Re: [PATCH v3 2/2] iio: potentiometer: Add driver support for AD5110

Jonathan Cameron
2021-08-15T14:36:28Z

On Sat, 14 Aug 2021 22:45:01 +0300
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Sat, Aug 14, 2021 at 8:57 PM Mugilraj Dhavachelvan
> <dmugil2000@gmail.com> wrote:
> >
> > The AD5110/AD5112/AD5114 provide a nonvolatile solution
> > for 128-/64-/32-position adjustment applications, offering
> > guaranteed low resistor tolerance errors of ±8% and up to
> > ±6 mA current density.
>
> Looks good enough to me, thanks!
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Applied to the togreg branch of iio.git with a tiny tweak to drop one of the
pair of blank lines at the end of ad5110.c
Pushed out as testing to let 0-day poke at it before I expose it to
linux-next.

Thanks,

Jonathan

>
> > Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5110_5112_5114.pdf
> > Signed-off-by: Mugilraj Dhavachelvan <dmugil2000@gmail.com>
> > ---
> > MAINTAINERS | 6 +
> > drivers/iio/potentiometer/Kconfig | 10 +
> > drivers/iio/potentiometer/Makefile | 1 +
> > drivers/iio/potentiometer/ad5110.c | 345 +++++++++++++++++++++++++++++
> > 4 files changed, 362 insertions(+)
> > create mode 100644 drivers/iio/potentiometer/ad5110.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index bd7aff0c120f..cf6e73b87b6e 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -452,6 +452,12 @@ S: Maintained
> > W: https://parisc.wiki.kernel.org/index.php/AD1889
> > F: sound/pci/ad1889.*
> >
> > +AD5110 ANALOG DEVICES DIGITAL POTENTIOMETERS DRIVER
> > +M: Mugilraj Dhavachelvan <dmugil2000@gmail.com>
> > +L: linux-iio@vger.kernel.org
> > +S: Supported
> > +F: drivers/iio/potentiometer/ad5110.c
> > +
> > AD525X ANALOG DEVICES DIGITAL POTENTIOMETERS DRIVER
> > M: Michael Hennerich <michael.hennerich@analog.com>
> > S: Supported
> > diff --git a/drivers/iio/potentiometer/Kconfig b/drivers/iio/potentiometer/Kconfig
> > index 4cac0173db8b..832df8da2bc6 100644
> > --- a/drivers/iio/potentiometer/Kconfig
> > +++ b/drivers/iio/potentiometer/Kconfig
> > @@ -6,6 +6,16 @@
> >
> > menu "Digital potentiometers"
> >
> > +config AD5110
> > + tristate "Analog Devices AD5110 and similar Digital Potentiometer driver"
> > + depends on I2C
> > + help
> > + Say yes here to build support for the Analog Devices AD5110, AD5112
> > + and AD5114 digital potentiometer chip.
> > +
> > + To compile this driver as a module, choose M here: the
> > + module will be called ad5110.
