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[v3,5/5] em28xx: write output frame resolution to regs 0x34+0x35 for em25xx family bridges

Message ID 1364319520-6628-6-git-send-email-fschaefer.oss@googlemail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Frank Schäfer March 26, 2013, 5:38 p.m. UTC 
The Windows driver writes the output resolution to registers 0x34 (width / 16)
and 0x35 (height / 16) always.
We don't know yet what these registers are used for.

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
---
 drivers/media/usb/em28xx/em28xx-core.c |    7 +++++++
 drivers/media/usb/em28xx/em28xx-reg.h  |    9 ++++++++-
 2 Dateien geändert, 15 Zeilen hinzugefügt(+), 1 Zeile entfernt(-)
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Patch

diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
index 575a46a..a802128 100644
--- a/drivers/media/usb/em28xx/em28xx-core.c
+++ b/drivers/media/usb/em28xx/em28xx-core.c
@@ -767,6 +767,13 @@  static void em28xx_capture_area_set(struct em28xx *dev, u8 hstart, u8 vstart,
 	em28xx_write_regs(dev, EM28XX_R1E_CWIDTH, &cwidth, 1);
 	em28xx_write_regs(dev, EM28XX_R1F_CHEIGHT, &cheight, 1);
 	em28xx_write_regs(dev, EM28XX_R1B_OFLOW, &overflow, 1);
+
+	/* FIXME: function/meaning of these registers ? */
+	/* FIXME: align width+height to multiples of 4 ?! */
+	if (dev->is_em25xx) {
+		em28xx_write_reg(dev, 0x34, width >> 4);
+		em28xx_write_reg(dev, 0x35, height >> 4);
+	}
 }
 
 static int em28xx_scaler_set(struct em28xx *dev, u16 h, u16 v)
diff --git a/drivers/media/usb/em28xx/em28xx-reg.h b/drivers/media/usb/em28xx/em28xx-reg.h
index 1b0ecd6..622871d 100644
--- a/drivers/media/usb/em28xx/em28xx-reg.h
+++ b/drivers/media/usb/em28xx/em28xx-reg.h
@@ -48,7 +48,7 @@ 
 #define EM28XX_CHIPCFG2_TS_PACKETSIZE_752	0x03
 
 
-	/* GPIO/GPO registers */
+/* GPIO/GPO registers */
 #define EM2880_R04_GPO	0x04    /* em2880-em2883 only */
 #define EM28XX_R08_GPIO	0x08	/* em2820 or upper */
 
@@ -167,6 +167,13 @@ 
 
 #define EM28XX_R34_VBI_START_H	0x34
 #define EM28XX_R35_VBI_START_V	0x35
+/*
+ * NOTE: the EM276x (and EM25xx, EM277x/8x ?) (camera bridges) use these
+ * registers for a different unknown purpose.
+ *   => register 0x34 is set to capture width / 16
+ *   => register 0x35 is set to capture height / 16
+ */
+
 #define EM28XX_R36_VBI_WIDTH	0x36
 #define EM28XX_R37_VBI_HEIGHT	0x37