Re: [PATCH v3 1/4] iio: adc: Add support for AD7091R5 ADC

From: Jonathan Cameron
Date: Sun Nov 10 2019 - 10:48:12 EST

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In reply to: Dan Carpenter: "Re: [PATCH v3 1/4] iio: adc: Add support for AD7091R5 ADC"
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On Thu, 7 Nov 2019 17:07:56 +0200
Beniamin Bia <beniamin.bia@xxxxxxxxxx> wrote:

> From: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
>
> AD7091 is 4-Channel, I2C, Ultra Low Power,12-Bit ADC.
>

I'd like to see a bit of info here about what other ad7091r parts exist
to explain the current split in files.

> Datasheet:
> Link: https://www.analog.com/media/en/technical-documentation/data-sheets/ad7091r-5.pdf
>
> Signed-off-by: Paul Cercueil <paul.cercueil@xxxxxxxxxx>
> Co-developed-by: Beniamin Bia <beniamin.bia@xxxxxxxxxx>
> Signed-off-by: Beniamin Bia <beniamin.bia@xxxxxxxxxx>

Was a close run thing, but there are just enough minor things between my
review here and Dan's that I think we need a v4 rather than me just cleaning
them up whilst applying.

Thanks,

Jonathan

> ---
> Changes in v3:
> -parameters for functions calls were aligned
> -iio_device_register replaced by devm_iio_device_register
> -duplication of regmap_update_bits calls removed in set_mode
>
> drivers/iio/adc/Kconfig | 7 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/ad7091r-base.c | 261 +++++++++++++++++++++++++++++++++
> drivers/iio/adc/ad7091r-base.h | 25 ++++
> drivers/iio/adc/ad7091r5.c | 102 +++++++++++++
> 5 files changed, 396 insertions(+)
> create mode 100644 drivers/iio/adc/ad7091r-base.c
> create mode 100644 drivers/iio/adc/ad7091r-base.h
> create mode 100644 drivers/iio/adc/ad7091r5.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 7e3286265a38..80b1b9551749 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -22,6 +22,13 @@ config AD7124
> To compile this driver as a module, choose M here: the module will be
> called ad7124.
>
> +config AD7091R5
> + tristate "Analog Devices AD7091R5 ADC Driver"
> + depends on I2C
> + select REGMAP_I2C
> + help
> + Say yes here to build support for Analog Devices AD7091R-5 ADC.
> +
> config AD7266
> tristate "Analog Devices AD7265/AD7266 ADC driver"
> depends on SPI_MASTER
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index ef9cc485fb67..55e44735aaac 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -6,6 +6,7 @@
> # When adding new entries keep the list in alphabetical order
> obj-$(CONFIG_AD_SIGMA_DELTA) += ad_sigma_delta.o
> obj-$(CONFIG_AD7124) += ad7124.o
> +obj-$(CONFIG_AD7091R5) += ad7091r5.o ad7091r-base.o
> obj-$(CONFIG_AD7266) += ad7266.o
> obj-$(CONFIG_AD7291) += ad7291.o
> obj-$(CONFIG_AD7298) += ad7298.o
> diff --git a/drivers/iio/adc/ad7091r-base.c b/drivers/iio/adc/ad7091r-base.c
> new file mode 100644
> index 000000000000..2ebc40dfd927
> --- /dev/null
> +++ b/drivers/iio/adc/ad7091r-base.c
> @@ -0,0 +1,261 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * AD7091RX Analog to Digital converter driver
> + *
> + * Copyright 2014-2019 Analog Devices Inc.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/iio/events.h>
> +#include <linux/iio/iio.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +
> +#include "ad7091r-base.h"
> +
> +#define AD7091R_REG_RESULT 0
> +#define AD7091R_REG_CHANNEL 1
> +#define AD7091R_REG_CONF 2
> +#define AD7091R_REG_ALERT 3
> +#define AD7091R_REG_CH_LOW_LIMIT(ch) ((ch) * 3 + 4)
> +#define AD7091R_REG_CH_HIGH_LIMIT(ch) ((ch) * 3 + 5)
> +#define AD7091R_REG_CH_HYSTERESIS(ch) ((ch) * 3 + 6)
> +
> +/* AD7091R_REG_RESULT */
> +#define AD7091R_REG_RESULT_CH_ID(x) (((x) >> 13) & 0x3)
> +#define AD7091R_REG_RESULT_CONV_RESULT(x) ((x) & 0xfff)
> +
> +/* AD7091R_REG_CONF */
> +#define AD7091R_REG_CONF_AUTO BIT(8)
> +#define AD7091R_REG_CONF_CMD BIT(10)
> +
> +#define AD7091R_REG_CONF_MODE_MASK \
> + (AD7091R_REG_CONF_AUTO | AD7091R_REG_CONF_CMD)
> +
> +enum ad7091r_mode {
> + AD7091R_MODE_SAMPLE,
> + AD7091R_MODE_COMMAND,
> + AD7091R_MODE_AUTOCYCLE,
> +};
> +
> +struct ad7091r_state {
> + struct device *dev;
> + struct regmap *map;
> + const struct ad7091r_chip_info *chip_info;
> + enum ad7091r_mode mode;
> + struct mutex lock;

