Message-ID: <20190303122200.6c39942d@archlinux>
Date:   Sun, 3 Mar 2019 12:22:00 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Marcelo Schmitt <marcelo.schmitt1@...il.com>
Cc:     lars@...afoo.de, Michael.Hennerich@...log.com, knaack.h@....de,
        pmeerw@...erw.net, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-usp@...glegroups.com
Subject: Re: [PATCH v2 4/4] staging: iio: ad5933: move out of staging

On Thu, 28 Feb 2019 23:53:31 -0300
Marcelo Schmitt <marcelo.schmitt1@...il.com> wrote:

> Move ad5933 impedance-analyzer driver from staging to mainline.
> 
> The ad5933 is a high precision impedance converter system solution that
> combines an on-board frequency generator with an analog-to-digital
> converter (ADC). This driver was designed to be compatible with both
> ad5933 and ad5934 chips.
> 
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt1@...il.com>
Hi Marcelo.

There seems to still be substantial changes needed related to the ABI,
so I'm not going to review the final state until those are done.

Do you have one of these to test?  Or can we arrange for someone else
to test the result?

It's rather easy for complex rework like you are doing (or going to do) to
have side effects that review might not catch - so I'd definitely like
to know the end result has been tested on the actual hardware!

Thanks for those docs. I suspected they would throw up some 'interesting'
issues around the ABI. It tends to happen with these older drivers
because we hadn't finished fully refining the interfaces when Michael
was developing this!

Jonathan

> ---
>  drivers/iio/impedance-analyzer/Kconfig        |  18 +
>  drivers/iio/impedance-analyzer/Makefile       |   5 +
>  drivers/iio/impedance-analyzer/ad5933.c       | 811 ++++++++++++++++++
>  .../staging/iio/impedance-analyzer/Kconfig    |  18 -
>  .../staging/iio/impedance-analyzer/Makefile   |   5 -
>  .../staging/iio/impedance-analyzer/ad5933.c   | 811 ------------------
>  6 files changed, 834 insertions(+), 834 deletions(-)
>  create mode 100644 drivers/iio/impedance-analyzer/Kconfig
>  create mode 100644 drivers/iio/impedance-analyzer/Makefile
>  create mode 100644 drivers/iio/impedance-analyzer/ad5933.c
>  delete mode 100644 drivers/staging/iio/impedance-analyzer/Kconfig
>  delete mode 100644 drivers/staging/iio/impedance-analyzer/Makefile
>  delete mode 100644 drivers/staging/iio/impedance-analyzer/ad5933.c
> 
> diff --git a/drivers/iio/impedance-analyzer/Kconfig b/drivers/iio/impedance-analyzer/Kconfig
> new file mode 100644
> index 000000000000..b9a679cdd146
> --- /dev/null
> +++ b/drivers/iio/impedance-analyzer/Kconfig
> @@ -0,0 +1,18 @@
> +#
> +# Impedance Converter, Network Analyzer drivers
> +#
> +menu "Network Analyzer, Impedance Converters"
> +
> +config AD5933
> +	tristate "Analog Devices AD5933, AD5934 driver"
> +	depends on I2C
> +	select IIO_BUFFER
> +	select IIO_KFIFO_BUF
> +	help
> +	  Say yes here to build support for Analog Devices Impedance Converter,
> +	  Network Analyzer, AD5933/4.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called ad5933.
