From 63b96983a5ddfedd7daea72dbbc08ea873c54f27 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Wed, 3 Apr 2019 14:40:10 +0200 Subject: i2c: core: introduce callbacks for atomic transfers We had the request to access devices very late when interrupts are not available anymore multiple times now. Mostly to prepare shutdown or reboot. Allow adapters to specify a specific callback for this case. Note that we fall back to the generic {master|smbus}_xfer callback if this new atomic one is not present. This is intentional to preserve the previous behaviour and avoid regressions. Because there are drivers not using interrupts or because it might have worked "accidently" before. Signed-off-by: Wolfram Sang Reviewed-by Andy Shevchenko Tested-by: Stefan Lengfeld Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'drivers/i2c/i2c-core.h') diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h index deea47c576e5..f9d0c417b5a5 100644 --- a/drivers/i2c/i2c-core.h +++ b/drivers/i2c/i2c-core.h @@ -43,10 +43,13 @@ static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap) { int ret = 0; - if (i2c_in_atomic_xfer_mode()) + if (i2c_in_atomic_xfer_mode()) { + WARN(!adap->algo->master_xfer_atomic && !adap->algo->smbus_xfer_atomic, + "No atomic I2C transfer handler for '%s'\n", dev_name(&adap->dev)); ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN; - else + } else { i2c_lock_bus(adap, I2C_LOCK_SEGMENT); + } return ret; } -- cgit v1.2.3