linux-kernel - Re: [PATCH v3 3/7] iio: imu: adis16480: Treat temperature scale in a generic way

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Date:   Sun, 3 Mar 2019 12:47:44 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Stefan Popa <stefan.popa@...log.com>
Cc:     <robh+dt@...nel.org>, <Michael.Hennerich@...log.com>,
        <knaack.h@....de>, <lars@...afoo.de>, <pmeerw@...erw.net>,
        <gregkh@...uxfoundation.org>, <linux-kernel@...r.kernel.org>,
        <linux-iio@...r.kernel.org>, <devicetree@...r.kernel.org>
Subject: Re: [PATCH v3 3/7] iio: imu: adis16480: Treat temperature scale in
 a generic way

On Wed, 27 Feb 2019 18:14:24 +0200
Stefan Popa <stefan.popa@...log.com> wrote:

> All supported devices provide internal temperature measurement from -40 C
> to +85 C, with +25 C representing value 0x00.
> 
> This patch treats the temperature scale in a generic way, similar to the
> accelerometer and gyroscope scales. So far, there are no temperature max
> scale differences between the supported devices. However, devices that
> will make use of this feature will be added in the future.
> 
> Signed-off-by: Stefan Popa <stefan.popa@...log.com>
Applied.  Thanks,

Jonathan

> ---
>  drivers/iio/imu/adis16480.c | 18 +++++++++++++++---
>  1 file changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/imu/adis16480.c b/drivers/iio/imu/adis16480.c
> index 150d814..5a2864a 100644
> --- a/drivers/iio/imu/adis16480.c
> +++ b/drivers/iio/imu/adis16480.c
> @@ -124,6 +124,7 @@ struct adis16480_chip_info {
>  	unsigned int gyro_max_scale;
>  	unsigned int accel_max_val;
>  	unsigned int accel_max_scale;
> +	unsigned int temp_scale;
>  };
>  
>  enum adis16480_int_pin {
> @@ -530,6 +531,7 @@ static int adis16480_read_raw(struct iio_dev *indio_dev,
>  	const struct iio_chan_spec *chan, int *val, int *val2, long info)
>  {
>  	struct adis16480 *st = iio_priv(indio_dev);
> +	unsigned int temp;
>  
>  	switch (info) {
>  	case IIO_CHAN_INFO_RAW:
> @@ -549,8 +551,13 @@ static int adis16480_read_raw(struct iio_dev *indio_dev,
>  			*val2 = 100; /* 0.0001 gauss */
>  			return IIO_VAL_INT_PLUS_MICRO;
>  		case IIO_TEMP:
> -			*val = 5;
> -			*val2 = 650000; /* 5.65 milli degree Celsius */
> +			/*
> +			 * +85 degrees Celsius = temp_max_scale
> +			 * +25 degrees Celsius = 0
> +			 * LSB, 25 degrees Celsius  = 60 / temp_max_scale
> +			 */
> +			*val = st->chip_info->temp_scale / 1000;
> +			*val2 = (st->chip_info->temp_scale % 1000) * 1000;
>  			return IIO_VAL_INT_PLUS_MICRO;
>  		case IIO_PRESSURE:
>  			*val = 0;
> @@ -561,7 +568,8 @@ static int adis16480_read_raw(struct iio_dev *indio_dev,
>  		}
>  	case IIO_CHAN_INFO_OFFSET:
>  		/* Only the temperature channel has a offset */
> -		*val = 4425; /* 25 degree Celsius = 0x0000 */
> +		temp = 25 * 1000000LL; /* 25 degree Celsius = 0x0000 */
> +		*val = DIV_ROUND_CLOSEST_ULL(temp, st->chip_info->temp_scale);
>  		return IIO_VAL_INT;
>  	case IIO_CHAN_INFO_CALIBBIAS:
>  		return adis16480_get_calibbias(indio_dev, chan, val);
> @@ -717,6 +725,7 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
>  		.gyro_max_scale = 300,
>  		.accel_max_val = IIO_M_S_2_TO_G(21973),
>  		.accel_max_scale = 18,
> +		.temp_scale = 5650, /* 5.65 milli degree Celsius */
>  	},
>  	[ADIS16480] = {
>  		.channels = adis16480_channels,
> @@ -725,6 +734,7 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
>  		.gyro_max_scale = 450,
>  		.accel_max_val = IIO_M_S_2_TO_G(12500),
>  		.accel_max_scale = 10,
> +		.temp_scale = 5650, /* 5.65 milli degree Celsius */
>  	},
>  	[ADIS16485] = {
>  		.channels = adis16485_channels,
> @@ -733,6 +743,7 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
>  		.gyro_max_scale = 450,
>  		.accel_max_val = IIO_M_S_2_TO_G(20000),
>  		.accel_max_scale = 5,
> +		.temp_scale = 5650, /* 5.65 milli degree Celsius */
>  	},
>  	[ADIS16488] = {
>  		.channels = adis16480_channels,
> @@ -741,6 +752,7 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
>  		.gyro_max_scale = 450,
>  		.accel_max_val = IIO_M_S_2_TO_G(22500),
>  		.accel_max_scale = 18,
> +		.temp_scale = 5650, /* 5.65 milli degree Celsius */
>  	},
>  };
>