> > +
> > config AD5272
> > tristate "Analog Devices AD5272 and similar Digital Potentiometer driver"
> > depends on I2C
> > diff --git a/drivers/iio/potentiometer/Makefile b/drivers/iio/potentiometer/Makefile
> > index 091adf3cdd0b..5ebb8e3bbd76 100644
> > --- a/drivers/iio/potentiometer/Makefile
> > +++ b/drivers/iio/potentiometer/Makefile
> > @@ -4,6 +4,7 @@
> > #
> >
> > # When adding new entries keep the list in alphabetical order
> > +obj-$(CONFIG_AD5110) += ad5110.o
> > obj-$(CONFIG_AD5272) += ad5272.o
> > obj-$(CONFIG_DS1803) += ds1803.o
> > obj-$(CONFIG_MAX5432) += max5432.o
> > diff --git a/drivers/iio/potentiometer/ad5110.c b/drivers/iio/potentiometer/ad5110.c
> > new file mode 100644
> > index 000000000000..ae18f9e115b2
> > --- /dev/null
> > +++ b/drivers/iio/potentiometer/ad5110.c
> > @@ -0,0 +1,345 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Analog Devices AD5110 digital potentiometer driver
> > + *
> > + * Copyright (C) 2021 Mugilraj Dhavachelvan <dmugil2000@gmail.com>
> > + *
> > + * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5110_5112_5114.pdf
> > + */
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/delay.h>
> > +#include <linux/device.h>
> > +#include <linux/i2c.h>
> > +#include <linux/module.h>
> > +
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/sysfs.h>
> > +
> > +/* AD5110 commands */
> > +#define AD5110_EEPROM_WR 1
> > +#define AD5110_RDAC_WR 2
> > +#define AD5110_SHUTDOWN 3
> > +#define AD5110_RESET 4
> > +#define AD5110_RDAC_RD 5
> > +#define AD5110_EEPROM_RD 6
> > +
> > +/* AD5110_EEPROM_RD data */
> > +#define AD5110_WIPER_POS 0
> > +#define AD5110_RESISTOR_TOL 1
> > +
> > +#define AD5110_WIPER_RESISTANCE 70
> > +
> > +struct ad5110_cfg {
> > + int max_pos;
> > + int kohms;
> > + int shift;
> > +};
> > +
> > +enum ad5110_type {
> > + AD5110_10,
> > + AD5110_80,
> > + AD5112_05,
> > + AD5112_10,
> > + AD5112_80,
> > + AD5114_10,
> > + AD5114_80,
> > +};
> > +
> > +static const struct ad5110_cfg ad5110_cfg[] = {
> > + [AD5110_10] = { .max_pos = 128, .kohms = 10 },
> > + [AD5110_80] = { .max_pos = 128, .kohms = 80 },
> > + [AD5112_05] = { .max_pos = 64, .kohms = 5, .shift = 1 },
> > + [AD5112_10] = { .max_pos = 64, .kohms = 10, .shift = 1 },
> > + [AD5112_80] = { .max_pos = 64, .kohms = 80, .shift = 1 },
> > + [AD5114_10] = { .max_pos = 32, .kohms = 10, .shift = 2 },
> > + [AD5114_80] = { .max_pos = 32, .kohms = 80, .shift = 2 },
> > +};
> > +
> > +struct ad5110_data {
> > + struct i2c_client *client;
> > + s16 tol; /* resistor tolerance */
> > + bool enable;
> > + struct mutex lock;
> > + const struct ad5110_cfg *cfg;
> > + /*
> > + * DMA (thus cache coherency maintenance) requires the
> > + * transfer buffers to live in their own cache lines.
> > + */
> > + u8 buf[2] ____cacheline_aligned;
> > +};
> > +
> > +static const struct iio_chan_spec ad5110_channels[] = {
> > + {
> > + .type = IIO_RESISTANCE,
> > + .output = 1,
> > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_OFFSET) |
> > + BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_ENABLE),
> > + },
> > +};
> > +
> > +static int ad5110_read(struct ad5110_data *data, u8 cmd, int *val)
> > +{
> > + int ret;
> > +
> > + mutex_lock(&data->lock);
> > + data->buf[0] = cmd;
> > + data->buf[1] = *val;
> > +
> > + ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
> > + if (ret < 0) {
> > + goto error;
> > + } else if (ret != sizeof(data->buf)) {
