[v3,4/4] drm: zte: add VGA driver support

Message ID 1491910226-7831-1-git-send-email-shawnguo@kernel.org
State New
Headers show
Series
  • Untitled series #1105
Related show

Commit Message

Shawn Guo April 11, 2017, 11:30 a.m.
From: Shawn Guo <shawn.guo@linaro.org>

It adds VGA driver support, which needs to configure corresponding VOU
interface in RGB_888 format, and thus the following changes are needed
on zx_vou.

 - Rename the CSC block of Graphic Layer a bit to make it more specific,
   and add CSC of Channel to support RGB output.
 - Bypass Dither block for RGB output.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
Changes for v3:
 - Set device state into disconnected when edid read fails in .get_modes
   hook.
 - Drop locking and add comments for understanding why it's not
   necessary.

Changes for v2:
 - Add return check for encoder and connector init function calls.
 - Improve comments in function zx_vga_irq_handler() to avoid confusion.
 - Add lock for VGA_AUTO_DETECT_SEL register access to avoid race
   condition between irq handler and .get_modes hook.
 drivers/gpu/drm/zte/Makefile      |   1 +
 drivers/gpu/drm/zte/zx_drm_drv.c  |   1 +
 drivers/gpu/drm/zte/zx_drm_drv.h  |   1 +
 drivers/gpu/drm/zte/zx_vga.c      | 531 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/zte/zx_vga_regs.h |  36 +++
 drivers/gpu/drm/zte/zx_vou.c      |  33 ++-
 drivers/gpu/drm/zte/zx_vou_regs.h |  12 +-
 7 files changed, 611 insertions(+), 4 deletions(-)
 create mode 100644 drivers/gpu/drm/zte/zx_vga.c
 create mode 100644 drivers/gpu/drm/zte/zx_vga_regs.h

Comments

Shawn Guo May 3, 2017, 12:44 a.m. | #1
Hi Sean,

On Tue, Apr 11, 2017 at 7:30 PM, Shawn Guo <shawnguo@kernel.org> wrote:
> From: Shawn Guo <shawn.guo@linaro.org>
>
> It adds VGA driver support, which needs to configure corresponding VOU
> interface in RGB_888 format, and thus the following changes are needed
> on zx_vou.
>
>  - Rename the CSC block of Graphic Layer a bit to make it more specific,
>    and add CSC of Channel to support RGB output.
>  - Bypass Dither block for RGB output.
>
> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
> Changes for v3:
>  - Set device state into disconnected when edid read fails in .get_modes
>    hook.
>  - Drop locking and add comments for understanding why it's not
>    necessary.

Are you okay with this version?  I need a 'go' from you to push the
series to drm-misc-next.

Shawn
Sean Paul May 3, 2017, 7:25 p.m. | #2
On Wed, May 03, 2017 at 08:44:53AM +0800, Shawn Guo wrote:
> Hi Sean,
> 
> On Tue, Apr 11, 2017 at 7:30 PM, Shawn Guo <shawnguo@kernel.org> wrote:
> > From: Shawn Guo <shawn.guo@linaro.org>
> >
> > It adds VGA driver support, which needs to configure corresponding VOU
> > interface in RGB_888 format, and thus the following changes are needed
> > on zx_vou.
> >
> >  - Rename the CSC block of Graphic Layer a bit to make it more specific,
> >    and add CSC of Channel to support RGB output.
> >  - Bypass Dither block for RGB output.
> >
> > Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
> > Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > ---
> > Changes for v3:
> >  - Set device state into disconnected when edid read fails in .get_modes
> >    hook.
> >  - Drop locking and add comments for understanding why it's not
> >    necessary.
> 
> Are you okay with this version?  I need a 'go' from you to push the
> series to drm-misc-next.

Apologies for the delay.

