linux-kernel - Re: [PATCH] Clear timestamp kfifo on trigger enabling

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Date:	Mon, 16 Feb 2015 22:21:27 +0100 (CET)
From:	Peter Meerwald <pmeerw@...erw.net>
To:	Viorel Suman <viorel.suman@...il.com>
cc:	Jonathan Cameron <jic23@...nel.org>, linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Clear timestamp kfifo on trigger enabling


> The timestamp kfifo must be cleared once the
> hardware fifo is reset, thus are removed
> timestamps related to unprocessed events from
> hardware fifo - see "inv_mpu6050_read_fifo"
> method implementation.

comments below
a prefix iio: in the subject would be nice 
 
> Signed-off-by: Viorel Suman <viorel.suman@...il.com>
> ---
>  drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c | 28 +++++++++++++++------------
>  1 file changed, 16 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> index 926fcce..b617920 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_trigger.c
> @@ -42,57 +42,61 @@ static void inv_scan_query(struct iio_dev *indio_dev)
>  static int inv_mpu6050_set_enable(struct iio_dev *indio_dev, bool enable)
>  {
>  	struct inv_mpu6050_state *st = iio_priv(indio_dev);
> -	int result;
> +	int result = 0;

no need to init result

the mutex could be obtained in the caller, i.e. 
inv_mpu_data_rdy_trigger_set_state(), simplifying the code and drastically 
reducing the size of this patch

the patch description does not explain a mutex is (now?) needed; probably 
this should be split out as a separate patch

>  
> +	mutex_lock(&indio_dev->mlock);
>  	if (enable) {
>  		result = inv_mpu6050_set_power_itg(st, true);
>  		if (result)
> -			return result;
> +			goto write_error;
>  		inv_scan_query(indio_dev);
>  		if (st->chip_config.gyro_fifo_enable) {
>  			result = inv_mpu6050_switch_engine(st, true,
>  					INV_MPU6050_BIT_PWR_GYRO_STBY);
>  			if (result)
> -				return result;
> +				goto write_error;
>  		}
>  		if (st->chip_config.accl_fifo_enable) {
>  			result = inv_mpu6050_switch_engine(st, true,
>  					INV_MPU6050_BIT_PWR_ACCL_STBY);
>  			if (result)
> -				return result;
> +				goto write_error;
>  		}
> +		inv_clear_kfifo(st);
>  		result = inv_reset_fifo(indio_dev);
>  		if (result)
> -			return result;
> +			goto write_error;
>  	} else {
>  		result = inv_mpu6050_write_reg(st, st->reg->fifo_en, 0);
>  		if (result)
> -			return result;
> +			goto write_error;
>  
>  		result = inv_mpu6050_write_reg(st, st->reg->int_enable, 0);
>  		if (result)
> -			return result;
> +			goto write_error;
>  
>  		result = inv_mpu6050_write_reg(st, st->reg->user_ctrl, 0);
>  		if (result)
> -			return result;
> +			goto write_error;
>  
>  		result = inv_mpu6050_switch_engine(st, false,
>  					INV_MPU6050_BIT_PWR_GYRO_STBY);
>  		if (result)
> -			return result;
> +			goto write_error;
>  
>  		result = inv_mpu6050_switch_engine(st, false,
>  					INV_MPU6050_BIT_PWR_ACCL_STBY);
>  		if (result)
> -			return result;
> +			goto write_error;
>  		result = inv_mpu6050_set_power_itg(st, false);
>  		if (result)
> -			return result;
> +			goto write_error;
>  	}
>  	st->chip_config.enable = enable;
> +write_error:
> +	mutex_unlock(&indio_dev->mlock);
>  
> -	return 0;
> +	return result;
>  }
>  
>  /**
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)
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