On Thu, 29 Nov 2018 11:02:46 -0200 Giuliano Augusto Faulin Belinassi <giuliano.belinassi@xxxxxx> wrote: > Hi A few follow ups from me having read the result in patch 2. Jonathan > > On Thu, Nov 29, 2018 at 9:18 AM Popa, Stefan Serban > <StefanSerban.Popa@xxxxxxxxxx> wrote: > > > > On Mi, 2018-11-28 at 16:15 -0200, Giuliano Belinassi wrote: > > > Previously, the AD7780 driver only supported gpio for the 'powerdown' > > > pin. This commit adds suppport for the 'gain' and 'filter' pin. > > > > > > Signed-off-by: Giuliano Belinassi <giuliano.belinassi@xxxxxx> > > > --- > > > Changes in v2: > > > - Now this patch is part of the patchset that aims to remove ad7780 > > > out of staging. https://marc.info/?l=linux-iio&m=154282349808890&w=2 > > > - Also, now it reads voltage and filter values from the userspace > > > instead of gpio pin states. > > > > Hello, > > Please see bellow. > > > > > > > > drivers/staging/iio/adc/ad7780.c | 78 ++++++++++++++++++++++++-- > > > include/linux/iio/adc/ad_sigma_delta.h | 5 ++ > > > 2 files changed, 79 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/staging/iio/adc/ad7780.c > > > b/drivers/staging/iio/adc/ad7780.c > > > index c4a85789c2db..05979a79fda3 100644 > > > --- a/drivers/staging/iio/adc/ad7780.c > > > +++ b/drivers/staging/iio/adc/ad7780.c > > > @@ -39,6 +39,12 @@ > > > #define AD7170_PATTERN (AD7780_PAT0 | AD7170_PAT2) > > > #define AD7170_PATTERN_MASK (AD7780_PAT0 | AD7780_PAT1 | > > > AD7170_PAT2) > > > > > > +#define AD7780_GAIN_GPIO 0 > > > +#define AD7780_FILTER_GPIO 1 > > > + > > > +#define AD7780_GAIN_MIDPOINT 64 > > > +#define AD7780_FILTER_MIDPOINT 13350 > > > + > > > struct ad7780_chip_info { > > > struct iio_chan_spec channel; > > > unsigned int pattern_mask; > > > @@ -50,6 +56,8 @@ struct ad7780_state { > > > const struct ad7780_chip_info *chip_info; > > > struct regulator *reg; > > > struct gpio_desc *powerdown_gpio; > > > + struct gpio_desc *gain_gpio; > > > + struct gpio_desc *filter_gpio; > > > unsigned int gain; > > > > > > struct ad_sigma_delta sd; > > > @@ -115,18 +123,65 @@ static int ad7780_read_raw(struct iio_dev > > > *indio_dev, > > > return -EINVAL; > > > } > > > > > > +static int ad7780_write_raw(struct iio_dev *indio_dev, > > > + struct iio_chan_spec const *chan, > > > + int val, > > > + int val2, > > > + long m) > > > +{ > > > + struct ad7780_state *st = iio_priv(indio_dev); > > > + const struct ad7780_chip_info *chip_info = st->chip_info; > > > + int uvref, gain; > > > + unsigned int full_scale; > > > + > > > + if (!chip_info->is_ad778x) > > > + return 0; > > > + > > > + switch (m) { > > > + case IIO_CHAN_INFO_SCALE: > > > + if (val != 0) > > > + return -EINVAL; > > > + > > > + uvref = regulator_get_voltage(st->reg); > > > > regulator_get_voltage() has already been called in the probe function and > > the result is stored in st->int_vref_mv. > > This was removed in commit 9eae69ddbc4717a0bd702eddac76c7848773bf71 > because the value was not being updated. But I agree if the vref > voltage is not going to change at all after the initialization, then > this value should be kept in memory. > > > My suggestion would be to use a local vref variable declared as unsigned > > int. It is my fault that I haven't explained correctly in the previous > > email, but you need to multiply vref_mv with 1000000LL in order to get the > > right precision: vref = st->int_vref_mv * 1000000LL. Afterwards you will be > > able to perform the divisions. > > Thanks for this info! :-) > Shouldn't we store this in uV (microVolts)? This will yield a more > accurate result after the multiplication. > > > > + > > > + if (uvref < 0) > > > + return uvref; > > > + > > > + full_scale = 1 << (chip_info->channel.scan_type.realbits > > > - 1); > > > + gain = DIV_ROUND_CLOSEST(uvref, full_scale); > > > + gain = DIV_ROUND_CLOSEST(gain, val2); > > > + > > > + gpiod_set_value(st->gain_gpio, gain < > > > AD7780_GAIN_MIDPOINT ? 0 : 1); > > > > Once the gain is set, you can store it in st->gain variable. > > Yes, we forgot it. > > > > > > + case IIO_CHAN_INFO_SAMP_FREQ: > > > + if (val2 != 0) > > > + return -EINVAL; comment I raised in patch 2 about the odd preciseness of insisting no decimal places, but matching any value based on a threshold on the whole number part. I'd also expect to see read_raw support for this. > > > + > > > + gpiod_set_value(st->filter_gpio, val < > > > AD7780_FILTER_MIDPOINT ? 