> > + ret = -EIO;
> > + goto error;
> > + }
> > +
> > + ret = i2c_master_recv_dmasafe(data->client, data->buf, 1);
> > + if (ret < 0) {
> > + goto error;
> > + } else if (ret != 1) {
> > + ret = -EIO;
> > + goto error;
> > + }
> > +
> > + *val = data->buf[0];
> > + ret = 0;
> > +
> > +error:
> > + mutex_unlock(&data->lock);
> > + return ret;
> > +}
> > +
> > +static int ad5110_write(struct ad5110_data *data, u8 cmd, u8 val)
> > +{
> > + int ret;
> > +
> > + mutex_lock(&data->lock);
> > + data->buf[0] = cmd;
> > + data->buf[1] = val;
> > +
> > + ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
> > + if (ret < 0) {
> > + goto error;
> > + } else if (ret != sizeof(data->buf)) {
> > + ret = -EIO;
> > + goto error;
> > + }
> > +
> > + ret = 0;
> > +
> > +error:
> > + mutex_unlock(&data->lock);
> > + return ret;
> > +}
> > +
> > +static int ad5110_resistor_tol(struct ad5110_data *data, u8 cmd, int val)
> > +{
> > + int ret;
> > +
> > + ret = ad5110_read(data, cmd, &val);
> > + if (ret)
> > + return ret;
> > +
> > + data->tol = data->cfg->kohms * (val & GENMASK(6, 0)) * 10 / 8;
> > + if (!(val & BIT(7)))
> > + data->tol *= -1;
> > +
> > + return 0;
> > +}
> > +
> > +static ssize_t store_eeprom_show(struct device *dev,
> > + struct device_attribute *attr,
> > + char *buf)
> > +{
> > + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> > + struct ad5110_data *data = iio_priv(indio_dev);
> > + int val = AD5110_WIPER_POS;
> > + int ret;
> > +
> > + ret = ad5110_read(data, AD5110_EEPROM_RD, &val);
> > + if (ret)
> > + return ret;
> > +
> > + val = val >> data->cfg->shift;
> > + return iio_format_value(buf, IIO_VAL_INT, 1, &val);
> > +}
> > +
> > +static ssize_t store_eeprom_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 ad5110_data *data = iio_priv(indio_dev);
> > + int ret;
> > +
> > + ret = ad5110_write(data, AD5110_EEPROM_WR, 0);
> > + if (ret) {
> > + dev_err(&data->client->dev, "RDAC to EEPROM write failed\n");
> > + return ret;
> > + }
> > +
> > + /* The storing of EEPROM data takes approximately 18 ms. */
> > + msleep(20);
> > +
> > + return len;
> > +}
> > +
> > +static IIO_DEVICE_ATTR_RW(store_eeprom, 0);
> > +
> > +static struct attribute *ad5110_attributes[] = {
> > + &iio_dev_attr_store_eeprom.dev_attr.attr,
> > + NULL
> > +};
> > +
> > +static const struct attribute_group ad5110_attribute_group = {
> > + .attrs = ad5110_attributes,
> > +};
> > +
> > +static int ad5110_read_raw(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + int *val, int *val2, long mask)
> > +{
> > + struct ad5110_data *data = iio_priv(indio_dev);
> > + int ret;
> > +
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + ret = ad5110_read(data, AD5110_RDAC_RD, val);
> > + if (ret)
> > + return ret;
> > +
> > + *val = *val >> data->cfg->shift;
> > + return IIO_VAL_INT;
> > + case IIO_CHAN_INFO_OFFSET:
> > + *val = AD5110_WIPER_RESISTANCE * data->cfg->max_pos;
> > + *val2 = 1000 * data->cfg->kohms + data->tol;
> > + return IIO_VAL_FRACTIONAL;
> > + case IIO_CHAN_INFO_SCALE:
> > + *val = 1000 * data->cfg->kohms + data->tol;
> > + *val2 = data->cfg->max_pos;
> > + return IIO_VAL_FRACTIONAL;
> > + case IIO_CHAN_INFO_ENABLE:
> > + *val = data->enable;
> > + return IIO_VAL_INT;
> > + default:
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +static int ad5110_write_raw(struct iio_dev *indio_dev,
> > + struct iio_chan_spec const *chan,
> > + int val, int val2, long mask)
