Message-ID: <20190214204814.kqblknn65pjcb3ve@renatolg>
Date:   Thu, 14 Feb 2019 18:48:15 -0200
From:   Renato Lui Geh <renatogeh@...il.com>
To:     Jonathan Cameron <jic23@...nel.org>
Cc:     Renato Lui Geh <renatogeh@...il.com>, lars@...afoo.de,
        Michael.Hennerich@...log.com, knaack.h@....de, pmeerw@...erw.net,
        gregkh@...uxfoundation.org, stefan.popa@...log.com,
        alexandru.Ardelean@...log.com, giuliano.belinassi@....br,
        linux-iio@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org, kernel-usp@...glegroups.com
Subject: Re: [PATCH v3 4/4] staging: iio: ad7780: moving ad7780 out of staging

On 02/09, Jonathan Cameron wrote:
>On Tue, 5 Feb 2019 15:14:03 -0200
>Renato Lui Geh <renatogeh@...il.com> wrote:
>
>> Move ad7780 ADC driver out of staging and into the mainline.
>>
>> The ad7780 is a sigma-delta analog to digital converter. This driver provides
>> reading voltage values and status bits from both the ad778x and ad717x series.
>> Its interface also allows writing on the FILTER and GAIN GPIO pins on the
>> ad778x.
>>
>> Signed-off-by: Renato Lui Geh <renatogeh@...il.com>
>> Signed-off-by: Giuliano Belinassi <giuliano.belinassi@....br>
>> Co-developed-by: Giuliano Belinassi <giuliano.belinassi@....br>
>
>This needs a device tree binding doc which should be reviewed before we move
>the driver out of staging.  Make sure to cc the dt-binding maintainers and
>list.  Doesn't really matter if that patch is before or after this one
>in the series but needs to be in the same series.

Ok! I see that some Analog dt-bindings are prefixed by adi and some are
not. Should I follow any naming standard?
>
>There are a few more minor tidy ups that would be nice to have inline
>given you are doing a v4. Stuff like this could have been cleaned up
>after moving out of staging (nothing wrong with improving non staging
>drivers after all) but always better to do it whilst we remember!
>
>> ---
>> Changes in v3:
>> 	- Changes unrelated to moving the driver to main tree were resent as
>> 	  individual patches
>>
>>  drivers/iio/adc/Kconfig          |  13 ++
>>  drivers/iio/adc/Makefile         |   1 +
>>  drivers/iio/adc/ad7780.c         | 359 +++++++++++++++++++++++++++++++
>>  drivers/staging/iio/adc/Kconfig  |  13 --
>>  drivers/staging/iio/adc/Makefile |   1 -
>>  drivers/staging/iio/adc/ad7780.c | 359 -------------------------------
>>  6 files changed, 373 insertions(+), 373 deletions(-)
>>  create mode 100644 drivers/iio/adc/ad7780.c
>>  delete mode 100644 drivers/staging/iio/adc/ad7780.c
>>
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index f3cc7a31bce5..2cdee166d0e9 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -108,6 +108,19 @@ config AD7766
>>  	  To compile this driver as a module, choose M here: the module will be
>>  	  called ad7766.
>>
>> +config AD7780
>> +	tristate "Analog Devices AD7780 and similar ADCs driver"
>> +	depends on SPI
>> +	depends on GPIOLIB || COMPILE_TEST
>> +	select AD_SIGMA_DELTA
>> +	help
>> +	  Say yes here to build support for Analog Devices AD7170, AD7171,
>> +	  AD7780 and AD7781 SPI analog to digital converters (ADC).
>> +	  If unsure, say N (but it's safe to say "Y").
>
>I wouldn't bother with this statement, doesn't add any real info!
>
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called ad7780.
>> +
>>  config AD7791
>>  	tristate "Analog Devices AD7791 ADC driver"
>>  	depends on SPI
>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>> index ea5031348052..b48852157115 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -15,6 +15,7 @@ obj-$(CONFIG_AD7606_IFACE_PARALLEL) += ad7606_par.o
>>  obj-$(CONFIG_AD7606_IFACE_SPI) += ad7606_spi.o
>>  obj-$(CONFIG_AD7606) += ad7606.o
>>  obj-$(CONFIG_AD7766) += ad7766.o
>> +obj-$(CONFIG_AD7780) += ad7780.o
>>  obj-$(CONFIG_AD7791) += ad7791.o
>>  obj-$(CONFIG_AD7793) += ad7793.o
>>  obj-$(CONFIG_AD7887) += ad7887.o
>> diff --git a/drivers/iio/adc/ad7780.c b/drivers/iio/adc/ad7780.c
>> new file mode 100644
>> index 000000000000..163e3c983598
>> --- /dev/null
>> +++ b/drivers/iio/adc/ad7780.c
>> @@ -0,0 +1,359 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * AD7170/AD7171 and AD7780/AD7781 SPI ADC driver
>> + *
>> + * Copyright 2011 Analog Devices Inc.
