Merge tag 'sunxi-drm-for-4.14' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux into drm-next

Allwinner DRM changes for 4.14

A few changes, but most notably improving the HDMI support merged in 4.13,
by reporting the DDC adapter as an i2c bus, and by adding CEC support
through the CEC framework.

* tag 'sunxi-drm-for-4.14' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux:
  sun4i_hdmi: add CEC support
  dt-bindings: display: sunxi: Improve endpoint ID scheme readability
  drm/sun4i: tcon: remove unused function
  drm/sun4i: Remove useless atomic_check
  drm/sun4i: Add if statement instead of depends on
  drm/sun4i: hdmi: Implement I2C adapter for A10s DDC bus
  drm/sun4i: constify drm_plane_helper_funcs

10 files changed, 359 insertions, 129 deletions

diff --git a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
index b83e6018041d..2ee6ff0ef98e 100644
--- a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
+++ b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
@@ -4,15 +4,33 @@ Allwinner A10 Display Pipeline
 The Allwinner A10 Display pipeline is composed of several components
 that are going to be documented below:
 
-For the input port of all components up to the TCON in the display
-pipeline, if there are multiple components, the local endpoint IDs
-must correspond to the index of the upstream block. For example, if
-the remote endpoint is Frontend 1, then the local endpoint ID must
-be 1.
-
-Conversely, for the output ports of the same group, the remote endpoint
-ID must be the index of the local hardware block. If the local backend
-is backend 1, then the remote endpoint ID must be 1.
+For all connections between components up to the TCONs in the display
+pipeline, when there are multiple components of the same type at the
+same depth, the local endpoint ID must be the same as the remote
+component's index. For example, if the remote endpoint is Frontend 1,
+then the local endpoint ID must be 1.
+
+    Frontend 0  [0] ------- [0]  Backend 0  [0] ------- [0]  TCON 0
+		[1] --   -- [1]             [1] --   -- [1]
+		      \ /                         \ /
+		       X                           X
+		      / \                         / \
+		[0] --   -- [0]             [0] --   -- [0]
+    Frontend 1  [1] ------- [1]  Backend 1  [1] ------- [1]  TCON 1
+
+For a two pipeline system such as the one depicted above, the lines
+represent the connections between the components, while the numbers
+within the square brackets corresponds to the ID of the local endpoint.
+
+The same rule also applies to DE 2.0 mixer-TCON connections:
+
+    Mixer 0  [0] ----------- [0]  TCON 0
+	     [1] ----   ---- [1]
+		     \ /
+		      X
+		     / \
+	     [0] ----   ---- [0]
+    Mixer 1  [1] ----------- [1]  TCON 1
 
 HDMI Encoder
 ------------
diff --git a/drivers/gpu/drm/sun4i/Kconfig b/drivers/gpu/drm/sun4i/Kconfig
index 5bcad8f5fb4f..06f05302ee75 100644
--- a/drivers/gpu/drm/sun4i/Kconfig
+++ b/drivers/gpu/drm/sun4i/Kconfig
@@ -13,17 +13,26 @@ config DRM_SUN4I
 	  Display Engine. If M is selected the module will be called
 	  sun4i-drm.
 
+if DRM_SUN4I
+
 config DRM_SUN4I_HDMI
        tristate "Allwinner A10 HDMI Controller Support"
-       depends on DRM_SUN4I
        default DRM_SUN4I
        help
 	  Choose this option if you have an Allwinner SoC with an HDMI
 	  controller.
 
+config DRM_SUN4I_HDMI_CEC
+       bool "Allwinner A10 HDMI CEC Support"
+       depends on DRM_SUN4I_HDMI
+       select CEC_CORE
+       depends on CEC_PIN
+       help
+	  Choose this option if you have an Allwinner SoC with an HDMI
+	  controller and want to use CEC.
+
 config DRM_SUN4I_BACKEND
 	tristate "Support for Allwinner A10 Display Engine Backend"
-	depends on DRM_SUN4I
 	default DRM_SUN4I
 	help
 	  Choose this option if you have an Allwinner SoC with the
@@ -33,10 +42,11 @@ config DRM_SUN4I_BACKEND
 
