linux-kernel - Re: [PATCH 3/4] iio: trigger: stm32-timer: fix get/set down count direction

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Date:   Sun, 30 Jul 2017 14:46:41 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Fabrice Gasnier <fabrice.gasnier@...com>
Cc:     <benjamin.gaignard@...aro.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <mcoquelin.stm32@...il.com>,
        <alexandre.torgue@...com>, <benjamin.gaignard@...com>,
        <linux-iio@...r.kernel.org>, <lars@...afoo.de>, <knaack.h@....de>,
        <pmeerw@...erw.net>
Subject: Re: [PATCH 3/4] iio: trigger: stm32-timer: fix get/set down count
 direction

On Thu, 27 Jul 2017 18:18:59 +0200
Fabrice Gasnier <fabrice.gasnier@...com> wrote:

> Fixes: 4adec7da0536 ("iio: stm32 trigger: Add quadrature encoder device")
> 
> This fixes two issues:
> - stm32_set_count_direction: to set down direction
> - stm32_get_count_direction: to get down direction
> 
> IIO core provides/expects value to be an index of iio_enum items array.
> This needs to be turned by these routines into TIM_CR1_DIR (e.g. BIT(4))
> value.
> Also, report error when attempting to write direction, when in encoder
> mode: in this case, direction is read only (given by encoder inputs).
> 
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@...com>
Applied to the fixes-togreg branch of iio.git.
Thanks,

Jonathan
> ---
>  drivers/iio/trigger/stm32-timer-trigger.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/trigger/stm32-timer-trigger.c b/drivers/iio/trigger/stm32-timer-trigger.c
> index 107918b..d28aa02 100644
> --- a/drivers/iio/trigger/stm32-timer-trigger.c
> +++ b/drivers/iio/trigger/stm32-timer-trigger.c
> @@ -594,13 +594,20 @@ static int stm32_get_quadrature_mode(struct iio_dev *indio_dev,
>  
>  static int stm32_set_count_direction(struct iio_dev *indio_dev,
>  				     const struct iio_chan_spec *chan,
> -				     unsigned int mode)
> +				     unsigned int dir)
>  {
>  	struct stm32_timer_trigger *priv = iio_priv(indio_dev);
> +	u32 val;
> +	int mode;
>  
> -	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_DIR, mode);
> +	/* In encoder mode, direction is RO (given by TI1/TI2 signals) */
> +	regmap_read(priv->regmap, TIM_SMCR, &val);
> +	mode = (val & TIM_SMCR_SMS) - 1;
> +	if ((mode >= 0) || (mode < ARRAY_SIZE(stm32_quadrature_modes)))
> +		return -EBUSY;
>  
> -	return 0;
> +	return regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_DIR,
> +				  dir ? TIM_CR1_DIR : 0);
>  }
>  
>  static int stm32_get_count_direction(struct iio_dev *indio_dev,
> @@ -611,7 +618,7 @@ static int stm32_get_count_direction(struct iio_dev *indio_dev,
>  
>  	regmap_read(priv->regmap, TIM_CR1, &cr1);
>  
> -	return (cr1 & TIM_CR1_DIR);
> +	return ((cr1 & TIM_CR1_DIR) ? 1 : 0);
>  }
>  
>  static const struct iio_enum stm32_count_direction_enum = {