Locks should always have documentation so we know exactly what their
scope is.

> +};
> +
> +static int ad7091r_set_mode(struct ad7091r_state *st, enum ad7091r_mode mode)
> +{
> + int ret, conf;
> +
> + switch (mode) {
> + case AD7091R_MODE_SAMPLE:
> + conf = 0;
> + break;
> + case AD7091R_MODE_COMMAND:
> + conf = AD7091R_REG_CONF_CMD;
> + break;
> + case AD7091R_MODE_AUTOCYCLE:
> + conf = AD7091R_REG_CONF_AUTO;
> + break;
> + default:
> + ret = -EINVAL;
> + break;
> + }
> +
> + ret = regmap_update_bits(st->map, AD7091R_REG_CONF,
> + AD7091R_REG_CONF_MODE_MASK, conf);
> + if (ret)
> + return ret;
> +
> + st->mode = mode;
> +
> + return ret;
> +}
> +
> +static int ad7091r_set_channel(struct ad7091r_state *st, unsigned int channel)
> +{
> + unsigned int foo;
> + int ret;
> +
> + /* AD7091R_REG_CHANNEL specified which channels to be converted */
> + ret = regmap_write(st->map, AD7091R_REG_CHANNEL,
> + BIT(channel) | (BIT(channel) << 8));
> + if (ret)
> + return ret;
> +
> + /*
> + * There is a latency of one conversion before the channel conversion
> + * sequence is updated
> + */
> + return regmap_read(st->map, AD7091R_REG_RESULT, &foo);
> +}
> +
> +static int ad7091r_read_one(struct iio_dev *iio_dev,
> + unsigned int channel, unsigned int *read_val)
> +{
> + struct ad7091r_state *st = iio_priv(iio_dev);
> + unsigned int val;
> + int ret;
> +
> + ret = ad7091r_set_channel(st, channel);
> + if (ret)
> + return ret;
> +
> + ret = regmap_read(st->map, AD7091R_REG_RESULT, &val);
> + if (ret)
> + return ret;
> +
> + if (AD7091R_REG_RESULT_CH_ID(val) != channel)
> + return -EIO;
> +
> + *read_val = AD7091R_REG_RESULT_CONV_RESULT(val);
> +
> + return 0;
> +}
> +
> +static int ad7091r_read_raw(struct iio_dev *iio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long m)
> +{
> + struct ad7091r_state *st = iio_priv(iio_dev);
> + unsigned int read_val;
> + int ret;
> +
> + mutex_lock(&st->lock);
> +
> + switch (m) {
> + case IIO_CHAN_INFO_RAW:
> + if (st->mode != AD7091R_MODE_COMMAND) {

This is currently pointless as only that mode seems to be used.
I guess we can leave it there ready for other modes to be implemented
but I would have preferred it to be introduced at that point.

