diff mbox series

[v3,4/7] iio: imu: adis16480: Calculate the sampling frequency in a generic way

Message ID 1551284068-4882-5-git-send-email-stefan.popa@analog.com (mailing list archive)
State New, archived
Headers show
Series iio: imu: adis16480: Add support for ADIS1649x family of devices | expand

Commit Message

Stefan Popa Feb. 27, 2019, 4:14 p.m. UTC
The adis1648x devices have an internal clock of 2.46 kSPS. The sampling
frequency is calculated by applying a decimation rate which can take the
maximum value of 2047.

Although all adis1648x devices are similar in this regard, devices that
will use this feature will be added in the future.

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
---
 drivers/iio/imu/adis16480.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

Comments

Jonathan Cameron March 3, 2019, 12:51 p.m. UTC | #1
On Wed, 27 Feb 2019 18:14:25 +0200
Stefan Popa <stefan.popa@analog.com> wrote:

> The adis1648x devices have an internal clock of 2.46 kSPS. The sampling
> frequency is calculated by applying a decimation rate which can take the
> maximum value of 2047.
> 
> Although all adis1648x devices are similar in this regard, devices that
> will use this feature will be added in the future.
> 
> Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Straight forward refactor so fine.

Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to play with it.

A comment inline about something in the old code!

Thanks,

Jonathan

> ---
>  drivers/iio/imu/adis16480.c | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/imu/adis16480.c b/drivers/iio/imu/adis16480.c
> index 5a2864a..92abc95 100644
> --- a/drivers/iio/imu/adis16480.c
> +++ b/drivers/iio/imu/adis16480.c
> @@ -125,6 +125,8 @@ struct adis16480_chip_info {
>  	unsigned int accel_max_val;
>  	unsigned int accel_max_scale;
>  	unsigned int temp_scale;
> +	unsigned int int_clk;
> +	unsigned int max_dec_rate;
>  };
>  
>  enum adis16480_int_pin {
> @@ -299,9 +301,9 @@ static int adis16480_set_freq(struct iio_dev *indio_dev, int val, int val2)
>  	if (t <= 0)
>  		return -EINVAL;
>  
> -	t = 2460000 / t;
> -	if (t > 2048)
> -		t = 2048;
> +	t = st->chip_info->int_clk / t;
> +	if (t > st->chip_info->max_dec_rate)
> +		t = st->chip_info->max_dec_rate;
>  
>  	if (t != 0)
>  		t--;
> @@ -320,7 +322,7 @@ static int adis16480_get_freq(struct iio_dev *indio_dev, int *val, int *val2)
>  	if (ret < 0)
>  		return ret;
>  
> -	freq = 2460000 / (t + 1);
> +	freq = st->chip_info->int_clk / (t + 1);

I'm a little curious about why t + 1?  Presumably to avoid weird rounding
issues, but maybe a nice addition would be a comment explaining this.

>  	*val = freq / 1000;
>  	*val2 = (freq % 1000) * 1000;
>  
> @@ -726,6 +728,8 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
>  		.accel_max_val = IIO_M_S_2_TO_G(21973),
>  		.accel_max_scale = 18,
>  		.temp_scale = 5650, /* 5.65 milli degree Celsius */
> +		.int_clk = 2460000,
> +		.max_dec_rate = 2048,
>  	},
>  	[ADIS16480] = {
>  		.channels = adis16480_channels,
> @@ -735,6 +739,8 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
>  		.accel_max_val = IIO_M_S_2_TO_G(12500),
>  		.accel_max_scale = 10,
>  		.temp_scale = 5650, /* 5.65 milli degree Celsius */
> +		.int_clk = 2460000,
> +		.max_dec_rate = 2048,
>  	},
>  	[ADIS16485] = {
>  		.channels = adis16485_channels,
> @@ -744,6 +750,8 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
>  		.accel_max_val = IIO_M_S_2_TO_G(20000),
>  		.accel_max_scale = 5,
>  		.temp_scale = 5650, /* 5.65 milli degree Celsius */
> +		.int_clk = 2460000,
> +		.max_dec_rate = 2048,
>  	},
>  	[ADIS16488] = {
>  		.channels = adis16480_channels,
> @@ -753,6 +761,8 @@ static const struct adis16480_chip_info adis16480_chip_info[] = {
>  		.accel_max_val = IIO_M_S_2_TO_G(22500),
>  		.accel_max_scale = 18,
>  		.temp_scale = 5650, /* 5.65 milli degree Celsius */
> +		.int_clk = 2460000,
> +		.max_dec_rate = 2048,
>  	},
>  };
>
diff mbox series

