Since there are uses for I2C_M_NOSTART which are much more sensible and standard than most of the protocol mangling functionality (the main one being gather writes to devices where something like a register address needs to be inserted before a block of data) create a new I2C_FUNC_NOSTART for this feature and update all the users to use it.
Also strengthen the disrecommendation of the protocol mangling while we're at it. In the case of regmap-i2c we remove the requirement for mangling as I2C_M_NOSTART is the only mangling feature which is being used. Signed-off-by: Mark Brown <[email protected]> --- Documentation/i2c/functionality | 8 +++++--- Documentation/i2c/i2c-protocol | 9 ++++++++- drivers/base/regmap/regmap-i2c.c | 2 +- drivers/i2c/algos/i2c-algo-bit.c | 2 +- drivers/i2c/busses/i2c-nuc900.c | 3 ++- drivers/i2c/busses/i2c-s3c2410.c | 3 ++- drivers/input/joystick/as5011.c | 1 + drivers/video/matrox/matroxfb_maven.c | 1 + include/linux/i2c.h | 5 +++-- 9 files changed, 24 insertions(+), 10 deletions(-) diff --git a/Documentation/i2c/functionality b/Documentation/i2c/functionality index 42c17c1..7cbd5da 100644 --- a/Documentation/i2c/functionality +++ b/Documentation/i2c/functionality @@ -18,9 +18,8 @@ For the most up-to-date list of functionality constants, please check adapters typically can not do these) I2C_FUNC_10BIT_ADDR Handles the 10-bit address extensions I2C_FUNC_PROTOCOL_MANGLING Knows about the I2C_M_IGNORE_NAK, - I2C_M_REV_DIR_ADDR, I2C_M_NOSTART and - I2C_M_NO_RD_ACK flags (which modify the - I2C protocol!) + I2C_M_REV_DIR_ADDR and I2C_M_NO_RD_ACK + flags (which modify the I2C protocol!). I2C_FUNC_SMBUS_QUICK Handles the SMBus write_quick command I2C_FUNC_SMBUS_READ_BYTE Handles the SMBus read_byte command I2C_FUNC_SMBUS_WRITE_BYTE Handles the SMBus write_byte command @@ -33,6 +32,7 @@ For the most up-to-date list of functionality constants, please check I2C_FUNC_SMBUS_WRITE_BLOCK_DATA Handles the SMBus write_block_data command I2C_FUNC_SMBUS_READ_I2C_BLOCK Handles the SMBus read_i2c_block_data command I2C_FUNC_SMBUS_WRITE_I2C_BLOCK Handles the SMBus write_i2c_block_data command + I2C_FUNC_NOSTART Can skip repeated start sequence A few combinations of the above flags are also defined for your convenience: @@ -50,6 +50,8 @@ A few combinations of the above flags are also defined for your convenience: emulated by a real I2C adapter (using the transparent emulation layer) +In kernel versions prior to 3.5 I2C_FUNC_NOSTART was implemented as +part of I2C_FUNC_PROTOCOL_MANGLING. ADAPTER IMPLEMENTATION ---------------------- diff --git a/Documentation/i2c/i2c-protocol b/Documentation/i2c/i2c-protocol index 10518dd..0b3e62d 100644 --- a/Documentation/i2c/i2c-protocol +++ b/Documentation/i2c/i2c-protocol @@ -49,7 +49,9 @@ a byte read, followed by a byte write: Modified transactions ===================== -We have found some I2C devices that needs the following modifications: +The following modifications to the I2C protocol can also be generated, +with the exception of I2C_M_NOSTART these are usually only needed to +work around device issues: Flag I2C_M_NOSTART: In a combined transaction, no 'S Addr Wr/Rd [A]' is generated at some @@ -60,6 +62,11 @@ We have found some I2C devices that needs the following modifications: we do not generate Addr, but we do generate the startbit S. This will probably confuse all other clients on your bus, so don't try this. + This is often used to gather transmits from multiple data buffers in + system memory into something that appears as a single transfer to the + I2C device but may also be used between direction changes by some + rare devices. + Flags I2C_M_REV_DIR_ADDR This toggles the Rd/Wr flag. That is, if you want to do a write, but need to emit an Rd instead of a Wr, or vice versa, you