Hello,
After do more study about devm_i2c_add_adapter, I will remove i2c_del_adapter in driver remove. Thanks your input.
>
> On 14/07/2023 09:45, Ryan Chen wrote:
>> Add i2c new register mode driver to support AST2600 i2c new register
>> mode. AST2600 i2c controller have legacy and new register mode. The
>> new register mode have global register support 4 base clock for scl
>> clock selection, and new clock divider mode. The i2c new register
>> mode have separate register set to control i2c master and slave.
>>
>> Signed-off-by: Ryan Chen <ryan_chen@xxxxxxxxxxxxxx>
>> ---
>
> ...
>
>> + ret = devm_i2c_add_adapter(dev, &i2c_bus->adap);
>> + if (ret)
>> + return ret;
>> +
>> + return 0;
>> +}
>> +
>> +static int ast2600_i2c_remove(struct platform_device *pdev) {
>> + struct ast2600_i2c_bus *i2c_bus = platform_get_drvdata(pdev);
>> +
>> + /* Disable everything. */
>> + writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
>> + writel(0, i2c_bus->reg_base + AST2600_I2CM_IER);
>> +
>> + i2c_del_adapter(&i2c_bus->adap);
>
>> I have doubts that you tested this. I think you have here double free/del of the adapter.
> Sorry, i can't catch your point for double free the adapter.
> It should use i2c_del_adapter in driver remove function.
> All the driver doing this
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-n
> pcm7xx.c#L2373
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-a
> ltera.c#L473
>
> Do you mean it is not necessary?
>Instead of giving you the fish, I think much more learning experience is to teach you how to fish. Please unbind your driver (echo the device name to proper unbind file in sysfs). The best if you build your kernel with KASAN.
Thanks, will do this test with unbind to understand your point.
