Commit 4e36c0f2 authored by Wolfram Sang's avatar Wolfram Sang Committed by Andi Shyti
Browse files

i2c: rcar: bring hardware to known state when probing 



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: default avatarDirk Behme <dirk.behme@de.bosch.com>
Reported-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Closes: https://lore.kernel.org/r/20240702045535.2000393-1-dirk.behme@de.bosch.com


Fixes: 6ccbe607 ("i2c: add Renesas R-Car I2C driver")
Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
parent 256abd8e

drivers/i2c/busses/i2c-rcar.c

+12 −5
Original line number Diff line number Diff line
@@ -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;