>
>I think you have done more than enough to this driver to add
>an additional copyright line if you want to!

Oh wow, that'd be awesome! Thanks! Should I just add my full name there?
>
>> + */
>> +
>> +#include <linux/interrupt.h>
>> +#include <linux/device.h>
>> +#include <linux/kernel.h>
>> +#include <linux/slab.h>
>> +#include <linux/sysfs.h>
>> +#include <linux/spi/spi.h>
>> +#include <linux/regulator/consumer.h>
>> +#include <linux/err.h>
>> +#include <linux/sched.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/module.h>
>> +
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/sysfs.h>
>> +#include <linux/iio/adc/ad_sigma_delta.h>
>> +
>> +#define AD7780_RDY		BIT(7)
>> +#define AD7780_FILTER		BIT(6)
>> +#define AD7780_ERR		BIT(5)
>> +#define AD7780_ID1		BIT(4)
>> +#define AD7780_ID0		BIT(3)
>> +#define AD7780_GAIN		BIT(2)
>> +#define AD7780_PAT1		BIT(1)
>> +#define AD7780_PAT0		BIT(0)
>These two bits of pattern don't really add anything. I'd drop them in
>favour of something like
>
>#define AD7780_PATTERN_GOOD 1
>#define AD7780_PATTERN_MASK GENMASK(1, 0)
>
>Same for ID for that matter.  These aren't one bit fields, so we shouldn't
>ever present them as such (though the datasheet confusingly sort of does
>so!)
>
>> +
>> +#define AD7780_PATTERN		(AD7780_PAT0)
>> +#define AD7780_PATTERN_MASK	(AD7780_PAT0 | AD7780_PAT1)
>> +
>> +#define AD7170_PAT2		BIT(2)
>> +
>> +#define AD7170_PATTERN		(AD7780_PAT0 | AD7170_PAT2)
>> +#define AD7170_PATTERN_MASK	(AD7780_PAT0 | AD7780_PAT1 | AD7170_PAT2)
>I'd use a value for the pattern directly and
>GENMASK for the mask.
>
>> +
>> +#define AD7780_GAIN_GPIO	0
>> +#define AD7780_FILTER_GPIO	1
>> +
>> +#define AD7780_GAIN_MIDPOINT	64
>> +#define AD7780_FILTER_MIDPOINT	13350
>> +
>> +static const unsigned int ad778x_gain[2]      = { 1, 128 };
>> +static const unsigned int ad778x_odr_avail[2] = { 10000, 16700 };
>> +
>> +struct ad7780_chip_info {
>> +	struct iio_chan_spec	channel;
>> +	unsigned int		pattern_mask;
>> +	unsigned int		pattern;
>> +	bool			is_ad778x;
>> +};
>> +
>> +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;
>> +	unsigned int			odr;
>> +	unsigned int			int_vref_mv;
>> +
>> +	struct ad_sigma_delta sd;
>> +};
>> +
>> +enum ad7780_supported_device_ids {
>> +	ID_AD7170,
>> +	ID_AD7171,
>> +	ID_AD7780,
>> +	ID_AD7781,
>> +};
>> +
>> +static struct ad7780_state *ad_sigma_delta_to_ad7780(struct ad_sigma_delta *sd)
>> +{
>> +	return container_of(sd, struct ad7780_state, sd);
>> +}
>> +
>> +static int ad7780_set_mode(struct ad_sigma_delta *sigma_delta,
>> +			   enum ad_sigma_delta_mode mode)
>> +{
>> +	struct ad7780_state *st = ad_sigma_delta_to_ad7780(sigma_delta);
>> +	unsigned int val;
>> +
>> +	switch (mode) {
>> +	case AD_SD_MODE_SINGLE:
>> +	case AD_SD_MODE_CONTINUOUS:
>> +		val = 1;
>> +		break;
>> +	default:
>> +		val = 0;
>> +		break;
>> +	}
>> +
>> +	gpiod_set_value(st->powerdown_gpio, val);
>> +
>> +	return 0;
>> +}
>> +
>> +static int ad7780_read_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);
>> +	int voltage_uv;
>> +
>> +	switch (m) {
>> +	case IIO_CHAN_INFO_RAW:
>> +		return ad_sigma_delta_single_conversion(indio_dev, chan, val);
