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SubjectRe: [PATCH 3/4] iio: fxas21002c: add ODR/Scale support
On Sat, 25 Aug 2018 22:19:09 +0100
Afonso Bordado <afonsobordado@az8.co> wrote:

> This patch adds support for reading/writing ODR/Scale
>
> We don't support the scale boost modes.
>
> Signed-off-by: Afonso Bordado <afonsobordado@az8.co>

A few trivial bits in here.

Jonathan

> ---
> drivers/iio/gyro/fxas21002c.c | 162 +++++++++++++++++++++++++++++++---
> 1 file changed, 149 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/iio/gyro/fxas21002c.c b/drivers/iio/gyro/fxas21002c.c
> index 6fef210630e0..dc0cb9848386 100644
> --- a/drivers/iio/gyro/fxas21002c.c
> +++ b/drivers/iio/gyro/fxas21002c.c
> @@ -7,7 +7,7 @@
> * IIO driver for FXAS21002C (7-bit I2C slave address 0x20 or 0x21).
> * Datasheet: https://www.nxp.com/docs/en/data-sheet/FXAS21002.pdf
> * TODO:
> - * ODR / Scale Support
> + * Scale boost mode
> * Power management
> * LowPass/HighPass Filters
> * Buffers
> @@ -40,7 +40,10 @@
> #define FXAS21002C_REG_F_EVENT 0x0A
> #define FXAS21002C_REG_INT_SRC_FLAG 0x0B
> #define FXAS21002C_REG_WHO_AM_I 0x0C
> +
> #define FXAS21002C_REG_CTRL_REG0 0x0D
> +#define FXAS21002C_SCALE_MASK (BIT(0) | BIT(1))

This is a 2 bit mask, not a direct combination of two
one bit different things, so better as GENMASK(1, 0) to
make that implicit.

> +
> #define FXAS21002C_REG_RT_CFG 0x0E
> #define FXAS21002C_REG_RT_SRC 0x0F
> #define FXAS21002C_REG_RT_THS 0x10
> @@ -52,13 +55,12 @@
> #define FXAS21002C_ACTIVE_BIT BIT(1)
> #define FXAS21002C_READY_BIT BIT(0)
>
> -#define FXAS21002C_REG_CTRL_REG2 0x14
> -#define FXAS21002C_REG_CTRL_REG3 0x15
> +#define FXAS21002C_ODR_SHIFT 2
> +#define FXAS21002C_ODR_MASK (BIT(2) | BIT(3) | BIT(4))
>
> -#define FXAS21002C_DEFAULT_ODR_HZ 800
>
> -// 0.0625 deg/s
> -#define FXAS21002C_DEFAULT_SENSITIVITY IIO_DEGREE_TO_RAD(62500)
> +#define FXAS21002C_REG_CTRL_REG2 0x14
> +#define FXAS21002C_REG_CTRL_REG3 0x15
>
> enum fxas21002c_id {
> ID_FXAS21002C,
> @@ -76,6 +78,40 @@ struct fxas21002c_data {
> struct regmap *regmap;
> };
>
> +enum fxas21002c_scale {
> + FXAS21002C_SCALE_62MDPS,
> + FXAS21002C_SCALE_31MDPS,
> + FXAS21002C_SCALE_15MDPS,
> + FXAS21002C_SCALE_7MDPS,
> +};
> +
> +static const int fxas21002c_anglevel_scale_avail[4][2] = {
> + [FXAS21002C_SCALE_62MDPS] = { 0, IIO_DEGREE_TO_RAD(62500) },
> + [FXAS21002C_SCALE_31MDPS] = { 0, IIO_DEGREE_TO_RAD(31250) },
> + [FXAS21002C_SCALE_15MDPS] = { 0, IIO_DEGREE_TO_RAD(15625) },
> + [FXAS21002C_SCALE_7MDPS] = { 0, IIO_DEGREE_TO_RAD(7812) },
> +};
> +
> +enum fxas21002c_odr {
> + FXAS21002C_ODR_800,
> + FXAS21002C_ODR_400,
> + FXAS21002C_ODR_200,
> + FXAS21002C_ODR_100,
> + FXAS21002C_ODR_50,
> + FXAS21002C_ODR_25,
> + FXAS21002C_ODR_12_5,
> +};
> +
> +static const int fxas21002c_sample_freq_avail[7][2] = {
> + [FXAS21002C_ODR_800] = { 800, 0 },
> + [FXAS21002C_ODR_400] = { 400, 0 },
> + [FXAS21002C_ODR_200] = { 200, 0 },
> + [FXAS21002C_ODR_100] = { 100, 0 },
> + [FXAS21002C_ODR_50] = { 50, 0 },
> + [FXAS21002C_ODR_25] = { 25, 0 },
> + [FXAS21002C_ODR_12_5] = { 12, 500000 },
> +};
> +
> static const struct regmap_range fxas21002c_writable_ranges[] = {
> regmap_reg_range(FXAS21002C_REG_F_SETUP, FXAS21002C_REG_F_SETUP),
> regmap_reg_range(FXAS21002C_REG_CTRL_REG0, FXAS21002C_REG_RT_CFG),
> @@ -242,6 +278,47 @@ static int fxas21002c_read_oneshot(struct fxas21002c_data *data,
> return IIO_VAL_INT;
> }
>
> +static int fxas21002c_scale_read(struct fxas21002c_data *data, int *val,
> + int *val2)
> +{
> + int ret;
> + unsigned int raw;
> +
> + ret = regmap_read(data->regmap, FXAS21002C_REG_CTRL_REG0, &raw);
> + if (ret)
> + return ret;
> +
> + raw &= FXAS21002C_SCALE_MASK;
> +
> + *val = fxas21002c_anglevel_scale_avail[raw][0];
> + *val2 = fxas21002c_anglevel_scale_avail[raw][1];
> +
> + return IIO_VAL_INT_PLUS_MICRO;
> +}
> +
> +static int fxas21002c_odr_read(struct fxas21002c_data *data, int *val,
> + int *val2)
> +{
> + int ret;
> + unsigned int raw;
> +
> + ret = regmap_read(data->regmap, FXAS21002C_REG_CTRL_REG1, &raw);
> + if (ret)
> + return ret;
> +
> + raw = (raw & FXAS21002C_ODR_MASK) >> FXAS21002C_ODR_SHIFT;
> +
> + // We don't use this mode but according to the datasheet its
> + // also a 12.5Hz
/*
* We...
* also..
*/

