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Date:   Sat, 2 Mar 2019 19:17:10 +0000
From:   Jonathan Cameron <jic23@kernel.org>
To:     Renato Lui Geh <renatogeh@gmail.com>
Cc:     lars@metafoo.de, Michael.Hennerich@analog.com, knaack.h@gmx.de,
        pmeerw@pmeerw.net, gregkh@linuxfoundation.org,
        stefan.popa@analog.com, alexandru.Ardelean@analog.com,
        giuliano.belinassi@usp.br, robh+dt@kernel.org,
        mark.rutland@arm.com, linux-iio@vger.kernel.org,
        devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
        kernel-usp@googlegroups.com, devicetree@vger.kernel.org
Subject: Re: [PATCH v4 8/9] staging: iio: ad7780: moving ad7780 out of
 staging
Message-ID: <20190302191710.6078f46a@archlinux>
In-Reply-To: <f4fc17090c7c48e5ae3ea7242ef23766047c0cd8.1551358569.git.renatogeh@gmail.com>
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        <f4fc17090c7c48e5ae3ea7242ef23766047c0cd8.1551358569.git.renatogeh@gmail.com>
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On Thu, 28 Feb 2019 11:26:08 -0300
Renato Lui Geh <renatogeh@gmail.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@gmail.com>
> Signed-off-by: Giuliano Belinassi <giuliano.belinassi@usp.br>
> Co-developed-by: Giuliano Belinassi <giuliano.belinassi@usp.br>

I think this is fine up to the minor tweaks Alex raised in the
precursor patches.  Should be good to move in v5 :)

Jonathan

> ---
> Changes in v3:
>  - Changes unrelated to moving the driver to main tree were resent as
>    individual patches
> Changes in v4:
>  - Removed line warning it was safe to build the ad7780 driver by
>    default
> 
> About the above change in v4, I was unsure whether it was ok to add this
> in this patch, as 'move out of staging' patches should be just that. But
> this change is so minimal I'm willing to risk a v5. Bottom line: should
> I add this change as another patch?
> 
>  drivers/iio/adc/Kconfig          |  12 +
>  drivers/iio/adc/Makefile         |   1 +
>  drivers/iio/adc/ad7780.c         | 365 +++++++++++++++++++++++++++++++
>  drivers/staging/iio/adc/Kconfig  |  13 --
>  drivers/staging/iio/adc/Makefile |   1 -
>  drivers/staging/iio/adc/ad7780.c | 365 -------------------------------
>  6 files changed, 378 insertions(+), 379 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..6b36a45bd09f 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -108,6 +108,18 @@ 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).
> +
> +	  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..aa1ddd0c45ee
> --- /dev/null
> +++ b/drivers/iio/adc/ad7780.c
> @@ -0,0 +1,365 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * AD7170/AD7171 and AD7780/AD7781 SPI ADC driver
> + *
> + * Copyright 2011 Analog Devices Inc.
> + * Copyright 2019 Renato Lui Geh
> + */
> +
> +#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/bits.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_GAIN		BIT(2)
> +
> +#define AD7170_ID		0
> +#define AD7171_ID		1
> +#define AD7780_ID		1
> +#define AD7781_ID		0
> +
> +#define AD7780_ID_MASK		(BIT(3) | BIT(4))
> +
> +#define AD7780_PATTERN_GOOD	1
> +#define AD7780_PATTERN_MASK	GENMASK(1, 0)
> +
> +#define AD7170_PATTERN_GOOD	5
> +#define AD7170_PATTERN_MASK	GENMASK(2, 0)
> +
> +#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;
> +	default:
> +	break;
> +	}
> +
> +	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;
> +	default:
> +	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;
> +
> +	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(1, 0, 0, bits, 32, wordsize - bits)
> +#define AD7170_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 = AD7170_CHANNEL(12, 24),
> +		.pattern = AD7170_PATTERN_GOOD,
> +		.pattern_mask = AD7170_PATTERN_MASK,
> +		.is_ad778x = false,
> +	},
> +	[ID_AD7171] = {
> +		.channel = AD7170_CHANNEL(16, 24),
> +		.pattern = AD7170_PATTERN_GOOD,
> +		.pattern_mask = AD7170_PATTERN_MASK,
> +		.is_ad778x = false,
> +	},
> +	[ID_AD7780] = {
> +		.channel = AD7780_CHANNEL(24, 32),
> +		.pattern = AD7780_PATTERN_GOOD,
> +		.pattern_mask = AD7780_PATTERN_MASK,
> +		.is_ad778x = true,
> +	},
> +	[ID_AD7781] = {
> +		.channel = AD7780_CHANNEL(20, 32),
> +		.pattern = AD7780_PATTERN_GOOD,
> +		.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,
> +							"adi,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,
> +							  "adi,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@analog.com>");
> +MODULE_DESCRIPTION("Analog Devices AD7780 and similar ADCs");
> +MODULE_LICENSE("GPL v2");