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Groups > linux.kernel > #1449771 > unrolled thread

[PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe

Started byGuenter Roeck <linux@roeck-us.net>
First post2016-07-25 21:40 +0200
Last post2016-07-26 08:50 +0200
Articles 5 — 3 participants

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  [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe Guenter Roeck <linux@roeck-us.net> - 2016-07-25 21:40 +0200
    Re: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe Heiko Stübner <heiko@sntech.de> - 2016-07-25 21:50 +0200
    Re: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on  probe Caesar Wang <wxt@rock-chips.com> - 2016-07-26 05:00 +0200
      Re: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on  probe Guenter Roeck <linux@roeck-us.net> - 2016-07-26 05:30 +0200
        Re: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on  probe Caesar Wang <wxt@rock-chips.com> - 2016-07-26 08:50 +0200

#1449771 — [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe

FromGuenter Roeck <linux@roeck-us.net>
Date2016-07-25 21:40 +0200
Subject[PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe
Message-ID<rYTTj-60-3@gated-at.bofh.it>
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@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);
+
 	platform_set_drvdata(pdev, indio_dev);
 
 	indio_dev->name = dev_name(&pdev->dev);
-- 
2.5.0

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#1449776

FromHeiko Stübner <heiko@sntech.de>
Date2016-07-25 21:50 +0200
Message-ID<rYU30-ak-17@gated-at.bofh.it>
In reply to#1449771
Am Montag, 25. Juli 2016, 12:39:00 schrieb Guenter Roeck:
> 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@roeck-us.net>

in my tests I hadn't notices that issue before, but that is likely because the 
bootloaders I had didn't enable the saradc. Anyway, that looks definitly sane, 
so

Reviewed-by: Heiko Stuebner <heiko@sntech.de>

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#1450332 — Re: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe

FromCaesar Wang <wxt@rock-chips.com>
Date2016-07-26 05:00 +0200
SubjectRe: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe
Message-ID<rZ0L7-4KQ-3@gated-at.bofh.it>
In reply to#1449771
Hi Guenter,

Thanks for fixing it.

On 2016年07月26日 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@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();
...
}


-
Caesar

> +
>   	platform_set_drvdata(pdev, indio_dev);
>   
>   	indio_dev->name = dev_name(&pdev->dev);


-- 
caesar wang | software engineer | wxt@rock-chip.com

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#1450349 — Re: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe

FromGuenter Roeck <linux@roeck-us.net>
Date2016-07-26 05:30 +0200
SubjectRe: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe
Message-ID<rZ1e9-59Z-1@gated-at.bofh.it>
In reply to#1450332
On 07/25/2016 07:51 PM, Caesar Wang wrote:
> Hi Guenter,
>
> Thanks for fixing it.
>
> On 2016年07月26日 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@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.

Guenter

>
> -
> Caesar
>
>> +
>>       platform_set_drvdata(pdev, indio_dev);
>>       indio_dev->name = dev_name(&pdev->dev);
>
>

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#1450412 — Re: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe

FromCaesar Wang <wxt@rock-chips.com>
Date2016-07-26 08:50 +0200
SubjectRe: [PATCH] iio: adc: rockchip_saradc: Explicitly disable ADC on probe
Message-ID<rZ4lH-744-7@gated-at.bofh.it>
In reply to#1450349
On 2016年07月26日 11:22, Guenter Roeck wrote:
> On 07/25/2016 07:51 PM, Caesar Wang wrote:
>> Hi Guenter,
>>
>> Thanks for fixing it.
>>
>> On 2016年07月26日 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@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);
>>
>>
>
>
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip


-- 
caesar wang | software engineer | wxt@rock-chip.com

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