Reviewed-by: Sean Paul <seanpaul@chromium.org>

> 
> Shawn

Patch

diff --git a/drivers/gpu/drm/zte/Makefile b/drivers/gpu/drm/zte/Makefile
index 01352b56c418..9df7766a7f9d 100644
--- a/drivers/gpu/drm/zte/Makefile
+++ b/drivers/gpu/drm/zte/Makefile
@@ -3,6 +3,7 @@  zxdrm-y := \
 	zx_hdmi.o \
 	zx_plane.o \
 	zx_tvenc.o \
+	zx_vga.o \
 	zx_vou.o
 
 obj-$(CONFIG_DRM_ZTE) += zxdrm.o
diff --git a/drivers/gpu/drm/zte/zx_drm_drv.c b/drivers/gpu/drm/zte/zx_drm_drv.c
index 5c6944a1e72c..8a6892eeb44f 100644
--- a/drivers/gpu/drm/zte/zx_drm_drv.c
+++ b/drivers/gpu/drm/zte/zx_drm_drv.c
@@ -248,6 +248,7 @@  static int zx_drm_remove(struct platform_device *pdev)
 	&zx_crtc_driver,
 	&zx_hdmi_driver,
 	&zx_tvenc_driver,
+	&zx_vga_driver,
 	&zx_drm_platform_driver,
 };
 
diff --git a/drivers/gpu/drm/zte/zx_drm_drv.h b/drivers/gpu/drm/zte/zx_drm_drv.h
index 5ca035b079c7..2a8cdc5f8be4 100644
--- a/drivers/gpu/drm/zte/zx_drm_drv.h
+++ b/drivers/gpu/drm/zte/zx_drm_drv.h
@@ -14,6 +14,7 @@ 
 extern struct platform_driver zx_crtc_driver;
 extern struct platform_driver zx_hdmi_driver;
 extern struct platform_driver zx_tvenc_driver;
+extern struct platform_driver zx_vga_driver;
 
