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i2c: quirks: add zero length checks 

Some adapters do not support a message length of 0. Add this as a quirk
so drivers don't have to open code it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Wolfram Sang 2018-07-23 22:26:05 +02:00 committed by Wolfram Sang
parent 5799c4b2f1
commit d9cfe2ce24
2 changed files with 10 additions and 0 deletions
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6
drivers/i2c/i2c-core-base.c
View File

@ -1839,9 +1839,15 @@ static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs,
if (msgs[i].flags & I2C_M_RD) {
if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
return i2c_quirk_error(adap, &msgs[i], "msg too long");
if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
return i2c_quirk_error(adap, &msgs[i], "no zero length");
} else {
if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
return i2c_quirk_error(adap, &msgs[i], "msg too long");
if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
return i2c_quirk_error(adap, &msgs[i], "no zero length");
}
}

4
include/linux/i2c.h
View File

@ -661,6 +661,10 @@ struct i2c_adapter_quirks {
I2C_AQ_COMB_READ_SECOND | I2C_AQ_COMB_SAME_ADDR)
/* clock stretching is not supported */
#define I2C_AQ_NO_CLK_STRETCH BIT(4)
/* message cannot have length of 0 */
#define I2C_AQ_NO_ZERO_LEN_READ BIT(5)
#define I2C_AQ_NO_ZERO_LEN_WRITE BIT(6)
#define I2C_AQ_NO_ZERO_LEN (I2C_AQ_NO_ZERO_LEN_READ | I2C_AQ_NO_ZERO_LEN_WRITE)
/*
* i2c_adapter is the structure used to identify a physical i2c bus along