On 2016?07?26? 11:22, Guenter Roeck wrote:
> On 07/25/2016 07:51 PM, Caesar Wang wrote:
>> Hi Guenter,
>>
>> Thanks for fixing it.
>>
>> On 2016?07?26? 03:39, Guenter Roeck wrote:
>>> If the ADC is read for the first time, the caller gets a timeout error,
>>> and the kernel log shows
>>>
>>> read channel() error: -110
>>>
>>> The ADC may be enabled on boot, and needs to be explicitly disabled
>>> for a read sequence to work (otherwise there is no completion
>>> interrupt).
>>> Disaple it explicitly in the probe function.
>>>
>>> Fixes: 44d6f2ef94f9 ("iio: adc: add driver for Rockchip saradc")
>>> Signed-off-by: Guenter Roeck <linux at roeck-us.net>
>>> ---
>>> drivers/iio/adc/rockchip_saradc.c | 3 +++
>>> 1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/iio/adc/rockchip_saradc.c
>>> b/drivers/iio/adc/rockchip_saradc.c
>>> index f9ad6c2d6821..6aa3271d86b5 100644
>>> --- a/drivers/iio/adc/rockchip_saradc.c
>>> +++ b/drivers/iio/adc/rockchip_saradc.c
>>> @@ -280,6 +280,9 @@ static int rockchip_saradc_probe(struct
>>> platform_device *pdev)
>>> goto err_pclk;
>>> }
>>> + /* Make sure ADC is disabled */
>>> + writel_relaxed(0, info->regs + SARADC_CTRL);
>>
>> I think we should reset the saradc controller.
>> Since make sure the reset value is 0 and loader-->kernel may even
>> cause harm, as my experience on tsadc.
>> (drivers/thermal/rockchip_thermal.c)
>>
>>
>> e.g.:
>> /**
>> * Reset SARADC Controller, reset all saradc registers.
>> */
>> static void rockchip_saradc_reset_controller(struct reset_control
>> *reset)
>> {
>> reset_control_assert(reset);
>> usleep_range(10, 20);
>> reset_control_deassert(reset);
>> }
>>
>> ..probe()
>> {
>> ...
>> rockchip_saradc_reset_controller();
>> ...
>> }
>>
>
> Ok, I'll give it a try.
>
I posted it on https://patchwork.kernel.org/patch/9247661/
> Guenter
>
>>
>> -
>> Caesar
>>
>>> +
>>> platform_set_drvdata(pdev, indio_dev);
>>> indio_dev->name = dev_name(&pdev->dev);
>>
>>
>
>
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--
caesar wang | software engineer | wxt at rock-chip.com