 static inline u32 zx_readl(void __iomem *reg)
 {
diff --git a/drivers/gpu/drm/zte/zx_vga.c b/drivers/gpu/drm/zte/zx_vga.c
new file mode 100644
index 000000000000..1e0811f775cb
--- /dev/null
+++ b/drivers/gpu/drm/zte/zx_vga.c
@@ -0,0 +1,531 @@ 
+/*
+ * Copyright (C) 2017 Sanechips Technology Co., Ltd.
+ * Copyright 2017 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drmP.h>
+
+#include "zx_drm_drv.h"
+#include "zx_vga_regs.h"
+#include "zx_vou.h"
+
+struct zx_vga_pwrctrl {
+	struct regmap *regmap;
+	u32 reg;
+	u32 mask;
+};
+
+struct zx_vga_i2c {
+	struct i2c_adapter adap;
+	struct mutex lock;
+};
+
+struct zx_vga {
+	struct drm_connector connector;
+	struct drm_encoder encoder;
+	struct zx_vga_i2c *ddc;
+	struct device *dev;
+	void __iomem *mmio;
+	struct clk *i2c_wclk;
+	struct zx_vga_pwrctrl pwrctrl;
+	struct completion complete;
+	bool connected;
+};
+
+#define to_zx_vga(x) container_of(x, struct zx_vga, x)
+
+static void zx_vga_encoder_enable(struct drm_encoder *encoder)
+{
+	struct zx_vga *vga = to_zx_vga(encoder);
+	struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
+
+	/* Set bit to power up VGA DACs */
+	regmap_update_bits(pwrctrl->regmap, pwrctrl->reg, pwrctrl->mask,
+			   pwrctrl->mask);
+
+	vou_inf_enable(VOU_VGA, encoder->crtc);
+}
+
+static void zx_vga_encoder_disable(struct drm_encoder *encoder)
+{
+	struct zx_vga *vga = to_zx_vga(encoder);
+	struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
+
+	vou_inf_disable(VOU_VGA, encoder->crtc);
+
+	/* Clear bit to power down VGA DACs */
+	regmap_update_bits(pwrctrl->regmap, pwrctrl->reg, pwrctrl->mask, 0);
+}
+
+static const struct drm_encoder_helper_funcs zx_vga_encoder_helper_funcs = {
+	.enable	= zx_vga_encoder_enable,
+	.disable = zx_vga_encoder_disable,
+};
+
+static const struct drm_encoder_funcs zx_vga_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
+static int zx_vga_connector_get_modes(struct drm_connector *connector)
+{
+	struct zx_vga *vga = to_zx_vga(connector);
+	struct edid *edid;
+	int ret;
+
+	/*
+	 * Clear both detection bits to switch I2C bus from device
+	 * detecting to EDID reading.
+	 */
+	zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, 0);
+
+	edid = drm_get_edid(connector, &vga->ddc->adap);
+	if (!edid) {
+		/*
+		 * If EDID reading fails, we set the device state into
+		 * disconnected.  Locking is not required here, since the
+		 * VGA_AUTO_DETECT_SEL register write in irq handler cannot
+		 * be triggered when both detection bits are cleared as above.
+		 */
+		zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL,
+			  VGA_DETECT_SEL_NO_DEVICE);
+		vga->connected = false;
+		return 0;
+	}
+
+	/*
+	 * As edid reading succeeds, device must be connected, so we set
+	 * up detection bit for unplug interrupt here.
+	 */
+	zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, VGA_DETECT_SEL_HAS_DEVICE);
+
+	drm_mode_connector_update_edid_property(connector, edid);
+	ret = drm_add_edid_modes(connector, edid);
+	kfree(edid);
+
+	return ret;
+}
+
+static enum drm_mode_status
+zx_vga_connector_mode_valid(struct drm_connector *connector,
+			    struct drm_display_mode *mode)
+{
+	return MODE_OK;
+}
+
+static struct drm_connector_helper_funcs zx_vga_connector_helper_funcs = {
+	.get_modes = zx_vga_connector_get_modes,
+	.mode_valid = zx_vga_connector_mode_valid,
+};
+
+static enum drm_connector_status
+zx_vga_connector_detect(struct drm_connector *connector, bool force)
+{
+	struct zx_vga *vga = to_zx_vga(connector);
+
+	return vga->connected ? connector_status_connected :
+				connector_status_disconnected;
+}
+
+static const struct drm_connector_funcs zx_vga_connector_funcs = {
+	.dpms = drm_atomic_helper_connector_dpms,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.detect = zx_vga_connector_detect,
+	.destroy = drm_connector_cleanup,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static int zx_vga_register(struct drm_device *drm, struct zx_vga *vga)
+{
+	struct drm_encoder *encoder = &vga->encoder;
+	struct drm_connector *connector = &vga->connector;
+	struct device *dev = vga->dev;
+	int ret;
+
+	encoder->possible_crtcs = VOU_CRTC_MASK;
+
+	ret = drm_encoder_init(drm, encoder, &zx_vga_encoder_funcs,
+			       DRM_MODE_ENCODER_DAC, NULL);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "failed to init encoder: %d\n", ret);
+		return ret;
+	};
+
+	drm_encoder_helper_add(encoder, &zx_vga_encoder_helper_funcs);
+
+	vga->connector.polled = DRM_CONNECTOR_POLL_HPD;
+
+	ret = drm_connector_init(drm, connector, &zx_vga_connector_funcs,
+				 DRM_MODE_CONNECTOR_VGA);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "failed to init connector: %d\n", ret);
+		goto clean_encoder;
+	};
+
+	drm_connector_helper_add(connector, &zx_vga_connector_helper_funcs);
+
