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From:   Dumitru Ceclan <mitrutzceclan@gmail.com>
To:     mitrutzceclan@gmail.com
Cc:     Lars-Peter Clausen <lars@metafoo.de>,
        Michael Hennerich <Michael.Hennerich@analog.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Cosmin Tanislav <demonsingur@gmail.com>,
        Alexander Sverdlin <alexander.sverdlin@gmail.com>,
        Hugo Villeneuve <hvilleneuve@dimonoff.com>,
        Okan Sahin <okan.sahin@analog.com>,
        Niklas Schnelle <schnelle@linux.ibm.com>,
        ChiYuan Huang <cy_huang@richtek.com>,
        Ramona Bolboaca <ramona.bolboaca@analog.com>,
        Ibrahim Tilki <Ibrahim.Tilki@analog.com>,
        ChiaEn Wu <chiaen_wu@richtek.com>,
        William Breathitt Gray <william.gray@linaro.org>,
        Lee Jones <lee@kernel.org>, Haibo Chen <haibo.chen@nxp.com>,
        Mike Looijmans <mike.looijmans@topic.nl>,
        =?UTF-8?q?Leonard=20G=C3=B6hrs?= <l.goehrs@pengutronix.de>,
        Ceclan Dumitru <dumitru.ceclan@analog.com>,
        linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] iio: adc: ad717x: add AD717X driver
Date:   Thu, 10 Aug 2023 12:33:17 +0300
Message-Id: <20230810093322.593259-2-mitrutzceclan@gmail.com>
In-Reply-To: <20230810093322.593259-1-mitrutzceclan@gmail.com>
References: <20230810093322.593259-1-mitrutzceclan@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The AD717x family offer a complete integrated Sigma-Delta ADC solution
which can be used in high precision, low noise single channel
applications or higher speed multiplexed applications. The Sigma-Delta
ADC is intended primarily for measurement of signals close to DC but also
delivers outstanding performance with input bandwidths out to ~10kHz.

Signed-off-by: Dumitru Ceclan <mitrutzceclan@gmail.com>
---
 drivers/iio/adc/Kconfig  |   7 +
 drivers/iio/adc/Makefile |   1 +
 drivers/iio/adc/ad717x.c | 999 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 1007 insertions(+)
 create mode 100644 drivers/iio/adc/ad717x.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index dc14bde31ac1..294a48b05769 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -54,6 +54,13 @@ config AD7124
 	  To compile this driver as a module, choose M here: the module will be
 	  called ad7124.
 
+config AD717X
+	tristate "Analog Devices AD717x driver"
+	depends on SPI_MASTER
+	select AD_SIGMA_DELTA
+	help
+	  Say yes here to build support for Analog Devices AD717x ADC.
+
 config AD7192
 	tristate "Analog Devices AD7190 AD7192 AD7193 AD7195 ADC driver"
 	depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index eb6e891790fb..e9491e4eff8d 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
 obj-$(CONFIG_AD4130) += ad4130.o
 obj-$(CONFIG_AD7091R5) += ad7091r5.o ad7091r-base.o
 obj-$(CONFIG_AD7124) += ad7124.o
+obj-$(CONFIG_AD717X) += ad717x.o
 obj-$(CONFIG_AD7192) += ad7192.o
 obj-$(CONFIG_AD7266) += ad7266.o
 obj-$(CONFIG_AD7280) += ad7280a.o
diff --git a/drivers/iio/adc/ad717x.c b/drivers/iio/adc/ad717x.c
new file mode 100644
index 000000000000..d14a3e0e2d93
--- /dev/null
+++ b/drivers/iio/adc/ad717x.c
@@ -0,0 +1,999 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * AD7172-2/AD7173-8/AD7175-2/AD7176-2 SPI ADC driver
+ * Copyright (C) 2023 Analog Devices, Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/sysfs.h>
+#include <linux/units.h>
+#include <linux/gpio/driver.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/adc/ad_sigma_delta.h>
+
