon *tcon);
 void sun4i_tcon_enable(struct sun4i_tcon *tcon);

drivers/gpu/drm/sun4i/sun6i_drc.c

+/*
+ * Copyright (C) 2016 Free Electrons
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+struct sun6i_drc {
+	struct clk		*bus_clk;
+	struct clk		*mod_clk;
+	struct reset_control	*reset;
+};
+
+static int sun6i_drc_bind(struct device *dev, struct device *master,
+			 void *data)
+{
+	struct sun6i_drc *drc;
+	int ret;
+
+	drc = devm_kzalloc(dev, sizeof(*drc), GFP_KERNEL);
+	if (!drc)
+		return -ENOMEM;
+	dev_set_drvdata(dev, drc);
+
+	drc->reset = devm_reset_control_get(dev, NULL);
+	if (IS_ERR(drc->reset)) {
+		dev_err(dev, "Couldn't get our reset line\n");
+		return PTR_ERR(drc->reset);
+	}
+
+	ret = reset_control_deassert(drc->reset);
+	if (ret) {
+		dev_err(dev, "Couldn't deassert our reset line\n");
+		return ret;
+	}
+
+	drc->bus_clk = devm_clk_get(dev, "ahb");
+	if (IS_ERR(drc->bus_clk)) {
+		dev_err(dev, "Couldn't get our bus clock\n");
+		ret = PTR_ERR(drc->bus_clk);
+		goto err_assert_reset;
+	}
+	clk_prepare_enable(drc->bus_clk);
+
+	drc->mod_clk = devm_clk_get(dev, "mod");
+	if (IS_ERR(drc->mod_clk)) {
+		dev_err(dev, "Couldn't get our mod clock\n");
+		ret = PTR_ERR(drc->mod_clk);
+		goto err_disable_bus_clk;
+	}
+	clk_prepare_enable(drc->mod_clk);
+
+	return 0;
+
+err_disable_bus_clk:
+	clk_disable_unprepare(drc->bus_clk);
+err_assert_reset:
+	reset_control_assert(drc->reset);
+	return ret;
+}
+
+static void sun6i_drc_unbind(struct device *dev, struct device *master,
+			    void *data)
+{
+	struct sun6i_drc *drc = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(drc->mod_clk);
+	clk_disable_unprepare(drc->bus_clk);
+	reset_control_assert(drc->reset);
+}
+
+static struct component_ops sun6i_drc_ops = {
+	.bind	= sun6i_drc_bind,
+	.unbind	= sun6i_drc_unbind,
+};
+
+static int sun6i_drc_probe(struct platform_device *pdev)
+{
+	return component_add(&pdev->dev, &sun6i_drc_ops);
+}
+
+static int sun6i_drc_remove(struct platform_device *pdev)
+{
+	component_del(&pdev->dev, &sun6i_drc_ops);
+
+	return 0;
+}
+
+static const struct of_device_id sun6i_drc_of_table[] = {
+	{ .compatible = "allwinner,sun8i-a33-drc" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sun6i_drc_of_table);
+
+static struct platform_driver sun6i_drc_platform_driver = {
+	.probe		= sun6i_drc_probe,
+	.remove		= sun6i_drc_remove,
+	.driver		= {
+		.name		= "sun6i-drc",
+		.of_match_table	= sun6i_drc_of_table,
+	},
+};
+module_platform_driver(sun6i_drc_platform_driver);
+
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_DESCRIPTION("Allwinner A31 Dynamic Range Control (DRC) Driver");
+MODULE_LICENSE("GPL");