+	ret = drm_mode_connector_attach_encoder(connector, encoder);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "failed to attach encoder: %d\n", ret);
+		goto clean_connector;
+	};
+
+	return 0;
+
+clean_connector:
+	drm_connector_cleanup(connector);
+clean_encoder:
+	drm_encoder_cleanup(encoder);
+	return ret;
+}
+
+static int zx_vga_pwrctrl_init(struct zx_vga *vga)
+{
+	struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
+	struct device *dev = vga->dev;
+	struct of_phandle_args out_args;
+	struct regmap *regmap;
+	int ret;
+
+	ret = of_parse_phandle_with_fixed_args(dev->of_node,
+				"zte,vga-power-control", 2, 0, &out_args);
+	if (ret)
+		return ret;
+
+	regmap = syscon_node_to_regmap(out_args.np);
+	if (IS_ERR(regmap)) {
+		ret = PTR_ERR(regmap);
+		goto out;
+	}
+
+	pwrctrl->regmap = regmap;
+	pwrctrl->reg = out_args.args[0];
+	pwrctrl->mask = out_args.args[1];
+
+out:
+	of_node_put(out_args.np);
+	return ret;
+}
+
+static int zx_vga_i2c_read(struct zx_vga *vga, struct i2c_msg *msg)
+{
+	int len = msg->len;
+	u8 *buf = msg->buf;
+	u32 offset = 0;
+	int i;
+
+	reinit_completion(&vga->complete);
+
+	/* Select combo write */
+	zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_COMBO, VGA_CMD_COMBO);
+	zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_RW, 0);
+
+	while (len > 0) {
+		u32 cnt;
+
+		/* Clear RX FIFO */
+		zx_writel_mask(vga->mmio + VGA_RXF_CTRL, VGA_RX_FIFO_CLEAR,
+			       VGA_RX_FIFO_CLEAR);
+
+		/* Data offset to read from */
+		zx_writel(vga->mmio + VGA_SUB_ADDR, offset);
+
+		/* Kick off the transfer */
+		zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_TRANS,
+			       VGA_CMD_TRANS);
+
+		if (!wait_for_completion_timeout(&vga->complete,
+						 msecs_to_jiffies(1000))) {
+			DRM_DEV_ERROR(vga->dev, "transfer timeout\n");
+			return -ETIMEDOUT;
+		}
+
+		cnt = zx_readl(vga->mmio + VGA_RXF_STATUS);
+		cnt = (cnt & VGA_RXF_COUNT_MASK) >> VGA_RXF_COUNT_SHIFT;
+		/* FIFO status may report more data than we need to read */
+		cnt = min_t(u32, len, cnt);
+
+		for (i = 0; i < cnt; i++)
+			*buf++ = zx_readl(vga->mmio + VGA_DATA);
+
+		len -= cnt;
+		offset += cnt;
+	}
+
+	return 0;
+}
+
+static int zx_vga_i2c_write(struct zx_vga *vga, struct i2c_msg *msg)
+{
+	/*
+	 * The DDC I2C adapter is only for reading EDID data, so we assume
+	 * that the write to this adapter must be the EDID data offset.
+	 */
+	if ((msg->len != 1) || ((msg->addr != DDC_ADDR)))
+		return -EINVAL;
+
+	/* Hardware will take care of the slave address shifting */
+	zx_writel(vga->mmio + VGA_DEVICE_ADDR, msg->addr);
+
+	return 0;
+}
+
+static int zx_vga_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+			   int num)
+{
+	struct zx_vga *vga = i2c_get_adapdata(adap);
+	struct zx_vga_i2c *ddc = vga->ddc;
+	int ret = 0;
+	int i;
+
+	mutex_lock(&ddc->lock);
+
+	for (i = 0; i < num; i++) {
+		if (msgs[i].flags & I2C_M_RD)
+			ret = zx_vga_i2c_read(vga, &msgs[i]);
+		else
+			ret = zx_vga_i2c_write(vga, &msgs[i]);
+
+		if (ret < 0)
+			break;
+	}
+
+	if (!ret)
+		ret = num;
+
+	mutex_unlock(&ddc->lock);
+
+	return ret;
+}
+
+static u32 zx_vga_i2c_func(struct i2c_adapter *adapter)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm zx_vga_algorithm = {
+	.master_xfer	= zx_vga_i2c_xfer,
+	.functionality	= zx_vga_i2c_func,
+};
+
+static int zx_vga_ddc_register(struct zx_vga *vga)
+{
+	struct device *dev = vga->dev;
+	struct i2c_adapter *adap;
+	struct zx_vga_i2c *ddc;
+	int ret;
+
+	ddc = devm_kzalloc(dev, sizeof(*ddc), GFP_KERNEL);
+	if (!ddc)
+		return -ENOMEM;
+
+	vga->ddc = ddc;
+	mutex_init(&ddc->lock);
+
+	adap = &ddc->adap;
+	adap->owner = THIS_MODULE;
+	adap->class = I2C_CLASS_DDC;
+	adap->dev.parent = dev;
+	adap->algo = &zx_vga_algorithm;
+	snprintf(adap->name, sizeof(adap->name), "zx vga i2c");
+
+	ret = i2c_add_adapter(adap);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "failed to add I2C adapter: %d\n", ret);
+		return ret;
+	}
+
+	i2c_set_adapdata(adap, vga);
+
+	return 0;
+}
+
+static irqreturn_t zx_vga_irq_thread(int irq, void *dev_id)
+{
+	struct zx_vga *vga = dev_id;
+
+	drm_helper_hpd_irq_event(vga->connector.dev);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t zx_vga_irq_handler(int irq, void *dev_id)
+{
+	struct zx_vga *vga = dev_id;
+	u32 status;
+
+	status = zx_readl(vga->mmio + VGA_I2C_STATUS);
+
+	/* Clear interrupt status */
+	zx_writel_mask(vga->mmio + VGA_I2C_STATUS, VGA_CLEAR_IRQ,
+		       VGA_CLEAR_IRQ);
+
+	if (status & VGA_DEVICE_CONNECTED) {
+		/*
+		 * Since VGA_DETECT_SEL bits need to be reset for switching DDC
+		 * bus from device detection to EDID read, rather than setting
+		 * up HAS_DEVICE bit here, we need to do that in .get_modes
+		 * hook for unplug detecting after EDID read succeeds.
+		 */
+		vga->connected = true;
+		return IRQ_WAKE_THREAD;
+	}
+
+	if (status & VGA_DEVICE_DISCONNECTED) {
+		zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL,