+#define AD717X_REG_COMMS		0x00
+#define AD717X_REG_ADC_MODE		0x01
+#define AD717X_REG_INTERFACE_MODE	0x02
+#define AD717X_REG_CRC			0x03
+#define AD717X_REG_DATA			0x04
+#define AD717X_REG_GPIO			0x06
+#define AD717X_REG_ID			0x07
+#define AD717X_REG_CH(x)		(0x10 + (x))
+#define AD717X_REG_SETUP(x)		(0x20 + (x))
+#define AD717X_REG_FILTER(x)		(0x28 + (x))
+#define AD717X_REG_OFFSET(x)		(0x30 + (x))
+#define AD717X_REG_GAIN(x)		(0x38 + (x))
+
+#define AD717X_CH_ENABLE		BIT(15)
+#define AD717X_CH_SETUP_SEL(x)		((x) << 12)
+#define AD717X_CH_SETUP_AINPOS(x)	((x) << 5)
+#define AD717X_CH_SETUP_AINNEG(x)	(x)
+
+#define AD717X_CH_ADDRESS(pos, neg) \
+	(AD717X_CH_SETUP_AINPOS(pos) | AD717X_CH_SETUP_AINNEG(neg))
+
+#define AD7172_ID			0x00d0
+#define AD7173_ID			0x30d0
+#define AD7175_ID			0x0cd0
+#define AD7176_ID			0x0c90
+#define AD717X_ID_MASK			0xfff0
+
+#define AD717X_ADC_MODE_REF_EN		BIT(15)
+#define AD717X_ADC_MODE_SING_CYC	BIT(13)
+#define AD717X_ADC_MODE_MODE_MASK	0x70
+#define AD717X_ADC_MODE_MODE(x)		((x) << 4)
+#define AD717X_ADC_MODE_CLOCKSEL_MASK	0xc
+#define AD717X_ADC_MODE_CLOCKSEL(x)	((x) << 2)
+
+#define AD717X_GPIO_PDSW	BIT(14)
+#define AD717X_GPIO_OP_EN2_3	BIT(13)
+#define AD717X_GPIO_MUX_IO	BIT(12)
+#define AD717X_GPIO_SYNC_EN	BIT(11)
+#define AD717X_GPIO_ERR_EN	BIT(10)
+#define AD717X_GPIO_ERR_DAT	BIT(9)
+#define AD717X_GPIO_GP_DATA3	BIT(7)
+#define AD717X_GPIO_GP_DATA2	BIT(6)
+#define AD717X_GPIO_IP_EN1	BIT(5)
+#define AD717X_GPIO_IP_EN0	BIT(4)
+#define AD717X_GPIO_OP_EN1	BIT(3)
+#define AD717X_GPIO_OP_EN0	BIT(2)
+#define AD717X_GPIO_GP_DATA1	BIT(1)
+#define AD717X_GPIO_GP_DATA0	BIT(0)
+
+#define AD717X_INTERFACE_DATA_STAT	BIT(6)
+#define AD717X_INTERFACE_DATA_STAT_EN(x)\
+	FIELD_PREP(AD717X_INTERFACE_DATA_STAT, x)
+
+#define AD717X_SETUP_BIPOLAR		BIT(12)
+#define AD717X_SETUP_AREF_BUF		(0x3 << 10)
+#define AD717X_SETUP_AIN_BUF		(0x3 << 8)
+#define AD717X_SETUP_REF_SEL_MASK	0x30
+#define AD717X_SETUP_REF_SEL_AVDD1_AVSS	0x30
+#define AD717X_SETUP_REF_SEL_INT_REF	0x20
+#define AD717X_SETUP_REF_SEL_EXT_REF2	0x10
+#define AD717X_SETUP_REF_SEL_EXT_REF	0x00
+
+#define AD717X_FILTER_ODR0_MASK		0x1f
+#define AD717X_MAX_CONFIGS		8
+
+enum ad717x_ids {
+	ID_AD7172_2,
+	ID_AD7173_8,
+	ID_AD7175_2,
+	ID_AD7176_2,
+};
+
+struct ad717x_device_info {
+	unsigned int id;
+	unsigned int num_inputs;
+	unsigned int num_channels;
+	unsigned int num_configs;
+	bool has_gp23;
+	bool has_temp;
+	unsigned int clock;
+
+	const unsigned int *sinc5_data_rates;
+	unsigned int num_sinc5_data_rates;
+};
+
+struct ad717x_channel_config {
+	bool live;
+	unsigned char cfg_slot;
+	/* Fields from this point are used to compare equality of configs */
+	unsigned char odr;
+	bool bipolar;
+	bool input_buf;
+};
+
+struct ad717x_channel {
+	unsigned int chan_reg;
+	struct ad717x_channel_config cfg;
+	unsigned int ain;
+};
+
+struct ad717x_state {
+	const struct ad717x_device_info *info;
+	struct ad_sigma_delta sd;
+	struct ad717x_channel *channels;
+	struct regulator *reg;
+	unsigned int adc_mode;
+	unsigned int interface_mode;
+	unsigned int num_channels;
+	struct mutex cfgs_lock; /* lock for configs access */
+	unsigned long cfg_slots_status; /* slots usage status bitmap*/
+	unsigned long long config_usage_counter;
+	unsigned long long *config_cnts;
+
+#ifdef CONFIG_GPIOLIB
+	struct gpio_chip gpiochip;
+	unsigned int gpio_reg;
+	unsigned int gpio_23_mask;
+#endif
+};
+
+static const unsigned int ad7173_sinc5_data_rates[] = {
