When probing, the hardware is not brought into a known state. This may be a problem when a hypervisor restarts Linux without resetting the hardware, leaving an old state running. Make sure the hardware gets initialized, especially interrupts should be cleared and disabled. Reported-by: Dirk Behme <dirk.behme@xxxxxxxxxxxx> Reported-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> Closes: https://lore.kernel.org/r/20240702045535.2000393-1-dirk.behme@xxxxxxxxxxxx Fixes: 6ccbe607132b ("i2c: add Renesas R-Car I2C driver") Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> --- Should go to for-current. Changes since v1: * renamed new function to *_reset_slave() instead of *_init_slave() which is more appropriate * do not mention refactorization in commit message * added Fixes tag drivers/i2c/busses/i2c-rcar.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 828aa2ea0fe4..ec73463ea9b5 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -257,6 +257,14 @@ static void rcar_i2c_init(struct rcar_i2c_priv *priv) } } +static void rcar_i2c_reset_slave(struct rcar_i2c_priv *priv) +{ + rcar_i2c_write(priv, ICSIER, 0); + rcar_i2c_write(priv, ICSSR, 0); + rcar_i2c_write(priv, ICSCR, SDBS); + rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */ +} + static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv) { int ret; @@ -1033,11 +1041,8 @@ static int rcar_unreg_slave(struct i2c_client *slave) /* ensure no irq is running before clearing ptr */ disable_irq(priv->irq); - rcar_i2c_write(priv, ICSIER, 0); - rcar_i2c_write(priv, ICSSR, 0); + rcar_i2c_reset_slave(priv); enable_irq(priv->irq); - rcar_i2c_write(priv, ICSCR, SDBS); - rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */ priv->slave = NULL; @@ -1152,7 +1157,9 @@ static int rcar_i2c_probe(struct platform_device *pdev) goto out_pm_disable; } - rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */ + /* Bring hardware to known state */ + rcar_i2c_init(priv); + rcar_i2c_reset_slave(priv); if (priv->devtype < I2C_RCAR_GEN3) { irqflags |= IRQF_NO_THREAD; -- 2.43.0