> +
> +endmenu
> diff --git a/drivers/iio/impedance-analyzer/Makefile b/drivers/iio/impedance-analyzer/Makefile
> new file mode 100644
> index 000000000000..7604d786583e
> --- /dev/null
> +++ b/drivers/iio/impedance-analyzer/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for Impedance Converter, Network Analyzer drivers
> +#
> +
> +obj-$(CONFIG_AD5933) += ad5933.o
> diff --git a/drivers/iio/impedance-analyzer/ad5933.c b/drivers/iio/impedance-analyzer/ad5933.c
> new file mode 100644
> index 000000000000..d75bdfbf93de
> --- /dev/null
> +++ b/drivers/iio/impedance-analyzer/ad5933.c
> @@ -0,0 +1,811 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * AD5933 AD5934 Impedance Converter, Network Analyzer
> + *
> + * Copyright 2011 Analog Devices Inc.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/sysfs.h>
> +#include <linux/types.h>
> +
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/kfifo_buf.h>
> +#include <linux/iio/sysfs.h>
> +
> +/* AD5933/AD5934 Registers */
> +#define AD5933_REG_CONTROL_HB		0x80	/* R/W, 1 byte */
> +#define AD5933_REG_CONTROL_LB		0x81	/* R/W, 1 byte */
> +#define AD5933_REG_FREQ_START		0x82	/* R/W, 3 bytes */
> +#define AD5933_REG_FREQ_INC		0x85	/* R/W, 3 bytes */
> +#define AD5933_REG_INC_NUM		0x88	/* R/W, 2 bytes, 9 bit */
> +#define AD5933_REG_SETTLING_CYCLES	0x8A	/* R/W, 2 bytes */
> +#define AD5933_REG_STATUS		0x8F	/* R, 1 byte */
> +#define AD5933_REG_TEMP_DATA		0x92	/* R, 2 bytes*/
> +#define AD5933_REG_REAL_DATA		0x94	/* R, 2 bytes*/
> +#define AD5933_REG_IMAG_DATA		0x96	/* R, 2 bytes*/
> +
> +/* AD5933_REG_CONTROL_HB Bits */
> +#define AD5933_CTRL_INIT_START_FREQ	(0x1 << 4)
> +#define AD5933_CTRL_START_SWEEP		(0x2 << 4)
> +#define AD5933_CTRL_INC_FREQ		(0x3 << 4)
> +#define AD5933_CTRL_REPEAT_FREQ		(0x4 << 4)
> +#define AD5933_CTRL_MEASURE_TEMP	(0x9 << 4)
> +#define AD5933_CTRL_POWER_DOWN		(0xA << 4)
> +#define AD5933_CTRL_STANDBY		(0xB << 4)
> +
> +#define AD5933_CTRL_RANGE_2000mVpp	(0x0 << 1)
> +#define AD5933_CTRL_RANGE_200mVpp	(0x1 << 1)
> +#define AD5933_CTRL_RANGE_400mVpp	(0x2 << 1)
> +#define AD5933_CTRL_RANGE_1000mVpp	(0x3 << 1)
> +#define AD5933_CTRL_RANGE(x)		((x) << 1)
> +
> +#define AD5933_CTRL_PGA_GAIN_1		(0x1 << 0)
> +#define AD5933_CTRL_PGA_GAIN_5		(0x0 << 0)
> +
> +/* AD5933_REG_CONTROL_LB Bits */
> +#define AD5933_CTRL_RESET		(0x1 << 4)
> +#define AD5933_CTRL_INT_SYSCLK		(0x0 << 3)
> +#define AD5933_CTRL_EXT_SYSCLK		(0x1 << 3)
> +
> +/* AD5933_REG_STATUS Bits */
> +#define AD5933_STAT_TEMP_VALID		(0x1 << 0)
> +#define AD5933_STAT_DATA_VALID		(0x1 << 1)
> +#define AD5933_STAT_SWEEP_DONE		(0x1 << 2)
> +
> +/* I2C Block Commands */
> +#define AD5933_I2C_BLOCK_WRITE		0xA0
> +#define AD5933_I2C_BLOCK_READ		0xA1
> +#define AD5933_I2C_ADDR_POINTER		0xB0
> +
> +/* Device Specs */
> +#define AD5933_INT_OSC_FREQ_Hz		16776000
> +#define AD5933_MAX_OUTPUT_FREQ_Hz	100000
> +#define AD5933_MAX_RETRIES		100
> +
> +#define AD5933_OUT_RANGE		1
> +#define AD5933_OUT_RANGE_AVAIL		2
> +#define AD5933_OUT_SETTLING_CYCLES	3
> +#define AD5933_IN_PGA_GAIN		4
> +#define AD5933_IN_PGA_GAIN_AVAIL	5
> +#define AD5933_FREQ_POINTS		6
> +
> +#define AD5933_POLL_TIME_ms		10
> +#define AD5933_INIT_EXCITATION_TIME_ms	100
> +
> +struct ad5933_state {
> +	struct i2c_client		*client;
> +	struct regulator		*reg;
> +	struct clk			*mclk;
> +	struct delayed_work		work;
> +	struct mutex			lock; /* Protect sensor state */
> +	unsigned long			mclk_hz;