+	6211000, 6211000, 6211000, 6211000, 6211000, 6211000, 5181000, 4444000,
+	3115000, 2597000, 1007000, 503800,  381000,  200300,  100500,  59520,
+	49680,	 20010,	  16333,   10000,   5000,    2500,    1250,
+};
+
+static const unsigned int ad7175_sinc5_data_rates[] = {
+	50000000, 41667000, 31250000, 27778000, 20833000, 17857000, 12500000,
+	10000000, 5000000,  2500000,  1000000,	500000,	  397500,   200000,
+	100000,	  59920,    49960,    20000,	16666,	  10000,    5000,
+};
+
+static const struct ad717x_device_info ad717x_device_info[] = {
+	[ID_AD7172_2] = {
+		.id = AD7172_ID,
+		.num_inputs = 5,
+		.num_channels = 4,
+		.num_configs = 4,
+		.has_gp23 = false,
+		.has_temp = true,
+		.clock = 2000000,
+		.sinc5_data_rates = ad7173_sinc5_data_rates,
+		.num_sinc5_data_rates = ARRAY_SIZE(ad7173_sinc5_data_rates),
+	},
+	[ID_AD7173_8] = {
+		.id = AD7173_ID,
+		.num_inputs = 17,
+		.num_channels = 16,
+		.num_configs = 8,
+		.has_gp23 = true,
+		.has_temp = true,
+		.clock = 2000000,
+		.sinc5_data_rates = ad7173_sinc5_data_rates,
+		.num_sinc5_data_rates = ARRAY_SIZE(ad7173_sinc5_data_rates),
+	},
+	[ID_AD7175_2] = {
+		.id = AD7175_ID,
+		.num_inputs = 5,
+		.num_channels = 4,
+		.num_configs = 4,
+		.has_gp23 = false,
+		.has_temp = true,
+		.clock = 16000000,
+		.sinc5_data_rates = ad7175_sinc5_data_rates,
+		.num_sinc5_data_rates = ARRAY_SIZE(ad7175_sinc5_data_rates),
+	},
+	[ID_AD7176_2] = {
+		.id = AD7176_ID,
+		.num_inputs = 5,
+		.num_channels = 4,
+		.num_configs = 4,
+		.has_gp23 = false,
+		.has_temp = false,
+		.clock = 16000000,
+		.sinc5_data_rates = ad7175_sinc5_data_rates,
+		.num_sinc5_data_rates = ARRAY_SIZE(ad7175_sinc5_data_rates),
+	},
+};
+
+#ifdef CONFIG_GPIOLIB
+
+static struct ad717x_state *gpiochip_to_ad717x(struct gpio_chip *chip)
+{
+	return container_of(chip, struct ad717x_state, gpiochip);
+}
+
+static int ad717x_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct ad717x_state *st = gpiochip_to_ad717x(chip);
+	unsigned int mask;
+	unsigned int value;
+	int ret;
+
+	switch (offset) {
+	case 0:
+		mask = AD717X_GPIO_GP_DATA0;
+		break;
+	case 1:
+		mask = AD717X_GPIO_GP_DATA1;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = ad_sd_read_reg(&st->sd, AD717X_REG_GPIO, 2, &value);
+	if (ret)
+		return ret;
+
+	return (bool)(value & mask);
+}
+
+static int ad717x_gpio_update(struct ad717x_state *st, unsigned int set_mask,
+			      unsigned int clr_mask)
+{
+	st->gpio_reg |= set_mask;
+	st->gpio_reg &= ~clr_mask;
+
+	return ad_sd_write_reg(&st->sd, AD717X_REG_GPIO, 2, st->gpio_reg);
+}
+
+static void ad717x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct ad717x_state *st = gpiochip_to_ad717x(chip);
+	unsigned int mask, set_mask, clr_mask;
+
+	switch (offset) {
+	case 0:
+		mask = AD717X_GPIO_GP_DATA0;
+		break;
+	case 1:
+		mask = AD717X_GPIO_GP_DATA1;
+		break;
+	case 2:
+		mask = AD717X_GPIO_GP_DATA2;
+		break;
+	case 3:
+		mask = AD717X_GPIO_GP_DATA3;
+		break;
+	default:
+		return;
+	}
+
+	if (value) {
+		set_mask = mask;
+		clr_mask = 0;
+	} else {
+		set_mask = 0;
+		clr_mask = mask;
+	}
+
+	ad717x_gpio_update(st, set_mask, clr_mask);
+}
+
+static int ad717x_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct ad717x_state *st = gpiochip_to_ad717x(chip);
+	unsigned int mask;
+
+	switch (offset) {
+	case 0:
+		mask = AD717X_GPIO_IP_EN0;
+		break;
+	case 1:
+		mask = AD717X_GPIO_IP_EN1;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return ad717x_gpio_update(st, mask, 0);
+}
+
