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Subject[PATCH 4.18 206/235] input: rohm_bu21023: switch to i2c_lock_bus(..., I2C_LOCK_SEGMENT)
Date
4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Rosin <peda@axentia.se>

[ Upstream commit 193c2a07cfaacb9249ab0e3d34bce32490879355 ]

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@axentia.se>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/input/touchscreen/rohm_bu21023.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/input/touchscreen/rohm_bu21023.c
+++ b/drivers/input/touchscreen/rohm_bu21023.c
@@ -304,7 +304,7 @@ static int rohm_i2c_burst_read(struct i2
msg[1].len = len;
msg[1].buf = buf;

- i2c_lock_adapter(adap);
+ i2c_lock_bus(adap, I2C_LOCK_SEGMENT);

for (i = 0; i < 2; i++) {
if (__i2c_transfer(adap, &msg[i], 1) < 0) {
@@ -313,7 +313,7 @@ static int rohm_i2c_burst_read(struct i2
}
}

- i2c_unlock_adapter(adap);
+ i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);

return ret;
}

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