mt6735: Add an RGB configuration sys attr driver for videox/corr10

Adds the RGB configuration node which leverages the gamma subsystem to
perform color correction.

The new node takes rgb triplets that range from 0-2000 each, computes
the gamma registers and dispatches them to the gamma correction
subsystem.

Change-Id: Iac9d3cbd4f423ccfffb8d665c29cfd251767a398

4 files changed, 111 insertions, 4 deletions

diff --git a/drivers/misc/mediatek/Kconfig.drivers b/drivers/misc/mediatek/Kconfig.drivers
index df07465a9..9962ba0ba 100644
--- a/drivers/misc/mediatek/Kconfig.drivers
+++ b/drivers/misc/mediatek/Kconfig.drivers
@@ -337,6 +337,12 @@ config MTK_DITHERING_SUPPORT
 	  avoid contour effect, but side effect is that dithering mechanism
 	  will make some noises
 
+config MTK_VIDEOX_CYNGN_LIVEDISPLAY
+	bool CONFIG_MTK_VIDEOX_CYNGN_LIVEDISPLAY
+	default n
+	help
+		Enable the RGB interface for color calibration.
+
 config MTK_LCM_PHYSICAL_ROTATION
 	string "MTK_LCM_PHYSICAL_ROTATION"
 	help
diff --git a/drivers/misc/mediatek/dispsys/mt6735/ddp_gamma.c b/drivers/misc/mediatek/dispsys/mt6735/ddp_gamma.c
index a9c47adda..e06b86070 100644
--- a/drivers/misc/mediatek/dispsys/mt6735/ddp_gamma.c
+++ b/drivers/misc/mediatek/dispsys/mt6735/ddp_gamma.c
@@ -110,11 +110,19 @@ static int disp_gamma_set_lut(const DISP_GAMMA_LUT_T __user *user_gamma_lut, voi
         printk(KERN_ERR "[GAMMA] disp_gamma_set_lut: no memory\n");
         return -EFAULT;
     }
-    
+
+#ifdef CONFIG_MTK_VIDEOX_CYNGN_LIVEDISPLAY
+    if (virt_addr_valid(user_gamma_lut)) {
+        memcpy(gamma_lut, user_gamma_lut, sizeof(DISP_GAMMA_LUT_T));
+    } else
+#endif
     if (copy_from_user(gamma_lut, user_gamma_lut, sizeof(DISP_GAMMA_LUT_T)) != 0) {
+        GAMMA_ERR("disp_gamma_set_lut: cannot copy from user mem");
         ret = -EFAULT;
         kfree(gamma_lut);
-    } else {
+    }
+
+    if (!ret) {
         id = gamma_lut->hw_id;
         if (0 <= id && id < DISP_GAMMA_TOTAL) {
             mutex_lock(&g_gamma_global_lock);
diff --git a/drivers/misc/mediatek/video/Kconfig b/drivers/misc/mediatek/video/Kconfig
index 08960d42a..bc16b08db 100644
--- a/drivers/misc/mediatek/video/Kconfig
+++ b/drivers/misc/mediatek/video/Kconfig
@@ -2,4 +2,4 @@ config MTK_VIDEO
   bool CONFIG_MTK_VIDEO
   default n
   help
-    CONFIG_MTK_VIDEO
+    CONFIG_MTK_VIDEO
\ No newline at end of file
diff --git a/drivers/misc/mediatek/videox/mt6735/mtk_disp_mgr.c b/drivers/misc/mediatek/videox/mt6735/mtk_disp_mgr.c
index 3632bd2f5..ca3c1170f 100644
--- a/drivers/misc/mediatek/videox/mt6735/mtk_disp_mgr.c
+++ b/drivers/misc/mediatek/videox/mt6735/mtk_disp_mgr.c
@@ -97,6 +97,13 @@ static dev_t mtk_disp_mgr_devno;
 static struct cdev *mtk_disp_mgr_cdev;
 static struct class *mtk_disp_mgr_class = NULL;
 
+#ifdef CONFIG_MTK_VIDEOX_CYNGN_LIVEDISPLAY
+static struct mtk_rgb_work_queue {
+        struct work_struct work;
+	struct mutex lock;
+} mtk_rgb_work_queue;
+#endif
+
 static SWITCH_MODE_INFO_STRUCT path_info;
 
 int ovl1_remove = 0;
@@ -2952,8 +2959,84 @@ static struct platform_device mtk_disp_mgr_device = {
     	.num_resources = 0,
 };
 
