summaryrefslogtreecommitdiffstats
path: root/drivers/media/dvb/dvb-usb/m920x.h
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/media/dvb/dvb-usb/m920x.h')
-rw-r--r--drivers/media/dvb/dvb-usb/m920x.h46
1 files changed, 39 insertions, 7 deletions
diff --git a/drivers/media/dvb/dvb-usb/m920x.h b/drivers/media/dvb/dvb-usb/m920x.h
index c354196ffe5d..7dd3db65c80e 100644
--- a/drivers/media/dvb/dvb-usb/m920x.h
+++ b/drivers/media/dvb/dvb-usb/m920x.h
@@ -19,17 +19,49 @@
#define M9206_MAX_FILTERS 8
-#define M9206_I2C_TUNER 0
-#define M9206_I2C_DEMOD 1
-#define M9206_I2C_MAX 2
+/*
+sequences found in logs:
+[index value]
+0x80 write addr
+(0x00 out byte)*
+0x40 out byte
+
+0x80 write addr
+(0x00 out byte)*
+0x80 read addr
+(0x21 in byte)*
+0x60 in byte
+
+this sequence works:
+0x80 read addr
+(0x21 in byte)*
+0x60 in byte
+
+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];
int filtering_enabled;
int rep_count;
- struct {
- unsigned char addr;
- unsigned char magic;
- }i2c_r[M9206_I2C_MAX];
};
#endif