drm/msm/sde: Add backlight class support for sde drm driver

Add backlight class support for sde drm driver which provides
sysfs interface to userspace to control display brightness.

Change-Id: I4f777618e8f2ff61e72beddb7a5bd1fa6e9dd5df
Signed-off-by: Vishnuvardhan Prodduturi <vproddut@codeaurora.org>

11 files changed, 193 insertions, 11 deletions

diff --git a/Documentation/devicetree/bindings/fb/mdss-dsi-panel.txt b/Documentation/devicetree/bindings/fb/mdss-dsi-panel.txt
index 9fc942cc627d..1fffb617248a 100644
--- a/Documentation/devicetree/bindings/fb/mdss-dsi-panel.txt
+++ b/Documentation/devicetree/bindings/fb/mdss-dsi-panel.txt
@@ -538,6 +538,7 @@ Example:
 		qcom,mdss-dsi-underflow-color = <0xff>;
 		qcom,mdss-dsi-bl-min-level = <1>;
 		qcom,mdss-dsi-bl-max-level = < 15>;
+		qcom,mdss-brightness-max-level = <255>;
 		qcom,mdss-dsi-interleave-mode = <0>;
 		qcom,mdss-dsi-panel-type = "dsi_video_mode";
 		qcom,mdss-dsi-te-check-enable;
diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
index 8a534316e240..f756c0c59ffa 100644
--- a/drivers/gpu/drm/msm/Makefile
+++ b/drivers/gpu/drm/msm/Makefile
@@ -41,6 +41,7 @@ msm_drm-y := \
 	sde/sde_kms.o \
 	sde/sde_plane.o \
 	sde/sde_connector.o \
+	sde/sde_backlight.o \
 	sde/sde_color_processing.o \
 	sde/sde_vbif.o
 
diff --git a/drivers/gpu/drm/msm/dsi-staging/dsi_display.c b/drivers/gpu/drm/msm/dsi-staging/dsi_display.c
index 825bf2dc3ec1..5a166a4bae93 100644
--- a/drivers/gpu/drm/msm/dsi-staging/dsi_display.c
+++ b/drivers/gpu/drm/msm/dsi-staging/dsi_display.c
@@ -36,6 +36,24 @@ static const struct of_device_id dsi_display_dt_match[] = {
 
 static struct dsi_display *main_display;
 
+int dsi_display_set_backlight(void *display, u32 bl_lvl)
+{
+	struct dsi_display *dsi_display = display;
+	struct dsi_panel *panel;
+	int rc = 0;
+
+	if (dsi_display == NULL)
+		return -EINVAL;
+
+	panel = dsi_display->panel;
+
+	rc = dsi_panel_set_backlight(panel, bl_lvl);
+	if (rc)
+		pr_err("unable to set backlight\n");
+
+	return rc;
+}
+
 static ssize_t debugfs_dump_info_read(struct file *file,
 				      char __user *buff,
 				      size_t count,
diff --git a/drivers/gpu/drm/msm/dsi-staging/dsi_display.h b/drivers/gpu/drm/msm/dsi-staging/dsi_display.h
index 813e7e385076..b77bf268dbd1 100644
--- a/drivers/gpu/drm/msm/dsi-staging/dsi_display.h
+++ b/drivers/gpu/drm/msm/dsi-staging/dsi_display.h
@@ -332,4 +332,5 @@ int dsi_display_set_tpg_state(struct dsi_display *display, bool enable);
 int dsi_display_clock_gate(struct dsi_display *display, bool enable);
 int dsi_dispaly_static_frame(struct dsi_display *display, bool enable);
 
+int dsi_display_set_backlight(void *display, u32 bl_lvl);
 #endif /* _DSI_DISPLAY_H_ */
diff --git a/drivers/gpu/drm/msm/dsi-staging/dsi_panel.c b/drivers/gpu/drm/msm/dsi-staging/dsi_panel.c
index 6e753f08a77e..28cfa1fba6d9 100644
--- a/drivers/gpu/drm/msm/dsi-staging/dsi_panel.c
+++ b/drivers/gpu/drm/msm/dsi-staging/dsi_panel.c
@@ -358,6 +358,23 @@ static int dsi_panel_led_bl_register(struct dsi_panel *panel,
 }
 #endif
 
