V4L/DVB (10088): video: sh_mobile_ceu cleanups and comments

This patch cleans up the sh_mobile_ceu driver and adds comments and
constants to clarify the magic sequence in sh_mobile_ceu_capture().

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 28 insertions, 21 deletions

diff --git a/drivers/media/video/sh_mobile_ceu_camera.c b/drivers/media/video/sh_mobile_ceu_camera.c
index 7d1a84426413..79eda0fed9f9 100644
--- a/drivers/media/video/sh_mobile_ceu_camera.c
+++ b/drivers/media/video/sh_mobile_ceu_camera.c
@@ -101,13 +101,12 @@ struct sh_mobile_ceu_dev {
 };
 
 static void ceu_write(struct sh_mobile_ceu_dev *priv,
-                      unsigned long reg_offs, unsigned long data)
+                      unsigned long reg_offs, u32 data)
 {
         iowrite32(data, priv->base + reg_offs);
 }
 
-static unsigned long ceu_read(struct sh_mobile_ceu_dev *priv,
-                              unsigned long reg_offs)
+static u32 ceu_read(struct sh_mobile_ceu_dev *priv, unsigned long reg_offs)
 {
         return ioread32(priv->base + reg_offs);
 }
@@ -155,18 +154,26 @@ static void free_buffer(struct videobuf_queue *vq,
         buf->vb.state = VIDEOBUF_NEEDS_INIT;
 }
 
+#define CEU_CETCR_MAGIC 0x0317f313 /* acknowledge magical interrupt sources */
+#define CEU_CETCR_IGRW (1 << 4) /* prohibited register access interrupt bit */
+#define CEU_CEIER_CPEIE (1 << 0) /* one-frame capture end interrupt */
+#define CEU_CAPCR_CTNCP (1 << 16) /* continuous capture mode (if set) */
+
+
 static void sh_mobile_ceu_capture(struct sh_mobile_ceu_dev *pcdev)
 {
         struct soc_camera_device *icd = pcdev->icd;
-        unsigned long phys_addr;
-
-        ceu_write(pcdev, CEIER, ceu_read(pcdev, CEIER) & ~1);
-        ceu_write(pcdev, CETCR, ~ceu_read(pcdev, CETCR) & 0x0317f313);
-        ceu_write(pcdev, CEIER, ceu_read(pcdev, CEIER) | 1);
+        dma_addr_t phys_addr;
 
-        ceu_write(pcdev, CAPCR, ceu_read(pcdev, CAPCR) & ~0x10000);
-
-        ceu_write(pcdev, CETCR, 0x0317f313 ^ 0x10);
+        /* The hardware is _very_ picky about this sequence. Especially
+         * the CEU_CETCR_MAGIC value. It seems like we need to acknowledge
+         * several not-so-well documented interrupt sources in CETCR.
+         */
+        ceu_write(pcdev, CEIER, ceu_read(pcdev, CEIER) & ~CEU_CEIER_CPEIE);
+        ceu_write(pcdev, CETCR, ~ceu_read(pcdev, CETCR) & CEU_CETCR_MAGIC);
+        ceu_write(pcdev, CEIER, ceu_read(pcdev, CEIER) | CEU_CEIER_CPEIE);
+        ceu_write(pcdev, CAPCR, ceu_read(pcdev, CAPCR) & ~CEU_CAPCR_CTNCP);
+        ceu_write(pcdev, CETCR, CEU_CETCR_MAGIC ^ CEU_CETCR_IGRW);
 
         if (!pcdev->active)
                 return;
@@ -179,7 +186,7 @@ static void sh_mobile_ceu_capture(struct sh_mobile_ceu_dev *pcdev)
         case V4L2_PIX_FMT_NV21:
         case V4L2_PIX_FMT_NV16:
         case V4L2_PIX_FMT_NV61:
-                phys_addr += (icd->width * icd->height);
+                phys_addr += icd->width * icd->height;
                 ceu_write(pcdev, CDACR, phys_addr);
         }
 
@@ -431,13 +438,13 @@ static int sh_mobile_ceu_set_bus_param(struct soc_camera_device *icd,
                 }
         }
 
-        if ((icd->current_fmt->fourcc == V4L2_PIX_FMT_NV21) ||
-            (icd->current_fmt->fourcc == V4L2_PIX_FMT_NV61))
+        if (icd->current_fmt->fourcc == V4L2_PIX_FMT_NV21 ||
+            icd->current_fmt->fourcc == V4L2_PIX_FMT_NV61)
                 value ^= 0x00000100; /* swap U, V to change from NV1x->NVx1 */
 
-        value |= (common_flags & SOCAM_VSYNC_ACTIVE_LOW) ? (1 << 1) : 0;
-        value |= (common_flags & SOCAM_HSYNC_ACTIVE_LOW) ? (1 << 0) : 0;
-        value |= (buswidth == 16) ? (1 << 12) : 0;
+        value |= common_flags & SOCAM_VSYNC_ACTIVE_LOW ? 1 << 1 : 0;
+        value |= common_flags & SOCAM_HSYNC_ACTIVE_LOW ? 1 << 0 : 0;
+        value |= buswidth == 16 ? 1 << 12 : 0;
         ceu_write(pcdev, CAMCR, value);
 
         ceu_write(pcdev, CAPCR, 0x00300000);
@@ -447,13 +454,13 @@ static int sh_mobile_ceu_set_bus_param(struct soc_camera_device *icd,
 
         if (yuv_mode) {
                 width = icd->width * 2;
-                width = (buswidth == 16) ? width / 2 : width;
+                width = buswidth == 16 ? width / 2 : width;
                 cfszr_width = cdwdr_width = icd->width;
         } else {
                 width = icd->width * ((icd->current_fmt->depth + 7) >> 3);
-                width = (buswidth == 16) ? width / 2 : width;
-                cfszr_width = (buswidth == 8) ? width / 2 : width;
-                cdwdr_width = (buswidth == 16) ? width * 2 : width;
+                width = buswidth == 16 ? width / 2 : width;
+                cfszr_width = buswidth == 8 ? width / 2 : width;
+                cdwdr_width = buswidth == 16 ? width * 2 : width;
         }
 
         ceu_write(pcdev, CAMOR, 0);