0 : 1); > > > > This is probably fine, although I am not a big fan of the ternary operator. > > A simple if else statement would do. However, I don't feel strongly about > > it, so feel free to disagree. > > > > > + break; > > > + } > > > + > > > + return 0; > > > +} > > > + > > > static int ad7780_postprocess_sample(struct ad_sigma_delta *sigma_delta, > > > unsigned int raw_sample) > > > { > > > struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta); > > > const struct ad7780_chip_info *chip_info = st->chip_info; > > > + int val; > > > > > > if ((raw_sample & AD7780_ERR) || > > > ((raw_sample & chip_info->pattern_mask) != chip_info- > > > >pattern)) > > > return -EIO; > > > > > > if (chip_info->is_ad778x) { > > > - if (raw_sample & AD7780_GAIN) > > > + val = raw_sample & AD7780_GAIN; > > > + > > > + if (val != gpiod_get_value(st->gain_gpio)) > > > + return -EIO; > > > > It is not obvious to me what is the point of this check. Maybe you can add > > a comment? > > It seems to be a redundancy check. It is getting the 32-bits > raw_output, getting the bit that represents the GAIN value and > checking if the pin is set accordingly (see Figure 22 of datasheet, > page 13). Is this correct? If yes we add a comment explaining this. > > > > > > + > > > + if (val) > > > st->gain = 1; > > > else > > > st->gain = 128; > > > > Do we still need this? I am not convinced. > No, I don't think so. Thanks for pointing this out :-) > > > > > > @@ -141,18 +196,20 @@ static const struct ad_sigma_delta_info > > > ad7780_sigma_delta_info = { > > > .has_registers = false, > > > }; > > > > > > -#define AD7780_CHANNEL(bits, wordsize) \ > > > +#define AD7170_CHANNEL(bits, wordsize) \ > > > AD_SD_CHANNEL_NO_SAMP_FREQ(1, 0, 0, bits, 32, wordsize - bits) > > > +#define AD7780_CHANNEL(bits, wordsize) \ > > > + AD_SD_CHANNEL_GAIN_FILTER(1, 0, 0, bits, 32, wordsize - bits) > > > > > > static const struct ad7780_chip_info ad7780_chip_info_tbl[] = { > > > [ID_AD7170] = { > > > - .channel = AD7780_CHANNEL(12, 24), > > > + .channel = AD7170_CHANNEL(12, 24), > > > .pattern = AD7170_PATTERN, > > > .pattern_mask = AD7170_PATTERN_MASK, > > > .is_ad778x = false, > > > }, > > > [ID_AD7171] = { > > > - .channel = AD7780_CHANNEL(16, 24), > > > + .channel = AD7170_CHANNEL(16, 24), > > > .pattern = AD7170_PATTERN, > > > .pattern_mask = AD7170_PATTERN_MASK, > > > .is_ad778x = false, > > > @@ -173,6 +230,7 @@ static const struct ad7780_chip_info > > > ad7780_chip_info_tbl[] = { > > > > > > static const struct iio_info ad7780_info = { > > > .read_raw = ad7780_read_raw, > > > + .write_raw = ad7780_write_raw, > > > }; > > > > > > static int ad7780_probe(struct spi_device *spi) > > > @@ -222,6 +280,18 @@ static int ad7780_probe(struct spi_device *spi) > > > goto error_disable_reg; > > > } > > > > > > + if (st->chip_info->is_ad778x) { > > > + st->gain_gpio = devm_gpiod_get_optional(&spi->dev, > > > + "gain", > > > + GPIOD_OUT_HIGH); > > > + if (IS_ERR(st->gain_gpio)) { > > > > if the GPIO is optional, then we should continue in case of -ENODEV. > > > > Shouldn't we have a devm_gpiod_get_optional() call also for filter_gpio? I had to check this one... * This is equivalent to gpiod_get(), except that when no GPIO was assigned to * the requested function it will return NULL. This is convenient for drivers * that need to handle optional GPIOs. So nope, it shouldn't return -ENODEV; unlike the clock equivalent which IIRC does... > > > > > + ret = PTR_ERR(st->gain_gpio); > > > + dev_err(&spi->dev, "Failed to request gain GPIO: > > > %d\n", > > > + ret); > > > + goto error_disable_reg; > > > + } > > > + } > > > + > > > ret = ad_sd_setup_buffer_and_trigger(indio_dev); > > > if (ret) > > > goto error_disable_reg; > > > diff --git a/include/linux/iio/adc/ad_sigma_delta.h > > > b/include/linux/iio/adc/ad_sigma_delta.h > > > index 730ead1a46df..6cadab6fd5fd 100644 > > > --- a/include/linux/iio/adc/ad_sigma_delta.h > > > +++ b/include/linux/iio/adc/ad_sigma_delta.h > > > @@ -173,6 +173,11 @@ int ad_sd_validate_trigger(struct iio_dev > > > *indio_dev, struct iio_trigger *trig); > > > __AD_SD_CHANNEL(_si, _channel, -1, _address, _bits, \ > > > _storagebits, _shift, NULL, IIO_VOLTAGE, 0) > > > > > > +#define AD_SD_CHANNEL_GAIN_FILTER(_si, _channel, _address, _bits, \ > > > + _storagebits, _shift) \ > > > + __AD_SD_CHANNEL(_si, _channel, -1, _address, _bits, \ > > > + _storagebits, _shift, NULL, IIO_VOLTAGE, > > > BIT(IIO_CHAN_INFO_RAW)) > > > + > > > #define AD_SD_TEMP_CHANNEL(_si, _address, _bits, _storagebits, _shift) \ > > > __AD_SD_CHANNEL(_si, 0, -1, _address, _bits, \ > > > _storagebits, _shift, NULL, IIO_TEMP, \ > > > > -- > > You received this message because you are subscribed to the Google Groups "Kernel USP" group. > > To unsubscribe from this group and stop receiving emails from it, send an email to kernel-usp+unsubscribe@xxxxxxxxxxxxxxxx. > > To post to this group, send email to kernel-usp@xxxxxxxxxxxxxxxx. > > To view this discussion on the web visit https://groups.google.com/d/msgid/kernel-usp/1543490289.11186.22.camel%40analog.com. > > For more options, visit https://groups.google.com/d/optout. _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
