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Re: [PATCH 2/2] iio: adc: ti_am335x_adc: Increase timeout value waiting for ADC sample

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  Re: [PATCH 2/2] iio: adc: ti_am335x_adc: Increase timeout value  waiting for ADC sample Jonathan Cameron <jic23@kernel.org> - 2016-08-15 17:50 +0200
    Re: [PATCH 2/2] iio: adc: ti_am335x_adc: Increase timeout value  waiting for ADC sample Vignesh R <vigneshr@ti.com> - 2016-08-17 13:20 +0200

#1462945 — Re: [PATCH 2/2] iio: adc: ti_am335x_adc: Increase timeout value waiting for ADC sample

On 08/08/16 12:05, Vignesh R wrote:
> Now that open delay and sample delay for each channel is configurable
> via DT, the default IDLE_TIMEOUT value is not enough as this is
> calculated based on hardcoded macros. This results in driver returning
> EBUSY sometimes. Fix this by increasing the timeout
> value based on maximum value possible to open delay and sample delays
> for each channel.
> 
> Signed-off-by: Vignesh R <vigneshr@ti.com>
As with patch 1 could you provide a fixes tag as well highlighting the
patch that introduced the issue. I'm thinking you are referring to:

iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
5dc11e810676ec4a5acb4423ccd33314bf74f4e54

> ---
>  drivers/iio/adc/ti_am335x_adc.c      | 2 +-
>  include/linux/mfd/ti_am335x_tscadc.h | 8 ++++----
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index bed9977a1863..c3cfacca2541 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -381,7 +381,7 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
>  
>  	am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
>  
> -	timeout = jiffies + usecs_to_jiffies
> +	timeout = jiffies + msecs_to_jiffies
>  				(IDLE_TIMEOUT * adc_dev->channels);
>  	/* Wait for Fifo threshold interrupt */
>  	while (1) {
> diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
> index 2567a87872b0..7f55b8b41032 100644
> --- a/include/linux/mfd/ti_am335x_tscadc.h
> +++ b/include/linux/mfd/ti_am335x_tscadc.h
> @@ -138,16 +138,16 @@
>  /*
>   * time in us for processing a single channel, calculated as follows:
>   *
> - * num cycles = open delay + (sample delay + conv time) * averaging
> + * max num cycles = open delay + (sample delay + conv time) * averaging
>   *
> - * num cycles: 152 + (1 + 13) * 16 = 376
> + * max num cycles: 262143 + (255 + 13) * 16 = 266431
>   *
>   * clock frequency: 26MHz / 8 = 3.25MHz
>   * clock period: 1 / 3.25MHz = 308ns
>   *
> - * processing time: 376 * 308ns = 116us
> + * max processing time: 266431 * 308ns = 83ms(approx)
>   */
> -#define IDLE_TIMEOUT 116 /* microsec */
> +#define IDLE_TIMEOUT 83 /* milliseconds */
>  
>  #define TSCADC_CELLS		2
>  
> 

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#1464515

On Monday 15 August 2016 09:17 PM, Jonathan Cameron wrote:
> On 08/08/16 12:05, Vignesh R wrote:
>> Now that open delay and sample delay for each channel is configurable
>> via DT, the default IDLE_TIMEOUT value is not enough as this is
>> calculated based on hardcoded macros. This results in driver returning
>> EBUSY sometimes. Fix this by increasing the timeout
>> value based on maximum value possible to open delay and sample delays
>> for each channel.
>>
>> Signed-off-by: Vignesh R <vigneshr@ti.com>
> As with patch 1 could you provide a fixes tag as well highlighting the
> patch that introduced the issue. I'm thinking you are referring to:
> 
> iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters
> 5dc11e810676ec4a5acb4423ccd33314bf74f4e54

Yes, will send v2 with fixes tag pointing to above commit. Thanks!

-- 
Regards
Vignesh

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