+static int ad717x_gpio_direction_output
+	(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct ad717x_state *st = gpiochip_to_ad717x(chip);
+	unsigned int set_mask, clr_mask, val_mask;
+
+	switch (offset) {
+	case 0:
+		set_mask = AD717X_GPIO_OP_EN0;
+		val_mask = AD717X_GPIO_GP_DATA0;
+		break;
+	case 1:
+		set_mask = AD717X_GPIO_OP_EN1;
+		val_mask = AD717X_GPIO_GP_DATA1;
+		break;
+	/* GP2 and GP3 can not be enabled independently */
+	case 2:
+		st->gpio_23_mask |= (1 << 2);
+		set_mask = AD717X_GPIO_OP_EN2_3;
+		val_mask = AD717X_GPIO_GP_DATA2;
+		break;
+	case 3:
+		st->gpio_23_mask |= (1 << 3);
+		set_mask = AD717X_GPIO_OP_EN2_3;
+		val_mask = AD717X_GPIO_GP_DATA3;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (value) {
+		set_mask |= val_mask;
+		clr_mask = 0;
+	} else {
+		clr_mask = val_mask;
+	}
+
+	return ad717x_gpio_update(st, set_mask, clr_mask);
+}
+
+static void ad717x_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	struct ad717x_state *st = gpiochip_to_ad717x(chip);
+	unsigned int mask;
+
+	switch (offset) {
+	case 0:
+		mask = AD717X_GPIO_OP_EN0 | AD717X_GPIO_IP_EN0;
+		break;
+	case 1:
+		mask = AD717X_GPIO_OP_EN1 | AD717X_GPIO_IP_EN1;
+		break;
+	case 2:
+		st->gpio_23_mask &= ~(1 << offset);
+		if (st->gpio_23_mask != 0)
+			return;
+		mask = AD717X_GPIO_OP_EN2_3;
+		break;
+	default:
+		return;
+	}
+
+	ad717x_gpio_update(st, 0, mask);
+}
+
+static int ad717x_gpio_init(struct ad717x_state *st)
+{
+	st->gpiochip.label = dev_name(&st->sd.spi->dev);
+	st->gpiochip.base = -1;
+	if (st->info->has_gp23)
+		st->gpiochip.ngpio = 4;
+	else
+		st->gpiochip.ngpio = 2;
+	st->gpiochip.parent = &st->sd.spi->dev;
+	st->gpiochip.can_sleep = true;
+	st->gpiochip.direction_input = ad717x_gpio_direction_input;
+	st->gpiochip.direction_output = ad717x_gpio_direction_output;
+	st->gpiochip.get = ad717x_gpio_get;
+	st->gpiochip.set = ad717x_gpio_set;
+	st->gpiochip.free = ad717x_gpio_free;
+	st->gpiochip.owner = THIS_MODULE;
+
+	return devm_gpiochip_add_data(&st->sd.spi->dev, &st->gpiochip, NULL);
+}
+
+#else
+
+static int ad717x_gpio_init(struct ad717x_state *st) { return 0 };
+static void ad717x_gpio_cleanup(struct ad717x_state *st) {};
+
+#endif
+
+static struct ad717x_state *ad_sigma_delta_to_ad717x(struct ad_sigma_delta *sd)
+{
+	return container_of(sd, struct ad717x_state, sd);
+}
+
+static void ad717x_reset_usage_cnts(struct ad717x_state *st)
+{
+	int i;
+
+	for (i = 0; i < st->info->num_configs; i++)
+		(st->config_cnts)[i] = 0;
+
+	st->config_usage_counter = 0;
+}
+
+static struct ad717x_channel_config *ad717x_find_live_config
+	(struct ad717x_state *st, struct ad717x_channel_config *cfg)
+{
+	struct ad717x_channel_config *cfg_aux;
+	ptrdiff_t cmp_size, offset;
+	int i;
+
+	offset = offsetof(struct ad717x_channel_config, cfg_slot) +
+		 sizeof(cfg->cfg_slot);
+	cmp_size = sizeof(*cfg) - offset;
+
+	for (i = 0; i < st->num_channels; i++) {
+		cfg_aux = &st->channels[i].cfg;
+
+		if (cfg_aux->live && !memcmp(((void *)cfg) + offset,
+					    ((void *)cfg_aux) + offset, cmp_size))
+			return cfg_aux;
+	}
+	return NULL;
+}
+
+static int ad717x_free_config_slot_lru(struct ad717x_state *st)
+{
+	int i, lru_position = 0;
+
+	for (i = 1; i < st->info->num_configs; i++)
+		if (st->config_cnts[i] < st->config_cnts[lru_position])
+			lru_position = i;
+
+	for (i = 0; i < st->num_channels; i++)
+		if (st->channels[i].cfg.cfg_slot == lru_position)
+			st->channels[i].cfg.live = false;
+