+			  VGA_DETECT_SEL_NO_DEVICE);
+		vga->connected = false;
+		return IRQ_WAKE_THREAD;
+	}
+
+	if (status & VGA_TRANS_DONE) {
+		complete(&vga->complete);
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static void zx_vga_hw_init(struct zx_vga *vga)
+{
+	unsigned long ref = clk_get_rate(vga->i2c_wclk);
+	int div;
+
+	/*
+	 * Set up I2C fast speed divider per formula below to get 400kHz.
+	 *   scl = ref / ((div + 1) * 4)
+	 */
+	div = DIV_ROUND_UP(ref / 1000, 400 * 4) - 1;
+	zx_writel(vga->mmio + VGA_CLK_DIV_FS, div);
+
+	/* Set up device detection */
+	zx_writel(vga->mmio + VGA_AUTO_DETECT_PARA, 0x80);
+	zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, VGA_DETECT_SEL_NO_DEVICE);
+
+	/*
+	 * We need to poke monitor via DDC bus to get connection irq
+	 * start working.
+	 */
+	zx_writel(vga->mmio + VGA_DEVICE_ADDR, DDC_ADDR);
+	zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_TRANS, VGA_CMD_TRANS);
+}
+
+static int zx_vga_bind(struct device *dev, struct device *master, void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct drm_device *drm = data;
+	struct resource *res;
+	struct zx_vga *vga;
+	int irq;
+	int ret;
+
+	vga = devm_kzalloc(dev, sizeof(*vga), GFP_KERNEL);
+	if (!vga)
+		return -ENOMEM;
+
+	vga->dev = dev;
+	dev_set_drvdata(dev, vga);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	vga->mmio = devm_ioremap_resource(dev, res);
+	if (IS_ERR(vga->mmio))
+		return PTR_ERR(vga->mmio);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	vga->i2c_wclk = devm_clk_get(dev, "i2c_wclk");
+	if (IS_ERR(vga->i2c_wclk)) {
+		ret = PTR_ERR(vga->i2c_wclk);
+		DRM_DEV_ERROR(dev, "failed to get i2c_wclk: %d\n", ret);
+		return ret;
+	}
+
+	ret = zx_vga_pwrctrl_init(vga);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "failed to init power control: %d\n", ret);
+		return ret;
+	}
+
+	ret = zx_vga_ddc_register(vga);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "failed to register ddc: %d\n", ret);
+		return ret;
+	}
+
+	ret = zx_vga_register(drm, vga);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "failed to register vga: %d\n", ret);
+		return ret;
+	}
+
+	init_completion(&vga->complete);
+
+	ret = devm_request_threaded_irq(dev, irq, zx_vga_irq_handler,
+					zx_vga_irq_thread, IRQF_SHARED,
+					dev_name(dev), vga);
+	if (ret) {
+		DRM_DEV_ERROR(dev, "failed to request threaded irq: %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(vga->i2c_wclk);
+	if (ret)
+		return ret;
+
+	zx_vga_hw_init(vga);
+
+	return 0;
+}
+
+static void zx_vga_unbind(struct device *dev, struct device *master,
+			  void *data)
+{
+	struct zx_vga *vga = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(vga->i2c_wclk);
+}
+
+static const struct component_ops zx_vga_component_ops = {
+	.bind = zx_vga_bind,
+	.unbind = zx_vga_unbind,
+};
+
+static int zx_vga_probe(struct platform_device *pdev)
+{
+	return component_add(&pdev->dev, &zx_vga_component_ops);
+}
+
+static int zx_vga_remove(struct platform_device *pdev)
+{
+	component_del(&pdev->dev, &zx_vga_component_ops);
+	return 0;
+}
+
+static const struct of_device_id zx_vga_of_match[] = {
+	{ .compatible = "zte,zx296718-vga", },
+	{ /* end */ },
+};
+MODULE_DEVICE_TABLE(of, zx_vga_of_match);
+
+struct platform_driver zx_vga_driver = {
+	.probe = zx_vga_probe,
+	.remove = zx_vga_remove,
+	.driver	= {
+		.name = "zx-vga",
+		.of_match_table	= zx_vga_of_match,
+	},
+};
diff --git a/drivers/gpu/drm/zte/zx_vga_regs.h b/drivers/gpu/drm/zte/zx_vga_regs.h
new file mode 100644
index 000000000000..feaa345fe6a6
--- /dev/null
+++ b/drivers/gpu/drm/zte/zx_vga_regs.h
@@ -0,0 +1,36 @@ 
+/*
+ * Copyright (C) 2017 Sanechips Technology Co., Ltd.
+ * Copyright 2017 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __ZX_VGA_REGS_H__
+#define __ZX_VGA_REGS_H__
+
+#define VGA_CMD_CFG			0x04
+#define VGA_CMD_TRANS			BIT(6)
+#define VGA_CMD_COMBO			BIT(5)
+#define VGA_CMD_RW			BIT(4)
+#define VGA_SUB_ADDR			0x0c
+#define VGA_DEVICE_ADDR			0x10
+#define VGA_CLK_DIV_FS			0x14
+#define VGA_RXF_CTRL			0x20
+#define VGA_RX_FIFO_CLEAR		BIT(7)
+#define VGA_DATA			0x24
+#define VGA_I2C_STATUS			0x28
+#define VGA_DEVICE_DISCONNECTED		BIT(7)
+#define VGA_DEVICE_CONNECTED		BIT(6)
+#define VGA_CLEAR_IRQ			BIT(4)
+#define VGA_TRANS_DONE			BIT(0)
+#define VGA_RXF_STATUS			0x30
+#define VGA_RXF_COUNT_SHIFT		2
+#define VGA_RXF_COUNT_MASK		GENMASK(7, 2)
+#define VGA_AUTO_DETECT_PARA		0x34
+#define VGA_AUTO_DETECT_SEL		0x38
+#define VGA_DETECT_SEL_HAS_DEVICE	BIT(1)
+#define VGA_DETECT_SEL_NO_DEVICE	BIT(0)
+
+#endif /* __ZX_VGA_REGS_H__ */
diff --git a/drivers/gpu/drm/zte/zx_vou.c b/drivers/gpu/drm/zte/zx_vou.c
index 2a2d90bd9425..cc5bdfc53e8e 100644
--- a/drivers/gpu/drm/zte/zx_vou.c
+++ b/drivers/gpu/drm/zte/zx_vou.c
@@ -23,6 +23,7 @@ 
 #include <drm/drm_plane_helper.h>
 #include <drm/drmP.h>
 