+int dsi_panel_set_backlight(struct dsi_panel *panel, u32 bl_lvl)
+{
+	int rc = 0;
+	struct dsi_backlight_config *bl = &panel->bl_config;
+
+	switch (bl->type) {
+	case DSI_BACKLIGHT_WLED:
+		led_trigger_event(bl->wled, bl_lvl);
+		break;
+	default:
+		pr_err("Backlight type(%d) not supported\n", bl->type);
+		rc = -ENOTSUPP;
+	}
+
+	return rc;
+}
+
 static int dsi_panel_bl_register(struct dsi_panel *panel)
 {
 	int rc = 0;
@@ -1423,18 +1440,28 @@ static int dsi_panel_parse_bl_config(struct dsi_panel *panel,
 	if (rc) {
 		pr_debug("[%s] bl-min-level unspecified, defaulting to zero\n",
 			 panel->name);
-		panel->bl_config.min_level = 0;
+		panel->bl_config.bl_min_level = 0;
 	} else {
-		panel->bl_config.min_level = val;
+		panel->bl_config.bl_min_level = val;
 	}
 
 	rc = of_property_read_u32(of_node, "qcom,mdss-dsi-bl-max-level", &val);
 	if (rc) {
-		pr_debug("[%s] bl-max-level unspecified, defaulting to 255\n",
+		pr_debug("[%s] bl-max-level unspecified, defaulting to max level\n",
+			 panel->name);
+		panel->bl_config.bl_max_level = MAX_BL_LEVEL;
+	} else {
+		panel->bl_config.bl_max_level = val;
+	}
+
+	rc = of_property_read_u32(of_node, "qcom,mdss-brightness-max-level",
+		&val);
+	if (rc) {
+		pr_debug("[%s] brigheness-max-level unspecified, defaulting to 255\n",
 			 panel->name);
-		panel->bl_config.max_level = 255;
+		panel->bl_config.brightness_max_level = 255;
 	} else {
-		panel->bl_config.max_level = val;
+		panel->bl_config.brightness_max_level = val;
 	}
 
 	if (panel->bl_config.type == DSI_BACKLIGHT_PWM) {
@@ -1834,8 +1861,6 @@ int dsi_panel_enable(struct dsi_panel *panel)
 		pr_err("[%s] failed to send DSI_CMD_SET_ON cmds, rc=%d\n",
 		       panel->name, rc);
 	}
-	/* TODO:  hack to enable backlight; */
-	led_trigger_event(panel->bl_config.wled, panel->bl_config.max_level);
 	mutex_unlock(&panel->panel_lock);
 	return rc;
 }
@@ -1873,8 +1898,6 @@ int dsi_panel_pre_disable(struct dsi_panel *panel)
 
 	mutex_lock(&panel->panel_lock);
 
-	/* TODO:  hack to disable backlight; */
-	led_trigger_event(panel->bl_config.wled, 0x0);
 	rc = dsi_panel_tx_cmd_set(panel, DSI_CMD_SET_PRE_OFF);
 	if (rc) {
 		pr_err("[%s] failed to send DSI_CMD_SET_PRE_OFF cmds, rc=%d\n",
diff --git a/drivers/gpu/drm/msm/dsi-staging/dsi_panel.h b/drivers/gpu/drm/msm/dsi-staging/dsi_panel.h
index 1009d94f13a1..4d21a4cf6428 100644
--- a/drivers/gpu/drm/msm/dsi-staging/dsi_panel.h
+++ b/drivers/gpu/drm/msm/dsi-staging/dsi_panel.h
@@ -27,6 +27,8 @@
 #include "dsi_ctrl_hw.h"
 #include "dsi_clk_pwr.h"
 