set this diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c index 9a3a8c5..157bbd5 100644 --- a/drivers/base/regmap/regmap-i2c.c +++ b/drivers/base/regmap/regmap-i2c.c @@ -40,7 +40,7 @@ static int regmap_i2c_gather_write(struct device *dev, /* If the I2C controller can't do a gather tell the core, it * will substitute in a linear write for us. */ - if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_PROTOCOL_MANGLING)) + if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART)) return -ENOTSUPP; xfer[0].addr = i2c->addr; diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index 7f0b832..fad22b0 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -608,7 +608,7 @@ bailout: static u32 bit_func(struct i2c_adapter *adap) { - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | + return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; diff --git a/drivers/i2c/busses/i2c-nuc900.c b/drivers/i2c/busses/i2c-nuc900.c index 03b6157..a26dfb8 100644 --- a/drivers/i2c/busses/i2c-nuc900.c +++ b/drivers/i2c/busses/i2c-nuc900.c @@ -502,7 +502,8 @@ static int nuc900_i2c_xfer(struct i2c_adapter *adap, /* declare our i2c functionality */ static u32 nuc900_i2c_func(struct i2c_adapter *adap) { - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART | + I2C_FUNC_PROTOCOL_MANGLING; } /* i2c bus registration info */ diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index 737f721..37b1f90 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -591,7 +591,8 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap, /* declare our i2c functionality */ static u32 s3c24xx_i2c_func(struct i2c_adapter *adap) { - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART | + I2C_FUNC_PROTOCOL_MANGLING; } /* i2c bus registration info */ diff --git a/drivers/input/joystick/as5011.c b/drivers/input/joystick/as5011.c index 3063464..57d19d4 100644 --- a/drivers/input/joystick/as5011.c +++ b/drivers/input/joystick/as5011.c @@ -231,6 +231,7 @@ static int __devinit as5011_probe(struct i2c_client *client, } if (!i2c_check_functionality(client->adapter, + I2C_FUNC_NOSTART | I2C_FUNC_PROTOCOL_MANGLING)) { dev_err(&client->dev, "need i2c bus that supports protocol mangling\n"); diff --git a/drivers/video/matrox/matroxfb_maven.c b/drivers/video/matrox/matroxfb_maven.c index 31b8f67..217678e 100644 --- a/drivers/video/matrox/matroxfb_maven.c +++ b/drivers/video/matrox/matroxfb_maven.c @@ -1243,6 +1243,7 @@ static int maven_probe(struct i2c_client *client, if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_WORD_DATA | I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_NOSTART | I2C_FUNC_PROTOCOL_MANGLING)) goto ERROR0; if (!(data = kzalloc(sizeof(*data), GFP_KERNEL))) { diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 195d8b3..85d4ef1 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -540,7 +540,7 @@ 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_NOSTART 0x4000 /* if I2C_FUNC_PROTOCOL_MANGLING */ +#define I2C_M_NOSTART 0x4000 /* if I2C_FUNC_NOSTART */ #define I2C_M_REV_DIR_ADDR 0x2000 /* if I2C_FUNC_PROTOCOL_MANGLING */ #define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */ #define I2C_M_NO_RD_ACK 0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */ @@ -553,8 +553,9 @@ struct i2c_msg { #define I2C_FUNC_I2C 0x00000001 #define I2C_FUNC_10BIT_ADDR 0x00000002 -#define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* I2C_M_NOSTART etc. */ +#define I2C_FUNC_PROTOCOL_MANGLING 0x00000004 /* I2C_M_IGNORE_NAK etc. */ #define I2C_FUNC_SMBUS_PEC 0x00000008 +#define I2C_FUNC_NOSTART 0x00000010 /* I2C_M_NOSTART */ #define I2C_FUNC_SMBUS_BLOCK_PROC_CALL 0x00008000 /* SMBus 2.0 */ #define I2C_FUNC_SMBUS_QUICK 0x00010000 #define I2C_FUNC_SMBUS_READ_BYTE 0x00020000 -- 1.7.10 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