+#include "zx_common_regs.h"
 #include "zx_drm_drv.h"
 #include "zx_plane.h"
 #include "zx_vou.h"
@@ -122,6 +123,8 @@  struct zx_crtc {
 	struct drm_plane *primary;
 	struct zx_vou_hw *vou;
 	void __iomem *chnreg;
+	void __iomem *chncsc;
+	void __iomem *dither;
 	const struct zx_crtc_regs *regs;
 	const struct zx_crtc_bits *bits;
 	enum vou_chn_type chn_type;
@@ -204,6 +207,11 @@  struct vou_inf {
 		.clocks_en_bits = BIT(15),
 		.clocks_sel_bits = BIT(11) | BIT(0),
 	},
+	[VOU_VGA] = {
+		.data_sel = VOU_RGB_888,
+		.clocks_en_bits = BIT(1),
+		.clocks_sel_bits = BIT(10),
+	},
 };
 
 static inline struct zx_vou_hw *crtc_to_vou(struct drm_crtc *crtc)
@@ -227,9 +235,26 @@  void vou_inf_enable(enum vou_inf_id id, struct drm_crtc *crtc)
 	struct zx_crtc *zcrtc = to_zx_crtc(crtc);
 	struct zx_vou_hw *vou = zcrtc->vou;
 	struct vou_inf *inf = &vou_infs[id];
+	void __iomem *dither = zcrtc->dither;
+	void __iomem *csc = zcrtc->chncsc;
 	bool is_main = zcrtc->chn_type == VOU_CHN_MAIN;
 	u32 data_sel_shift = id << 1;
 