 config DRM_SUN8I_MIXER
 	tristate "Support for Allwinner Display Engine 2.0 Mixer"
-	depends on DRM_SUN4I
 	default MACH_SUN8I
 	help
 	  Choose this option if you have an Allwinner SoC with the
 	  Allwinner Display Engine 2.0, which has a mixer to do some
 	  graphics mixture and feed graphics to TCON, If M is
 	  selected the module will be called sun8i-mixer.
+
+endif
diff --git a/drivers/gpu/drm/sun4i/Makefile b/drivers/gpu/drm/sun4i/Makefile
index e29fd3a2ba9c..43c753cafc88 100644
--- a/drivers/gpu/drm/sun4i/Makefile
+++ b/drivers/gpu/drm/sun4i/Makefile
@@ -2,6 +2,7 @@ sun4i-drm-y += sun4i_drv.o
 sun4i-drm-y += sun4i_framebuffer.o
 
 sun4i-drm-hdmi-y += sun4i_hdmi_enc.o
+sun4i-drm-hdmi-y += sun4i_hdmi_i2c.o
 sun4i-drm-hdmi-y += sun4i_hdmi_ddc_clk.o
 sun4i-drm-hdmi-y += sun4i_hdmi_tmds_clk.o
 
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi.h b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
index 2f2f2ff1ea63..1457750988da 100644
--- a/drivers/gpu/drm/sun4i/sun4i_hdmi.h
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi.h
@@ -15,6 +15,8 @@
 #include <drm/drm_connector.h>
 #include <drm/drm_encoder.h>
 
+#include <media/cec.h>
+
 #define SUN4I_HDMI_CTRL_REG		0x004
 #define SUN4I_HDMI_CTRL_ENABLE			BIT(31)
 
@@ -86,6 +88,11 @@
 #define SUN4I_HDMI_PLL_DBG0_TMDS_PARENT_MASK	BIT(21)
 #define SUN4I_HDMI_PLL_DBG0_TMDS_PARENT_SHIFT	21
 
+#define SUN4I_HDMI_CEC			0x214
+#define SUN4I_HDMI_CEC_ENABLE			BIT(11)
+#define SUN4I_HDMI_CEC_TX			BIT(9)
+#define SUN4I_HDMI_CEC_RX			BIT(8)
+
 #define SUN4I_HDMI_PKT_CTRL_REG(n)	(0x2f0 + (4 * (n)))
 #define SUN4I_HDMI_PKT_CTRL_TYPE(n, t)		((t) << (((n) % 4) * 4))
 
@@ -96,6 +103,7 @@
 #define SUN4I_HDMI_DDC_CTRL_ENABLE		BIT(31)
 #define SUN4I_HDMI_DDC_CTRL_START_CMD		BIT(30)
 #define SUN4I_HDMI_DDC_CTRL_FIFO_DIR_MASK	BIT(8)
+#define SUN4I_HDMI_DDC_CTRL_FIFO_DIR_WRITE	(1 << 8)
 #define SUN4I_HDMI_DDC_CTRL_FIFO_DIR_READ	(0 << 8)
 #define SUN4I_HDMI_DDC_CTRL_RESET		BIT(0)
 
@@ -105,14 +113,34 @@
 #define SUN4I_HDMI_DDC_ADDR_OFFSET(off)		(((off) & 0xff) << 8)
 #define SUN4I_HDMI_DDC_ADDR_SLAVE(addr)		((addr) & 0xff)
 
+#define SUN4I_HDMI_DDC_INT_STATUS_REG		0x50c
+#define SUN4I_HDMI_DDC_INT_STATUS_ILLEGAL_FIFO_OPERATION	BIT(7)
+#define SUN4I_HDMI_DDC_INT_STATUS_DDC_RX_FIFO_UNDERFLOW		BIT(6)
+#define SUN4I_HDMI_DDC_INT_STATUS_DDC_TX_FIFO_OVERFLOW		BIT(5)
+#define SUN4I_HDMI_DDC_INT_STATUS_FIFO_REQUEST			BIT(4)
+#define SUN4I_HDMI_DDC_INT_STATUS_ARBITRATION_ERROR		BIT(3)
+#define SUN4I_HDMI_DDC_INT_STATUS_ACK_ERROR			BIT(2)
+#define SUN4I_HDMI_DDC_INT_STATUS_BUS_ERROR			BIT(1)
+#define SUN4I_HDMI_DDC_INT_STATUS_TRANSFER_COMPLETE		BIT(0)
+
 #define SUN4I_HDMI_DDC_FIFO_CTRL_REG	0x510
 #define SUN4I_HDMI_DDC_FIFO_CTRL_CLEAR		BIT(31)
+#define SUN4I_HDMI_DDC_FIFO_CTRL_RX_THRES(n)	(((n) & 0xf) << 4)
+#define SUN4I_HDMI_DDC_FIFO_CTRL_RX_THRES_MASK	GENMASK(7, 4)
+#define SUN4I_HDMI_DDC_FIFO_CTRL_RX_THRES_MAX	(BIT(4) - 1)
+#define SUN4I_HDMI_DDC_FIFO_CTRL_TX_THRES(n)	((n) & 0xf)
+#define SUN4I_HDMI_DDC_FIFO_CTRL_TX_THRES_MASK	GENMASK(3, 0)
+#define SUN4I_HDMI_DDC_FIFO_CTRL_TX_THRES_MAX	(BIT(4) - 1)
 