> +	unsigned char			ctrl_hb;
> +	unsigned char			ctrl_lb;
> +	unsigned int			range_avail[4];
> +	unsigned short			vref_mv;
> +	unsigned short			settling_cycles;
> +	unsigned short			freq_points;
> +	unsigned int			freq_start;
> +	unsigned int			freq_inc;
> +	unsigned int			state;
> +	unsigned int			poll_time_jiffies;
> +};
> +
> +#define AD5933_CHANNEL(_type, _extend_name, _info_mask_separate, _address, \
> +		_scan_index, _realbits) { \
> +	.type = (_type), \
> +	.extend_name = (_extend_name), \
> +	.info_mask_separate = (_info_mask_separate), \
> +	.address = (_address), \
> +	.scan_index = (_scan_index), \
> +	.scan_type = { \
> +		.sign = 's', \
> +		.realbits = (_realbits), \
> +		.storagebits = 16, \
> +	}, \
> +}
> +
> +static const struct iio_chan_spec ad5933_channels[] = {
> +	AD5933_CHANNEL(IIO_TEMP, NULL, BIT(IIO_CHAN_INFO_RAW) |
> +		BIT(IIO_CHAN_INFO_SCALE), AD5933_REG_TEMP_DATA, -1, 14),
> +	/* Ring Channels */
> +	AD5933_CHANNEL(IIO_VOLTAGE, "real", 0, AD5933_REG_REAL_DATA, 0, 16),
> +	AD5933_CHANNEL(IIO_VOLTAGE, "imag", 0, AD5933_REG_IMAG_DATA, 1, 16),
> +};
> +
> +static int ad5933_i2c_write(struct i2c_client *client, u8 reg, u8 len, u8 *data)
> +{
> +	int ret;
> +
> +	while (len--) {
> +		ret = i2c_smbus_write_byte_data(client, reg++, *data++);
> +		if (ret < 0) {
> +			dev_err(&client->dev, "I2C write error\n");
> +			return ret;
> +		}
> +	}
> +	return 0;
> +}
> +
> +static int ad5933_i2c_read(struct i2c_client *client, u8 reg, u8 len, u8 *data)
> +{
> +	int ret;
> +
> +	while (len--) {
> +		ret = i2c_smbus_read_byte_data(client, reg++);
> +		if (ret < 0) {
> +			dev_err(&client->dev, "I2C read error\n");
> +			return ret;
> +		}
> +		*data++ = ret;
> +	}
> +	return 0;
> +}
> +
> +static int ad5933_cmd(struct ad5933_state *st, unsigned char cmd)
> +{
> +	unsigned char dat = st->ctrl_hb | cmd;
> +
> +	return ad5933_i2c_write(st->client,
> +			AD5933_REG_CONTROL_HB, 1, &dat);
> +}
> +
> +static int ad5933_reset(struct ad5933_state *st)
> +{
> +	unsigned char dat = st->ctrl_lb | AD5933_CTRL_RESET;
> +
> +	return ad5933_i2c_write(st->client,
> +			AD5933_REG_CONTROL_LB, 1, &dat);
> +}
> +
> +static int ad5933_wait_busy(struct ad5933_state *st, unsigned char event)
> +{
> +	unsigned char val, timeout = AD5933_MAX_RETRIES;
> +	int ret;
> +
> +	while (timeout--) {
> +		ret =  ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &val);
> +		if (ret < 0)
> +			return ret;
> +		if (val & event)
> +			return val;
> +		cpu_relax();
> +		mdelay(1);
> +	}
> +
> +	return -EAGAIN;
> +}
> +
> +static int ad5933_set_freq(struct ad5933_state *st,
> +			   unsigned int reg, unsigned long freq)
> +{
> +	unsigned long long freqreg;
> +	union {
> +		__be32 d32;
> +		u8 d8[4];
> +	} dat;
> +
> +	freqreg = (u64)freq * (u64)(1 << 27);
> +	do_div(freqreg, st->mclk_hz / 4);
> +
> +	switch (reg) {
> +	case AD5933_REG_FREQ_START:
> +		st->freq_start = freq;
> +		break;
> +	case AD5933_REG_FREQ_INC:
> +		st->freq_inc = freq;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	dat.d32 = cpu_to_be32(freqreg);
> +	return ad5933_i2c_write(st->client, reg, 3, &dat.d8[1]);
> +}
> +
> +static int ad5933_setup(struct ad5933_state *st)
> +{
> +	__be16 dat;
> +	int ret;
> +
> +	ret = ad5933_reset(st);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ad5933_set_freq(st, AD5933_REG_FREQ_START, 10000);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ad5933_set_freq(st, AD5933_REG_FREQ_INC, 200);