+	if (inf->data_sel != VOU_YUV444) {
+		/* Enable channel CSC for RGB output */
+		zx_writel_mask(csc + CSC_CTRL0, CSC_COV_MODE_MASK,
+			       CSC_BT709_IMAGE_YCBCR2RGB << CSC_COV_MODE_SHIFT);
+		zx_writel_mask(csc + CSC_CTRL0, CSC_WORK_ENABLE,
+			       CSC_WORK_ENABLE);
+
+		/* Bypass Dither block for RGB output */
+		zx_writel_mask(dither + OSD_DITHER_CTRL0, DITHER_BYSPASS,
+			       DITHER_BYSPASS);
+	} else {
+		zx_writel_mask(csc + CSC_CTRL0, CSC_WORK_ENABLE, 0);
+		zx_writel_mask(dither + OSD_DITHER_CTRL0, DITHER_BYSPASS, 0);
+	}
+
 	/* Select data format */
 	zx_writel_mask(vou->vouctl + VOU_INF_DATA_SEL, 0x3 << data_sel_shift,
 		       inf->data_sel << data_sel_shift);
@@ -502,20 +527,24 @@  static int zx_crtc_init(struct drm_device *drm, struct zx_vou_hw *vou,
 
 	if (chn_type == VOU_CHN_MAIN) {
 		zplane->layer = vou->osd + MAIN_GL_OFFSET;
-		zplane->csc = vou->osd + MAIN_CSC_OFFSET;
+		zplane->csc = vou->osd + MAIN_GL_CSC_OFFSET;
 		zplane->hbsc = vou->osd + MAIN_HBSC_OFFSET;
 		zplane->rsz = vou->otfppu + MAIN_RSZ_OFFSET;
 		zplane->bits = &zx_gl_bits[0];
 		zcrtc->chnreg = vou->osd + OSD_MAIN_CHN;
+		zcrtc->chncsc = vou->osd + MAIN_CHN_CSC_OFFSET;
+		zcrtc->dither = vou->osd + MAIN_DITHER_OFFSET;
 		zcrtc->regs = &main_crtc_regs;
 		zcrtc->bits = &main_crtc_bits;
 	} else {
 		zplane->layer = vou->osd + AUX_GL_OFFSET;
-		zplane->csc = vou->osd + AUX_CSC_OFFSET;
+		zplane->csc = vou->osd + AUX_GL_CSC_OFFSET;
 		zplane->hbsc = vou->osd + AUX_HBSC_OFFSET;
 		zplane->rsz = vou->otfppu + AUX_RSZ_OFFSET;
 		zplane->bits = &zx_gl_bits[1];
 		zcrtc->chnreg = vou->osd + OSD_AUX_CHN;
+		zcrtc->chncsc = vou->osd + AUX_CHN_CSC_OFFSET;
+		zcrtc->dither = vou->osd + AUX_DITHER_OFFSET;
 		zcrtc->regs = &aux_crtc_regs;
 		zcrtc->bits = &aux_crtc_bits;
 	}
diff --git a/drivers/gpu/drm/zte/zx_vou_regs.h b/drivers/gpu/drm/zte/zx_vou_regs.h
index c066ef123434..5a218351b497 100644
--- a/drivers/gpu/drm/zte/zx_vou_regs.h
+++ b/drivers/gpu/drm/zte/zx_vou_regs.h
@@ -13,13 +13,17 @@ 
 
