On Thu, 10 Aug 2023 at 07:22, Jian Zhang <zhangjian.3032@xxxxxxxxxxxxx> wrote: > > When the `CONFIG_I2C_SLAVE` option is enabled and the device operates > as a slave, a situation arises where the master sends a START signal > without the accompanying STOP signal. This action results in a > persistent I2C bus timeout. The core issue stems from the fact that > the i2c controller remains in a slave read state without a timeout > mechanism. As a consequence, the bus perpetually experiences timeouts. > > This proposed patch addresses this problem by introducing a status > check during i2c transmit timeouts. In the event that the controller > is in a slave read state, the i2c controller will be reset to restore > proper functionality and allow the I2C bus to resume normal operation. > > Signed-off-by: Jian Zhang <zhangjian.3032@xxxxxxxxxxxxx> Tommy has submitted a similar fix: https://lore.kernel.org/linux-i2c/20230906004910.4157305-1-tommy_huang@xxxxxxxxxxxxxx/ His change is very heavy handed; it reinitialises the bus including re-parsing the device tree (!). Should we have merged this fix instead? If not, are you able to confirm that his change fixes your issue? Cheers, Joel > --- > drivers/i2c/busses/i2c-aspeed.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c > index e76befe3f60f..1a95205fc946 100644 > --- a/drivers/i2c/busses/i2c-aspeed.c > +++ b/drivers/i2c/busses/i2c-aspeed.c > @@ -113,6 +113,7 @@ > ASPEED_I2CD_M_RX_CMD | \ > ASPEED_I2CD_M_TX_CMD | \ > ASPEED_I2CD_M_START_CMD) > +#define ASPEED_I2CD_SLAVE_CMDS_MASK GENMASK(31, 29) > > /* 0x18 : I2CD Slave Device Address Register */ > #define ASPEED_I2CD_DEV_ADDR_MASK GENMASK(6, 0) > @@ -706,6 +707,22 @@ static int aspeed_i2c_master_xfer(struct i2c_adapter *adap, > ASPEED_I2CD_BUS_BUSY_STS)) > aspeed_i2c_recover_bus(bus); > > +#if IS_ENABLED(CONFIG_I2C_SLAVE) > + /* > + * If master timed out and bus is in slave mode. > + * reset the slave mode. > + */ > + if (readl(bus->base + ASPEED_I2C_CMD_REG) & ASPEED_I2CD_SLAVE_CMDS_MASK) { > + spin_lock_irqsave(&bus->lock, flags); > + u32 func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG); > + > + writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG); > + writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG); > + bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE; > + spin_unlock_irqrestore(&bus->lock, flags); > + } > +#endif > + > /* > * If timed out and the state is still pending, drop the pending > * master command. > -- > 2.30.2 >