>> +	case IIO_CHAN_INFO_SCALE:
>> +		voltage_uv = regulator_get_voltage(st->reg);
>> +		if (voltage_uv < 0)
>> +			return voltage_uv;
>> +		voltage_uv /= 1000;
>> +		*val = voltage_uv * st->gain;
>> +		*val2 = chan->scan_type.realbits - 1;
>> +		st->int_vref_mv = voltage_uv;
>> +		return IIO_VAL_FRACTIONAL_LOG2;
>> +	case IIO_CHAN_INFO_OFFSET:
>> +		*val = -(1 << (chan->scan_type.realbits - 1));
>> +		return IIO_VAL_INT;
>> +	case IIO_CHAN_INFO_SAMP_FREQ:
>> +		*val = st->odr;
>> +		return IIO_VAL_INT;
>> +	}
>> +
>> +	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;
>> +	unsigned long long vref;
>> +	unsigned int full_scale, gain;
>> +
>> +	if (!chip_info->is_ad778x)
>> +		return 0;
>> +
>> +	switch (m) {
>> +	case IIO_CHAN_INFO_SCALE:
>> +		if (val != 0)
>> +			return -EINVAL;
>> +
>> +		vref = st->int_vref_mv * 1000000LL;
>> +		full_scale = 1 << (chip_info->channel.scan_type.realbits - 1);
>> +		gain = DIV_ROUND_CLOSEST(vref, full_scale);
>> +		gain = DIV_ROUND_CLOSEST(gain, val2);
>> +		st->gain = gain;
>> +		if (gain < AD7780_GAIN_MIDPOINT)
>> +			gain = 0;
>> +		else
>> +			gain = 1;
>> +		gpiod_set_value(st->gain_gpio, gain);
>> +	break;
>> +	case IIO_CHAN_INFO_SAMP_FREQ:
>> +		if (1000*val + val2/1000 < AD7780_FILTER_MIDPOINT)
>> +			val = 0;
>> +		else
>> +			val = 1;
>> +		st->odr = ad778x_odr_avail[val];
>> +		gpiod_set_value(st->filter_gpio, val);
>> +	break;
>We'll get a warning here due to the lack of a default handler.
>It's pointless except to suppress the warning, but best to add one.
>
>> +	}
>> +
>> +	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;
>> +
>> +	if ((raw_sample & AD7780_ERR) ||
>> +	    ((raw_sample & chip_info->pattern_mask) != chip_info->pattern))
>> +		return -EIO;
>> +
>> +	if (chip_info->is_ad778x) {
>> +		st->gain = ad778x_gain[raw_sample & AD7780_GAIN];
>> +		st->odr = ad778x_odr_avail[raw_sample & AD7780_FILTER];
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct ad_sigma_delta_info ad7780_sigma_delta_info = {
>> +	.set_mode = ad7780_set_mode,
>> +	.postprocess_sample = ad7780_postprocess_sample,
>> +	.has_registers = false,
>> +};
>> +
>> +#define AD7780_CHANNEL(bits, wordsize) \
>> +	AD_SD_CHANNEL_NO_SAMP_FREQ(1, 0, 0, bits, 32, wordsize - bits)
>> +
>> +static const struct ad7780_chip_info ad7780_chip_info_tbl[] = {
>> +	[ID_AD7170] = {
>> +		.channel = AD7780_CHANNEL(12, 24),
>> +		.pattern = AD7170_PATTERN,
>> +		.pattern_mask = AD7170_PATTERN_MASK,
>> +		.is_ad778x = false,
>> +	},
>> +	[ID_AD7171] = {
>> +		.channel = AD7780_CHANNEL(16, 24),
>> +		.pattern = AD7170_PATTERN,
>> +		.pattern_mask = AD7170_PATTERN_MASK,
>> +		.is_ad778x = false,
>> +	},
>> +	[ID_AD7780] = {
>> +		.channel = AD7780_CHANNEL(24, 32),
>> +		.pattern = AD7780_PATTERN,
>> +		.pattern_mask = AD7780_PATTERN_MASK,
>> +		.is_ad778x = true,
>> +	},
>> +	[ID_AD7781] = {
>> +		.channel = AD7780_CHANNEL(20, 32),
>> +		.pattern = AD7780_PATTERN,
>> +		.pattern_mask = AD7780_PATTERN_MASK,
>> +		.is_ad778x = true,
>> +	},
>> +};
>> +
>> +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)
>> +{
>> +	struct ad7780_state *st;
>> +	struct iio_dev *indio_dev;
>> +	int ret;
>> +
