On 18/04/15 06:15, Kuppuswamy Sathyanarayanan wrote:
> Added rate control support for ALS and proximity
> threshold interrupts.Also, Added support to modify
> and read ALS & proximity sensor sampling frequency.
>
> LTR-501 supports interrupt rate control using persistence
> register settings. Writing <n> to persistence register
> would generate interrupt only if there are <n> consecutive
> data values outside the threshold range.
>
> Since we don't have any existing ABI's to directly
> control the persistence register count, we have implemented
> the rate control using IIO_EV_INFO_PERIOD. _period event
> attribute represents the amount of time in seconds an
> event should be true for the device to generate the
> interrupt. So using _period value and device frequency,
> persistence count is calculated in driver using following
> logic.
>
> count = period / measurement_rate
>
> If the given period is not a multiple of measurement rate then
> we round up the value to next multiple.
>
> This patch also handles change to persistence count whenever
> there is change in frequency.
Thanks for your continued hard work on this!
Anyhow, mostly this is stalled on the patch 2 questions, but I have
made a few little suggestions inline.
Note that the term 'rate' is somewhat ambiguous so I'd use sampling_period
which is better defined. Rate is often a frequency measurement.
Also, a few arrays that should be const + the places they are used should
also have the parameters as const.
Thanks,
Jonathan
>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> ---
> drivers/iio/light/ltr501.c | 389 ++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 382 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index 8ead137..d635ff4 100644
> --- a/drivers/iio/light/ltr501.c
> +++ b/drivers/iio/light/ltr501.c
> @@ -9,7 +9,7 @@
> *
> * 7-bit I2C slave address 0x23
> *
> - * TODO: measurement rate, IR LED characteristics
> + * TODO: IR LED characteristics
> */
>
> #include <linux/module.h>
> @@ -29,6 +29,7 @@
>
> #define LTR501_ALS_CONTR 0x80 /* ALS operation mode, SW reset */
> #define LTR501_PS_CONTR 0x81 /* PS operation mode */
> +#define LTR501_PS_MEAS_RATE 0x84 /* measurement rate*/
> #define LTR501_ALS_MEAS_RATE 0x85 /* ALS integ time, measurement rate*/
> #define LTR501_PART_ID 0x86
> #define LTR501_MANUFAC_ID 0x87
> @@ -41,6 +42,7 @@
> #define LTR501_PS_THRESH_LOW 0x92 /* 11 bit, ps lower threshold */
> #define LTR501_ALS_THRESH_UP 0x97 /* 16 bit, ALS upper threshold */
> #define LTR501_ALS_THRESH_LOW 0x99 /* 16 bit, ALS lower threshold */
> +#define LTR501_INTR_PRST 0x9e /* ps thresh, als thresh */
> #define LTR501_MAX_REG 0x9f
>
> #define LTR501_ALS_CONTR_SW_RESET BIT(2)
> @@ -58,6 +60,9 @@
> #define LTR501_PS_THRESH_MASK 0x7ff
> #define LTR501_ALS_THRESH_MASK 0xffff
>
> +#define LTR501_ALS_DEF_PERIOD 500000
> +#define LTR501_PS_DEF_PERIOD 100000
> +
> #define LTR501_REGMAP_NAME "ltr501_regmap"
>
> static int int_time_mapping[] = {100000, 50000, 200000, 400000};
> @@ -65,17 +70,119 @@ static int int_time_mapping[] = {100000, 50000, 200000, 400000};
> static struct reg_field reg_it = REG_FIELD(LTR501_ALS_MEAS_RATE, 3, 4);
> static struct reg_field reg_als_intr = REG_FIELD(LTR501_INTR, 0, 0);
> static struct reg_field reg_ps_intr = REG_FIELD(LTR501_INTR, 1, 1);
> +static struct reg_field reg_als_rate = REG_FIELD(LTR501_ALS_MEAS_RATE, 0, 2);
> +static struct reg_field reg_ps_rate = REG_FIELD(LTR501_PS_MEAS_RATE, 0, 3);
> +static struct reg_field reg_als_prst = REG_FIELD(LTR501_INTR_PRST, 0, 3);
> +static struct reg_field reg_ps_prst = REG_FIELD(LTR501_INTR_PRST, 4, 7);
> +
> +struct ltr501_samp_table {
> + int freq_val; /* repetition frequency in micro HZ*/
> + int time_val; /* repetition rate in micro seconds */
> +};
>
> struct ltr501_data {
> struct i2c_client *client;
> struct mutex lock_als, lock_ps;
> u8 als_contr, ps_contr;
> + int als_period, ps_period; /* period in micro seconds */
> struct regmap *regmap;
> struct regmap_field *reg_it;
> struct regmap_field *reg_als_intr;
> struct regmap_field *reg_ps_intr;
> + struct regmap_field *reg_als_rate;
> + struct regmap_field *reg_ps_rate;
> + struct regmap_field *reg_als_prst;
> + struct regmap_field *reg_ps_prst;
> +};
> +
const. Also ideally prefix the name. More that plausible
that als_sampling_table might turn up in a header at some
point in the future.