Patch

diff --git a/drivers/iio/imu/adis16480.c b/drivers/iio/imu/adis16480.c
index 5a2864a..92abc95 100644
--- a/drivers/iio/imu/adis16480.c
+++ b/drivers/iio/imu/adis16480.c
@@ -125,6 +125,8 @@  struct adis16480_chip_info {
 	unsigned int accel_max_val;
 	unsigned int accel_max_scale;
 	unsigned int temp_scale;
+	unsigned int int_clk;
+	unsigned int max_dec_rate;
 };
 
 enum adis16480_int_pin {
@@ -299,9 +301,9 @@  static int adis16480_set_freq(struct iio_dev *indio_dev, int val, int val2)
 	if (t <= 0)
 		return -EINVAL;
 
-	t = 2460000 / t;
-	if (t > 2048)
-		t = 2048;
+	t = st->chip_info->int_clk / t;
+	if (t > st->chip_info->max_dec_rate)
+		t = st->chip_info->max_dec_rate;
 
 	if (t != 0)
 		t--;
@@ -320,7 +322,7 @@  static int adis16480_get_freq(struct iio_dev *indio_dev, int *val, int *val2)
 	if (ret < 0)
 		return ret;
 
-	freq = 2460000 / (t + 1);
+	freq = st->chip_info->int_clk / (t + 1);
 	*val = freq / 1000;
 	*val2 = (freq % 1000) * 1000;
 
@@ -726,6 +728,8 @@  static const struct adis16480_chip_info adis16480_chip_info[] = {
 		.accel_max_val = IIO_M_S_2_TO_G(21973),
 		.accel_max_scale = 18,
 		.temp_scale = 5650, /* 5.65 milli degree Celsius */
+		.int_clk = 2460000,
+		.max_dec_rate = 2048,
 	},
 	[ADIS16480] = {
 		.channels = adis16480_channels,
@@ -735,6 +739,8 @@  static const struct adis16480_chip_info adis16480_chip_info[] = {
 		.accel_max_val = IIO_M_S_2_TO_G(12500),
 		.accel_max_scale = 10,
 		.temp_scale = 5650, /* 5.65 milli degree Celsius */
+		.int_clk = 2460000,
+		.max_dec_rate = 2048,
 	},
 	[ADIS16485] = {
 		.channels = adis16485_channels,
@@ -744,6 +750,8 @@  static const struct adis16480_chip_info adis16480_chip_info[] = {
 		.accel_max_val = IIO_M_S_2_TO_G(20000),
 		.accel_max_scale = 5,
 		.temp_scale = 5650, /* 5.65 milli degree Celsius */
+		.int_clk = 2460000,
+		.max_dec_rate = 2048,
 	},
 	[ADIS16488] = {
 		.channels = adis16480_channels,
@@ -753,6 +761,8 @@  static const struct adis16480_chip_info adis16480_chip_info[] = {
 		.accel_max_val = IIO_M_S_2_TO_G(22500),
 		.accel_max_scale = 18,
 		.temp_scale = 5650, /* 5.65 milli degree Celsius */
+		.int_clk = 2460000,
+		.max_dec_rate = 2048,
 	},
 };