[v2,2/2] iio: adc: ti_am335x_adc: Increase timeout value waiting for ADC sample
diff mbox

Message ID 20160817121301.21785-3-vigneshr@ti.com
State New
Headers show

Commit Message

Vignesh Raghavendra Aug. 17, 2016, 12:13 p.m. UTC
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.

Fixes: 5dc11e810676e ("iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters")
Signed-off-by: Vignesh R <vigneshr@ti.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
---

v2: Add fixes tag.

 drivers/iio/adc/ti_am335x_adc.c      | 2 +-
 include/linux/mfd/ti_am335x_tscadc.h | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

Comments

Jonathan Cameron Aug. 21, 2016, 6:49 p.m. UTC | #1
On 17/08/16 13:13, 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.
> 
> Fixes: 5dc11e810676e ("iio: adc: ti_am335x_adc: make sample delay, open delay, averaging DT parameters")
> Signed-off-by: Vignesh R <vigneshr@ti.com>
> Acked-by: Lee Jones <lee.jones@linaro.org>
Applied to the fixes-togreg branch of iio.git and marked for stable.

Thanks,

Jonathan
> ---
> 
> v2: Add fixes tag.
> 
>  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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Patch
diff mbox

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