> +static struct ltr501_samp_table als_sampling_table[] = {
> + {20000000, 50000}, {10000000, 100000},
> + {5000000, 200000}, {2000000, 500000},
> + {1000000, 1000000}, {500000, 2000000},
> + {500000, 2000000}, {500000, 2000000}
> +};
> +
const
> +static struct ltr501_samp_table ps_sampling_table[] = {
> + {20000000, 50000}, {14285714, 70000},
> + {10000000, 100000}, {5000000, 200000},
> + {2000000, 500000}, {1000000, 1000000},
> + {500000, 2000000}, {500000, 2000000},
> + {500000, 2000000}
> };
>
> +static unsigned int ltr501_match_samp_freq(struct ltr501_samp_table *table,
> + int len, int val, int val2)
> +{
> + int i, freq;
> +
> + freq = val * 1000000 + val2;
> +
> + for (i = 0; i < len; i++) {
> + if (table[i].freq_val == freq)
> + return i;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int ltr501_read_samp_freq(struct regmap_field *field,
> + struct ltr501_samp_table *freq,
> + int len, int *val, int *val2)
> +{
> + int ret, i;
> +
> + ret = regmap_field_read(field, &i);
> + if (ret < 0)
> + return ret;
> +
> + if (i < 0 || i >= len)
> + return -EINVAL;
> +
> + *val = freq[i].freq_val / 1000000;
> + *val2 = freq[i].freq_val % 1000000;
> +
> + return IIO_VAL_INT_PLUS_MICRO;
> +}
> +
> +static int ltr501_write_samp_freq(struct ltr501_data *data,
> + struct regmap_field *field,
> + struct ltr501_samp_table *freq,
> + int len, int val, int val2)
> +{
> + int i, ret;
> +
> + i = ltr501_match_samp_freq(als_sampling_table,
> + ARRAY_SIZE(als_sampling_table),
> + val, val2);
> +
> + if (i < 0)
> + return i;
> +
> + mutex_lock(&data->lock_als);
> + ret = regmap_field_write(data->reg_als_rate, i);
> + mutex_unlock(&data->lock_als);
> +
> + return ret;
> +}
> +
read_samp_period.
Rate is normally used to mean a frequency.
I wonder if the code would be shorter and simpler if you
define a utility function here and then do two specific
versions for als and ps? Would allow dropping a lot of
parameters elsewhere for a couple of extra lines here.