> +	if (ret < 0)
> +		return ret;
> +
> +	st->settling_cycles = 10;
> +	dat = cpu_to_be16(st->settling_cycles);
> +
> +	ret = ad5933_i2c_write(st->client,
> +			       AD5933_REG_SETTLING_CYCLES,
> +			       2, (u8 *)&dat);
> +	if (ret < 0)
> +		return ret;
> +
> +	st->freq_points = 100;
> +	dat = cpu_to_be16(st->freq_points);
> +
> +	return ad5933_i2c_write(st->client, AD5933_REG_INC_NUM, 2, (u8 *)&dat);
> +}
> +
> +static void ad5933_calc_out_ranges(struct ad5933_state *st)
> +{
> +	int i;
> +	unsigned int normalized_3v3[4] = {1980, 198, 383, 970};
> +
> +	for (i = 0; i < 4; i++)
> +		st->range_avail[i] = normalized_3v3[i] * st->vref_mv / 3300;
> +}
> +
> +/*
> + * handles: AD5933_REG_FREQ_START and AD5933_REG_FREQ_INC
> + */
> +
> +static ssize_t ad5933_show_frequency(struct device *dev,
> +				     struct device_attribute *attr,
> +				     char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct ad5933_state *st = iio_priv(indio_dev);
> +	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	int ret;
> +	unsigned long long freqreg;
> +	union {
> +		__be32 d32;
> +		u8 d8[4];
> +	} dat;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return ret;
> +	ret = ad5933_i2c_read(st->client, this_attr->address, 3, &dat.d8[1]);
> +	iio_device_release_direct_mode(indio_dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	freqreg = be32_to_cpu(dat.d32) & 0xFFFFFF;
> +
> +	freqreg = (u64)freqreg * (u64)(st->mclk_hz / 4);
> +	do_div(freqreg, 1 << 27);
> +
> +	return sprintf(buf, "%d\n", (int)freqreg);
> +}
> +
> +static ssize_t ad5933_store_frequency(struct device *dev,
> +				      struct device_attribute *attr,
> +				      const char *buf,
> +				      size_t len)
> +{
> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct ad5933_state *st = iio_priv(indio_dev);
> +	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	unsigned long val;
> +	int ret;
> +
> +	ret = kstrtoul(buf, 10, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val > AD5933_MAX_OUTPUT_FREQ_Hz)
> +		return -EINVAL;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return ret;
> +	ret = ad5933_set_freq(st, this_attr->address, val);
> +	iio_device_release_direct_mode(indio_dev);
> +
> +	return ret ? ret : len;
> +}
> +
> +static IIO_DEVICE_ATTR(out_voltage0_freq_start, 0644,
> +			ad5933_show_frequency,
> +			ad5933_store_frequency,
> +			AD5933_REG_FREQ_START);
> +
> +static IIO_DEVICE_ATTR(out_voltage0_freq_increment, 0644,
> +			ad5933_show_frequency,
> +			ad5933_store_frequency,
> +			AD5933_REG_FREQ_INC);
> +
> +static ssize_t ad5933_show(struct device *dev,
> +			   struct device_attribute *attr,
> +			   char *buf)
> +{
> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct ad5933_state *st = iio_priv(indio_dev);
> +	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	int ret = 0, len = 0;
> +
> +	mutex_lock(&st->lock);
> +	switch ((u32)this_attr->address) {
> +	case AD5933_OUT_RANGE:
> +		len = sprintf(buf, "%u\n",
> +			      st->range_avail[(st->ctrl_hb >> 1) & 0x3]);
> +		break;
> +	case AD5933_OUT_RANGE_AVAIL:
> +		len = sprintf(buf, "%u %u %u %u\n", st->range_avail[0],
> +			      st->range_avail[3], st->range_avail[2],
> +			      st->range_avail[1]);
> +		break;
> +	case AD5933_OUT_SETTLING_CYCLES:
> +		len = sprintf(buf, "%d\n", st->settling_cycles);
> +		break;
> +	case AD5933_IN_PGA_GAIN:
> +		len = sprintf(buf, "%s\n",
> +			      (st->ctrl_hb & AD5933_CTRL_PGA_GAIN_1) ?