 #define SUN4I_HDMI_DDC_FIFO_DATA_REG	0x518
+
 #define SUN4I_HDMI_DDC_BYTE_COUNT_REG	0x51c
+#define SUN4I_HDMI_DDC_BYTE_COUNT_MAX		(BIT(10) - 1)
 
 #define SUN4I_HDMI_DDC_CMD_REG		0x520
 #define SUN4I_HDMI_DDC_CMD_EXPLICIT_EDDC_READ	6
+#define SUN4I_HDMI_DDC_CMD_IMPLICIT_READ	5
+#define SUN4I_HDMI_DDC_CMD_IMPLICIT_WRITE	3
 
 #define SUN4I_HDMI_DDC_CLK_REG		0x528
 #define SUN4I_HDMI_DDC_CLK_M(m)			(((m) & 0x7) << 3)
@@ -146,12 +174,16 @@ struct sun4i_hdmi {
 	struct clk		*ddc_clk;
 	struct clk		*tmds_clk;
 
+	struct i2c_adapter	*i2c;
+
 	struct sun4i_drv	*drv;
 
 	bool			hdmi_monitor;
+	struct cec_adapter	*cec_adap;
 };
 
 int sun4i_ddc_create(struct sun4i_hdmi *hdmi, struct clk *clk);
 int sun4i_tmds_create(struct sun4i_hdmi *hdmi);
+int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi);
 
 #endif /* _SUN4I_HDMI_H_ */
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
index f5d0d6bd1084..9ea6cd5a1370 100644
--- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
@@ -29,8 +29,6 @@
 #include "sun4i_hdmi.h"
 #include "sun4i_tcon.h"
 
-#define DDC_SEGMENT_ADDR	0x30
-
 static inline struct sun4i_hdmi *
 drm_encoder_to_sun4i_hdmi(struct drm_encoder *encoder)
 {
@@ -184,93 +182,13 @@ static const struct drm_encoder_funcs sun4i_hdmi_funcs = {
 	.destroy	= drm_encoder_cleanup,
 };
 
-static int sun4i_hdmi_read_sub_block(struct sun4i_hdmi *hdmi,
-				     unsigned int blk, unsigned int offset,
-				     u8 *buf, unsigned int count)
-{
-	unsigned long reg;
-	int i;
-
-	reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
-	reg &= ~SUN4I_HDMI_DDC_CTRL_FIFO_DIR_MASK;
-	writel(reg | SUN4I_HDMI_DDC_CTRL_FIFO_DIR_READ,
-	       hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
-
-	writel(SUN4I_HDMI_DDC_ADDR_SEGMENT(offset >> 8) |
-	       SUN4I_HDMI_DDC_ADDR_EDDC(DDC_SEGMENT_ADDR << 1) |
-	       SUN4I_HDMI_DDC_ADDR_OFFSET(offset) |
-	       SUN4I_HDMI_DDC_ADDR_SLAVE(DDC_ADDR),
-	       hdmi->base + SUN4I_HDMI_DDC_ADDR_REG);
-
-	reg = readl(hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG);
-	writel(reg | SUN4I_HDMI_DDC_FIFO_CTRL_CLEAR,
-	       hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG);
-
-	writel(count, hdmi->base + SUN4I_HDMI_DDC_BYTE_COUNT_REG);
-	writel(SUN4I_HDMI_DDC_CMD_EXPLICIT_EDDC_READ,
-	       hdmi->base + SUN4I_HDMI_DDC_CMD_REG);
-
-	reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
-	writel(reg | SUN4I_HDMI_DDC_CTRL_START_CMD,
-	       hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
-
-	if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG, reg,
-			       !(reg & SUN4I_HDMI_DDC_CTRL_START_CMD),
-			       100, 100000))
-		return -EIO;
-
-	for (i = 0; i < count; i++)
-		buf[i] = readb(hdmi->base + SUN4I_HDMI_DDC_FIFO_DATA_REG);
-
-	return 0;
-}
-
-static int sun4i_hdmi_read_edid_block(void *data, u8 *buf, unsigned int blk,
-				      size_t length)
-{
-	struct sun4i_hdmi *hdmi = data;
-	int retry = 2, i;
-
-	do {
-		for (i = 0; i < length; i += SUN4I_HDMI_DDC_FIFO_SIZE) {
-			unsigned char offset = blk * EDID_LENGTH + i;
-			unsigned int count = min((unsigned int)SUN4I_HDMI_DDC_FIFO_SIZE,
-						 length - i);
-			int ret;
-
-			ret = sun4i_hdmi_read_sub_block(hdmi, blk, offset,
-							buf + i, count);
-			if (ret)
-				return ret;
-		}
-	} while (!drm_edid_block_valid(buf, blk, true, NULL) && (retry--));
-
-	return 0;
-}
-
 static int sun4i_hdmi_get_modes(struct drm_connector *connector)
 {
 	struct sun4i_hdmi *hdmi = drm_connector_to_sun4i_hdmi(connector);
-	unsigned long reg;
 	struct edid *edid;
 	int ret;
 