The kernel style is very fussy about comment syntax. It may seem silly but when
you read a lot of code these little thing being consistent help.

> + if (raw == 7)
> + raw = FXAS21002C_ODR_12_5;
> +
> + *val = fxas21002c_sample_freq_avail[raw][0];
> + *val2 = fxas21002c_sample_freq_avail[raw][1];
> +
> + return IIO_VAL_INT_PLUS_MICRO;
> +}
> +
> static int fxas21002c_read_raw(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan, int *val,
> int *val2, long mask)
> @@ -255,24 +332,83 @@ static int fxas21002c_read_raw(struct iio_dev *indio_dev,
> if (chan->type != IIO_ANGL_VEL)
> return -EINVAL;
>
> - *val = 0;
> - *val2 = FXAS21002C_DEFAULT_SENSITIVITY;
> -
> - return IIO_VAL_INT_PLUS_MICRO;
> + return fxas21002c_scale_read(data, val, val2);
> case IIO_CHAN_INFO_SAMP_FREQ:
> if (chan->type != IIO_ANGL_VEL)
> return -EINVAL;
>
> - *val = FXAS21002C_DEFAULT_ODR_HZ;
> -
> - return IIO_VAL_INT;
> + return fxas21002c_odr_read(data, val, val2);
> }
>
> return -EINVAL;
> }
>
> +static int fxas21002c_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int val,
> + int val2, long mask)
> +{
> + struct fxas21002c_data *data = iio_priv(indio_dev);
> + int ret = -EINVAL;
> + int i;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + for (i = 0; i < ARRAY_SIZE(fxas21002c_sample_freq_avail); i++) {
> + if (fxas21002c_sample_freq_avail[i][0] == val &&
> + fxas21002c_sample_freq_avail[i][1] == val2)
> + break;
> + }
> +
> + if (i == ARRAY_SIZE(fxas21002c_sample_freq_avail))
> + break;
> +
> + ret = regmap_update_bits(data->regmap, FXAS21002C_REG_CTRL_REG1,
return regmap_update_bits...

> + FXAS21002C_ODR_MASK,
> + i << FXAS21002C_ODR_SHIFT);
> +
> + break;
> + case IIO_CHAN_INFO_SCALE:
> + for (i = 0; i < ARRAY_SIZE(fxas21002c_anglevel_scale_avail);
> + i++) {
> + if (fxas21002c_anglevel_scale_avail[i][0] == val &&
> + fxas21002c_anglevel_scale_avail[i][1] == val2)
> + break;
> + }
> +
> + if (i == ARRAY_SIZE(fxas21002c_anglevel_scale_avail))
> + break;
> +
> + ret = regmap_update_bits(data->regmap, FXAS21002C_REG_CTRL_REG0,
return regmap_update_bits.
> + FXAS21002C_SCALE_MASK, i);
> +
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static IIO_CONST_ATTR(anglevel_scale_available,
> + "0.001090831 " // 62.5 mdps
/* ... */
> + "0.000545415 " // 31.25 mdps
> + "0.000272708 " // 15.625 mdps
> + "0.000136354"); // 7.8125 mdps
> +
> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("800 400 200 100 50 25 12.5");
> +
> +static struct attribute *fxas21002c_attributes[] = {
> + &iio_const_attr_anglevel_scale_available.dev_attr.attr,
> + &iio_const_attr_sampling_frequency_available.dev_attr.attr,
> + NULL
> +};
> +
> +static const struct attribute_group fxas21002c_attribute_group = {
> + .attrs = fxas21002c_attributes,
> +};
> +
> static const struct iio_info fxas21002c_info = {
> .read_raw = fxas21002c_read_raw,
> + .write_raw = fxas21002c_write_raw,
> + .attrs = &fxas21002c_attribute_group,
> };
>
> static int fxas21002c_probe(struct i2c_client *client,

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