> > +{
> > + struct ad5110_data *data = iio_priv(indio_dev);
> > + int ret;
> > +
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + if (val > data->cfg->max_pos || val < 0)
> > + return -EINVAL;
> > +
> > + return ad5110_write(data, AD5110_RDAC_WR, val << data->cfg->shift);
> > + case IIO_CHAN_INFO_ENABLE:
> > + if (val < 0 || val > 1)
> > + return -EINVAL;
> > + if (data->enable == val)
> > + return 0;
> > + ret = ad5110_write(data, AD5110_SHUTDOWN, val ? 0 : 1);
> > + if (ret)
> > + return ret;
> > + data->enable = val;
> > + return 0;
> > + default:
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +static const struct iio_info ad5110_info = {
> > + .read_raw = ad5110_read_raw,
> > + .write_raw = ad5110_write_raw,
> > + .attrs = &ad5110_attribute_group,
> > +};
> > +
> > +#define AD5110_COMPATIBLE(of_compatible, cfg) { \
> > + .compatible = of_compatible, \
> > + .data = &ad5110_cfg[cfg], \
> > +}
> > +
> > +static const struct of_device_id ad5110_of_match[] = {
> > + AD5110_COMPATIBLE("adi,ad5110-10", AD5110_10),
> > + AD5110_COMPATIBLE("adi,ad5110-80", AD5110_80),
> > + AD5110_COMPATIBLE("adi,ad5112-05", AD5112_05),
> > + AD5110_COMPATIBLE("adi,ad5112-10", AD5112_10),
> > + AD5110_COMPATIBLE("adi,ad5112-80", AD5112_80),
> > + AD5110_COMPATIBLE("adi,ad5114-10", AD5114_10),
> > + AD5110_COMPATIBLE("adi,ad5114-80", AD5114_80),
> > + { }
> > +};
> > +MODULE_DEVICE_TABLE(of, ad5110_of_match);
> > +
> > +static const struct i2c_device_id ad5110_id[] = {
> > + { "ad5110-10", AD5110_10 },
> > + { "ad5110-80", AD5110_80 },
> > + { "ad5112-05", AD5112_05 },
> > + { "ad5112-10", AD5112_10 },
> > + { "ad5112-80", AD5112_80 },
> > + { "ad5114-10", AD5114_10 },
> > + { "ad5114-80", AD5114_80 },
> > + { }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, ad5110_id);
> > +
> > +static int ad5110_probe(struct i2c_client *client)
> > +{
> > + struct device *dev = &client->dev;
> > + struct iio_dev *indio_dev;
> > + struct ad5110_data *data;
> > + int ret;
> > +
> > + indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
> > + if (!indio_dev)
> > + return -ENOMEM;
> > +
> > + data = iio_priv(indio_dev);
> > + data->client = client;
> > + mutex_init(&data->lock);
> > + data->enable = 1;
> > + data->cfg = device_get_match_data(dev);
> > +
> > + /* refresh RDAC register with EEPROM */
> > + ret = ad5110_write(data, AD5110_RESET, 0);
> > + if (ret) {
> > + dev_err(dev, "Refresh RDAC with EEPROM failed\n");
> > + return ret;
> > + }
> > +
> > + ret = ad5110_resistor_tol(data, AD5110_EEPROM_RD, AD5110_RESISTOR_TOL);
> > + if (ret) {
> > + dev_err(dev, "Read resistor tolerance failed\n");
> > + return ret;
> > + }
> > +
> > + indio_dev->modes = INDIO_DIRECT_MODE;
> > + indio_dev->info = &ad5110_info;
> > + indio_dev->channels = ad5110_channels;
> > + indio_dev->num_channels = ARRAY_SIZE(ad5110_channels);
> > + indio_dev->name = client->name;
> > +
> > + return devm_iio_device_register(dev, indio_dev);
> > +}
> > +
> > +static struct i2c_driver ad5110_driver = {
> > + .driver = {
> > + .name = "ad5110",
> > + .of_match_table = ad5110_of_match,
> > + },
> > + .probe_new = ad5110_probe,
> > + .id_table = ad5110_id,
> > +};
> > +module_i2c_driver(ad5110_driver);
> > +
> > +MODULE_AUTHOR("Mugilraj Dhavachelvan <dmugil2000@gmail.com>");
> > +MODULE_DESCRIPTION("AD5110 digital potentiometer");
> > +MODULE_LICENSE("GPL v2");
> > +
> > --
> > 2.25.1
> >
>
>