msm: dsi: add direct HBM

Go directly to HBM mode and add old sysfs path for compatibility with existing apps. This preserves the stock HBM implementation, which doesn't ramp up right away.

Author: flar2

drivers/gpu/drm/msm/dsi-staging/dsi_backlight.c

@@ -33,6 +33,63 @@
 #define BL_STATE_STANDBY	BL_CORE_FBBLANK
 #define BL_STATE_LP		BL_CORE_DRIVER1
 #define BL_STATE_LP2		BL_CORE_DRIVER2
+#define BL_HBM 			1023
+
+static int hbm_enable = 0;
+static struct dsi_backlight_config *bl_g;
+static struct device *fb0_device;
+
+static void enable_hbm(int enable)
+{
+	struct dsi_panel *panel = container_of(bl_g, struct dsi_panel, bl_config);
+	struct hbm_data *hbm = bl_g->hbm;
+	struct hbm_range *range = NULL;
+	u32 target_range = enable ? bl_g->hbm->num_ranges - 1 : 0;
+	range = hbm->ranges + target_range;
+
+	if(dsi_panel_cmd_set_transfer(panel, &range->dsi_cmd))
+		pr_err("Failed to send command for range %d\n",	enable);
+}
+
+static ssize_t hbm_show(struct device *device, struct device_attribute *attr,
+		      char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", hbm_enable);
+}
+
+static ssize_t hbm_store(struct device *device, struct device_attribute *attr,
+		       const char *buf, size_t count)
+{
+	int ret, val;
+
+	ret = kstrtoint(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	if (val < 0 || val > 1)
+		val = 0;
+
+	hbm_enable = val;
+	enable_hbm(hbm_enable);
+	backlight_update_status(bl_g->bl_device);
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(hbm);
+
+static void fb0_init_device(struct dsi_backlight_config *bl)
+{
+	bl_g = bl;
+	fb0_device = device_create(fb_class, NULL, MKDEV(0, 0), NULL, "fb0");
+	if (IS_ERR(fb0_device)) {
+		fb0_device = NULL;
+		return;
+	}
+
+	if (device_create_file(fb0_device, &dev_attr_hbm))
+		pr_warn("unable to create hbm node\n");
+}
 
 struct dsi_backlight_pwm_config {
 	bool pwm_pmi_control;
@@ -385,6 +442,10 @@ static u32 dsi_backlight_calculate(struct dsi_backlight_config *bl,
 	bl_temp = mult_frac(bl_temp, bl->bl_scale_ad,
 			MAX_AD_BL_SCALE_LEVEL);
 
+	if (hbm_enable) {
+		return BL_HBM;
+	}
+
 	if (panel->hbm_mode)
 		bl_lvl = dsi_backlight_calculate_hbm(bl, bl_temp);
 	else
@@ -711,6 +772,9 @@ static int dsi_backlight_register(struct dsi_backlight_config *bl)
 	if (sysfs_create_groups(&bl->bl_device->dev.kobj, bl_device_groups))
 		pr_warn("unable to create device groups\n");
 
+	//make dummy fb0 device so we have the old standard hbm sysfs path
+	fb0_init_device(bl);
+
 	reg = regulator_get(panel->parent, "lab");
 	if (!PTR_ERR_OR_ZERO(reg)) {
 		pr_info("LAB regulator found\n");