-	/* Reset i2c controller */
-	writel(SUN4I_HDMI_DDC_CTRL_ENABLE | SUN4I_HDMI_DDC_CTRL_RESET,
-	       hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
-	if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG, reg,
-			       !(reg & SUN4I_HDMI_DDC_CTRL_RESET),
-			       100, 2000))
-		return -EIO;
-
-	writel(SUN4I_HDMI_DDC_LINE_CTRL_SDA_ENABLE |
-	       SUN4I_HDMI_DDC_LINE_CTRL_SCL_ENABLE,
-	       hdmi->base + SUN4I_HDMI_DDC_LINE_CTRL_REG);
-
-	clk_prepare_enable(hdmi->ddc_clk);
-	clk_set_rate(hdmi->ddc_clk, 100000);
-
-	edid = drm_do_get_edid(connector, sun4i_hdmi_read_edid_block, hdmi);
+	edid = drm_get_edid(connector, hdmi->i2c);
 	if (!edid)
 		return 0;
 
@@ -279,11 +197,10 @@ static int sun4i_hdmi_get_modes(struct drm_connector *connector)
 			 hdmi->hdmi_monitor ? "an HDMI" : "a DVI");
 
 	drm_mode_connector_update_edid_property(connector, edid);
+	cec_s_phys_addr_from_edid(hdmi->cec_adap, edid);
 	ret = drm_add_edid_modes(connector, edid);
 	kfree(edid);
 
-	clk_disable_unprepare(hdmi->ddc_clk);
-
 	return ret;
 }
 
@@ -299,8 +216,10 @@ sun4i_hdmi_connector_detect(struct drm_connector *connector, bool force)
 
 	if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_HPD_REG, reg,
 			       reg & SUN4I_HDMI_HPD_HIGH,
-			       0, 500000))
+			       0, 500000)) {
+		cec_phys_addr_invalidate(hdmi->cec_adap);
 		return connector_status_disconnected;
+	}
 
 	return connector_status_connected;
 }
@@ -314,6 +233,40 @@ static const struct drm_connector_funcs sun4i_hdmi_connector_funcs = {
 	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
 };
 
+#ifdef CONFIG_DRM_SUN4I_HDMI_CEC
+static bool sun4i_hdmi_cec_pin_read(struct cec_adapter *adap)
+{
+	struct sun4i_hdmi *hdmi = cec_get_drvdata(adap);
+
+	return readl(hdmi->base + SUN4I_HDMI_CEC) & SUN4I_HDMI_CEC_RX;
+}
+
+static void sun4i_hdmi_cec_pin_low(struct cec_adapter *adap)
+{
+	struct sun4i_hdmi *hdmi = cec_get_drvdata(adap);
+
+	/* Start driving the CEC pin low */
+	writel(SUN4I_HDMI_CEC_ENABLE, hdmi->base + SUN4I_HDMI_CEC);
+}
+
+static void sun4i_hdmi_cec_pin_high(struct cec_adapter *adap)
+{
+	struct sun4i_hdmi *hdmi = cec_get_drvdata(adap);
+
+	/*
+	 * Stop driving the CEC pin, the pull up will take over
+	 * unless another CEC device is driving the pin low.
+	 */
+	writel(0, hdmi->base + SUN4I_HDMI_CEC);
+}
+
+static const struct cec_pin_ops sun4i_hdmi_cec_pin_ops = {
+	.read = sun4i_hdmi_cec_pin_read,
+	.low = sun4i_hdmi_cec_pin_low,
+	.high = sun4i_hdmi_cec_pin_high,
+};
+#endif
+
 static int sun4i_hdmi_bind(struct device *dev, struct device *master,
 			   void *data)
 {
@@ -406,9 +359,9 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
 		SUN4I_HDMI_PLL_CTRL_PLL_EN;
 	writel(reg, hdmi->base + SUN4I_HDMI_PLL_CTRL_REG);
 