+#define MAX_BL_LEVEL 4096
+
 enum dsi_panel_rotation {
 	DSI_PANEL_ROTATE_NONE = 0,
 	DSI_PANEL_ROTATE_HV_FLIP,
@@ -101,8 +103,9 @@ struct dsi_panel_cmd_set {
 struct dsi_backlight_config {
 	enum dsi_backlight_type type;
 
-	u32 min_level;
-	u32 max_level;
+	u32 bl_min_level;
+	u32 bl_max_level;
+	u32 brightness_max_level;
 
 	int en_gpio;
 	/* PWM params */
@@ -113,6 +116,7 @@ struct dsi_backlight_config {
 
 	/* WLED params */
 	struct led_trigger *wled;
+	struct backlight_device *bd;
 };
 
 struct dsi_reset_seq {
@@ -195,4 +199,5 @@ int dsi_panel_unprepare(struct dsi_panel *panel);
 
 int dsi_panel_post_unprepare(struct dsi_panel *panel);
 
+int dsi_panel_set_backlight(struct dsi_panel *panel, u32 bl_lvl);
 #endif /* _DSI_PANEL_H_ */
diff --git a/drivers/gpu/drm/msm/sde/sde_backlight.c b/drivers/gpu/drm/msm/sde/sde_backlight.c
new file mode 100644
index 000000000000..9034eeb944fe
--- /dev/null
+++ b/drivers/gpu/drm/msm/sde/sde_backlight.c
@@ -0,0 +1,103 @@
+/* Copyright (c) 2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "sde_connector.h"
+#include <linux/backlight.h>
+#include "dsi_drm.h"
+
+#define SDE_BRIGHT_TO_BL(out, v, bl_max, max_bright) do {\
+	out = (2 * (v) * (bl_max) + max_bright);\
+	do_div(out, 2 * max_bright);\
+} while (0)
+
+static int sde_backlight_device_update_status(struct backlight_device *bd)
+{
+	int brightness;
+	struct drm_connector *connector;
+	struct dsi_display *display;
+	struct sde_connector *c_conn;
+	int bl_lvl;
+
+	brightness = bd->props.brightness;
+
+	if ((bd->props.power != FB_BLANK_UNBLANK) ||
+			(bd->props.state & BL_CORE_FBBLANK) ||
+			(bd->props.state & BL_CORE_SUSPENDED))
+		brightness = 0;
+
+	connector = bl_get_data(bd);
+	c_conn = to_sde_connector(connector);
+	display = (struct dsi_display *) c_conn->display;
+	if (brightness > display->panel->bl_config.bl_max_level)
+		brightness = display->panel->bl_config.bl_max_level;
+
+	/* This maps UI brightness into driver backlight level with
+	 *        rounding
+	 */
+	SDE_BRIGHT_TO_BL(bl_lvl, brightness,
+			display->panel->bl_config.bl_max_level,
+			display->panel->bl_config.brightness_max_level);
+
+	if (!bl_lvl && brightness)
+		bl_lvl = 1;
+
+	if (c_conn->ops.set_backlight)
+		c_conn->ops.set_backlight(c_conn->display, bl_lvl);
+
+	return 0;
+}
+
+static int sde_backlight_device_get_brightness(struct backlight_device *bd)
+{
+	return 0;
+}
+
+static const struct backlight_ops sde_backlight_device_ops = {
+	.update_status = sde_backlight_device_update_status,
+	.get_brightness = sde_backlight_device_get_brightness,
+};
+
+int sde_backlight_setup(struct drm_connector *connector)
+{
+	struct sde_connector *c_conn;
+	struct backlight_device *bd;
+	struct backlight_properties props;
+	struct dsi_display *display;
+	struct dsi_backlight_config *bl_config;
+
+	if (!connector)
+		return -EINVAL;
+
+	c_conn = to_sde_connector(connector);
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_RAW;
+	props.power = FB_BLANK_UNBLANK;
+
+	switch (c_conn->connector_type) {
+	case DRM_MODE_CONNECTOR_DSI:
+		display = (struct dsi_display *) c_conn->display;
+		bl_config = &display->panel->bl_config;
+		props.max_brightness = bl_config->brightness_max_level;
+		props.brightness = bl_config->brightness_max_level;
+		bd = backlight_device_register("sde-backlight",
+				connector->kdev,
+				connector,
+				&sde_backlight_device_ops, &props);
+		if (IS_ERR(bd)) {
+			pr_err("Failed to register backlight: %ld\n",
+					    PTR_ERR(bd));
+			return -ENODEV;
+		}
+	}
+
+	return 0;
+}
diff --git a/drivers/gpu/drm/msm/sde/sde_backlight.h b/drivers/gpu/drm/msm/sde/sde_backlight.h
new file mode 100644
index 000000000000..1ea130592302
--- /dev/null
+++ b/drivers/gpu/drm/msm/sde/sde_backlight.h
@@ -0,0 +1,18 @@
+/* Copyright (c) 2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _SDE_BACKLIGHT_H_
+#define _SDE_BACKLIGHT_H_
+
+int sde_backlight_setup(struct drm_connector *connector);
+
+#endif /* _SDE_BACKLIGHT_H_ */
diff --git a/drivers/gpu/drm/msm/sde/sde_connector.c b/drivers/gpu/drm/msm/sde/sde_connector.c
index 056cf60004f6..6bc69cb1e578 100644
--- a/drivers/gpu/drm/msm/sde/sde_connector.c
+++ b/drivers/gpu/drm/msm/sde/sde_connector.c
@@ -15,6 +15,7 @@
 