+	assign_bit(lru_position, &st->cfg_slots_status, 0);
+	return lru_position;
+}
+
+static int ad717x_load_config(struct ad717x_state *st,
+			      struct ad717x_channel_config *cfg)
+{
+	unsigned int config;
+	int free_cfg_slot, ret;
+
+	free_cfg_slot = find_first_zero_bit(&st->cfg_slots_status,
+					    st->info->num_configs);
+	if (free_cfg_slot == st->info->num_configs)
+		free_cfg_slot = ad717x_free_config_slot_lru(st);
+
+	assign_bit(free_cfg_slot, &st->cfg_slots_status, 1);
+	cfg->cfg_slot = free_cfg_slot;
+
+	config = AD717X_SETUP_REF_SEL_INT_REF;
+
+	if (cfg->bipolar)
+		config |= AD717X_SETUP_BIPOLAR;
+
+	if (cfg->input_buf)
+		config |= AD717X_SETUP_AIN_BUF;
+
+	ret = ad_sd_write_reg(&st->sd, AD717X_REG_SETUP(free_cfg_slot), 2, config);
+	if (ret)
+		return ret;
+
+	config = AD717X_FILTER_ODR0_MASK & cfg->odr;
+	return ad_sd_write_reg(&st->sd, AD717X_REG_FILTER(free_cfg_slot), 2, config);
+}
+
+static int ad717x_config_channel(struct ad717x_state *st, int addr)
+{
+	struct ad717x_channel_config *cfg = &st->channels[addr].cfg;
+	struct ad717x_channel_config *live_cfg;
+	int ret = 0;
+
+	if (!cfg->live) {
+		live_cfg = ad717x_find_live_config(st, cfg);
+		if (!live_cfg) {
+			ret = ad717x_load_config(st, cfg);
+			if (ret < 0)
+				return ret;
+		} else {
+			cfg->cfg_slot = live_cfg->cfg_slot;
+		}
+	}
+
+	cfg->live = true;
+	if (st->config_usage_counter == U64_MAX)
+		ad717x_reset_usage_cnts(st);
+
+	st->config_usage_counter++;
+	st->config_cnts[cfg->cfg_slot] = st->config_usage_counter;
+
+	return 0;
+}
+
+static int ad717x_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
+{
+	struct ad717x_state *st = ad_sigma_delta_to_ad717x(sd);
+	unsigned int val;
+	int ret;
+
+	ret = ad717x_config_channel(st, channel);
+	if (ret < 0)
+		return ret;
+
+	val = AD717X_CH_ENABLE |
+	      AD717X_CH_SETUP_SEL(st->channels[channel].cfg.cfg_slot) |
+	      st->channels[channel].ain;
+
+	return ad_sd_write_reg(&st->sd, AD717X_REG_CH(channel), 2, val);
+}
+
+static int ad717x_set_mode(struct ad_sigma_delta *sd,
+			   enum ad_sigma_delta_mode mode)
+{
+	struct ad717x_state *st = ad_sigma_delta_to_ad717x(sd);
+
+	st->adc_mode &= ~AD717X_ADC_MODE_MODE_MASK;
+	st->adc_mode |= AD717X_ADC_MODE_MODE(mode);
+
+	return ad_sd_write_reg(&st->sd, AD717X_REG_ADC_MODE, 2, st->adc_mode);
+}
+
+static int ad717x_append_status(struct ad_sigma_delta *sd, bool append)
+{
+	struct ad717x_state *st = container_of(sd, struct ad717x_state, sd);
+	unsigned int interface_mode = st->interface_mode;
+	int ret;
+
+	interface_mode |= AD717X_INTERFACE_DATA_STAT_EN(append);
+	ret = ad_sd_write_reg(&st->sd, AD717X_REG_INTERFACE_MODE, 2, interface_mode);
+	if (ret < 0)
+		return ret;
+
+	st->interface_mode = interface_mode;
+
+	return 0;
+}
+
+static int ad717x_disable_all(struct ad_sigma_delta *sd)
+{
+	struct ad717x_state *st = container_of(sd, struct ad717x_state, sd);
+	int ret;
+	int i;
+
+	for (i = 0; i < st->num_channels; i++) {
+		ret = ad_sd_write_reg(sd, AD717X_REG_CH(i), 2, 0);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static struct ad_sigma_delta_info ad717x_sigma_delta_info = {
+	.set_channel = ad717x_set_channel,
+	.append_status = ad717x_append_status,
+	.disable_all = ad717x_disable_all,
+	.set_mode = ad717x_set_mode,
+	.has_registers = true,
+	.addr_shift = 0,
+	.read_mask = BIT(6),
+	.status_ch_mask = GENMASK(3, 0),
+	.data_reg = AD717X_REG_DATA,
+	.irq_flags = IRQF_TRIGGER_FALLING
+};
+
+static int ad717x_setup(struct iio_dev *indio_dev)
+{
