diff options
Diffstat (limited to 'drivers/iio/potentiometer/ad5272.c')
| -rw-r--r-- | drivers/iio/potentiometer/ad5272.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/drivers/iio/potentiometer/ad5272.c b/drivers/iio/potentiometer/ad5272.c new file mode 100644 index 000000000..154f9a5da --- /dev/null +++ b/drivers/iio/potentiometer/ad5272.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Analog Devices AD5272 digital potentiometer driver + * Copyright (C) 2018 Phil Reid <preid@electromag.com.au> + * + * Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf + * + * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address + * ad5272 1 1024 20, 50, 100 01011xx + * ad5274 1 256 20, 100 01011xx + */ + +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/iio/iio.h> +#include <linux/module.h> + +#define AD5272_RDAC_WR 1 +#define AD5272_RDAC_RD 2 +#define AD5272_RESET 4 +#define AD5272_CTL 7 + +#define AD5272_RDAC_WR_EN BIT(1) + +struct ad5272_cfg { + int max_pos; + int kohms; + int shift; +}; + +enum ad5272_type { + AD5272_020, + AD5272_050, + AD5272_100, + AD5274_020, + AD5274_100, +}; + +static const struct ad5272_cfg ad5272_cfg[] = { + [AD5272_020] = { .max_pos = 1024, .kohms = 20 }, + [AD5272_050] = { .max_pos = 1024, .kohms = 50 }, + [AD5272_100] = { .max_pos = 1024, .kohms = 100 }, + [AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 }, + [AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 }, +}; + +struct ad5272_data { + struct i2c_client *client; + struct mutex lock; + const struct ad5272_cfg *cfg; + u8 buf[2] ____cacheline_aligned; +}; + +static const struct iio_chan_spec ad5272_channel = { + .type = IIO_RESISTANCE, + .output = 1, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), +}; + +static int ad5272_write(struct ad5272_data *data, int reg, int val) +{ + int ret; + + data->buf[0] = (reg << 2) | ((val >> 8) & 0x3); + data->buf[1] = (u8)val; + + mutex_lock(&data->lock); + ret = i2c_master_send(data->client, data->buf, sizeof(data->buf)); + mutex_unlock(&data->lock); + return ret < 0 ? ret : 0; +} + +static int ad5272_read(struct ad5272_data *data, int reg, int *val) +{ + int ret; + + data->buf[0] = reg << 2; + data->buf[1] = 0; + + mutex_lock(&data->lock); + ret = i2c_master_send(data->client, data->buf, sizeof(data->buf)); + if (ret < 0) + goto error; + + ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf)); + if (ret < 0) + goto error; + + *val = ((data->buf[0] & 0x3) << 8) | data->buf[1]; + ret = 0; +error: + mutex_unlock(&data->lock); + return ret; +} + +static int ad5272_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct ad5272_data *data = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: { + ret = ad5272_read(data, AD5272_RDAC_RD, val); + *val = *val >> data->cfg->shift; + return ret ? ret : IIO_VAL_INT; + } + case IIO_CHAN_INFO_SCALE: + *val = 1000 * data->cfg->kohms; + *val2 = data->cfg->max_pos; + return IIO_VAL_FRACTIONAL; + } + + return -EINVAL; +} + +static int ad5272_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct ad5272_data *data = iio_priv(indio_dev); + + if (mask != IIO_CHAN_INFO_RAW) + return -EINVAL; + + if (val >= data->cfg->max_pos || val < 0 || val2) + return -EINVAL; + + return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift); +} + +static const struct iio_info ad5272_info = { + .read_raw = ad5272_read_raw, + .write_raw = ad5272_write_raw, +}; + +static int ad5272_reset(struct ad5272_data *data) +{ + struct gpio_desc *reset_gpio; + + reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset", + GPIOD_OUT_LOW); + if (IS_ERR(reset_gpio)) + return PTR_ERR(reset_gpio); + + if (reset_gpio) { + udelay(1); + gpiod_set_value(reset_gpio, 1); + } else { + ad5272_write(data, AD5272_RESET, 0); + } + usleep_range(1000, 2000); + + return 0; +} + +static int ad5272_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct device *dev = &client->dev; + struct iio_dev *indio_dev; + struct ad5272_data *data; + int ret; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + i2c_set_clientdata(client, indio_dev); + + data = iio_priv(indio_dev); + data->client = client; + mutex_init(&data->lock); + data->cfg = &ad5272_cfg[id->driver_data]; + + ret = ad5272_reset(data); + if (ret) + return ret; + + ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN); + if (ret < 0) + return -ENODEV; + + indio_dev->dev.parent = dev; + indio_dev->info = &ad5272_info; + indio_dev->channels = &ad5272_channel; + indio_dev->num_channels = 1; + indio_dev->name = client->name; + + return devm_iio_device_register(dev, indio_dev); +} + +#if defined(CONFIG_OF) +static const struct of_device_id ad5272_dt_ids[] = { + { .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 }, + { .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 }, + { .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 }, + { .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 }, + { .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 }, + {} +}; +MODULE_DEVICE_TABLE(of, ad5272_dt_ids); +#endif /* CONFIG_OF */ + +static const struct i2c_device_id ad5272_id[] = { + { "ad5272-020", AD5272_020 }, + { "ad5272-050", AD5272_050 }, + { "ad5272-100", AD5272_100 }, + { "ad5274-020", AD5274_020 }, + { "ad5274-100", AD5274_100 }, + {} +}; +MODULE_DEVICE_TABLE(i2c, ad5272_id); + +static struct i2c_driver ad5272_driver = { + .driver = { + .name = "ad5272", + .of_match_table = of_match_ptr(ad5272_dt_ids), + }, + .probe = ad5272_probe, + .id_table = ad5272_id, +}; + +module_i2c_driver(ad5272_driver); + +MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>"); +MODULE_DESCRIPTION("AD5272 digital potentiometer"); +MODULE_LICENSE("GPL v2"); |