>> +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
>> +	if (!indio_dev)
>> +		return -ENOMEM;
>> +
>> +	st = iio_priv(indio_dev);
>> +	st->gain = 1;
>> +
>> +	ad_sd_init(&st->sd, indio_dev, spi, &ad7780_sigma_delta_info);
>> +
>> +	st->chip_info =
>> +		&ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
>> +
>> +	spi_set_drvdata(spi, indio_dev);
>> +
>> +	indio_dev->dev.parent = &spi->dev;
>> +	indio_dev->name = spi_get_device_id(spi)->name;
>> +	indio_dev->modes = INDIO_DIRECT_MODE;
>> +	indio_dev->channels = &st->chip_info->channel;
>> +	indio_dev->num_channels = 1;
>> +	indio_dev->info = &ad7780_info;
>> +
>> +	st->powerdown_gpio = devm_gpiod_get_optional(&spi->dev,
>> +						     "powerdown",
>> +						     GPIOD_OUT_LOW);
>> +	if (IS_ERR(st->powerdown_gpio)) {
>> +		ret = PTR_ERR(st->powerdown_gpio);
>> +		dev_err(&spi->dev, "Failed to request powerdown GPIO: %d\n",
>> +			ret);
>> +		return ret;
>> +	}
>> +
>> +	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)) {
>> +			ret = PTR_ERR(st->gain_gpio);
>> +			dev_err(&spi->dev, "Failed to request gain GPIO: %d\n",
>> +				ret);
>> +			return ret;
>> +		}
>> +
>> +		st->filter_gpio = devm_gpiod_get_optional(&spi->dev,
>> +							  "filter",
>> +							  GPIOD_OUT_HIGH);
>> +		if (IS_ERR(st->filter_gpio)) {
>> +			ret = PTR_ERR(st->filter_gpio);
>> +			dev_err(&spi->dev,
>> +				"Failed to request filter GPIO: %d\n",
>> +				ret);
>> +			return ret;
>> +		}
>> +	}
>> +
>> +	st->reg = devm_regulator_get(&spi->dev, "avdd");
>> +	if (IS_ERR(st->reg))
>> +		return PTR_ERR(st->reg);
>> +
>> +	ret = regulator_enable(st->reg);
>> +	if (ret) {
>> +		dev_err(&spi->dev, "Failed to enable specified AVdd supply\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = ad_sd_setup_buffer_and_trigger(indio_dev);
>> +	if (ret)
>> +		goto error_disable_reg;
>> +
>> +	ret = iio_device_register(indio_dev);
>> +	if (ret)
>> +		goto error_cleanup_buffer_and_trigger;
>> +
>> +	return 0;
>> +
>> +error_cleanup_buffer_and_trigger:
>> +	ad_sd_cleanup_buffer_and_trigger(indio_dev);
>> +error_disable_reg:
>> +	regulator_disable(st->reg);
>> +
>> +	return ret;
>> +}
>> +
>> +static int ad7780_remove(struct spi_device *spi)
>> +{
>> +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
>> +	struct ad7780_state *st = iio_priv(indio_dev);
>> +
>> +	iio_device_unregister(indio_dev);
>> +	ad_sd_cleanup_buffer_and_trigger(indio_dev);
>> +
>> +	regulator_disable(st->reg);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct spi_device_id ad7780_id[] = {
>> +	{"ad7170", ID_AD7170},
>> +	{"ad7171", ID_AD7171},
>> +	{"ad7780", ID_AD7780},
>> +	{"ad7781", ID_AD7781},
>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(spi, ad7780_id);
>> +
>> +static struct spi_driver ad7780_driver = {
>> +	.driver = {
>> +		.name	= "ad7780",
>> +	},
>> +	.probe		= ad7780_probe,
>> +	.remove		= ad7780_remove,
>> +	.id_table	= ad7780_id,
>> +};
>> +module_spi_driver(ad7780_driver);
>> +
>> +MODULE_AUTHOR("Michael Hennerich <michael.hennerich@...log.com>");
>> +MODULE_DESCRIPTION("Analog Devices AD7780 and similar ADCs");
>> +MODULE_LICENSE("GPL v2");

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