[PATCH] em28xx: fix+improve the register (usb control message) debugging

[Frank Schäfer]

- avoid duplicate debugging messages in em28xx_read_reg_req_len()
- do not describe successful usb transfers in em28xx_read_reg_len()
  as "failed"
- report errors in em28xx_write_regs_req(), too
- print the usb error numbers, too

Signed-off-by: Frank Schäfer <fschaefer....@googlemail.com>
---
 drivers/media/usb/em28xx/em28xx-core.c | 35 +++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/media/usb/em28xx/em28xx-core.c 
b/drivers/media/usb/em28xx/em28xx-core.c
index 19ccff41c7eb..76d3c2a5f9e4 100644
--- a/drivers/media/usb/em28xx/em28xx-core.c
+++ b/drivers/media/usb/em28xx/em28xx-core.c
@@ -91,22 +91,16 @@ int em28xx_read_reg_req_len(struct em28xx *dev, u8 req, u16 
reg,
        if (len > URB_MAX_CTRL_SIZE)
                return -EINVAL;
 
-       em28xx_regdbg("(pipe 0x%08x): IN:  %02x %02x %02x %02x %02x %02x %02x 
%02x ",
-                    pipe, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
-                    req, 0, 0,
-                    reg & 0xff, reg >> 8,
-                    len & 0xff, len >> 8);
-
        mutex_lock(&dev->ctrl_urb_lock);
        ret = usb_control_msg(udev, pipe, req,
                              USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                              0x0000, reg, dev->urb_buf, len, HZ);
        if (ret < 0) {
-               em28xx_regdbg("(pipe 0x%08x): IN:  %02x %02x %02x %02x %02x 
%02x %02x %02x  failed\n",
+               em28xx_regdbg("(pipe 0x%08x): IN:  %02x %02x %02x %02x %02x 
%02x %02x %02x  failed with error %i\n",
                             pipe, USB_DIR_IN | USB_TYPE_VENDOR | 
USB_RECIP_DEVICE,
                             req, 0, 0,
                             reg & 0xff, reg >> 8,
-                            len & 0xff, len >> 8);
+                            len & 0xff, len >> 8, ret);
                mutex_unlock(&dev->ctrl_urb_lock);
                return usb_translate_errors(ret);
        }
@@ -116,7 +110,7 @@ int em28xx_read_reg_req_len(struct em28xx *dev, u8 req, u16 
reg,
 
        mutex_unlock(&dev->ctrl_urb_lock);
 
-       em28xx_regdbg("(pipe 0x%08x): IN:  %02x %02x %02x %02x %02x %02x %02x 
%02x  failed <<< %*ph\n",
+       em28xx_regdbg("(pipe 0x%08x): IN:  %02x %02x %02x %02x %02x %02x %02x 
%02x <<< %*ph\n",
                     pipe, USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                     req, 0, 0,
                     reg & 0xff, reg >> 8,
@@ -164,13 +158,6 @@ int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 
reg, char *buf,
        if ((len < 1) || (len > URB_MAX_CTRL_SIZE))
                return -EINVAL;
 
-       em28xx_regdbg("(pipe 0x%08x): OUT: %02x %02x %02x %02x %02x %02x %02x 
%02x >>> %*ph\n",
-                     pipe,
-                     USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
-                     req, 0, 0,
-                     reg & 0xff, reg >> 8,
-                     len & 0xff, len >> 8, len, buf);
-
        mutex_lock(&dev->ctrl_urb_lock);
        memcpy(dev->urb_buf, buf, len);
        ret = usb_control_msg(udev, pipe, req,
@@ -178,8 +165,22 @@ int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 
reg, char *buf,
                              0x0000, reg, dev->urb_buf, len, HZ);
        mutex_unlock(&dev->ctrl_urb_lock);
 
-       if (ret < 0)
+       if (ret < 0) {
+               em28xx_regdbg("(pipe 0x%08x): OUT:  %02x %02x %02x %02x %02x 
%02x %02x %02x >>> %*ph  failed with error %i\n",
+                             pipe,
+                             USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+                             req, 0, 0,
+                             reg & 0xff, reg >> 8,
+                             len & 0xff, len >> 8, len, buf, ret);
                return usb_translate_errors(ret);
+       }
+
+       em28xx_regdbg("(pipe 0x%08x): OUT:  %02x %02x %02x %02x %02x %02x %02x 
%02x >>> %*ph\n",
+                     pipe,
+                     USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+                     req, 0, 0,
+                     reg & 0xff, reg >> 8,
+                     len & 0xff, len >> 8, len, buf);
 
        if (dev->wait_after_write)
                msleep(dev->wait_after_write);
-- 
2.12.2