 #include "sde_kms.h"
 #include "sde_connector.h"
+#include "sde_backlight.h"
 
 static const struct drm_prop_enum_list e_topology_name[] = {
 	{SDE_RM_TOPOLOGY_UNKNOWN,	"sde_unknown"},
@@ -536,6 +537,14 @@ struct drm_connector *sde_connector_init(struct drm_device *dev,
 		goto error_unregister_conn;
 	}
 
+	if (c_conn->ops.set_backlight) {
+		rc = sde_backlight_setup(&c_conn->base);
+		if (rc) {
+			pr_err("failed to setup backlight, rc=%d\n", rc);
+			goto error_unregister_conn;
+		}
+	}
+
 	/* create properties */
 	msm_property_init(&c_conn->property_info, &c_conn->base.base, dev,
 			priv->conn_property, c_conn->property_data,
diff --git a/drivers/gpu/drm/msm/sde/sde_connector.h b/drivers/gpu/drm/msm/sde/sde_connector.h
index cca934d52914..9580282291db 100644
--- a/drivers/gpu/drm/msm/sde/sde_connector.h
+++ b/drivers/gpu/drm/msm/sde/sde_connector.h
@@ -111,6 +111,8 @@ struct sde_connector_ops {
 	 * Returns: Zero on success
 	 */
 	int (*get_info)(struct msm_display_info *info, void *display);
+
+	int (*set_backlight)(void *display, u32 bl_lvl);
 };
 
 /**
diff --git a/drivers/gpu/drm/msm/sde/sde_kms.c b/drivers/gpu/drm/msm/sde/sde_kms.c
index a7c33adce36d..40a594df7c5b 100644
--- a/drivers/gpu/drm/msm/sde/sde_kms.c
+++ b/drivers/gpu/drm/msm/sde/sde_kms.c
@@ -436,6 +436,7 @@ static int _sde_kms_setup_displays(struct drm_device *dev,
 		.get_modes =  dsi_connector_get_modes,
 		.mode_valid = dsi_conn_mode_valid,
 		.get_info =   dsi_display_get_info,
+		.set_backlight = dsi_display_set_backlight
 	};
 	static const struct sde_connector_ops wb_ops = {
 		.post_init =    sde_wb_connector_post_init,