+	struct ad717x_state *st = iio_priv(indio_dev);
+	unsigned int id;
+	u8 *buf;
+	int ret;
+
+	/* reset the serial interface */
+	buf = kcalloc(8, sizeof(*buf), GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	memset(buf, 0xff, 8);
+	ret = spi_write(st->sd.spi, buf, 8);
+	kfree(buf);
+	if (ret < 0)
+		return ret;
+
+	/* datasheet recommends a delay of at least 500us after reset */
+	usleep_range(500, 1000);
+
+	ret = ad_sd_read_reg(&st->sd, AD717X_REG_ID, 2, &id);
+	if (ret)
+		return ret;
+
+	id &= AD717X_ID_MASK;
+	if (id != st->info->id)
+		dev_warn(&st->sd.spi->dev, "Unexpected device id: %x, expected: %x\n",
+					    id, st->info->id);
+
+	mutex_init(&st->cfgs_lock);
+	st->adc_mode |= AD717X_ADC_MODE_REF_EN | AD717X_ADC_MODE_SING_CYC;
+	st->interface_mode = 0x0;
+
+	st->config_usage_counter = 0;
+	st->config_cnts = devm_kzalloc(&indio_dev->dev,
+				       st->info->num_configs * sizeof(u64),
+				       GFP_KERNEL);
+	if (!st->config_cnts)
+		return -ENOMEM;
+
+	/* All channels are enabled by default after a reset */
+	ret = ad717x_disable_all(&st->sd);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int ad717x_read_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan, int *val, int *val2, long info)
+{
+	struct ad717x_state *st = iio_priv(indio_dev);
+	unsigned int reg;
+	int ret;
+
+	switch (info) {
+	case IIO_CHAN_INFO_RAW:
+		ret = ad_sigma_delta_single_conversion(indio_dev, chan, val);
+		if (ret < 0)
+			return ret;
+
+		/* disable channel after single conversion */
+		ret = ad_sd_write_reg(&st->sd, AD717X_REG_CH(chan->address), 2,
+				      0);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->type == IIO_TEMP) {
+			*val = 250000000;
+			*val2 = 800273203; /* (2**24 * 477) / 10 */
+			return IIO_VAL_FRACTIONAL;
+		} else {
+			*val = 2500;
+			if (chan->differential)
+				*val2 = 23;
+			else
+				*val2 = 24;
+			return IIO_VAL_FRACTIONAL_LOG2;
+		}
+	case IIO_CHAN_INFO_OFFSET:
+		if (chan->type == IIO_TEMP) {
+			*val = -874379;
+		} else {
+			if (chan->differential)
+				*val = -(1 << (chan->scan_type.realbits - 1));
+			else
+				*val = 0;
+		}
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		reg = st->channels[chan->address].cfg.odr;
+
+		*val = st->info->sinc5_data_rates[reg] / MILLI;
+		*val2 = (st->info->sinc5_data_rates[reg] % MILLI) * MILLI;
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+	return -EINVAL;
+}
+
+static int ad717x_write_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan, int val, int val2, long info)
+{
+	struct ad717x_state *st = iio_priv(indio_dev);
+	struct ad717x_channel_config *cfg;
+	unsigned int freq, i, reg;
+	int ret = 0;
+
+	mutex_lock(&st->cfgs_lock);
+	if (iio_buffer_enabled(indio_dev)) {
+		mutex_unlock(&st->cfgs_lock);
+		return -EBUSY;
+	}
+
+	switch (info) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		freq = val * MILLI + val2 / MILLI;
+
+		for (i = 0; i < st->info->num_sinc5_data_rates - 1; i++) {
+			if (freq >= st->info->sinc5_data_rates[i])
+				break;
+		}
+
+		cfg = &st->channels[chan->address].cfg;
+		cfg->odr = i;
+
+		if (cfg->live) {
+			ret = ad_sd_read_reg(&st->sd, AD717X_REG_FILTER(cfg->cfg_slot), 2, &reg);
+			if (ret)
+				break;
+			reg &= ~AD717X_FILTER_ODR0_MASK;
+			reg |= i;
+			ret = ad_sd_write_reg(&st->sd, AD717X_REG_FILTER(cfg->cfg_slot), 2, reg);
+		}
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	mutex_unlock(&st->cfgs_lock);
+	return ret;
+}
+
+static int ad717x_write_raw_get_fmt(struct iio_dev *indio_dev,
