SCCB is a serial communication bus developed by Omnivision. Its 2-wire
mode is very similar to SMBus byte data transactions, but requires the
controller to ignore the ACK bit and to insert a stop condition after
each message.
Add a device SCCB flag and a message stop flag to be passed to
controller drivers.
Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
drivers/i2c/i2c-core.c | 13 ++++++++++++-
include/linux/i2c.h | 2 ++
2 files changed, 14 insertions(+), 1 deletions(-)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index feb7dc3..8cfa660 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1939,6 +1939,12 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
u8 partial_pec = 0;
int status;
+ if (unlikely(flags & I2C_CLIENT_SCCB) && size != I2C_SMBUS_BYTE_DATA) {
+ dev_err(&adapter->dev,
+ "SCCB devices only support I2C_SMBUS_BYTE_DATA\n");
+ return -EINVAL;
+ }
+
msgbuf0[0] = command;
switch (size) {
case I2C_SMBUS_QUICK:
@@ -1956,6 +1962,11 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
}
break;
case I2C_SMBUS_BYTE_DATA:
+ if (unlikely(flags & I2C_CLIENT_SCCB)) {
+ msg[0].flags |= I2C_M_IGNORE_NAK | I2C_M_STOP;
+ msg[1].flags |= I2C_M_IGNORE_NAK | I2C_M_STOP;
+ }
+
if (read_write == I2C_SMBUS_READ)
msg[1].len = 1;
else {
@@ -2105,7 +2116,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
int try;
s32 res;
- flags &= I2C_M_TEN | I2C_CLIENT_PEC;
+ flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
if (adapter->algo->smbus_xfer) {
i2c_lock_adapter(adapter);
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 195d8b3..bd42914 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -420,6 +420,7 @@ void i2c_lock_adapter(struct i2c_adapter *);
void i2c_unlock_adapter(struct i2c_adapter *);
/*flags for the client struct: */
+#define I2C_CLIENT_SCCB 0x02 /* Use Omnivision SCCB protocol */
#define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */
#define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */
/* Must equal I2C_M_TEN below */
@@ -540,6 +541,7 @@ struct i2c_msg {
__u16 flags;
#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
#define I2C_M_RD 0x0001 /* read data, from slave to master */
+#define I2C_M_STOP 0x8000 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_NOSTART 0x4000 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_REV_DIR_ADDR 0x2000 /* if I2C_FUNC_PROTOCOL_MANGLING */
#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */
--
1.7.3.4
--
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