diff options
| author | Marek Behún <kabel@kernel.org> | 2021-04-08 04:00:00 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@kernel.org> | 2021-04-15 22:13:19 +0200 |
| commit | 39930213e7779b9c4257499972b8afb8858f1a2d (patch) | |
| tree | 39feba35d1d635c23526d99c5bc634110d77ee54 | |
| parent | d434405aaab7d0ebc516b68a8fc4100922d7f5ef (diff) | |
i2c: mv64xxx: Fix random system lock caused by runtime PM
I noticed a weird bug with this driver on Marvell CN9130 Customer
Reference Board.
Sometime after boot, the system locks with the following message:
[104.071363] i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0
The system does not respond afterwards, only warns about RCU stalls.
This first appeared with commit e5c02cf54154 ("i2c: mv64xxx: Add runtime
PM support").
With further experimentation I discovered that adding a delay into
mv64xxx_i2c_hw_init() fixes this issue. This function is called before
every xfer, due to how runtime PM works in this driver. It seems that in
order to work correctly, a delay is needed after the bus is reset in
this function.
Since there already is a known erratum with this controller needing a
delay, I assume that this is just another place this needs to be
applied. Therefore I apply the delay only if errata_delay is true.
Signed-off-by: Marek Behún <kabel@kernel.org>
Acked-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
| -rw-r--r-- | drivers/i2c/busses/i2c-mv64xxx.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index c590d36b5fd1..5c8e94b6cdb5 100644 --- a/drivers/i2c/busses/i2c-mv64xxx.c +++ b/drivers/i2c/busses/i2c-mv64xxx.c @@ -221,6 +221,10 @@ mv64xxx_i2c_hw_init(struct mv64xxx_i2c_data *drv_data) writel(0, drv_data->reg_base + drv_data->reg_offsets.ext_addr); writel(MV64XXX_I2C_REG_CONTROL_TWSIEN | MV64XXX_I2C_REG_CONTROL_STOP, drv_data->reg_base + drv_data->reg_offsets.control); + + if (drv_data->errata_delay) + udelay(5); + drv_data->state = MV64XXX_I2C_STATE_IDLE; } |