On Wed, Nov 1, 2017 at 12:44 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> On 10/31/2017 07:04 PM, Stafford Horne wrote:
>>
>> On Tue, Oct 31, 2017 at 06:53:15PM -0700, Guenter Roeck wrote:
>>>
>>> On 10/31/2017 06:34 PM, Joel Stanley wrote:
>>>>
>>>> The ASPEED SoC must deassert a reset in order to use the PWM/tach
>>>> peripheral.
>>>>
>>>> The device tree bindings are updated to document the resets phandle, and
>>>> the example is updated to match what is expected for both the reset and
>>>> clock phandle. Note that the bindings should have always had the reset
>>>> controller, as the hardware is unusable without it.
>>>>
>>>> Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
>>>
>>>
>>> Presumably the driver is being used. This change makes it incompatible
>>> with
>>> existing users. This is unacceptable; after all, it is possible that the
>>> device is taken out of reset by ROMMON or BIOS.
>>>
>>> On top of that, the reset controller code is quite strict and issues a
>>> backtrace if CONFIG_RESET_CONTROLLER is not enabled. Yet, there is no
>>> dependency added on RESET_CONTROLLER. You might want to consider making
>>> the new control optional and using
>>> devm_reset_control_get_optional_exclusive().
>>>
>>> The DT change should be a separate patch.
>>>
>>> More comments below.
>>
>>
>> [..]
>>
>>>> return PTR_ERR_OR_ZERO(hwmon);
>>>> }
>>>> +static int aspeed_pwm_tacho_remove(struct platform_device *pdev)
>>>> +{
>>>> + struct aspeed_pwm_tacho_data *priv = platform_get_drvdata(pdev);
>>>> +
>>>> + reset_control_deassert(priv->rst);
>>>
>>>
>>> This seems to be quite pointless. Also, did you test this code ?
>>>
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> static const struct of_device_id of_pwm_tacho_match_table[] = {
>>>> { .compatible = "aspeed,ast2400-pwm-tacho", },
>>>> { .compatible = "aspeed,ast2500-pwm-tacho", },
>>>> @@ -969,6 +989,7 @@ MODULE_DEVICE_TABLE(of, of_pwm_tacho_match_table);
>>>> static struct platform_driver aspeed_pwm_tacho_driver = {
>>>> .probe = aspeed_pwm_tacho_probe,
>>>> + .probe = aspeed_pwm_tacho_remove,
>>
>>
>> Also, this cant be right (should be .remove)?
>>
>
> Nice. Makes me really wonder what this code would do. Does this even compile
> ?
It compiled. And booted, but it didn't do much :) I rushed sending out
the patch a bit, sorry.
I've spent today I did some closer testing with a fixed v2 and I do
get values out of the device. I don't have access to a machine that I
can see the fans spinning on, so it's hard to know if the values are
correct. I'll send it out tomorrow with a request for testing.
Cheers,
Joel
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