[PATCHv15 4/7] fbmon: add videomode helpers

[Steffen Trumtrar <s.trumtrar@pengutronix.de>]

Add a function to convert from the generic videomode to a fb_videomode.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
 drivers/video/fbmon.c |   51 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/fb.h    |    6 ++++++
 2 files changed, 57 insertions(+)

diff --git a/drivers/video/fbmon.c b/drivers/video/fbmon.c
index cef6557..733553b 100644
--- a/drivers/video/fbmon.c
+++ b/drivers/video/fbmon.c
@@ -30,6 +30,7 @@
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/slab.h>
+#include <linux/videomode.h>
 #include <video/edid.h>
 #ifdef CONFIG_PPC_OF
 #include <asm/prom.h>
@@ -1373,6 +1374,56 @@ int fb_get_mode(int flags, u32 val, struct fb_var_screeninfo *var, struct fb_inf
 	kfree(timings);
 	return err;
 }
+
+#if IS_ENABLED(CONFIG_VIDEOMODE)
+int fb_videomode_from_videomode(const struct videomode *vm,
+				struct fb_videomode *fbmode)
+{
+	unsigned int htotal, vtotal;
+
+	fbmode->xres = vm->hactive;
+	fbmode->left_margin = vm->hback_porch;
+	fbmode->right_margin = vm->hfront_porch;
+	fbmode->hsync_len = vm->hsync_len;
+
+	fbmode->yres = vm->vactive;
+	fbmode->upper_margin = vm->vback_porch;
+	fbmode->lower_margin = vm->vfront_porch;
+	fbmode->vsync_len = vm->vsync_len;
+
+	/* prevent division by zero in KHZ2PICOS macro */
+	fbmode->pixclock = vm->pixelclock ? KHZ2PICOS(vm->pixelclock / 1000) : 0;
+
+	fbmode->sync = 0;
+	fbmode->vmode = 0;
+	if (vm->hah)
+		fbmode->sync |= FB_SYNC_HOR_HIGH_ACT;
+	if (vm->vah)
+		fbmode->sync |= FB_SYNC_VERT_HIGH_ACT;
+	if (vm->interlaced)
+		fbmode->vmode |= FB_VMODE_INTERLACED;
+	if (vm->doublescan)
+		fbmode->vmode |= FB_VMODE_DOUBLE;
+	fbmode->flag = 0;
+
+	htotal = vm->hactive + vm->hfront_porch + vm->hback_porch +
+		 vm->hsync_len;
+	vtotal = vm->vactive + vm->vfront_porch + vm->vback_porch +
+		 vm->vsync_len;
+	/* prevent division by zero */
+	if (htotal && vtotal)
+		fbmode->refresh = vm->pixelclock / (htotal * vtotal);
+	/* a mode must have htotal and vtotal != 0 or it is invalid */
+	else {
+		fbmode->refresh = 0;
+		return -EINVAL;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fb_videomode_from_videomode);
+#endif
+
 #else
 int fb_parse_edid(unsigned char *edid, struct fb_var_screeninfo *var)
 {
diff --git a/include/linux/fb.h b/include/linux/fb.h
index c7a9571..4404ec2 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -19,6 +19,7 @@ struct vm_area_struct;
 struct fb_info;
 struct device;
 struct file;
+struct videomode;
 
 /* Definitions below are used in the parsed monitor specs */
 #define FB_DPMS_ACTIVE_OFF	1
@@ -714,6 +715,11 @@ extern void fb_destroy_modedb(struct fb_videomode *modedb);
 extern int fb_find_mode_cvt(struct fb_videomode *mode, int margins, int rb);
 extern unsigned char *fb_ddc_read(struct i2c_adapter *adapter);
 
+#if IS_ENABLED(CONFIG_VIDEOMODE)
+extern int fb_videomode_from_videomode(const struct videomode *vm,
+				       struct fb_videomode *fbmode);
+#endif
+
 /* drivers/video/modedb.c */
 #define VESA_MODEDB_SIZE 34
 extern void fb_var_to_videomode(struct fb_videomode *mode,
-- 
1.7.10.4