drm/sun4i: Add LVDS support

The TCON supports the LVDS interface to output to a panel or a bridge.
Let's add support for it.

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/7fbb85f33ee1d5009fde4f0d7d236e11ca58b114.1513854122.git-series.maxime.ripard@free-electrons.com

1 files changed, 237 insertions, 2 deletions

diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 41d325c0420f..65c18f6ef693 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -31,10 +31,52 @@
 #include "sun4i_crtc.h"
 #include "sun4i_dotclock.h"
 #include "sun4i_drv.h"
+#include "sun4i_lvds.h"
 #include "sun4i_rgb.h"
 #include "sun4i_tcon.h"
 #include "sunxi_engine.h"
 
+static struct drm_connector *sun4i_tcon_get_connector(const struct drm_encoder *encoder)
+{
+	struct drm_connector *connector;
+	struct drm_connector_list_iter iter;
+
+	drm_connector_list_iter_begin(encoder->dev, &iter);
+	drm_for_each_connector_iter(connector, &iter)
+		if (connector->encoder == encoder) {
+			drm_connector_list_iter_end(&iter);
+			return connector;
+		}
+	drm_connector_list_iter_end(&iter);
+
+	return NULL;
+}
+
+static int sun4i_tcon_get_pixel_depth(const struct drm_encoder *encoder)
+{
+	struct drm_connector *connector;
+	struct drm_display_info *info;
+
+	connector = sun4i_tcon_get_connector(encoder);
+	if (!connector)
+		return -EINVAL;
+
+	info = &connector->display_info;
+	if (info->num_bus_formats != 1)
+		return -EINVAL;
+
+	switch (info->bus_formats[0]) {
+	case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
+		return 18;
+
+	case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
+	case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
+		return 24;
+	}
+
+	return -EINVAL;
+}
+
 static void sun4i_tcon_channel_set_status(struct sun4i_tcon *tcon, int channel,
 					  bool enabled)
 {
@@ -65,13 +107,63 @@ static void sun4i_tcon_channel_set_status(struct sun4i_tcon *tcon, int channel,
 		clk_disable_unprepare(clk);
 }
 
+static void sun4i_tcon_lvds_set_status(struct sun4i_tcon *tcon,
+				       const struct drm_encoder *encoder,
+				       bool enabled)
+{
+	if (enabled) {
+		u8 val;
+
+		regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_IF_REG,
+				   SUN4I_TCON0_LVDS_IF_EN,
+				   SUN4I_TCON0_LVDS_IF_EN);
+
+		/*
+		 * As their name suggest, these values only apply to the A31
+		 * and later SoCs. We'll have to rework this when merging
+		 * support for the older SoCs.
+		 */
+		regmap_write(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
+			     SUN6I_TCON0_LVDS_ANA0_C(2) |
+			     SUN6I_TCON0_LVDS_ANA0_V(3) |
+			     SUN6I_TCON0_LVDS_ANA0_PD(2) |
+			     SUN6I_TCON0_LVDS_ANA0_EN_LDO);
+		udelay(2);
+
+		regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
+				   SUN6I_TCON0_LVDS_ANA0_EN_MB,
+				   SUN6I_TCON0_LVDS_ANA0_EN_MB);
+		udelay(2);
+
+		regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
+				   SUN6I_TCON0_LVDS_ANA0_EN_DRVC,
+				   SUN6I_TCON0_LVDS_ANA0_EN_DRVC);
+
+		if (sun4i_tcon_get_pixel_depth(encoder) == 18)
+			val = 7;
+		else
+			val = 0xf;
+
+		regmap_write_bits(tcon->regs, SUN4I_TCON0_LVDS_ANA0_REG,
+				  SUN6I_TCON0_LVDS_ANA0_EN_DRVD(0xf),
+				  SUN6I_TCON0_LVDS_ANA0_EN_DRVD(val));
+	} else {
+		regmap_update_bits(tcon->regs, SUN4I_TCON0_LVDS_IF_REG,
+				   SUN4I_TCON0_LVDS_IF_EN, 0);
+	}
+}
+
 void sun4i_tcon_set_status(struct sun4i_tcon *tcon,
 			   const struct drm_encoder *encoder,
 			   bool enabled)
 {
+	bool is_lvds = false;
 	int channel;
 
 	switch (encoder->encoder_type) {
+	case DRM_MODE_ENCODER_LVDS:
+		is_lvds = true;
+		/* Fallthrough */
 	case DRM_MODE_ENCODER_NONE:
 		channel = 0;
 		break;
@@ -84,10 +176,16 @@ void sun4i_tcon_set_status(struct sun4i_tcon *tcon,
 		return;
 	}
 
