There was a bug I2C adapter writes and reads one byte too much.
As the most I2C clients has auto-increment register addressing
this leads next register from the target register overwritten by
garbage data.
As a change remove whole register address byte usage and write
data directly to the I2C bus without saying what are register
address bytes to firmware.
Signed-off-by: Antti Palosaari <crope@xxxxxx>
Cc: Michael Buesch <m@xxxxxxx>
Cc: Hans-Frieder Vogt <hfvogt@xxxxxxx>
Cc: Gianluca Gennari <gennarone@xxxxxxxxx>
---
drivers/media/dvb/dvb-usb/af9035.c | 34 ++++++++++++++++++++++++++--------
1 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/drivers/media/dvb/dvb-usb/af9035.c b/drivers/media/dvb/dvb-usb/af9035.c
index 131ead2..83859c4 100644
--- a/drivers/media/dvb/dvb-usb/af9035.c
+++ b/drivers/media/dvb/dvb-usb/af9035.c
@@ -224,6 +224,22 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
if (mutex_lock_interruptible(&d->i2c_mutex) < 0)
return -EAGAIN;
+ /*
+ * I2C sub header is 5 bytes long. Meaning of those bytes are:
+ * 0: data len
+ * 1: I2C addr << 1
+ * 2: reg addr len
+ * byte 3 and 4 can be used as reg addr
+ * 3: reg addr MSB
+ * used when reg addr len is set to 2
+ * 4: reg addr LSB
+ * used when reg addr len is set to 1 or 2
+ *
+ * For the simplify we do not use register addr at all.
+ * NOTE: As a firmware knows tuner type there is very small possibility
+ * there could be some tuner I2C hacks done by firmware and this may
+ * lead problems if firmware expects those bytes are used.
+ */
if (num == 2 && !(msg[0].flags & I2C_M_RD) &&
(msg[1].flags & I2C_M_RD)) {
if (msg[0].len > 40 || msg[1].len > 40) {
@@ -237,14 +253,15 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
msg[1].len);
} else {
/* I2C */
- u8 buf[4 + msg[0].len];
+ u8 buf[5 + msg[0].len];
struct usb_req req = { CMD_I2C_RD, 0, sizeof(buf),
buf, msg[1].len, msg[1].buf };
buf[0] = msg[1].len;
buf[1] = msg[0].addr << 1;
- buf[2] = 0x01;
- buf[3] = 0x00;
- memcpy(&buf[4], msg[0].buf, msg[0].len);
+ buf[2] = 0x00; /* reg addr len */
+ buf[3] = 0x00; /* reg addr MSB */
+ buf[4] = 0x00; /* reg addr LSB */
+ memcpy(&buf[5], msg[0].buf, msg[0].len);
ret = af9035_ctrl_msg(d->udev, &req);
}
} else if (num == 1 && !(msg[0].flags & I2C_M_RD)) {
@@ -259,14 +276,15 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
msg[0].len - 3);
} else {
/* I2C */
- u8 buf[4 + msg[0].len];
+ u8 buf[5 + msg[0].len];
struct usb_req req = { CMD_I2C_WR, 0, sizeof(buf), buf,
0, NULL };
buf[0] = msg[0].len;
buf[1] = msg[0].addr << 1;
- buf[2] = 0x01;
- buf[3] = 0x00;
- memcpy(&buf[4], msg[0].buf, msg[0].len);
+ buf[2] = 0x00; /* reg addr len */
+ buf[3] = 0x00; /* reg addr MSB */
+ buf[4] = 0x00; /* reg addr LSB */
+ memcpy(&buf[5], msg[0].buf, msg[0].len);
ret = af9035_ctrl_msg(d->udev, &req);
}
} else {
--
1.7.7.6
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