+				    struct iio_chan_spec const *chan, long mask)
+{
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+
+static int ad717x_update_scan_mode(struct iio_dev *indio_dev,
+				   const unsigned long *scan_mask)
+{
+	struct ad717x_state *st = iio_priv(indio_dev);
+	bool bit_set;
+	int ret;
+	int i;
+
+	mutex_lock(&st->cfgs_lock);
+	for (i = 0; i < st->num_channels; i++) {
+		bit_set = test_bit(i, scan_mask);
+		if (bit_set)
+			ret = ad717x_set_channel(&st->sd, i);
+		else
+			ret = ad_sd_write_reg(&st->sd, AD717X_REG_CH(i), 2, 0);
+
+		if (ret < 0) {
+			mutex_unlock(&st->cfgs_lock);
+			return ret;
+		}
+	}
+
+	mutex_unlock(&st->cfgs_lock);
+
+	return 0;
+}
+
+static int ad717x_debug(struct iio_dev *indio_dev, unsigned int reg,
+			unsigned int writeval, unsigned int *readval)
+{
+	struct ad717x_state *st = iio_priv(indio_dev);
+	u8 reg_size = 2;
+
+	if (reg == 0)
+		reg_size = 1;
+	else if (reg == AD717X_REG_CRC || reg == AD717X_REG_DATA ||
+		 reg >= AD717X_REG_OFFSET(0))
+		reg_size = 3;
+
+	if (readval)
+		return ad_sd_read_reg(&st->sd, reg, reg_size, readval);
+
+	return ad_sd_write_reg(&st->sd, reg, reg_size, writeval);
+}
+
+static const struct iio_info ad717x_info = {
+	.read_raw = &ad717x_read_raw,
+	.write_raw = &ad717x_write_raw,
+	.write_raw_get_fmt = &ad717x_write_raw_get_fmt,
+	.debugfs_reg_access = &ad717x_debug,
+	.validate_trigger = ad_sd_validate_trigger,
+	.update_scan_mode = ad717x_update_scan_mode,
+};
+
+static const struct iio_chan_spec ad717x_channel_template = {
+	.type = IIO_VOLTAGE,
+	.indexed = 1,
+	.channel = 0,
+	.address = AD717X_CH_ADDRESS(0, 0),
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_SCALE),
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	.scan_index = 0,
+	.scan_type = {
+		.sign = 'u',
+		.realbits = 24,
+		.storagebits = 32,
+		.shift = 0,
+		.endianness = IIO_BE,
+	},
+};
+
+static const struct iio_chan_spec ad717x_temp_iio_channel_template = {
+	.type = IIO_TEMP,
+	.indexed = 1,
+	.channel = 17,
+	.channel2 = 18,
+	.address = 0,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	.scan_index = 0,
+	.scan_type = {
+		.sign = 'u',
+		.realbits = 24,
+		.storagebits = 32,
+		.shift = 0,
+		.endianness = IIO_BE,
+	},
+};
+
+static int ad717x_of_parse_channel_config(struct iio_dev *indio_dev)
+{
+	struct ad717x_state *st = iio_priv(indio_dev);
+	struct ad717x_channel *channels_st_priv;
+	struct fwnode_handle *child;
+	struct device *dev = indio_dev->dev.parent;
+	struct iio_chan_spec *chan;
+	unsigned int num_channels = 0;
+	unsigned int ain[2], chan_index = 0;
+	bool use_temp = false;
+	int ret;
+
+	num_channels = device_get_child_node_count(dev);
+
+	if (device_property_read_bool(dev, "adi,temp-channel")) {
+		if (!st->info->has_temp) {
+			dev_err(indio_dev->dev.parent,
+				"Current chip does not support temperature channel");
+			return -EINVAL;
+		}
+
+		num_channels++;
+		use_temp = true;
+	}
+
+	st->num_channels = num_channels;
+
+	if (num_channels == 0)
+		return 0;
+
+	chan = devm_kcalloc(indio_dev->dev.parent, sizeof(*chan), num_channels,
+			    GFP_KERNEL);
+	if (!chan)
+		return -ENOMEM;
+
+	channels_st_priv = devm_kcalloc(indio_dev->dev.parent, num_channels,
+					sizeof(*channels_st_priv), GFP_KERNEL);
+	if (!channels_st_priv)
+		return -ENOMEM;
+
+	indio_dev->channels = chan;
+	indio_dev->num_channels = num_channels;
+	st->channels = channels_st_priv;
+
+	if (use_temp) {
+		chan[chan_index] = ad717x_temp_iio_channel_template;