-	ret = sun4i_ddc_create(hdmi, hdmi->tmds_clk);
+	ret = sun4i_hdmi_i2c_create(dev, hdmi);
 	if (ret) {
-		dev_err(dev, "Couldn't create the DDC clock\n");
+		dev_err(dev, "Couldn't create the HDMI I2C adapter\n");
 		return ret;
 	}
 
@@ -421,13 +374,26 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
 			       NULL);
 	if (ret) {
 		dev_err(dev, "Couldn't initialise the HDMI encoder\n");
-		return ret;
+		goto err_del_i2c_adapter;
 	}
 
 	hdmi->encoder.possible_crtcs = drm_of_find_possible_crtcs(drm,
 								  dev->of_node);
-	if (!hdmi->encoder.possible_crtcs)
-		return -EPROBE_DEFER;
+	if (!hdmi->encoder.possible_crtcs) {
+		ret = -EPROBE_DEFER;
+		goto err_del_i2c_adapter;
+	}
+
+#ifdef CONFIG_DRM_SUN4I_HDMI_CEC
+	hdmi->cec_adap = cec_pin_allocate_adapter(&sun4i_hdmi_cec_pin_ops,
+		hdmi, "sun4i", CEC_CAP_TRANSMIT | CEC_CAP_LOG_ADDRS |
+		CEC_CAP_PASSTHROUGH | CEC_CAP_RC);
+	ret = PTR_ERR_OR_ZERO(hdmi->cec_adap);
+	if (ret < 0)
+		goto err_cleanup_connector;
+	writel(readl(hdmi->base + SUN4I_HDMI_CEC) & ~SUN4I_HDMI_CEC_TX,
+	       hdmi->base + SUN4I_HDMI_CEC);
+#endif
 
 	drm_connector_helper_add(&hdmi->connector,
 				 &sun4i_hdmi_connector_helper_funcs);
@@ -444,12 +410,18 @@ static int sun4i_hdmi_bind(struct device *dev, struct device *master,
 	hdmi->connector.polled = DRM_CONNECTOR_POLL_CONNECT |
 		DRM_CONNECTOR_POLL_DISCONNECT;
 
+	ret = cec_register_adapter(hdmi->cec_adap, dev);
+	if (ret < 0)
+		goto err_cleanup_connector;
 	drm_mode_connector_attach_encoder(&hdmi->connector, &hdmi->encoder);
 
 	return 0;
 
 err_cleanup_connector:
+	cec_delete_adapter(hdmi->cec_adap);
 	drm_encoder_cleanup(&hdmi->encoder);
+err_del_i2c_adapter:
+	i2c_del_adapter(hdmi->i2c);
 	return ret;
 }
 
@@ -458,8 +430,10 @@ static void sun4i_hdmi_unbind(struct device *dev, struct device *master,
 {
 	struct sun4i_hdmi *hdmi = dev_get_drvdata(dev);
 
+	cec_unregister_adapter(hdmi->cec_adap);
 	drm_connector_cleanup(&hdmi->connector);
 	drm_encoder_cleanup(&hdmi->encoder);
+	i2c_del_adapter(hdmi->i2c);
 }
 
