diff options
| -rw-r--r-- | drivers/media/dvb/dvb-usb/m920x.c | 52 | ||||
| -rw-r--r-- | drivers/media/dvb/dvb-usb/m920x.h | 28 |
2 files changed, 47 insertions, 33 deletions
diff --git a/drivers/media/dvb/dvb-usb/m920x.c b/drivers/media/dvb/dvb-usb/m920x.c index 621819f6597..08469ccabb7 100644 --- a/drivers/media/dvb/dvb-usb/m920x.c +++ b/drivers/media/dvb/dvb-usb/m920x.c @@ -141,43 +141,43 @@ static int m9206_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int i, j; int ret = 0; + if (!num) + return -EINVAL; + if (mutex_lock_interruptible(&d->i2c_mutex) < 0) return -EAGAIN; for (i = 0; i < num; i++) { - if (msg[i].flags & I2C_M_RD) { - - if ((ret = m9206_write(d->udev, M9206_I2C, (msg[i].addr << 1) | 0x01, 0x80)) != 0) + if (msg[i].flags & (I2C_M_NO_RD_ACK|I2C_M_IGNORE_NAK|I2C_M_TEN)) { + ret = -ENOTSUPP; + goto unlock; + } + /* Send START & address/RW bit */ + if (!(msg[i].flags & I2C_M_NOSTART)) { + if ((ret = m9206_write(d->udev, M9206_I2C, (msg[i].addr<<1)|(msg[i].flags&I2C_M_RD?0x01:00), 0x80)) != 0) goto unlock; - - for(j = 0; j < msg[i].len; j++) { - if (j + 1 == msg[i].len && i + 1== num) { - if ((ret = m9206_read(d->udev, M9206_I2C, 0x0, 0x60, &msg[i].buf[j], msg[i].len)) != 0) - goto unlock; - } else { - if ((ret = m9206_read(d->udev, M9206_I2C, 0x0, 0x21, &msg[i].buf[j], msg[i].len)) != 0) - goto unlock; - } + /* Should check for ack here, if we knew how. */ + } + if (msg[i].flags & I2C_M_RD) { + for (j = 0; j < msg[i].len; j++) { + /* Last byte of transaction? Send STOP, otherwise send ACK. */ + int stop = (i+1 == num && j+1 == msg[i].len)?0x40:0x01; + if ((ret = m9206_read(d->udev, M9206_I2C, 0x0, 0x20|stop, &msg[i].buf[j], 1)) != 0) + goto unlock; } - } else { - if ((ret = m9206_write(d->udev, M9206_I2C, msg[i].addr << 1, 0x80)) != 0) - goto unlock; - - for(j = 0; j < msg[i].len; j++) { - if (j + 1 == msg[i].len && i + 1== num) { - if ((ret = m9206_write(d->udev, M9206_I2C, msg[i].buf[j], 0x40)) != 0) - goto unlock; - - } else { - if ((ret = m9206_write(d->udev, M9206_I2C, msg[i].buf[j], 0x0)) != 0) - goto unlock; - } + for (j = 0; j < msg[i].len; j++) { + /* Last byte of transaction? Then send STOP. */ + int stop = (i+1 == num && j+1 == msg[i].len)?0x40:0x00; + if ((ret = m9206_write(d->udev, M9206_I2C, msg[i].buf[j], stop)) != 0) + goto unlock; + /* Should check for ack here too. */ } } } ret = num; - unlock: + +unlock: mutex_unlock(&d->i2c_mutex); return ret; diff --git a/drivers/media/dvb/dvb-usb/m920x.h b/drivers/media/dvb/dvb-usb/m920x.h index c5ef592cbfe..7dd3db65c80 100644 --- a/drivers/media/dvb/dvb-usb/m920x.h +++ b/drivers/media/dvb/dvb-usb/m920x.h @@ -37,13 +37,27 @@ this sequence works: (0x21 in byte)* 0x60 in byte -_my guess_: -0x80: begin i2c transfer using address. value=address<<1|(reading?1:0) -0x00: write byte -0x21: read byte, more to follow -0x40: write last byte of message sequence -0x60: read last byte of message sequence - */ +Guess at API of the I2C function: +I2C operation is done one byte at a time with USB control messages. The +index the messages is sent to is made up of a set of flags that control +the I2C bus state: +0x80: Send START condition. After a START condition, one would normally + always send the 7-bit slave I2C address as the 7 MSB, followed by + the read/write bit as the LSB. +0x40: Send STOP condition. This should be set on the last byte of an + I2C transaction. +0x20: Read a byte from the slave. As opposed to writing a byte to the + slave. The slave will normally not produce any data unless you + set the R/W bit to 1 when sending the slave's address after the + START condition. +0x01: Respond with ACK, as opposed to a NACK. For a multi-byte read, + the master should send an ACK, that is pull SDA low during the 9th + clock cycle, after every byte but the last. This flags only makes + sense when bit 0x20 is set, indicating a read. + +What any other bits might mean, or how to get the slave's ACK/NACK +response to a write, is unknown. +*/ struct m9206_state { u16 filters[M9206_MAX_FILTERS]; |