i2c: aspeed: Fix i2c bus hang in slave read

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.

In this case, the i2c bus will be reset, but the slave_state reset is
missing.

Fixes: fee465150b45 ("i2c: aspeed: Reset the i2c controller when timeout occurs")
Signed-off-by: Jian Zhang <zhangjian.3032@bytedance.com>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Tested-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Reviewed-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 5a416b3..28e2a5f 100644 (file)
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -749,6 +749,8 @@ static void __aspeed_i2c_reg_slave(struct aspeed_i2c_bus *bus, u16 slave_addr)
        func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG);
        func_ctrl_reg_val |= ASPEED_I2CD_SLAVE_EN;
        writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG);
+
+       bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
 }
 
 static int aspeed_i2c_reg_slave(struct i2c_client *client)
@@ -765,7 +767,6 @@ static int aspeed_i2c_reg_slave(struct i2c_client *client)
        __aspeed_i2c_reg_slave(bus, client->addr);
 
        bus->slave = client;
-       bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
        spin_unlock_irqrestore(&bus->lock, flags);
 
        return 0;