 static const struct component_ops sun4i_hdmi_ops = {
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c
new file mode 100644
index 000000000000..2e42d09ab42e
--- /dev/null
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2016 Maxime Ripard <maxime.ripard@free-electrons.com>
+ * Copyright (C) 2017 Jonathan Liu <net147@gmail.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/i2c.h>
+#include <linux/iopoll.h>
+
+#include "sun4i_hdmi.h"
+
+#define SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK ( \
+	SUN4I_HDMI_DDC_INT_STATUS_ILLEGAL_FIFO_OPERATION | \
+	SUN4I_HDMI_DDC_INT_STATUS_DDC_RX_FIFO_UNDERFLOW | \
+	SUN4I_HDMI_DDC_INT_STATUS_DDC_TX_FIFO_OVERFLOW | \
+	SUN4I_HDMI_DDC_INT_STATUS_ARBITRATION_ERROR | \
+	SUN4I_HDMI_DDC_INT_STATUS_ACK_ERROR | \
+	SUN4I_HDMI_DDC_INT_STATUS_BUS_ERROR \
+)
+
+/* FIFO request bit is set when FIFO level is above RX_THRESHOLD during read */
+#define RX_THRESHOLD SUN4I_HDMI_DDC_FIFO_CTRL_RX_THRES_MAX
+/* FIFO request bit is set when FIFO level is below TX_THRESHOLD during write */
+#define TX_THRESHOLD 1
+
+static int fifo_transfer(struct sun4i_hdmi *hdmi, u8 *buf, int len, bool read)
+{
+	/*
+	 * 1 byte takes 9 clock cycles (8 bits + 1 ACK) = 90 us for 100 kHz
+	 * clock. As clock rate is fixed, just round it up to 100 us.
+	 */
+	const unsigned long byte_time_ns = 100;
+	const u32 mask = SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK |
+			 SUN4I_HDMI_DDC_INT_STATUS_FIFO_REQUEST |
+			 SUN4I_HDMI_DDC_INT_STATUS_TRANSFER_COMPLETE;
+	u32 reg;
+
+	/* Limit transfer length by FIFO threshold */
+	len = min_t(int, len, read ? (RX_THRESHOLD + 1) :
+			      (SUN4I_HDMI_DDC_FIFO_SIZE - TX_THRESHOLD + 1));
+
+	/* Wait until error, FIFO request bit set or transfer complete */
+	if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_INT_STATUS_REG, reg,
+			       reg & mask, len * byte_time_ns, 100000))
+		return -ETIMEDOUT;
+
+	if (reg & SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK)
+		return -EIO;
+
+	if (read)
+		readsb(hdmi->base + SUN4I_HDMI_DDC_FIFO_DATA_REG, buf, len);
+	else
+		writesb(hdmi->base + SUN4I_HDMI_DDC_FIFO_DATA_REG, buf, len);
+
+	/* Clear FIFO request bit */
+	writel(SUN4I_HDMI_DDC_INT_STATUS_FIFO_REQUEST,
+	       hdmi->base + SUN4I_HDMI_DDC_INT_STATUS_REG);
+
+	return len;
+}
+
+static int xfer_msg(struct sun4i_hdmi *hdmi, struct i2c_msg *msg)
+{
+	int i, len;
+	u32 reg;
+
+	/* Set FIFO direction */
+	reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
+	reg &= ~SUN4I_HDMI_DDC_CTRL_FIFO_DIR_MASK;
+	reg |= (msg->flags & I2C_M_RD) ?
+	       SUN4I_HDMI_DDC_CTRL_FIFO_DIR_READ :
+	       SUN4I_HDMI_DDC_CTRL_FIFO_DIR_WRITE;
+	writel(reg, hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
+
+	/* Set I2C address */
+	writel(SUN4I_HDMI_DDC_ADDR_SLAVE(msg->addr),
+	       hdmi->base + SUN4I_HDMI_DDC_ADDR_REG);
+
+	/* Set FIFO RX/TX thresholds and clear FIFO */
+	reg = readl(hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG);
+	reg |= SUN4I_HDMI_DDC_FIFO_CTRL_CLEAR;
+	reg &= ~SUN4I_HDMI_DDC_FIFO_CTRL_RX_THRES_MASK;
+	reg |= SUN4I_HDMI_DDC_FIFO_CTRL_RX_THRES(RX_THRESHOLD);
+	reg &= ~SUN4I_HDMI_DDC_FIFO_CTRL_TX_THRES_MASK;
+	reg |= SUN4I_HDMI_DDC_FIFO_CTRL_TX_THRES(TX_THRESHOLD);
+	writel(reg, hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG);
+	if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_FIFO_CTRL_REG,
+			       reg,
+			       !(reg & SUN4I_HDMI_DDC_FIFO_CTRL_CLEAR),
+			       100, 2000))
+		return -EIO;
+
+	/* Set transfer length */