> +			      "1" : "0.2");
> +		break;
> +	case AD5933_IN_PGA_GAIN_AVAIL:
> +		len = sprintf(buf, "1 0.2\n");
> +		break;
> +	case AD5933_FREQ_POINTS:
> +		len = sprintf(buf, "%d\n", st->freq_points);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +	mutex_unlock(&st->lock);
> +	return ret ? ret : len;
> +}
> +
> +static ssize_t ad5933_store(struct device *dev,
> +			    struct device_attribute *attr,
> +			    const char *buf,
> +			    size_t len)
> +{
> +	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> +	struct ad5933_state *st = iio_priv(indio_dev);
> +	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	u16 val;
> +	int i, ret = 0;
> +	__be16 dat;
> +
> +	if (this_attr->address != AD5933_IN_PGA_GAIN) {
> +		ret = kstrtou16(buf, 10, &val);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return ret;
> +	mutex_lock(&st->lock);
> +	switch ((u32)this_attr->address) {
> +	case AD5933_OUT_RANGE:
> +		ret = -EINVAL;
> +		for (i = 0; i < 4; i++)
> +			if (val == st->range_avail[i]) {
> +				st->ctrl_hb &= ~AD5933_CTRL_RANGE(0x3);
> +				st->ctrl_hb |= AD5933_CTRL_RANGE(i);
> +				ret = ad5933_cmd(st, 0);
> +				break;
> +			}
> +		break;
> +	case AD5933_IN_PGA_GAIN:
> +		if (sysfs_streq(buf, "1")) {
> +			st->ctrl_hb |= AD5933_CTRL_PGA_GAIN_1;
> +		} else if (sysfs_streq(buf, "0.2")) {
> +			st->ctrl_hb &= ~AD5933_CTRL_PGA_GAIN_1;
> +		} else {
> +			ret = -EINVAL;
> +			break;
> +		}
> +		ret = ad5933_cmd(st, 0);
> +		break;
> +	case AD5933_OUT_SETTLING_CYCLES:
> +		val = clamp(val, (u16)0, (u16)0x7FF);
> +		st->settling_cycles = val;
> +
> +		/* 2x, 4x handling, see datasheet */
> +		if (val > 1022)
> +			val = (val >> 2) | (3 << 9);
> +		else if (val > 511)
> +			val = (val >> 1) | (1 << 9);
> +
> +		dat = cpu_to_be16(val);
> +		ret = ad5933_i2c_write(st->client,
> +				       AD5933_REG_SETTLING_CYCLES,
> +				       2, (u8 *)&dat);
> +		break;
> +	case AD5933_FREQ_POINTS:
> +		val = clamp(val, (u16)0, (u16)511);
> +		st->freq_points = val;
> +
> +		dat = cpu_to_be16(val);
> +		ret = ad5933_i2c_write(st->client, AD5933_REG_INC_NUM, 2,
> +				       (u8 *)&dat);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +	mutex_unlock(&st->lock);
> +	iio_device_release_direct_mode(indio_dev);
> +	return ret ? ret : len;
> +}
> +
> +static IIO_DEVICE_ATTR(out_voltage0_scale, 0644,
> +			ad5933_show,
> +			ad5933_store,
> +			AD5933_OUT_RANGE);
> +
> +static IIO_DEVICE_ATTR(out_voltage0_scale_available, 0444,
> +			ad5933_show,
> +			NULL,
> +			AD5933_OUT_RANGE_AVAIL);
> +
> +static IIO_DEVICE_ATTR(in_voltage0_scale, 0644,
> +			ad5933_show,
> +			ad5933_store,
> +			AD5933_IN_PGA_GAIN);
> +
> +static IIO_DEVICE_ATTR(in_voltage0_scale_available, 0444,
> +			ad5933_show,
> +			NULL,
> +			AD5933_IN_PGA_GAIN_AVAIL);
> +
> +static IIO_DEVICE_ATTR(out_voltage0_freq_points, 0644,
> +			ad5933_show,
> +			ad5933_store,
> +			AD5933_FREQ_POINTS);
> +
> +static IIO_DEVICE_ATTR(out_voltage0_settling_cycles, 0644,
> +			ad5933_show,
> +			ad5933_store,
> +			AD5933_OUT_SETTLING_CYCLES);
> +
> +/*
> + * note:
> + * ideally we would handle the scale attributes via the iio_info
> + * (read|write)_raw methods, however this part is a untypical since we
> + * don't create dedicated sysfs channel attributes for out0 and in0.