+	if (is_lvds && !enabled)
+		sun4i_tcon_lvds_set_status(tcon, encoder, false);
+
 	regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
 			   SUN4I_TCON_GCTL_TCON_ENABLE,
 			   enabled ? SUN4I_TCON_GCTL_TCON_ENABLE : 0);
 
+	if (is_lvds && enabled)
+		sun4i_tcon_lvds_set_status(tcon, encoder, true);
+
 	sun4i_tcon_channel_set_status(tcon, channel, enabled);
 }
 
@@ -170,6 +268,75 @@ static void sun4i_tcon0_mode_set_common(struct sun4i_tcon *tcon,
 		     SUN4I_TCON0_BASIC0_Y(mode->crtc_vdisplay));
 }
 
+static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon *tcon,
+				      const struct drm_encoder *encoder,
+				      const struct drm_display_mode *mode)
+{
+	unsigned int bp;
+	u8 clk_delay;
+	u32 reg, val = 0;
+
+	tcon->dclk_min_div = 7;
+	tcon->dclk_max_div = 7;
+	sun4i_tcon0_mode_set_common(tcon, mode);
+
+	/* Adjust clock delay */
+	clk_delay = sun4i_tcon_get_clk_delay(mode, 0);
+	regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
+			   SUN4I_TCON0_CTL_CLK_DELAY_MASK,
+			   SUN4I_TCON0_CTL_CLK_DELAY(clk_delay));
+
+	/*
+	 * This is called a backporch in the register documentation,
+	 * but it really is the back porch + hsync
+	 */
+	bp = mode->crtc_htotal - mode->crtc_hsync_start;
+	DRM_DEBUG_DRIVER("Setting horizontal total %d, backporch %d\n",
+			 mode->crtc_htotal, bp);
+
+	/* Set horizontal display timings */
+	regmap_write(tcon->regs, SUN4I_TCON0_BASIC1_REG,
+		     SUN4I_TCON0_BASIC1_H_TOTAL(mode->htotal) |
+		     SUN4I_TCON0_BASIC1_H_BACKPORCH(bp));
+
+	/*
+	 * This is called a backporch in the register documentation,
+	 * but it really is the back porch + hsync
+	 */
+	bp = mode->crtc_vtotal - mode->crtc_vsync_start;
+	DRM_DEBUG_DRIVER("Setting vertical total %d, backporch %d\n",
+			 mode->crtc_vtotal, bp);
+
+	/* Set vertical display timings */
+	regmap_write(tcon->regs, SUN4I_TCON0_BASIC2_REG,
+		     SUN4I_TCON0_BASIC2_V_TOTAL(mode->crtc_vtotal * 2) |
+		     SUN4I_TCON0_BASIC2_V_BACKPORCH(bp));
+
+	reg = SUN4I_TCON0_LVDS_IF_CLK_SEL_TCON0 |
+		SUN4I_TCON0_LVDS_IF_DATA_POL_NORMAL |
+		SUN4I_TCON0_LVDS_IF_CLK_POL_NORMAL;
+	if (sun4i_tcon_get_pixel_depth(encoder) == 24)
+		reg |= SUN4I_TCON0_LVDS_IF_BITWIDTH_24BITS;
+	else
+		reg |= SUN4I_TCON0_LVDS_IF_BITWIDTH_18BITS;
+
+	regmap_write(tcon->regs, SUN4I_TCON0_LVDS_IF_REG, reg);
+
+	/* Setup the polarity of the various signals */
+	if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
+		val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE;
+
+	if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
+		val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE;
+
+	regmap_write(tcon->regs, SUN4I_TCON0_IO_POL_REG, val);
+
+	/* Map output pins to channel 0 */
+	regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
+			   SUN4I_TCON_GCTL_IOMAP_MASK,
+			   SUN4I_TCON_GCTL_IOMAP_TCON0);
+}
+
 static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon,
 				     const struct drm_display_mode *mode)
 {
@@ -336,6 +503,9 @@ void sun4i_tcon_mode_set(struct sun4i_tcon *tcon,
 			 const struct drm_display_mode *mode)
 {
 	switch (encoder->encoder_type) {
+	case DRM_MODE_ENCODER_LVDS:
+		sun4i_tcon0_mode_set_lvds(tcon, encoder, mode);
+		break;
 	case DRM_MODE_ENCODER_NONE:
 		sun4i_tcon0_mode_set_rgb(tcon, mode);
 		sun4i_tcon_set_mux(tcon, 0, encoder);
@@ -667,7 +837,9 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
 	struct drm_device *drm = data;
 	struct sun4i_drv *drv = drm->dev_private;
 	struct sunxi_engine *engine;
+	struct device_node *remote;
 	struct sun4i_tcon *tcon;
+	bool has_lvds_rst, has_lvds_alt, can_lvds;
 	int ret;
 
