[PATCH v2 02/10] i2c: mux: pca9541: switch to i2c_lock_bus(..., I2C_LOCK_SEGMENT)

From: Peter Rosin
Date: Wed Jun 20 2018 - 01:19:05 EST


Locking the root adapter for __i2c_transfer will deadlock if the
device sits behind a mux-locked I2C mux. Switch to the finer-grained
i2c_lock_bus with the I2C_LOCK_SEGMENT flag. If the device does not
sit behind a mux-locked mux, the two locking variants are equivalent.

Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
---
drivers/i2c/muxes/i2c-mux-pca9541.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c
index 6a39adaf433f..bc7c8cee5a8c 100644
--- a/drivers/i2c/muxes/i2c-mux-pca9541.c
+++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
@@ -345,11 +345,11 @@ static int pca9541_probe(struct i2c_client *client,

/*
* I2C accesses are unprotected here.
- * We have to lock the adapter before releasing the bus.
+ * We have to lock the I2C segment before releasing the bus.
*/
- i2c_lock_adapter(adap);
+ i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
pca9541_release_bus(client);
- i2c_unlock_adapter(adap);
+ i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);

/* Create mux adapter */

--
2.11.0