> +static int ltr501_read_samp_rate(struct regmap_field *field,
> + struct ltr501_samp_table *table,
> + int len, int *val)
> +{
> + int ret, i;
> +
> + ret = regmap_field_read(field, &i);
> + if (ret < 0)
> + return ret;
> +
> + if (i < 0 || i >= len)
> + return -EINVAL;
> +
> + *val = table[i].time_val;
> +
> + return IIO_VAL_INT;
> +}
> +
> static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
> {
> int tries = 100;
> @@ -172,6 +279,116 @@ static int ltr501_read_ps(struct ltr501_data *data)
> return status;
> }
>
> +static int ltr501_read_intr_prst(struct ltr501_data *data,
> + enum iio_chan_type type,
> + int *val2)
> +{
> + int ret, rate, prst;
> +
> + switch (type) {
> + case IIO_INTENSITY:
> + ret = regmap_field_read(data->reg_als_prst, &prst);
> + if (ret < 0)
> + return ret;
> +
> + ret = ltr501_read_samp_rate(data->reg_als_rate,
> + als_sampling_table,
> + ARRAY_SIZE(als_sampling_table),
> + &rate);
> +
> + if (ret < 0)
> + return ret;
> + *val2 = rate * prst;
> + return IIO_VAL_INT_PLUS_MICRO;
> + case IIO_PROXIMITY:
> + ret = regmap_field_read(data->reg_ps_prst, &prst);
> + if (ret < 0)
> + return ret;
> +
> + ret = ltr501_read_samp_rate(data->reg_ps_rate,
> + ps_sampling_table,
> + ARRAY_SIZE(ps_sampling_table),
> + &rate);
> +
> + if (ret < 0)
> + return ret;
> +
> + *val2 = rate * prst;
> + return IIO_VAL_INT_PLUS_MICRO;
> + default:
> + return -EINVAL;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int ltr501_write_intr_prst(struct ltr501_data *data,
> + enum iio_chan_type type,
> + int val, int val2)
> +{
> + int ret, rate, new_val;
> + unsigned long period;
> +
> + if (val < 0 || val2 < 0)
> + return -EINVAL;
> +
> + /* period in microseconds */
> + period = ((val * 1000000) + val2);
> +
> + switch (type) {
> + case IIO_INTENSITY:
> + ret = ltr501_read_samp_rate(data->reg_als_rate,
> + als_sampling_table,
> + ARRAY_SIZE(als_sampling_table),
> + &rate);
> + if (ret < 0)
> + return ret;
> +
> + /* period should be atleast equal to rate */
Event period should be at least equal to sampling period (not rate which
is a term used indicate how often per second - e.g. a frequency).
> + if (period < rate)
> + return -EINVAL;
> +
> + new_val = DIV_ROUND_UP(period, rate);
> + if (new_val < 0 || new_val > 0x0f)
> + return -EINVAL;
> +
> + mutex_lock(&data->lock_als);
> + ret = regmap_field_write(data->reg_als_prst, new_val);
> + mutex_unlock(&data->lock_als);
> + if (ret >= 0)
> + data->als_period = period;
> +
> + return ret;
> + case IIO_PROXIMITY:
> + ret = ltr501_read_samp_rate(data->reg_ps_rate,
> + ps_sampling_table,
> + ARRAY_SIZE(ps_sampling_table),
> + &rate);
> + if (ret < 0)
> + return ret;
> +
> + /* period should be atleast equal to rate */
> + if (period < rate)
> + return -EINVAL;
> +
> + new_val = DIV_ROUND_UP(period, rate);
> + if (new_val < 0 || new_val > 0x0f)
> + return -EINVAL;
> +
> + mutex_lock(&data->lock_ps);
> + ret = regmap_field_write(data->reg_ps_prst, new_val);
> + mutex_unlock(&data->lock_ps);
> + if (ret >= 0)
> + data->ps_period = period;
> +
> + return ret;
> + default:
> + return -EINVAL;
> + }
> +
> + return -EINVAL;
> +}
> +
> static const struct iio_event_spec ltr501_als_event_spec[] = {
> {
> .type = IIO_EV_TYPE_THRESH,
> @@ -184,7 +401,8 @@ static const struct iio_event_spec ltr501_als_event_spec[] = {
> }, {
> .type = IIO_EV_TYPE_THRESH,
> .dir = IIO_EV_DIR_EITHER,
> - .mask_separate = BIT(IIO_EV_INFO_ENABLE),
> + .mask_separate = BIT(IIO_EV_INFO_ENABLE) |
> + BIT(IIO_EV_INFO_PERIOD),
> },
>
> };
> @@ -201,7 +419,8 @@ static const struct iio_event_spec ltr501_pxs_event_spec[] = {
> }, {