> + */
> +static struct attribute *ad5933_attributes[] = {
> +	&iio_dev_attr_out_voltage0_scale.dev_attr.attr,
> +	&iio_dev_attr_out_voltage0_scale_available.dev_attr.attr,
> +	&iio_dev_attr_out_voltage0_freq_start.dev_attr.attr,
> +	&iio_dev_attr_out_voltage0_freq_increment.dev_attr.attr,
> +	&iio_dev_attr_out_voltage0_freq_points.dev_attr.attr,
> +	&iio_dev_attr_out_voltage0_settling_cycles.dev_attr.attr,
> +	&iio_dev_attr_in_voltage0_scale.dev_attr.attr,
> +	&iio_dev_attr_in_voltage0_scale_available.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group ad5933_attribute_group = {
> +	.attrs = ad5933_attributes,
> +};
> +
> +static int ad5933_read_raw(struct iio_dev *indio_dev,
> +			   struct iio_chan_spec const *chan,
> +			   int *val,
> +			   int *val2,
> +			   long m)
> +{
> +	struct ad5933_state *st = iio_priv(indio_dev);
> +	__be16 dat;
> +	int ret;
> +
> +	switch (m) {
> +	case IIO_CHAN_INFO_RAW:
> +		ret = iio_device_claim_direct_mode(indio_dev);
> +		if (ret)
> +			return ret;
> +		ret = ad5933_cmd(st, AD5933_CTRL_MEASURE_TEMP);
> +		if (ret < 0)
> +			goto out;
> +		ret = ad5933_wait_busy(st, AD5933_STAT_TEMP_VALID);
> +		if (ret < 0)
> +			goto out;
> +
> +		ret = ad5933_i2c_read(st->client,
> +				      AD5933_REG_TEMP_DATA,
> +				      2, (u8 *)&dat);
> +		if (ret < 0)
> +			goto out;
> +		iio_device_release_direct_mode(indio_dev);
> +		*val = sign_extend32(be16_to_cpu(dat), 13);
> +
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = 1000;
> +		*val2 = 5;
> +		return IIO_VAL_FRACTIONAL_LOG2;
> +	}
> +
> +	return -EINVAL;
> +out:
> +	iio_device_release_direct_mode(indio_dev);
> +	return ret;
> +}
> +
> +static const struct iio_info ad5933_info = {
> +	.read_raw = ad5933_read_raw,
> +	.attrs = &ad5933_attribute_group,
> +};
> +
> +static int ad5933_ring_preenable(struct iio_dev *indio_dev)
> +{
> +	struct ad5933_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	if (bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength))
> +		return -EINVAL;
> +
> +	ret = ad5933_reset(st);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ad5933_cmd(st, AD5933_CTRL_STANDBY);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ad5933_cmd(st, AD5933_CTRL_INIT_START_FREQ);
> +	if (ret < 0)
> +		return ret;
> +
> +	st->state = AD5933_CTRL_INIT_START_FREQ;
> +
> +	return 0;
> +}
> +
> +static int ad5933_ring_postenable(struct iio_dev *indio_dev)
> +{
> +	struct ad5933_state *st = iio_priv(indio_dev);
> +
> +	/*
> +	 * AD5933_CTRL_INIT_START_FREQ:
> +	 * High Q complex circuits require a long time to reach steady state.