+#ifdef CONFIG_MTK_VIDEOX_CYNGN_LIVEDISPLAY
+#define MAX_LUT_SCALE 2000
+#define PROGRESSION_SCALE 1000
+static u32 mtk_disp_ld_r = MAX_LUT_SCALE;
+static u32 mtk_disp_ld_g = MAX_LUT_SCALE;
+static u32 mtk_disp_ld_b = MAX_LUT_SCALE;
+
+static ssize_t mtk_disp_ld_get_rgb(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%d %d %d\n", mtk_disp_ld_r, mtk_disp_ld_g, mtk_disp_ld_b);
+}
+
+/**
+ * The default gamma array is an arithmetic progression with alpha=2 and n0=0 and
+ * n = 512.
+ *
+ * We scale it linearly with the color passed to this RGB interface. The display
+ * subsystem has a color precision of 10 bits which means that values from [0-1024[
+ * are acceptable.
+ *
+ * In order to avoid floating point computations in kernel space we scale the alpha
+ * value by 1000 and then scale back the result using integer division.
+ */
+static ssize_t mtk_disp_ld_set_rgb(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	int r = MAX_LUT_SCALE, g = MAX_LUT_SCALE, b = MAX_LUT_SCALE;
+
+	if (count > 19)
+		return -EINVAL;
+
+	sscanf(buf, "%d %d %d", &r, &g, &b);
+
+	if (r < 0 || r > MAX_LUT_SCALE) return -EINVAL;
+	if (g < 0 || g > MAX_LUT_SCALE) return -EINVAL;
+	if (b < 0 || b > MAX_LUT_SCALE) return -EINVAL;
+
+	cancel_work_sync(&mtk_rgb_work_queue.work);
+	mtk_disp_ld_r = r;
+	mtk_disp_ld_g = g;
+	mtk_disp_ld_b = b;
+	schedule_work(&mtk_rgb_work_queue.work);
+
+	return count;
+}
+
+static DEVICE_ATTR(rgb, S_IRUGO | S_IWUSR | S_IWGRP, mtk_disp_ld_get_rgb, mtk_disp_ld_set_rgb);
+
+static void mtk_disp_rgb_work(struct work_struct *work) {
+        struct mtk_rgb_work_queue *rgb_wq = container_of(work, struct mtk_rgb_work_queue, work);
+	int r = mtk_disp_ld_r, g = mtk_disp_ld_g, b = mtk_disp_ld_b;
+	int i, gammutR, gammutG, gammutB, ret;
+	DISP_GAMMA_LUT_T *gamma;
+
+	mutex_lock(&rgb_wq->lock);
+
+	gamma = kzalloc(sizeof(DISP_GAMMA_LUT_T), GFP_KERNEL);
+	gamma->hw_id = 0;
+	for (i = 0; i < 512; i++) {
+		gammutR = i * r / PROGRESSION_SCALE;
+		gammutG = i * g / PROGRESSION_SCALE;
+		gammutB = i * b / PROGRESSION_SCALE;
+
+		gamma->lut[i] = GAMMA_ENTRY(gammutR, gammutG, gammutB);
+	}
+
+	ret = primary_display_user_cmd(DISP_IOCTL_SET_GAMMALUT, (unsigned long)gamma);
+
+	kfree(gamma);
+	mutex_unlock(&rgb_wq->lock);
+}
+#endif
+
 static int __init mtk_disp_mgr_init(void)
 {
+    	int rc = 0;
+
     	if(platform_device_register(&mtk_disp_mgr_device))
     	{
         	return -ENODEV;
@@ -2965,12 +3048,22 @@ static int __init mtk_disp_mgr_init(void)
         	return -ENODEV;
     	}
 
+#ifdef CONFIG_MTK_VIDEOX_CYNGN_LIVEDISPLAY
+    	rc = sysfs_create_file(&(mtk_disp_mgr_device.dev.kobj), &dev_attr_rgb.attr);
+    	mutex_init(&mtk_rgb_work_queue.lock);
+    	INIT_WORK(&mtk_rgb_work_queue.work, mtk_disp_rgb_work);
+#endif
 
-    	return 0;
+    	return rc;
 }
 
 static void __exit mtk_disp_mgr_exit(void)
 {
+#ifdef CONFIG_MTK_VIDEOX_CYNGN_LIVEDISPLAY
+	mutex_destroy(&mtk_rgb_work_queue.lock);
+	sysfs_remove_file(&(mtk_disp_mgr_device.dev.kobj), &dev_attr_rgb.attr);
+#endif
+
 	cdev_del(mtk_disp_mgr_cdev);
 	unregister_chrdev_region(mtk_disp_mgr_devno, 1);