> .type = IIO_EV_TYPE_THRESH,
> .dir = IIO_EV_DIR_EITHER,
> - .mask_separate = BIT(IIO_EV_INFO_ENABLE),
> + .mask_separate = BIT(IIO_EV_INFO_ENABLE) |
> + BIT(IIO_EV_INFO_PERIOD),
> },
> };
>
> @@ -228,7 +447,8 @@ static const struct iio_chan_spec ltr501_channels[] = {
> LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0,
> ltr501_als_event_spec, ARRAY_SIZE(ltr501_als_event_spec)),
> LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
> - BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME),
> + BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_INT_TIME) |
> + BIT(IIO_CHAN_INFO_SAMP_FREQ),
> NULL, 0),
> {
> .type = IIO_PROXIMITY,
> @@ -314,6 +534,23 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
> default:
> return -EINVAL;
> }
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + switch (chan->type) {
> + case IIO_INTENSITY:
> + ret = ltr501_read_samp_freq(data->reg_als_rate,
> + als_sampling_table,
> + ARRAY_SIZE(als_sampling_table),
> + val, val2);
> + return ret;
> + case IIO_PROXIMITY:
> + ret = ltr501_read_samp_freq(data->reg_ps_rate,
> + ps_sampling_table,
> + ARRAY_SIZE(ps_sampling_table),
> + val, val2);
> + return ret;
> + default:
> + return -EINVAL;
> + }
> }
> return -EINVAL;
> }
> @@ -334,7 +571,7 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
> int val, int val2, long mask)
> {
> struct ltr501_data *data = iio_priv(indio_dev);
> - int i;
> + int i, ret, freq_val, freq_val2;
>
> if (iio_buffer_enabled(indio_dev))
> return -EBUSY;
> @@ -376,6 +613,57 @@ static int ltr501_write_raw(struct iio_dev *indio_dev,
> default:
> return -EINVAL;
> }
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + switch (chan->type) {
> + case IIO_INTENSITY:
> + ret = ltr501_read_samp_freq(data->reg_als_rate,
> + als_sampling_table,
> + ARRAY_SIZE(als_sampling_table),
> + &freq_val, &freq_val2);
> + ret = ltr501_write_samp_freq(data, data->reg_als_rate,
> + als_sampling_table,
> + ARRAY_SIZE(als_sampling_table),
> + val, val2);
> + if (ret < 0)
> + return ret;
> +
> + /* update persistence count when changing frequency */
> + ret = ltr501_write_intr_prst(data, chan->type,
> + 0, data->als_period);
> +
> + if (ret < 0)
> + return ltr501_write_samp_freq(data,
> + data->reg_als_rate,
> + als_sampling_table,
> + ARRAY_SIZE(als_sampling_table),
> + freq_val, freq_val2);
> + return ret;
> + case IIO_PROXIMITY:
> + ret = ltr501_read_samp_freq(data->reg_ps_rate,
> + ps_sampling_table,
> + ARRAY_SIZE(ps_sampling_table),
> + &freq_val, &freq_val2);
> + ret = ltr501_write_samp_freq(data, data->reg_ps_rate,
> + ps_sampling_table,
> + ARRAY_SIZE(ps_sampling_table),
> + val, val2);
> + if (ret < 0)
> + return ret;
> +
> + /* update persistence count when changing frequency */
> + ret = ltr501_write_intr_prst(data, chan->type,
> + 0, data->ps_period);
> +
> + if (ret < 0)
> + return ltr501_write_samp_freq(data,
> + data->reg_ps_rate,
> + ps_sampling_table,
> + ARRAY_SIZE(ps_sampling_table),
> + freq_val, freq_val2);
> + return ret;
> + default:
> + return -EINVAL;
> + }
> }
> return -EINVAL;
> }
> @@ -499,6 +787,55 @@ static int ltr501_write_thresh(struct iio_dev *indio_dev,
> return -EINVAL;
> }
>
> +static int ltr501_read_event(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + enum iio_event_type type,
> + enum iio_event_direction dir,
> + enum iio_event_info info,
> + int *val, int *val2)
> +{
> + int ret;
> +
> + switch (info) {
> + case IIO_EV_INFO_VALUE:
> + return ltr501_read_thresh(indio_dev, chan, type, dir,
> + info, val, val2);
> + case IIO_EV_INFO_PERIOD:
> + ret = ltr501_read_intr_prst(iio_priv(indio_dev),
> + chan->type, val2);
