Appeases the warning "parport0 (bw-qcam): use data_reverse for this!"
Signed-off-by: Brett T. Warden <brett.warden@gmail.com>
---
It seems to work fine with my Quickcam under 2.6.22.
diff --git a/drivers/media/video/bw-qcam.c b/drivers/media/video/bw-qcam.c
index 7d47cbe..01e47ed 100644
--- a/drivers/media/video/bw-qcam.c
+++ b/drivers/media/video/bw-qcam.c
@@ -107,6 +107,11 @@ static inline void write_lpcontrol(struct
qcam_device *q, int d)
parport_write_control(q->pport, d);
}+static inline void reverse_port(struct qcam_device *q)
+{
+ parport_data_reverse(q->pport);
+}
+
static int qc_waithand(struct qcam_device *q, int val);
static int qc_command(struct qcam_device *q, int command);
static int qc_readparam(struct qcam_device *q);
@@ -369,7 +374,11 @@ static void qc_reset(struct qcam_device *q)
break;case QC_ANY:
- write_lpcontrol(q, 0x20);
+ /*
+ * Replaced with reverse_port
+ * write_lpcontrol(q, 0x20);
+ */
+ reverse_port(q);
write_lpdata(q, 0x75);if (read_lpdata(q) != 0x75) {
@@ -512,10 +521,12 @@ static inline int qc_readbytes(struct
qcam_device *q, char buffer[])
switch (q->port_mode & QC_MODE_MASK)
{
case QC_BIDIR: /* Bi-directional Port */
- write_lpcontrol(q, 0x26);
+ reverse_port(q);
+ write_lpcontrol(q, 0x6);
lo = (qc_waithand2(q, 1) >> 1);
hi = (read_lpstatus(q) >> 3) & 0x1f;
- write_lpcontrol(q, 0x2e);
+ reverse_port(q);
+ write_lpcontrol(q, 0xe);
lo2 = (qc_waithand2(q, 0) >> 1);
hi2 = (read_lpst...
---
~Randy
Phaedrus says that Quality is about caring.
-
Just as an aside, if you've tested this and it works, then there's no
point to keep the write_lpcontrol even as a comment. Kill those four
lines, and if someone's interested in what happened they'll just look
at the file history.Ray
-
Point taken, thanks for the feedback.
---
diff --git a/drivers/media/video/bw-qcam.c b/drivers/media/video/bw-qcam.c
index 7d47cbe..0ba92e3 100644
--- a/drivers/media/video/bw-qcam.c
+++ b/drivers/media/video/bw-qcam.c
@@ -107,6 +107,11 @@ static inline void write_lpcontrol(struct
qcam_device *q, int d)
parport_write_control(q->pport, d);
}+static inline void reverse_port(struct qcam_device *q)
+{
+ parport_data_reverse(q->pport);
+}
+
static int qc_waithand(struct qcam_device *q, int val);
static int qc_command(struct qcam_device *q, int command);
static int qc_readparam(struct qcam_device *q);
@@ -369,7 +374,7 @@ static void qc_reset(struct qcam_device *q)
break;case QC_ANY:
- write_lpcontrol(q, 0x20);
+ reverse_port(q);
write_lpdata(q, 0x75);if (read_lpdata(q) != 0x75) {
@@ -512,10 +517,12 @@ static inline int qc_readbytes(struct
qcam_device *q, char buffer[])
switch (q->port_mode & QC_MODE_MASK)
{
case QC_BIDIR: /* Bi-directional Port */
- write_lpcontrol(q, 0x26);
+ reverse_port(q);
+ write_lpcontrol(q, 0x6);
lo = (qc_waithand2(q, 1) >> 1);
hi = (read_lpstatus(q) >> 3) & 0x1f;
- write_lpcontrol(q, 0x2e);
+ reverse_port(q);
+ write_lpcontrol(q, 0xe);
lo2 = (qc_waithand2(q, 0) >> 1);
hi2 = (read_lpstatus(q) >> 3) & 0x1f;
switch (q->bpp)
@@ -613,10 +620,13 @@ static long qc_capture(struct qcam_device * q,
char __user *buf, unsigned long lif ((q->port_mode & QC_MODE_MASK) == QC_BIDIR)
{
- write_lpcontrol(q, 0x2e); /* turn port...