+		channels_st_priv[chan_index].ain =
+			AD717X_CH_ADDRESS(chan[chan_index].channel, chan[chan_index].channel2);
+		channels_st_priv[chan_index].cfg.bipolar = false;
+		channels_st_priv[chan_index].cfg.input_buf = true;
+		chan_index++;
+	}
+
+	device_for_each_child_node(dev, child) {
+		ret = fwnode_property_read_u32_array(child, "diff-channels", ain, 2);
+		if (ret) {
+			fwnode_handle_put(child);
+			return ret;
+		}
+
+		if (ain[0] >= st->info->num_inputs ||
+		    ain[1] >= st->info->num_inputs) {
+			dev_err(indio_dev->dev.parent,
+				"Input pin number out of range for pair (%d %d).", ain[0], ain[1]);
+			fwnode_handle_put(child);
+			return -EINVAL;
+		}
+
+		chan[chan_index] = ad717x_channel_template;
+		chan[chan_index].address = chan_index;
+		chan[chan_index].scan_index = chan_index;
+		chan[chan_index].channel = ain[0];
+		chan[chan_index].channel2 = ain[1];
+
+		channels_st_priv[chan_index].ain =
+			AD717X_CH_ADDRESS(ain[0], ain[1]);
+		channels_st_priv[chan_index].chan_reg = chan_index;
+		channels_st_priv[chan_index].cfg.input_buf = true;
+		channels_st_priv[chan_index].cfg.odr = 0;
+
+		chan[chan_index].differential = fwnode_property_read_bool(child, "adi,bipolar");
+		if (chan[chan_index].differential) {
+			chan[chan_index].info_mask_separate |= BIT(IIO_CHAN_INFO_OFFSET);
+			channels_st_priv[chan_index].cfg.bipolar = true;
+		}
+
+		chan_index++;
+	}
+
+	return 0;
+}
+
+static int ad717x_probe(struct spi_device *spi)
+{
+	struct ad717x_state *st;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	if (!spi->irq) {
+		dev_err(&spi->dev, "No IRQ specified\n");
+		return -ENODEV;
+	}
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	st->info = device_get_match_data(&spi->dev);
+	if (!st->info)
+		return -ENODEV;
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &ad717x_info;
+
+	ad717x_sigma_delta_info.num_slots = st->info->num_configs;
+	ret = ad_sd_init(&st->sd, indio_dev, spi, &ad717x_sigma_delta_info);
+	if (ret < 0)
+		return ret;
+
+	spi_set_drvdata(spi, indio_dev);
+
+	ret = ad717x_of_parse_channel_config(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
+	if (ret < 0)
+		return ret;
+
+	ret = ad717x_setup(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_device_register(&spi->dev, indio_dev);
+	if (ret)
+		return ret;
+
+	return ad717x_gpio_init(st);
+}
+
+static const struct of_device_id ad717x_of_match[] = {
+	{ .compatible = "adi,ad7172-2",
+	  .data = &ad717x_device_info[ID_AD7172_2] },
+	{ .compatible = "adi,ad7173-8",
+	  .data = &ad717x_device_info[ID_AD7173_8] },
+	{ .compatible = "adi,ad7175-2",
+	  .data = &ad717x_device_info[ID_AD7175_2] },
+	{ .compatible = "adi,ad7176-2",
+	  .data = &ad717x_device_info[ID_AD7176_2] },
+	{}
+}
+MODULE_DEVICE_TABLE(of, ad717x_of_match);
+
+static const struct spi_device_id ad717x_id_table[] = {
+	{ "ad7172-2", },
+	{ "ad7173-8", },
+	{ "ad7175-2", },
+	{ "ad7176-2", },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, ad717x_id_table);
+
+static struct spi_driver ad717x_driver = {
+	.driver = {
+		.name	= "ad717x",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(ad717x_of_match),
+	},
+	.probe		= ad717x_probe,
+	.id_table	= ad717x_id_table,
+};
+module_spi_driver(ad717x_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafo.de>");
+MODULE_AUTHOR("Dumitru Ceclan <dumitru.ceclan@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7172/AD7173/AD7175/AD7176 ADC driver");
+MODULE_LICENSE("GPL v2");
-- 
2.30.2