> +	 * To facilitate the measurement of such impedances, this mode allows
> +	 * the user full control of the settling time requirement before
> +	 * entering start frequency sweep mode where the impedance measurement
> +	 * takes place. In this mode the impedance is excited with the
> +	 * programmed start frequency (ad5933_ring_preenable),
> +	 * but no measurement takes place.
> +	 */
> +
> +	schedule_delayed_work(&st->work,
> +			      msecs_to_jiffies(AD5933_INIT_EXCITATION_TIME_ms));
> +	return 0;
> +}
> +
> +static int ad5933_ring_postdisable(struct iio_dev *indio_dev)
> +{
> +	struct ad5933_state *st = iio_priv(indio_dev);
> +
> +	cancel_delayed_work_sync(&st->work);
> +	return ad5933_cmd(st, AD5933_CTRL_POWER_DOWN);
> +}
> +
> +static const struct iio_buffer_setup_ops ad5933_ring_setup_ops = {
> +	.preenable = ad5933_ring_preenable,
> +	.postenable = ad5933_ring_postenable,
> +	.postdisable = ad5933_ring_postdisable,
> +};
> +
> +static int ad5933_register_ring_funcs_and_init(struct iio_dev *indio_dev)
> +{
> +	struct iio_buffer *buffer;
> +
> +	buffer = iio_kfifo_allocate();
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	iio_device_attach_buffer(indio_dev, buffer);
> +
> +	/* Ring buffer functions - here trigger setup related */
> +	indio_dev->setup_ops = &ad5933_ring_setup_ops;
> +
> +	return 0;
> +}
> +
> +static void ad5933_work(struct work_struct *work)
> +{
> +	struct ad5933_state *st = container_of(work,
> +		struct ad5933_state, work.work);
> +	struct iio_dev *indio_dev = i2c_get_clientdata(st->client);
> +	__be16 buf[2];
> +	int val[2];
> +	unsigned char status;
> +	int ret;
> +
> +	if (st->state == AD5933_CTRL_INIT_START_FREQ) {
> +		/* start sweep */
> +		ad5933_cmd(st, AD5933_CTRL_START_SWEEP);
> +		st->state = AD5933_CTRL_START_SWEEP;
> +		schedule_delayed_work(&st->work, st->poll_time_jiffies);
> +		return;
> +	}
> +
> +	ret = ad5933_i2c_read(st->client, AD5933_REG_STATUS, 1, &status);
> +	if (ret)
> +		return;
> +
> +	if (status & AD5933_STAT_DATA_VALID) {
> +		int scan_count = bitmap_weight(indio_dev->active_scan_mask,
> +					       indio_dev->masklength);
> +		ret = ad5933_i2c_read(st->client,
> +				test_bit(1, indio_dev->active_scan_mask) ?
