The current code first configures register EM28XX_R06_I2C_CLK, which includes
i2c speed, ack, wait and (on some devices) i2c bus selection.
The register value usually comes from the board definition.
em28xx_i2c_register() is called afterwards, which also tries to read the eeprom.
If the device uses i2c bus B, eeprom reading fails.
Fix the problem by selecting bus A before calling em28xx_i2c_register() and
apply the board settings for register EM28XX_R06_I2C_CLK afterwards.
I also noticed that this is what the Windows driver does.
To be sure the i2c bus scan works as expected/before, remove its call from
em28xx_i2c_register() and call it directly after the i2c bus has been configured.
Signed-off-by: Frank Schäfer <fschaefer.oss@xxxxxxxxxxxxxx>
---
drivers/media/usb/em28xx/em28xx-cards.c | 31 ++++++++++++++++++++-----------
drivers/media/usb/em28xx/em28xx-i2c.c | 7 -------
2 Dateien geändert, 20 Zeilen hinzugefügt(+), 18 Zeilen entfernt(-)
diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c
index 9332d05..0d74734 100644
--- a/drivers/media/usb/em28xx/em28xx-cards.c
+++ b/drivers/media/usb/em28xx/em28xx-cards.c
@@ -66,6 +66,10 @@ module_param(usb_xfer_mode, int, 0444);
MODULE_PARM_DESC(usb_xfer_mode,
"USB transfer mode for frame data (-1 = auto, 0 = prefer isoc, 1 = prefer bulk)");
+static unsigned int i2c_scan;
+module_param(i2c_scan, int, 0444);
+MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
+
/* Bitmask marking allocated devices from 0 to EM28XX_MAXBOARDS - 1 */
static unsigned long em28xx_devused;
@@ -3074,8 +3078,20 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
snprintf(dev->name, sizeof(dev->name), "%s #%d", chip_name, dev->devno);
}
+ /* Select i2c bus A (if necessary) */
+ if (dev->chip_id == CHIP_ID_EM2874 ||
+ dev->chip_id == CHIP_ID_EM28174 ||
+ dev->chip_id == CHIP_ID_EM2884)
+ em28xx_write_reg_bits(dev, EM28XX_R06_I2C_CLK, 0, EM2874_I2C_SECONDARY_BUS_SELECT);
+ /* Register i2c bus */
+ retval = em28xx_i2c_register(dev);
+ if (retval < 0) {
+ em28xx_errdev("%s: em28xx_i2c_register - error [%d]!\n",
+ __func__, retval);
+ return retval;
+ }
+ /* Configure i2c bus */
if (!dev->board.is_em2800) {
- /* Resets I2C speed */
retval = em28xx_write_reg(dev, EM28XX_R06_I2C_CLK, dev->board.i2c_speed);
if (retval < 0) {
em28xx_errdev("%s: em28xx_write_reg failed!"
@@ -3084,6 +3100,9 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
return retval;
}
}
+ /* Scan i2c bus */
+ if (i2c_scan)
+ em28xx_do_i2c_scan(dev);
retval = v4l2_device_register(&interface->dev, &dev->v4l2_dev);
if (retval < 0) {
@@ -3094,14 +3113,6 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
v4l2_ctrl_handler_init(hdl, 8);
dev->v4l2_dev.ctrl_handler = hdl;
- /* register i2c bus */
- retval = em28xx_i2c_register(dev);
- if (retval < 0) {
- em28xx_errdev("%s: em28xx_i2c_register - error [%d]!\n",
- __func__, retval);
- goto unregister_dev;
- }
-
/*
* Default format, used for tvp5150 or saa711x output formats
*/
@@ -3173,8 +3184,6 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev,
fail:
em28xx_i2c_unregister(dev);
v4l2_ctrl_handler_free(&dev->ctrl_handler);
-
-unregister_dev:
v4l2_device_unregister(&dev->v4l2_dev);
return retval;
diff --git a/drivers/media/usb/em28xx/em28xx-i2c.c b/drivers/media/usb/em28xx/em28xx-i2c.c
index 19f3e4f..ebe4b20 100644
--- a/drivers/media/usb/em28xx/em28xx-i2c.c
+++ b/drivers/media/usb/em28xx/em28xx-i2c.c
@@ -33,10 +33,6 @@
/* ----------------------------------------------------------- */
-static unsigned int i2c_scan;
-module_param(i2c_scan, int, 0444);
-MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");
-
static unsigned int i2c_debug;
module_param(i2c_debug, int, 0644);
MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
@@ -606,9 +602,6 @@ int em28xx_i2c_register(struct em28xx *dev)
return retval;
}
- if (i2c_scan)
- em28xx_do_i2c_scan(dev);
-
return 0;
}
--
1.7.10.4
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