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Mon, 11 Nov 2019 15:01:55 -0800 (PST) MIME-Version: 1.0 References: <20190923121714.13672-1-andrea.merello@gmail.com> <20191111153517.13862-1-andrea.merello@gmail.com> <20191111153517.13862-4-andrea.merello@gmail.com> In-Reply-To: <20191111153517.13862-4-andrea.merello@gmail.com> From: Matt Ranostay Date: Tue, 12 Nov 2019 08:01:44 +0900 Message-ID: Subject: Re: [v2 3/9] iio: max31856: add support for configuring the HW averaging To: Andrea Merello Cc: Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Colin Ian King , Patrick Havelange , Paresh Chaudhary , Matt Weber , Chuhong Yuan , Daniel Gomez , "open list:IIO SUBSYSTEM AND DRIVERS" Content-Type: text/plain; charset="UTF-8" Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Tue, Nov 12, 2019 at 12:35 AM Andrea Merello wrote: > > This sensor can perform samples averaging in hardware, but currently the > driver leaves this setting alone (default is no averaging). > > This patch binds this HW setting to the "oversampling_ratio" IIO attribute > and allows the user to set the averaging as desired (the HW supports > averaging of 2, 5, 8 or 16 samples; in-between values are rounded up). > > Cc: Hartmut Knaack > Cc: Lars-Peter Clausen > Cc: Peter Meerwald-Stadler > Cc: Colin Ian King > Cc: Patrick Havelange > Cc: Paresh Chaudhary > Cc: Matt Weber > Cc: Matt Ranostay > Cc: Chuhong Yuan > Cc: Daniel Gomez > Cc: linux-iio@vger.kernel.org > Signed-off-by: Andrea Merello > --- > drivers/iio/temperature/max31856.c | 46 +++++++++++++++++++++++++++++- > 1 file changed, 45 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/temperature/max31856.c b/drivers/iio/temperature/max31856.c > index d97ba9ee1598..9f0f4f65dccd 100644 > --- a/drivers/iio/temperature/max31856.c > +++ b/drivers/iio/temperature/max31856.c > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > #include > /* > * The MSB of the register value determines whether the following byte will > @@ -24,6 +25,8 @@ > #define MAX31856_CR0_OCFAULT BIT(4) > #define MAX31856_CR0_OCFAULT_MASK GENMASK(5, 4) > #define MAX31856_CR0_FILTER_50HZ BIT(0) > +#define MAX31856_AVERAGING_MASK GENMASK(6, 4) > +#define MAX31856_AVERAGING_SHIFT 4 > #define MAX31856_TC_TYPE_MASK GENMASK(3, 0) > #define MAX31856_FAULT_OVUV BIT(1) > #define MAX31856_FAULT_OPEN BIT(0) > @@ -50,7 +53,10 @@ static const struct iio_chan_spec max31856_channels[] = { > { /* Thermocouple Temperature */ > .type = IIO_TEMP, > .info_mask_separate = > - BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), > + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) | > + BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE), Adding IIO_CHAN_INFO_THERMOCOUPLE_TYPE shouldn't happen in this patchset, since it isn't related to the oversampling. - Matt > + .info_mask_shared_by_type = > + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) > }, > { /* Cold Junction Temperature */ > .type = IIO_TEMP, > @@ -58,6 +64,8 @@ static const struct iio_chan_spec max31856_channels[] = { > .modified = 1, > .info_mask_separate = > BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), > + .info_mask_shared_by_type = > + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) > }, > }; > > @@ -65,6 +73,7 @@ struct max31856_data { > struct spi_device *spi; > u32 thermocouple_type; > bool filter_50hz; > + int averaging; > }; > > static int max31856_read(struct max31856_data *data, u8 reg, > @@ -109,6 +118,10 @@ static int max31856_init(struct max31856_data *data) > > reg_cr1_val &= ~MAX31856_TC_TYPE_MASK; > reg_cr1_val |= data->thermocouple_type; > + > + reg_cr1_val &= ~MAX31856_AVERAGING_MASK; > + reg_cr1_val |= data->averaging << MAX31856_AVERAGING_SHIFT; > + > ret = max31856_write(data, MAX31856_CR1_REG, reg_cr1_val); > if (ret) > return ret; > @@ -217,6 +230,9 @@ static int max31856_read_raw(struct iio_dev *indio_dev, > return IIO_VAL_INT_PLUS_MICRO; > } > break; > + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: > + *val = 1 << data->averaging; > + return IIO_VAL_INT; > default: > ret = -EINVAL; > break; > @@ -225,6 +241,33 @@ static int max31856_read_raw(struct iio_dev *indio_dev, > return ret; > } > > +static int max31856_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct max31856_data *data = iio_priv(indio_dev); > + int msb; > + > + switch (mask) { > + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: > + if (val > 16 || val < 1) > + return -EINVAL; > + msb = fls(val) - 1; > + /* Round up to next 2pow if needed */ > + if (BIT(msb) < val) > + msb++; > + > + data->averaging = msb; > + max31856_init(data); > + break; > + > + default: > + return -EINVAL; > + } > + > + return 0; > +} > + > static ssize_t show_fault(struct device *dev, u8 faultbit, char *buf) > { > struct iio_dev *indio_dev = dev_to_iio_dev(dev); > @@ -313,6 +356,7 @@ static const struct attribute_group max31856_group = { > > static const struct iio_info max31856_info = { > .read_raw = max31856_read_raw, > + .write_raw = max31856_write_raw, > .attrs = &max31856_group, > }; > > -- > 2.17.1 >