diff options
Diffstat (limited to 'linux/drivers/media/video/pvrusb2')
| -rw-r--r-- | linux/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h | 1 | ||||
| -rw-r--r-- | linux/drivers/media/video/pvrusb2/pvrusb2-i2c-core.c | 91 |
2 files changed, 92 insertions, 0 deletions
diff --git a/linux/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h b/linux/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h index ec6c35b8d..ff18fc548 100644 --- a/linux/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h +++ b/linux/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h @@ -225,6 +225,7 @@ struct pvr2_hdw { struct i2c_adapter i2c_adap; struct i2c_algorithm i2c_algo; pvr2_i2c_func i2c_func[PVR2_I2C_FUNC_CNT]; + int i2c_cx25840_hack_state; int i2c_linked; unsigned int i2c_pend_types; /* Which types of update are needed */ unsigned long i2c_pend_mask; /* Change bits we need to scan */ diff --git a/linux/drivers/media/video/pvrusb2/pvrusb2-i2c-core.c b/linux/drivers/media/video/pvrusb2/pvrusb2-i2c-core.c index e1d3803b3..6d7c909ce 100644 --- a/linux/drivers/media/video/pvrusb2/pvrusb2-i2c-core.c +++ b/linux/drivers/media/video/pvrusb2/pvrusb2-i2c-core.c @@ -182,6 +182,8 @@ int pvr2_i2c_basic_op(struct pvr2_hdw *hdw, } } +#ifdef CONFIG_VIDEO_PVRUSB2_24XXX + /* This is a special entry point that is entered if an I2C operation is attempted to a wm8775 chip on model 24xxx hardware. Autodetect of this part doesn't work, but we know it is really there. So let's look for @@ -196,6 +198,94 @@ static int i2c_hack_wm8775(struct pvr2_hdw *hdw, return pvr2_i2c_basic_op(hdw,i2c_addr,wdata,wlen,rdata,rlen); } +/* This is a special entry point that is entered if an I2C operation is + attempted to a cx25840 chip on model 24xxx hardware. This chip can + sometimes wedge itself. Worse still, when this happens msp3400 can + falsely detect this part and then the system gets hosed up after msp3400 + gets confused and dies. What we want to do here is try to keep msp3400 + away and also try to notice if the chip is wedged and send a warning to + the system log. */ +static int i2c_hack_cx25840(struct pvr2_hdw *hdw, + u8 i2c_addr,u8 *wdata,u16 wlen,u8 *rdata,u16 rlen) +{ + int ret; + unsigned int subaddr; + u8 wbuf[2]; + int state = hdw->i2c_cx25840_hack_state; + + if (!(rlen || wlen)) { + // Probe attempt - always just succeed and don't bother the + // hardware (this helps to make the state machine further + // down somewhat easier). + return 0; + } + + /* We're looking for the exact pattern where the revision register + is being read. The cx25840 module will always look at the + revision register first. Any other pattern of access therefore + has to be a probe attempt from somebody else so we'll reject it. + Normally we could just let each client just probe the part + anyway, but when the cx25840 is wedged, msp3400 will get a false + positive and that just screws things up... */ + + if (wlen == 0) { + switch (state) { + case 1: subaddr = 0x0100; break; + case 2: subaddr = 0x0101; break; + default: goto fail; + } + } else if (wlen == 2) { + subaddr = (wdata[0] << 8) | wdata[1]; + switch (subaddr) { + case 0x0100: state = 1; break; + case 0x0101: state = 2; break; + default: goto fail; + } + } else { + goto fail; + } + if (!rlen) goto success; + state = 0; + if (rlen != 1) goto fail; + + /* If we get to here then we have a legitimate read for one of the + two revision bytes, so pass it through. */ + wbuf[0] = subaddr >> 8; + wbuf[1] = subaddr; + ret = pvr2_i2c_basic_op(hdw,i2c_addr,wbuf,2,rdata,rlen); + + if ((ret != 0) || (*rdata == 0x04) || (*rdata == 0x0a)) { + pvr2_trace(PVR2_TRACE_ERROR_LEGS, + "WARNING: Detected a wedged cx25840 chip;" + " the device will not work."); + pvr2_trace(PVR2_TRACE_ERROR_LEGS, + "WARNING: Try power cycling the pvrusb2 device."); + pvr2_trace(PVR2_TRACE_ERROR_LEGS, + "WARNING: Disabling further access to the device" + " to prevent other foul-ups."); + // This blocks all further communication with the part. + hdw->i2c_func[0x44] = 0; + pvr2_hdw_render_useless(hdw); + goto fail; + } + + /* Success! Now let's just step out of the way and let the cx25840 + module do its work normally from now on... */ + pvr2_trace(PVR2_TRACE_INIT,"cx25840 appears to be OK," + " dropping its I2C filter"); + hdw->i2c_func[0x44] = pvr2_i2c_basic_op; + + success: + hdw->i2c_cx25840_hack_state = state; + return 0; + + fail: + hdw->i2c_cx25840_hack_state = state; + return -EIO; +} + +#endif /* CONFIG_VIDEO_PVRUSB2_24XXX */ + /* This is a very, very limited I2C adapter implementation. We can only support what we actually know will work on the device... */ static int pvr2_i2c_xfer(struct i2c_adapter *i2c_adap, @@ -818,6 +908,7 @@ void pvr2_i2c_core_init(struct pvr2_hdw *hdw) // the I2C transfer stack to let things work better. if (hdw->hdw_type == PVR2_HDW_TYPE_24XXX) { hdw->i2c_func[0x1b] = i2c_hack_wm8775; + hdw->i2c_func[0x44] = i2c_hack_cx25840; } #endif |