> +				AD5933_REG_REAL_DATA : AD5933_REG_IMAG_DATA,
> +				scan_count * 2, (u8 *)buf);
> +		if (ret)
> +			return;
> +
> +		if (scan_count == 2) {
> +			val[0] = be16_to_cpu(buf[0]);
> +			val[1] = be16_to_cpu(buf[1]);
> +		} else {
> +			val[0] = be16_to_cpu(buf[0]);
> +		}
> +		iio_push_to_buffers(indio_dev, val);
> +	} else {
> +		/* no data available - try again later */
> +		schedule_delayed_work(&st->work, st->poll_time_jiffies);
> +		return;
> +	}
> +
> +	if (status & AD5933_STAT_SWEEP_DONE) {
> +		/*
> +		 * last sample received - power down do
> +		 * nothing until the ring enable is toggled
> +		 */
> +		ad5933_cmd(st, AD5933_CTRL_POWER_DOWN);
> +	} else {
> +		/* we just received a valid datum, move on to the next */
> +		ad5933_cmd(st, AD5933_CTRL_INC_FREQ);
> +		schedule_delayed_work(&st->work, st->poll_time_jiffies);
> +	}
> +}
> +
> +static int ad5933_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	int ret;
> +	struct ad5933_state *st;
> +	struct iio_dev *indio_dev;
> +	unsigned long ext_clk_hz = 0;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +	st->client = client;
> +
> +	mutex_init(&st->lock);
> +
> +	st->reg = devm_regulator_get(&client->dev, "vdd");
> +	if (IS_ERR(st->reg))
> +		return PTR_ERR(st->reg);
> +
> +	ret = regulator_enable(st->reg);
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to enable specified VDD supply\n");
> +		return ret;
> +	}
> +	ret = regulator_get_voltage(st->reg);
> +
> +	if (ret < 0)
> +		goto error_disable_reg;
> +
> +	st->vref_mv = ret / 1000;
> +
> +	st->mclk = devm_clk_get(&client->dev, "mclk");
> +	if (IS_ERR(st->mclk) && PTR_ERR(st->mclk) != -ENOENT) {
> +		ret = PTR_ERR(st->mclk);
> +		goto error_disable_reg;
> +	}
> +
> +	if (!IS_ERR(st->mclk)) {
> +		ret = clk_prepare_enable(st->mclk);
> +		if (ret < 0)
> +			goto error_disable_reg;
> +		ext_clk_hz = clk_get_rate(st->mclk);
> +	}
> +
> +	if (ext_clk_hz) {
> +		st->mclk_hz = ext_clk_hz;
> +		st->ctrl_lb = AD5933_CTRL_EXT_SYSCLK;
> +	} else {
> +		st->mclk_hz = AD5933_INT_OSC_FREQ_Hz;
> +		st->ctrl_lb = AD5933_CTRL_INT_SYSCLK;
> +	}
> +
> +	ad5933_calc_out_ranges(st);
> +	INIT_DELAYED_WORK(&st->work, ad5933_work);
> +	st->poll_time_jiffies = msecs_to_jiffies(AD5933_POLL_TIME_ms);
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &ad5933_info;
> +	indio_dev->name = id->name;
> +	indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
> +	indio_dev->channels = ad5933_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(ad5933_channels);
> +
> +	ret = ad5933_register_ring_funcs_and_init(indio_dev);
> +	if (ret)
> +		goto error_disable_mclk;
> +
> +	ret = ad5933_setup(st);
> +	if (ret)
> +		goto error_unreg_ring;
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret)
> +		goto error_unreg_ring;
> +
> +	return 0;
> +
> +error_unreg_ring:
> +	iio_kfifo_free(indio_dev->buffer);
> +error_disable_mclk:
> +	clk_disable_unprepare(st->mclk);
> +error_disable_reg:
> +	regulator_disable(st->reg);
> +
> +	return ret;
> +}
> +
> +static int ad5933_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct ad5933_state *st = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +	iio_kfifo_free(indio_dev->buffer);
> +	regulator_disable(st->reg);
> +	clk_disable_unprepare(st->mclk);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id ad5933_id[] = {
> +	{ "ad5933", 0 },
> +	{ "ad5934", 0 },
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, ad5933_id);
> +
> +static const struct of_device_id ad5933_of_match[] = {
> +	{ .compatible = "adi,ad5933" },
> +	{ .compatible = "adi,ad5934" },
> +	{ },
> +};
> +
> +MODULE_DEVICE_TABLE(of, ad5933_of_match);
> +
> +static struct i2c_driver ad5933_driver = {
> +	.driver = {
> +		.name = "ad5933",
> +		.of_match_table = ad5933_of_match,
> +	},
> +	.probe = ad5933_probe,
> +	.remove = ad5933_remove,
> +	.id_table = ad5933_id,
> +};
> +module_i2c_driver(ad5933_driver);
> +
> +MODULE_AUTHOR("Michael Hennerich <michael.hennerich@...log.com>");
> +MODULE_DESCRIPTION("Analog Devices AD5933 Impedance Conv. Network Analyzer");
> +MODULE_LICENSE("GPL v2");

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