I thought all of the comments made sense and will be addressed in my
next revision,
except the following:
>> +static int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus)
>> +{
>> + unsigned long time_left, flags;
>> + int ret = 0;
>> + u32 command;
>> +
>> + spin_lock_irqsave(&bus->lock, flags);
>> + command = readl(bus->base + ASPEED_I2C_CMD_REG);
>> +
>> + if (command & ASPEED_I2CD_SDA_LINE_STS) {
>> + /* Bus is idle: no recovery needed. */
>> + if (command & ASPEED_I2CD_SCL_LINE_STS)
>> + goto out;
>> + dev_dbg(bus->dev, "bus hung (state %x), attempting recovery\n",
>> + command);
>> +
>> + reinit_completion(&bus->cmd_complete);
>> + writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
>> + spin_unlock_irqrestore(&bus->lock, flags);
>> +
>> + time_left = wait_for_completion_timeout(
>> + &bus->cmd_complete, bus->adap.timeout);
>> +
>> + spin_lock_irqsave(&bus->lock, flags);
>> + if (time_left == 0)
>> + goto reset_out;
>> + else if (bus->cmd_err)
>> + goto reset_out;
>> + /* Recovery failed. */
>> + else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
>> + ASPEED_I2CD_SCL_LINE_STS))
>> + goto reset_out;
>> + /* Bus error. */
>> + } else {
>> + dev_dbg(bus->dev, "bus hung (state %x), attempting recovery\n",
>> + command);
>
> Same dbg message as in the condition? Move it out of the 'if'?
Message is the same; that's true; however, I only want to print this
if I am actually doing
the recovery. There is a case in the first condition where we actually
don't attempt recovery.
(See both SDA and SCL high). Nevertheless, now that I am looking at
this. I think it might
make sense to make the dbg statements different since I can explain
what type of recovery
I am attempting.
>
>> +
>> + reinit_completion(&bus->cmd_complete);
>> + writel(ASPEED_I2CD_BUS_RECOVER_CMD,
>> + bus->base + ASPEED_I2C_CMD_REG);
>
> Out of interest: What does the RECOVER_CMD do?
According to the documentation, it attempts to create 1 to 8 SCL
cycles to force any stuck
device to let go of the SDA line. It then puts the hardware in a sane
state once it detects
that the bus has been recovered. I will put a comment to this effect.
>
>> + spin_unlock_irqrestore(&bus->lock, flags);
>> +
>> + time_left = wait_for_completion_timeout(
>> + &bus->cmd_complete, bus->adap.timeout);
>> +
>> + spin_lock_irqsave(&bus->lock, flags);
>> + if (time_left == 0)
>> + goto reset_out;
>> + else if (bus->cmd_err)
>> + goto reset_out;
>> + /* Recovery failed. */
>> + else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
>> + ASPEED_I2CD_SDA_LINE_STS))
>> + goto reset_out;
>> + }
>> +
>> +out:
>> + spin_unlock_irqrestore(&bus->lock, flags);
>> +
>> + return ret;
>> +
>> +reset_out:
>> + spin_unlock_irqrestore(&bus->lock, flags);
>> +
>> + return aspeed_i2c_reset(bus);
>> +}
Cheers!
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