diff options
Diffstat (limited to 'drivers/iio/potentiometer/ad5110.c')
| -rw-r--r-- | drivers/iio/potentiometer/ad5110.c | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/drivers/iio/potentiometer/ad5110.c b/drivers/iio/potentiometer/ad5110.c new file mode 100644 index 000000000000..d4eeedae56e5 --- /dev/null +++ b/drivers/iio/potentiometer/ad5110.c @@ -0,0 +1,344 @@ +// 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"); |