 	engine = sun4i_tcon_find_engine(drv, dev->of_node);
@@ -698,6 +870,54 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
 		return ret;
 	}
 
+	/*
+	 * This can only be made optional since we've had DT nodes
+	 * without the LVDS reset properties.
+	 *
+	 * If the property is missing, just disable LVDS, and print a
+	 * warning.
+	 */
+	tcon->lvds_rst = devm_reset_control_get_optional(dev, "lvds");
+	if (IS_ERR(tcon->lvds_rst)) {
+		dev_err(dev, "Couldn't get our reset line\n");
+		return PTR_ERR(tcon->lvds_rst);
+	} else if (tcon->lvds_rst) {
+		has_lvds_rst = true;
+		reset_control_reset(tcon->lvds_rst);
+	} else {
+		has_lvds_rst = false;
+	}
+
+	/*
+	 * This can only be made optional since we've had DT nodes
+	 * without the LVDS reset properties.
+	 *
+	 * If the property is missing, just disable LVDS, and print a
+	 * warning.
+	 */
+	if (tcon->quirks->has_lvds_alt) {
+		tcon->lvds_pll = devm_clk_get(dev, "lvds-alt");
+		if (IS_ERR(tcon->lvds_pll)) {
+			if (PTR_ERR(tcon->lvds_pll) == -ENOENT) {
+				has_lvds_alt = false;
+			} else {
+				dev_err(dev, "Couldn't get the LVDS PLL\n");
+				return PTR_ERR(tcon->lvds_rst);
+			}
+		} else {
+			has_lvds_alt = true;
+		}
+	}
+
+	if (!has_lvds_rst || (tcon->quirks->has_lvds_alt && !has_lvds_alt)) {
+		dev_warn(dev,
+			 "Missing LVDS properties, Please upgrade your DT\n");
+		dev_warn(dev, "LVDS output disabled\n");
+		can_lvds = false;
+	} else {
+		can_lvds = true;
+	}
+
 	ret = sun4i_tcon_init_clocks(dev, tcon);
 	if (ret) {
 		dev_err(dev, "Couldn't init our TCON clocks\n");
@@ -729,7 +949,21 @@ static int sun4i_tcon_bind(struct device *dev, struct device *master,
 		goto err_free_clocks;
 	}
 
-	ret = sun4i_rgb_init(drm, tcon);
+	/*
+	 * If we have an LVDS panel connected to the TCON, we should
+	 * just probe the LVDS connector. Otherwise, just probe RGB as
+	 * we used to.
+	 */
+	remote = of_graph_get_remote_node(dev->of_node, 1, 0);
+	if (of_device_is_compatible(remote, "panel-lvds"))
+		if (can_lvds)
+			ret = sun4i_lvds_init(drm, tcon);
+		else
+			ret = -EINVAL;
+	else
+		ret = sun4i_rgb_init(drm, tcon);
+	of_node_put(remote);
+
 	if (ret < 0)
 		goto err_free_clocks;
 
@@ -879,6 +1113,7 @@ static const struct sun4i_tcon_quirks sun5i_a13_quirks = {
 
 static const struct sun4i_tcon_quirks sun6i_a31_quirks = {
 	.has_channel_1		= true,
+	.has_lvds_alt		= true,
 	.needs_de_be_mux	= true,
 	.set_mux		= sun6i_tcon_set_mux,
 };
@@ -895,7 +1130,7 @@ static const struct sun4i_tcon_quirks sun7i_a20_quirks = {
 };
 
 static const struct sun4i_tcon_quirks sun8i_a33_quirks = {
-	/* nothing is supported */
+	.has_lvds_alt		= true,
 };
 
 static const struct sun4i_tcon_quirks sun8i_v3s_quirks = {