> + *val = *val2 / 1000000;
> + *val2 = *val2 % 1000000;
> + return ret;
> + default:
> + return -EINVAL;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int ltr501_write_event(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + enum iio_event_type type,
> + enum iio_event_direction dir,
> + enum iio_event_info info,
> + int val, int val2)
> +{
> + switch (info) {
> + case IIO_EV_INFO_VALUE:
> + if (val2 != 0)
> + return -EINVAL;
> + return ltr501_write_thresh(indio_dev, chan, type, dir,
> + info, val, val2);
> + case IIO_EV_INFO_PERIOD:
> + return ltr501_write_intr_prst(iio_priv(indio_dev), chan->type,
> + val, val2);
> + default:
> + return -EINVAL;
> + }
> +
> + return -EINVAL;
> +}
> +
> static int ltr501_read_event_config(struct iio_dev *indio_dev,
> const struct iio_chan_spec *chan,
> enum iio_event_type type,
> @@ -557,11 +894,13 @@ static int ltr501_write_event_config(struct iio_dev *indio_dev,
> static IIO_CONST_ATTR(in_proximity_scale_available, "1 0.25 0.125 0.0625");
> static IIO_CONST_ATTR(in_intensity_scale_available, "1 0.005");
> static IIO_CONST_ATTR_INT_TIME_AVAIL("0.05 0.1 0.2 0.4");
> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("20 10 5 2 1 0.5");
>
> static struct attribute *ltr501_attributes[] = {
> &iio_const_attr_in_proximity_scale_available.dev_attr.attr,
> &iio_const_attr_in_intensity_scale_available.dev_attr.attr,
> &iio_const_attr_integration_time_available.dev_attr.attr,
> + &iio_const_attr_sampling_frequency_available.dev_attr.attr,
> NULL
> };
>
> @@ -580,8 +919,8 @@ static const struct iio_info ltr501_info = {
> .read_raw = ltr501_read_raw,
> .write_raw = ltr501_write_raw,
> .attrs = <r501_attribute_group,
> - .read_event_value = <r501_read_thresh,
> - .write_event_value = <r501_write_thresh,
> + .read_event_value = <r501_read_event,
> + .write_event_value = <r501_write_event,
> .read_event_config = <r501_read_event_config,
> .write_event_config = <r501_write_event_config,
> .driver_module = THIS_MODULE,
> @@ -694,6 +1033,14 @@ static int ltr501_init(struct ltr501_data *data)
>
> data->ps_contr = status | LTR501_CONTR_ACTIVE;
>
> + ret = ltr501_read_intr_prst(data, IIO_INTENSITY, &data->als_period);
> + if (ret < 0)
> + return ret;
> +
> + ret = ltr501_read_intr_prst(data, IIO_PROXIMITY, &data->ps_period);
> + if (ret < 0)
> + return ret;
> +
> return ltr501_write_contr(data, data->als_contr, data->ps_contr);
> }
>
> @@ -764,6 +1111,34 @@ static int ltr501_probe(struct i2c_client *client,
> return PTR_ERR(data->reg_ps_intr);
> }
>
> + data->reg_als_rate = devm_regmap_field_alloc(&client->dev, regmap,
> + reg_als_rate);
> + if (IS_ERR(data->reg_als_rate)) {
> + dev_err(&client->dev, "ALS samp rate field init failed.\n");
> + return PTR_ERR(data->reg_als_rate);
> + }
> +
> + data->reg_ps_rate = devm_regmap_field_alloc(&client->dev, regmap,
> + reg_ps_rate);
> + if (IS_ERR(data->reg_ps_rate)) {
> + dev_err(&client->dev, "PS samp rate field init failed.\n");
> + return PTR_ERR(data->reg_ps_rate);
> + }
> +
> + data->reg_als_prst = devm_regmap_field_alloc(&client->dev, regmap,
> + reg_als_prst);
> + if (IS_ERR(data->reg_als_prst)) {
> + dev_err(&client->dev, "ALS prst reg field init failed\n");
> + return PTR_ERR(data->reg_als_prst);
> + }
> +
> + data->reg_ps_prst = devm_regmap_field_alloc(&client->dev, regmap,
> + reg_ps_prst);
> + if (IS_ERR(data->reg_ps_prst)) {
> + dev_err(&client->dev, "PS prst reg field init failed.\n");
> + return PTR_ERR(data->reg_ps_prst);
> + }
> +
> ret = regmap_read(data->regmap, LTR501_PART_ID, &partid);
> if (ret < 0)
> return ret;
>
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