> + ret = -EBUSY;
> + goto unlock;
> + }
> +
> + ret = ad7091r_read_one(iio_dev, chan->channel, &read_val);
> + if (ret)
> + goto unlock;
> +
> + *val = read_val;
> + ret = IIO_VAL_INT;
> + break;
> +
> + default:
> + ret = -EINVAL;
> + break;
> + }
> +
> +unlock:
> + mutex_unlock(&st->lock);
> + return ret;
> +}
> +
> +static const struct iio_info ad7091r_info = {
> + .read_raw = ad7091r_read_raw,
> +};
> +
> +static irqreturn_t ad7091r_event_handler(int irq, void *private)
> +{
> + struct ad7091r_state *st = (struct ad7091r_state *) private;
> + struct iio_dev *iio_dev = dev_get_drvdata(st->dev);
> + unsigned int i, read_val;
> + int ret;
> + s64 timestamp = iio_get_time_ns(iio_dev);
> +
> + ret = regmap_read(st->map, AD7091R_REG_ALERT, &read_val);
> + if (ret)
> + return IRQ_HANDLED;
> +
> + for (i = 0; i < st->chip_info->num_channels; i++) {
> + if (read_val & BIT(i * 2))
> + iio_push_event(iio_dev,
> + IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
> + IIO_EV_TYPE_THRESH,
> + IIO_EV_DIR_RISING), timestamp);
> + if (read_val & BIT(i * 2 + 1))
> + iio_push_event(iio_dev,
> + IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
> + IIO_EV_TYPE_THRESH,
> + IIO_EV_DIR_FALLING), timestamp);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +int ad7091r_probe(struct device *dev, const char *name,
> + const struct ad7091r_chip_info *chip_info,
> + struct regmap *map, int irq)
> +{
> + struct iio_dev *iio_dev;
> + struct ad7091r_state *st;
> + int ret;
> +
> + iio_dev = devm_iio_device_alloc(dev, sizeof(*st));
> + if (!iio_dev)
> + return -ENOMEM;
> +
> + st = iio_priv(iio_dev);
> + st->dev = dev;
> + st->chip_info = chip_info;
> + st->map = map;
> +
> + iio_dev->dev.parent = dev;
> + iio_dev->name = name;
> + iio_dev->info = &ad7091r_info;
> + iio_dev->modes = INDIO_DIRECT_MODE;
> +
> + iio_dev->num_channels = chip_info->num_channels;
> + iio_dev->channels = chip_info->channels;
> +
> + if (irq) {
> + ret = devm_request_threaded_irq(dev, irq, NULL,
> + ad7091r_event_handler,
> + IRQF_TRIGGER_FALLING | IRQF_ONESHOT, name, st);
> + if (ret)
> + return ret;
> + }
> +
> + /* Use command mode by default to convert only desired channels*/
> + ret = ad7091r_set_mode(st, AD7091R_MODE_COMMAND);
> + if (ret)
> + return ret;
> +
> + return devm_iio_device_register(dev, iio_dev);
> +}
> +EXPORT_SYMBOL_GPL(ad7091r_probe);
> +
> +static bool ad7091r_writeable_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case AD7091R_REG_RESULT:
> + case AD7091R_REG_ALERT:
> + return false;
> + default:
> + return true;
> + }
> +}
> +
> +static bool ad7091r_volatile_reg(struct device *dev, unsigned int reg)
> +{
> + switch (reg) {
> + case AD7091R_REG_RESULT:
> + case AD7091R_REG_ALERT:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
> +const struct regmap_config ad7091r_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 16,
> + .writeable_reg = ad7091r_writeable_reg,
> + .volatile_reg = ad7091r_volatile_reg,
> +};
> +EXPORT_SYMBOL_GPL(ad7091r_regmap_config);
> +
> +MODULE_AUTHOR("Beniamin Bia <beniamin.bia@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Analog Devices AD7091Rx multi-channel converters");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/iio/adc/ad7091r-base.h b/drivers/iio/adc/ad7091r-base.h
> new file mode 100644
> index 000000000000..5f1147735953
> --- /dev/null
> +++ b/drivers/iio/adc/ad7091r-base.h
> @@ -0,0 +1,25 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * AD7091RX Analog to Digital converter driver
> + *
> + * Copyright 2014-2019 Analog Devices Inc.
> + */
> +
> +#ifndef __DRIVERS_IIO_ADC_AD7091R_BASE_H__
> +#define __DRIVERS_IIO_ADC_AD7091R_BASE_H__
> +
> +struct device;
> +struct ad7091r_state;
> +
> +struct ad7091r_chip_info {
> + unsigned int num_channels;
> + const struct iio_chan_spec *channels;
> +};
> +
> +extern const struct regmap_config ad7091r_regmap_config;
> +
> +int ad7091r_probe(struct device *dev, const char *name,
> + const struct ad7091r_chip_info *chip_info,
> + struct regmap *map, int irq);
> +
> +#endif /* __DRIVERS_IIO_ADC_AD7091R5_BASE_H__ */

Comment doesn't match the define (R vs R5).