Better, and do you have time for two (possibly stupid) questions? In
each of the last cases it looks like the transformation is from a
write_lpcontrol -> reverse_port and a write_lpcontrol (old address -
0x20). Except the first one, which merely has the reverse_port. One
would think that there should be a write_lpcontrol(q, 0x0); after that
one.Also, is the reverse port sticky, or does it only apply to the next
write? If it's only the next, then maybe a different name would be
better. If it's sticky, then I think the code is wrong...Ray
-
In response to Randy's and your questions, here's what I understand:
The error message comes from parport_pc_write_control in
include/linux/parport_pc.h, which is called by bw-qcam's
write_lpcontrol():static __inline__ void parport_pc_write_control (struct parport *p,
unsigned char d)
{
const unsigned char wm = (PARPORT_CONTROL_STROBE |
PARPORT_CONTROL_AUTOFD |
PARPORT_CONTROL_INIT |
PARPORT_CONTROL_SELECT);/* Take this out when drivers have adapted to newer interface. */
if (d & 0x20) {
printk (KERN_DEBUG "%s (%s): use data_reverse for this!\n",
p->name, p->cad->name);
parport_pc_data_reverse (p);
}__parport_pc_frob_control (p, wm, d & wm);
}The mask wm works out to 0x0f, so first it calls
parport_pc_data_reverse(), then masks off the high nibble with the
reverse flag and makes the regular call.Looking at that more carefully, I'm not sure whether I need to add the
write_lpcontrol(q, 0) after the first call. Other than that, I believe
I'm following the same procedure.As for whether data_reverse is sticky, I don't know... I'll see what I
can find out.--
Brett Warden
-
Fixes use of parport_write_control() to match the newer interface that
requires explicit parport_data_reverse() and parport_data_forward()
calls. This eliminates the following error message and restores the
original intended behavior:parport0 (bw-qcam): use data_reverse for this!
Also increases threshold in qc_detect() from 300 to 400, as my camera
often results in a count of approx 330. Added a kernel error message
to indicate detection failure.Signed-off-by: Brett T. Warden <brett.warden@gmail.com>
---
Thanks Ray and Randy for your comments, and for pointing out that I
needed to reset the port to forward mode!diff --git a/drivers/media/video/bw-qcam.c b/drivers/media/video/bw-qcam.c
index 7d47cbe..961e377 100644
--- a/drivers/media/video/bw-qcam.c
+++ b/drivers/media/video/bw-qcam.c
@@ -104,6 +104,17 @@ static inline void write_lpdata(struct
qcam_device *q, int d)static inline void write_lpcontrol(struct qcam_device *q, int d)
{
+ if(0x20 & d) {
+ /* Set bidirectional mode to reverse (data in) */
+ parport_data_reverse(q->pport);
+ } else {
+ /* Set bidirectional mode to forward (data out) */
+ parport_data_forward(q->pport);
+ }
+
+ /* Now issue the regular port command, but strip out the
+ * direction flag */
+ d &= ~0x20;
parport_write_control(q->pport, d);
}@@ -344,10 +355,13 @@ static int qc_detect(struct qcam_device *q)
/* Be (even more) liberal in what you accept... *//* if (count > 30 && count < 200) */
- if (count > 20 && count < 300)
+ if (count > 20 && count < 400)
+ {
return 1; /* found */
- else
+ } else {
+ printk(KERN_ERR "No Quickcam found on port %s\n",
q->pport->name);
return 0; /* not found */
+ }
}--
Brett Warden
-
On Thu, 27 Sep 2007 12:28:31 -0700
Acked-by: Alan Cox <alan@redhat.com>
-
