On 01/03/16 10:31, Gregor Boirie wrote: > Add support for setting and retrieving OverSampling Rate independently for > each of the temperature and pressure channels. This allows userspace to > fine tune hardware sampling process according to the following tradeoffs : > * the higher the OSR, the finer the resolution ; > * the higher the OSR, the lower the noise ; > BUT: > * the higher the OSR, the larger the drift ; > * the higher the OSR, the longer the response time, i.e. less samples per > unit of time. > > Signed-off-by: Gregor Boirie <gregor.boirie@xxxxxxxxxx> Applied to the togreg branch of iio.git - initially pushed out as testing for the autobuilders to play with it. Thanks, Jonathan > --- > drivers/iio/pressure/ms5611.h | 20 ++++--- > drivers/iio/pressure/ms5611_core.c | 105 ++++++++++++++++++++++++++++++++++++- > drivers/iio/pressure/ms5611_i2c.c | 12 ++--- > drivers/iio/pressure/ms5611_spi.c | 19 +++---- > 4 files changed, 133 insertions(+), 23 deletions(-) > > diff --git a/drivers/iio/pressure/ms5611.h b/drivers/iio/pressure/ms5611.h > index 8b08e4b..d725a307 100644 > --- a/drivers/iio/pressure/ms5611.h > +++ b/drivers/iio/pressure/ms5611.h > @@ -19,12 +19,6 @@ > #define MS5611_RESET 0x1e > #define MS5611_READ_ADC 0x00 > #define MS5611_READ_PROM_WORD 0xA0 > -#define MS5611_START_TEMP_CONV 0x58 > -#define MS5611_START_PRESSURE_CONV 0x48 > - > -#define MS5611_CONV_TIME_MIN 9040 > -#define MS5611_CONV_TIME_MAX 10000 > - > #define MS5611_PROM_WORDS_NB 8 > > enum { > @@ -39,10 +33,24 @@ struct ms5611_chip_info { > s32 *temp, s32 *pressure); > }; > > +/* > + * OverSampling Rate descriptor. > + * Warning: cmd MUST be kept aligned on a word boundary (see > + * m5611_spi_read_adc_temp_and_pressure in ms5611_spi.c). > + */ > +struct ms5611_osr { > + unsigned long conv_usec; > + u8 cmd; > + unsigned short rate; > +}; > + > struct ms5611_state { > void *client; > struct mutex lock; > > + const struct ms5611_osr *pressure_osr; > + const struct ms5611_osr *temp_osr; > + > int (*reset)(struct device *dev); > int (*read_prom_word)(struct device *dev, int index, u16 *word); > int (*read_adc_temp_and_pressure)(struct device *dev, > diff --git a/drivers/iio/pressure/ms5611_core.c b/drivers/iio/pressure/ms5611_core.c > index a9c4d49..a2a871b 100644 > --- a/drivers/iio/pressure/ms5611_core.c > +++ b/drivers/iio/pressure/ms5611_core.c > @@ -18,11 +18,44 @@ > #include <linux/delay.h> > #include <linux/regulator/consumer.h> > > +#include <linux/iio/sysfs.h> > #include <linux/iio/buffer.h> > #include <linux/iio/triggered_buffer.h> > #include <linux/iio/trigger_consumer.h> > #include "ms5611.h" > > +#define MS5611_INIT_OSR(_cmd, _conv_usec, _rate) \ > + { .cmd = _cmd, .conv_usec = _conv_usec, .rate = _rate } > + > +static const struct ms5611_osr ms5611_avail_pressure_osr[] = { > + MS5611_INIT_OSR(0x40, 600, 256), > + MS5611_INIT_OSR(0x42, 1170, 512), > + MS5611_INIT_OSR(0x44, 2280, 1024), > + MS5611_INIT_OSR(0x46, 4540, 2048), > + MS5611_INIT_OSR(0x48, 9040, 4096) > +}; > + > +static const struct ms5611_osr ms5611_avail_temp_osr[] = { > + MS5611_INIT_OSR(0x50, 600, 256), > + MS5611_INIT_OSR(0x52, 1170, 512), > + MS5611_INIT_OSR(0x54, 2280, 1024), > + MS5611_INIT_OSR(0x56, 4540, 2048), > + MS5611_INIT_OSR(0x58, 9040, 4096) > +}; > + > +static const char ms5611_show_osr[] = "256 512 1024 2048 4096"; > + > +static IIO_CONST_ATTR(oversampling_ratio_available, ms5611_show_osr); > + > +static struct attribute *ms5611_attributes[] = { > + &iio_const_attr_oversampling_ratio_available.dev_attr.attr, > + NULL, > +}; > + > +static const struct attribute_group ms5611_attribute_group = { > + .attrs = ms5611_attributes, > +}; > + > static bool ms5611_prom_is_valid(u16 *prom, size_t len) > { > int i, j; > @@ -239,11 +272,70 @@ static int ms5611_read_raw(struct iio_dev *indio_dev, > default: > return -EINVAL; > } > + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: > + if (chan->type != IIO_TEMP && chan->type != IIO_PRESSURE) > + break; > + mutex_lock(&st->lock); > + if (chan->type == IIO_TEMP) > + *val = (int)st->temp_osr->rate; > + else > + *val = (int)st->pressure_osr->rate; > + mutex_unlock(&st->lock); > + return IIO_VAL_INT; > } > > return -EINVAL; > } > > +static const struct ms5611_osr *ms5611_find_osr(int rate, > + const struct ms5611_osr *osr, > + size_t count) > +{ > + unsigned int r; > + > + for (r = 0; r < count; r++) > + if ((unsigned short)rate == osr[r].rate) > + break; > + if (r >= count) > + return NULL; > + return &osr[r]; > +} > + > +static int ms5611_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct ms5611_state *st = iio_priv(indio_dev); > + const struct ms5611_osr *osr = NULL; > + > + if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO) > + return -EINVAL; > + > + if (chan->type == IIO_TEMP) > + osr = ms5611_find_osr(val, ms5611_avail_temp_osr, > + ARRAY_SIZE(ms5611_avail_temp_osr)); > + else if (chan->type == IIO_PRESSURE) > + osr = ms5611_find_osr(val, ms5611_avail_pressure_osr, > + ARRAY_SIZE(ms5611_avail_pressure_osr)); > + if (!osr) > + return -EINVAL; > + > + mutex_lock(&st->lock); > + > + if (iio_buffer_enabled(indio_dev)) { > + mutex_unlock(&st->lock); > + return -EBUSY; > + } > + > + if (chan->type == IIO_TEMP) > + st->temp_osr = osr; > + else > + st->pressure_osr = osr; > + > + mutex_unlock(&st->lock); > + return 0; > +} > + > static const unsigned long ms5611_scan_masks[] = {0x3, 0}; > > static struct ms5611_chip_info chip_info_tbl[] = { > @@ -259,7 +351,8 @@ static const struct iio_chan_spec ms5611_channels[] = { > { > .type = IIO_PRESSURE, > .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | > - BIT(IIO_CHAN_INFO_SCALE), > + BIT(IIO_CHAN_INFO_SCALE) | > + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), > .scan_index = 0, > .scan_type = { > .sign = 's', > @@ -271,7 +364,8 @@ static const struct iio_chan_spec ms5611_channels[] = { > { > .type = IIO_TEMP, > .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | > - BIT(IIO_CHAN_INFO_SCALE), > + BIT(IIO_CHAN_INFO_SCALE) | > + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), > .scan_index = 1, > .scan_type = { > .sign = 's', > @@ -285,6 +379,8 @@ static const struct iio_chan_spec ms5611_channels[] = { > > static const struct iio_info ms5611_info = { > .read_raw = &ms5611_read_raw, > + .write_raw = &ms5611_write_raw, > + .attrs = &ms5611_attribute_group, > .driver_module = THIS_MODULE, > }; > > @@ -323,6 +419,11 @@ int ms5611_probe(struct iio_dev *indio_dev, struct device *dev, > > mutex_init(&st->lock); > st->chip_info = &chip_info_tbl[type]; > + st->temp_osr = > + &ms5611_avail_temp_osr[ARRAY_SIZE(ms5611_avail_temp_osr) - 1]; > + st->pressure_osr = > + &ms5611_avail_pressure_osr[ARRAY_SIZE(ms5611_avail_pressure_osr) > + - 1]; > indio_dev->dev.parent = dev; > indio_dev->name = name; > indio_dev->info = &ms5611_info; > diff --git a/drivers/iio/pressure/ms5611_i2c.c b/drivers/iio/pressure/ms5611_i2c.c > index 57a8f2c..55fb5fc 100644 > --- a/drivers/iio/pressure/ms5611_i2c.c > +++ b/drivers/iio/pressure/ms5611_i2c.c > @@ -63,23 +63,23 @@ static int ms5611_i2c_read_adc_temp_and_pressure(struct device *dev, > { > int ret; > struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev)); > + const struct ms5611_osr *osr = st->temp_osr; > > - ret = i2c_smbus_write_byte(st->client, MS5611_START_TEMP_CONV); > + ret = i2c_smbus_write_byte(st->client, osr->cmd); > if (ret < 0) > return ret; > > - usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX); > - > + usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL)); > ret = ms5611_i2c_read_adc(st, temp); > if (ret < 0) > return ret; > > - ret = i2c_smbus_write_byte(st->client, MS5611_START_PRESSURE_CONV); > + osr = st->pressure_osr; > + ret = i2c_smbus_write_byte(st->client, osr->cmd); > if (ret < 0) > return ret; > > - usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX); > - > + usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL)); > return ms5611_i2c_read_adc(st, pressure); > } > > diff --git a/drivers/iio/pressure/ms5611_spi.c b/drivers/iio/pressure/ms5611_spi.c > index 7ec0c64..7600483 100644 > --- a/drivers/iio/pressure/ms5611_spi.c > +++ b/drivers/iio/pressure/ms5611_spi.c > @@ -56,28 +56,29 @@ static int ms5611_spi_read_adc(struct device *dev, s32 *val) > static int ms5611_spi_read_adc_temp_and_pressure(struct device *dev, > s32 *temp, s32 *pressure) > { > - u8 cmd; > int ret; > struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev)); > + const struct ms5611_osr *osr = st->temp_osr; > > - cmd = MS5611_START_TEMP_CONV; > - ret = spi_write_then_read(st->client, &cmd, 1, NULL, 0); > + /* > + * Warning: &osr->cmd MUST be aligned on a word boundary since used as > + * 2nd argument (void*) of spi_write_then_read. > + */ > + ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0); > if (ret < 0) > return ret; > > - usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX); > - > + usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL)); > ret = ms5611_spi_read_adc(dev, temp); > if (ret < 0) > return ret; > > - cmd = MS5611_START_PRESSURE_CONV; > - ret = spi_write_then_read(st->client, &cmd, 1, NULL, 0); > + osr = st->pressure_osr; > + ret = spi_write_then_read(st->client, &osr->cmd, 1, NULL, 0); > if (ret < 0) > return ret; > > - usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX); > - > + usleep_range(osr->conv_usec, osr->conv_usec + (osr->conv_usec / 10UL)); > return ms5611_spi_read_adc(dev, pressure); > } > > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html