+	writel(msg->len, hdmi->base + SUN4I_HDMI_DDC_BYTE_COUNT_REG);
+
+	/* Set command */
+	writel(msg->flags & I2C_M_RD ?
+	       SUN4I_HDMI_DDC_CMD_IMPLICIT_READ :
+	       SUN4I_HDMI_DDC_CMD_IMPLICIT_WRITE,
+	       hdmi->base + SUN4I_HDMI_DDC_CMD_REG);
+
+	/* Clear interrupt status bits */
+	writel(SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK |
+	       SUN4I_HDMI_DDC_INT_STATUS_FIFO_REQUEST |
+	       SUN4I_HDMI_DDC_INT_STATUS_TRANSFER_COMPLETE,
+	       hdmi->base + SUN4I_HDMI_DDC_INT_STATUS_REG);
+
+	/* Start command */
+	reg = readl(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
+	writel(reg | SUN4I_HDMI_DDC_CTRL_START_CMD,
+	       hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
+
+	/* Transfer bytes */
+	for (i = 0; i < msg->len; i += len) {
+		len = fifo_transfer(hdmi, msg->buf + i, msg->len - i,
+				    msg->flags & I2C_M_RD);
+		if (len <= 0)
+			return len;
+	}
+
+	/* Wait for command to finish */
+	if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG,
+			       reg,
+			       !(reg & SUN4I_HDMI_DDC_CTRL_START_CMD),
+			       100, 100000))
+		return -EIO;
+
+	/* Check for errors */
+	reg = readl(hdmi->base + SUN4I_HDMI_DDC_INT_STATUS_REG);
+	if ((reg & SUN4I_HDMI_DDC_INT_STATUS_ERROR_MASK) ||
+	    !(reg & SUN4I_HDMI_DDC_INT_STATUS_TRANSFER_COMPLETE)) {
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int sun4i_hdmi_i2c_xfer(struct i2c_adapter *adap,
+			       struct i2c_msg *msgs, int num)
+{
+	struct sun4i_hdmi *hdmi = i2c_get_adapdata(adap);
+	u32 reg;
+	int err, i, ret = num;
+
+	for (i = 0; i < num; i++) {
+		if (!msgs[i].len)
+			return -EINVAL;
+		if (msgs[i].len > SUN4I_HDMI_DDC_BYTE_COUNT_MAX)
+			return -EINVAL;
+	}
+
+	/* Reset I2C controller */
+	writel(SUN4I_HDMI_DDC_CTRL_ENABLE | SUN4I_HDMI_DDC_CTRL_RESET,
+	       hdmi->base + SUN4I_HDMI_DDC_CTRL_REG);
+	if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_DDC_CTRL_REG, reg,
+			       !(reg & SUN4I_HDMI_DDC_CTRL_RESET),
+			       100, 2000))
+		return -EIO;
+
+	writel(SUN4I_HDMI_DDC_LINE_CTRL_SDA_ENABLE |
+	       SUN4I_HDMI_DDC_LINE_CTRL_SCL_ENABLE,
+	       hdmi->base + SUN4I_HDMI_DDC_LINE_CTRL_REG);
+
+	clk_prepare_enable(hdmi->ddc_clk);
+	clk_set_rate(hdmi->ddc_clk, 100000);
+
+	for (i = 0; i < num; i++) {
+		err = xfer_msg(hdmi, &msgs[i]);
+		if (err) {
+			ret = err;
+			break;
+		}
+	}
+
+	clk_disable_unprepare(hdmi->ddc_clk);
+	return ret;
+}
+
+static u32 sun4i_hdmi_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm sun4i_hdmi_i2c_algorithm = {
+	.master_xfer	= sun4i_hdmi_i2c_xfer,
+	.functionality	= sun4i_hdmi_i2c_func,
+};
+
+int sun4i_hdmi_i2c_create(struct device *dev, struct sun4i_hdmi *hdmi)
+{
+	struct i2c_adapter *adap;
+	int ret = 0;
+
+	ret = sun4i_ddc_create(hdmi, hdmi->tmds_clk);
+	if (ret)
+		return ret;
+
+	adap = devm_kzalloc(dev, sizeof(*adap), GFP_KERNEL);
+	if (!adap)
+		return -ENOMEM;
+
+	adap->owner = THIS_MODULE;
+	adap->class = I2C_CLASS_DDC;
+	adap->algo = &sun4i_hdmi_i2c_algorithm;
+	strlcpy(adap->name, "sun4i_hdmi_i2c adapter", sizeof(adap->name));
+	i2c_set_adapdata(adap, hdmi);
+
+	ret = i2c_add_adapter(adap);
+	if (ret)
+		return ret;
+
+	hdmi->i2c = adap;
+
+	return ret;
+}
diff --git a/drivers/gpu/drm/sun4i/sun4i_layer.c b/drivers/gpu/drm/sun4i/sun4i_layer.c
index d45f3a1a0a29..7bddf12548d3 100644
--- a/drivers/gpu/drm/sun4i/sun4i_layer.c
+++ b/drivers/gpu/drm/sun4i/sun4i_layer.c
@@ -25,12 +25,6 @@ struct sun4i_plane_desc {
 	       uint32_t                nformats;
 };
 