 /* Sub-module offset */
 #define MAIN_GL_OFFSET			0x130
-#define MAIN_CSC_OFFSET			0x580
+#define MAIN_GL_CSC_OFFSET		0x580
+#define MAIN_CHN_CSC_OFFSET		0x6c0
 #define MAIN_HBSC_OFFSET		0x820
+#define MAIN_DITHER_OFFSET		0x960
 #define MAIN_RSZ_OFFSET			0x600 /* OTFPPU sub-module */
 
 #define AUX_GL_OFFSET			0x200
-#define AUX_CSC_OFFSET			0x5d0
+#define AUX_GL_CSC_OFFSET		0x5d0
+#define AUX_CHN_CSC_OFFSET		0x710
 #define AUX_HBSC_OFFSET			0x860
+#define AUX_DITHER_OFFSET		0x970
 #define AUX_RSZ_OFFSET			0x800
 
 #define OSD_VL0_OFFSET			0x040
@@ -78,6 +82,10 @@ 
 #define CHN_INTERLACE_BUF_CTRL		0x24
 #define CHN_INTERLACE_EN		BIT(2)
 
+/* Dither registers */
+#define OSD_DITHER_CTRL0		0x00
+#define DITHER_BYSPASS			BIT(31)
+
 /* TIMING_CTRL registers */
 #define TIMING_TC_ENABLE		0x04
 #define AUX_TC_EN			BIT(1)