> diff --git a/drivers/iio/adc/ad7091r5.c b/drivers/iio/adc/ad7091r5.c
> new file mode 100644
> index 000000000000..f7b3326032e8
> --- /dev/null
> +++ b/drivers/iio/adc/ad7091r5.c
> @@ -0,0 +1,102 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * AD7091R5 Analog to Digital converter driver
> + *
> + * Copyright 2014-2019 Analog Devices Inc.
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/iio/iio.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +
> +#include "ad7091r-base.h"
> +
> +static const struct iio_event_spec ad7091r5_events[] = {
> + {
> + .type = IIO_EV_TYPE_THRESH,
> + .dir = IIO_EV_DIR_RISING,
> + .mask_separate = BIT(IIO_EV_INFO_VALUE) |
> + BIT(IIO_EV_INFO_ENABLE),
> + },
> + {
> + .type = IIO_EV_TYPE_THRESH,
> + .dir = IIO_EV_DIR_FALLING,
> + .mask_separate = BIT(IIO_EV_INFO_VALUE) |
> + BIT(IIO_EV_INFO_ENABLE),
> + },
> + {
> + .type = IIO_EV_TYPE_THRESH,
> + .dir = IIO_EV_DIR_EITHER,
> + .mask_separate = BIT(IIO_EV_INFO_HYSTERESIS),
> + },
> +};
> +
> +#define AD7091R_CHANNEL(idx, bits, ev, num_ev) { \
> + .type = IIO_VOLTAGE, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .indexed = 1, \
> + .channel = idx, \
> + .event_spec = ev, \
> + .num_event_specs = num_ev, \
> +}
> +static const struct iio_chan_spec ad7091r5_channels_irq[] = {
> + AD7091R_CHANNEL(0, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
> + AD7091R_CHANNEL(1, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
> + AD7091R_CHANNEL(2, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
> + AD7091R_CHANNEL(3, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
> +};
> +
> +static const struct iio_chan_spec ad7091r5_channels_noirq[] = {
> + AD7091R_CHANNEL(0, 12, NULL, 0),
> + AD7091R_CHANNEL(1, 12, NULL, 0),
> + AD7091R_CHANNEL(2, 12, NULL, 0),
> + AD7091R_CHANNEL(3, 12, NULL, 0),
> +};
> +#undef AD7091R_CHANNEL

Why?

> +
> +static const struct ad7091r_chip_info ad7091r5_chip_info_irq = {
> + .channels = ad7091r5_channels_irq,
> + .num_channels = ARRAY_SIZE(ad7091r5_channels_irq),
> +};
> +
> +static const struct ad7091r_chip_info ad7091r5_chip_info_noirq = {
> + .channels = ad7091r5_channels_noirq,
> + .num_channels = ARRAY_SIZE(ad7091r5_channels_noirq),
> +};
> +
> +static int ad7091r5_i2c_probe(struct i2c_client *i2c,
> + const struct i2c_device_id *id)
> +{
> + const struct ad7091r_chip_info *chip_info;
> + struct regmap *map = devm_regmap_init_i2c(i2c, &ad7091r_regmap_config);
> +
> + if (IS_ERR(map))
> + return PTR_ERR(map);
> +
> + if (i2c->irq)
> + chip_info = &ad7091r5_chip_info_irq;
> + else
> + chip_info = &ad7091r5_chip_info_noirq;
> +
> + return ad7091r_probe(&i2c->dev, id->name, chip_info, map, i2c->irq);
> +}
> +
> +static const struct i2c_device_id ad7091r5_i2c_ids[] = {
> + {"ad7091r5", 0},
> + {}
> +};
> +MODULE_DEVICE_TABLE(i2c, ad7091r5_i2c_ids);

Please add the devicetree specific table as well.
In theory, one day we might get rid of the old i2c fallback paths
that make this work.

> +
> +static struct i2c_driver ad7091r5_driver = {
> + .driver = {
> + .name = "ad7091r5",
> + },
> + .probe = ad7091r5_i2c_probe,
> + .id_table = ad7091r5_i2c_ids,
> +};
> +module_i2c_driver(ad7091r5_driver);
> +
> +MODULE_AUTHOR("Beniamin Bia <beniamin.bia@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Analog Devices AD7091R5 multi-channel ADC driver");
> +MODULE_LICENSE("GPL v2");

Next message: Jonathan Cameron: "Re: [PATCH v3 2/4] iio: adc: ad7091r5: Add scale and external VREF support"
Previous message: Jens Axboe: "Re: KASAN: invalid-free in io_sqe_files_unregister"
In reply to: Dan Carpenter: "Re: [PATCH v3 1/4] iio: adc: Add support for AD7091R5 ADC"
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