-static int sun4i_backend_layer_atomic_check(struct drm_plane *plane,
-					    struct drm_plane_state *state)
-{
-	return 0;
-}
-
 static void sun4i_backend_layer_atomic_disable(struct drm_plane *plane,
 					       struct drm_plane_state *old_state)
 {
@@ -52,8 +46,7 @@ static void sun4i_backend_layer_atomic_update(struct drm_plane *plane,
 	sun4i_backend_layer_enable(backend, layer->id, true);
 }
 
-static struct drm_plane_helper_funcs sun4i_backend_layer_helper_funcs = {
-	.atomic_check	= sun4i_backend_layer_atomic_check,
+static const struct drm_plane_helper_funcs sun4i_backend_layer_helper_funcs = {
 	.atomic_disable	= sun4i_backend_layer_atomic_disable,
 	.atomic_update	= sun4i_backend_layer_atomic_update,
 };
diff --git a/drivers/gpu/drm/sun4i/sun4i_rgb.c b/drivers/gpu/drm/sun4i/sun4i_rgb.c
index 42a238bbb899..7cd7090ad63a 100644
--- a/drivers/gpu/drm/sun4i/sun4i_rgb.c
+++ b/drivers/gpu/drm/sun4i/sun4i_rgb.c
@@ -127,13 +127,6 @@ static const struct drm_connector_funcs sun4i_rgb_con_funcs = {
 	.atomic_destroy_state	= drm_atomic_helper_connector_destroy_state,
 };
 
-static int sun4i_rgb_atomic_check(struct drm_encoder *encoder,
-				  struct drm_crtc_state *crtc_state,
-				  struct drm_connector_state *conn_state)
-{
-	return 0;
-}
-
 static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
 {
 	struct sun4i_rgb *rgb = drm_encoder_to_sun4i_rgb(encoder);
@@ -181,7 +174,6 @@ static void sun4i_rgb_encoder_mode_set(struct drm_encoder *encoder,
 }
 
 static struct drm_encoder_helper_funcs sun4i_rgb_enc_helper_funcs = {
-	.atomic_check	= sun4i_rgb_atomic_check,
 	.mode_set	= sun4i_rgb_encoder_mode_set,
 	.disable	= sun4i_rgb_encoder_disable,
 	.enable		= sun4i_rgb_encoder_enable,
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.h b/drivers/gpu/drm/sun4i/sun4i_tcon.h
index e3c50ecdcd04..552c88ec16be 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.h
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.h
@@ -194,8 +194,6 @@ void sun4i_tcon_channel_enable(struct sun4i_tcon *tcon, int channel);
 void sun4i_tcon_enable_vblank(struct sun4i_tcon *tcon, bool enable);
 
 /* Mode Related Controls */
-void sun4i_tcon_switch_interlace(struct sun4i_tcon *tcon,
-				 bool enable);
 void sun4i_tcon_set_mux(struct sun4i_tcon *tcon, int channel,
 			struct drm_encoder *encoder);
 void sun4i_tcon0_mode_set(struct sun4i_tcon *tcon,
diff --git a/drivers/gpu/drm/sun4i/sun4i_tv.c b/drivers/gpu/drm/sun4i/sun4i_tv.c
index 4edf15e299ab..050cfd43c7a0 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tv.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tv.c
@@ -341,13 +341,6 @@ static void sun4i_tv_mode_to_drm_mode(const struct tv_mode *tv_mode,
 	mode->vtotal = mode->vsync_end  + tv_mode->vback_porch;
 }
 
-static int sun4i_tv_atomic_check(struct drm_encoder *encoder,
-				 struct drm_crtc_state *crtc_state,
-				 struct drm_connector_state *conn_state)
-{
-	return 0;
-}
-
 static void sun4i_tv_disable(struct drm_encoder *encoder)
 {
 	struct sun4i_tv *tv = drm_encoder_to_sun4i_tv(encoder);
@@ -489,7 +482,6 @@ static void sun4i_tv_mode_set(struct drm_encoder *encoder,
 }
 
 static struct drm_encoder_helper_funcs sun4i_tv_helper_funcs = {
-	.atomic_check	= sun4i_tv_atomic_check,
 	.disable	= sun4i_tv_disable,
 	.enable		= sun4i_tv_enable,
 	.mode_set	= sun4i_tv_mode_set,