diff options
Diffstat (limited to 'drivers/iio/adc/max34408.c')
| -rw-r--r-- | drivers/iio/adc/max34408.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/drivers/iio/adc/max34408.c b/drivers/iio/adc/max34408.c new file mode 100644 index 000000000000..6c2ea2bc52c6 --- /dev/null +++ b/drivers/iio/adc/max34408.c @@ -0,0 +1,276 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * IIO driver for Maxim MAX34409/34408 ADC, 4-Channels/2-Channels, 8bits, I2C + * + * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX34408-MAX34409.pdf + * + * TODO: ALERT interrupt, Overcurrent delay, Shutdown delay + */ + +#include <linux/bitfield.h> +#include <linux/init.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/property.h> +#include <linux/regmap.h> + +#include <linux/iio/iio.h> +#include <linux/iio/types.h> + +#define MAX34408_STATUS_REG 0x0 +#define MAX34408_CONTROL_REG 0x1 +#define MAX34408_OCDELAY_REG 0x2 +#define MAX34408_SDDELAY_REG 0x3 + +#define MAX34408_ADC1_REG 0x4 +#define MAX34408_ADC2_REG 0x5 +/* ADC3 & ADC4 always returns 0x0 on 34408 */ +#define MAX34409_ADC3_REG 0x6 +#define MAX34409_ADC4_REG 0x7 + +#define MAX34408_OCT1_REG 0x8 +#define MAX34408_OCT2_REG 0x9 +#define MAX34409_OCT3_REG 0xA +#define MAX34409_OCT4_REG 0xB + +#define MAX34408_DID_REG 0xC +#define MAX34408_DCYY_REG 0xD +#define MAX34408_DCWW_REG 0xE + +/* Bit masks for status register */ +#define MAX34408_STATUS_OC_MSK GENMASK(1, 0) +#define MAX34409_STATUS_OC_MSK GENMASK(3, 0) +#define MAX34408_STATUS_SHTDN BIT(4) +#define MAX34408_STATUS_ENA BIT(5) + +/* Bit masks for control register */ +#define MAX34408_CONTROL_AVG0 BIT(0) +#define MAX34408_CONTROL_AVG1 BIT(1) +#define MAX34408_CONTROL_AVG2 BIT(2) +#define MAX34408_CONTROL_ALERT BIT(3) + +#define MAX34408_DEFAULT_AVG 0x4 + +/* Bit masks for over current delay */ +#define MAX34408_OCDELAY_OCD_MSK GENMASK(6, 0) +#define MAX34408_OCDELAY_RESET BIT(7) + +/* Bit masks for shutdown delay */ +#define MAX34408_SDDELAY_SHD_MSK GENMASK(6, 0) +#define MAX34408_SDDELAY_RESET BIT(7) + +#define MAX34408_DEFAULT_RSENSE 1000 + +/** + * struct max34408_data - max34408/max34409 specific data. + * @regmap: device register map. + * @dev: max34408 device. + * @lock: lock for protecting access to device hardware registers, mostly + * for read modify write cycles for control registers. + * @input_rsense: Rsense values in uOhm, will be overwritten by + * values from channel nodes. + */ +struct max34408_data { + struct regmap *regmap; + struct device *dev; + struct mutex lock; + u32 input_rsense[4]; +}; + +static const struct regmap_config max34408_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = MAX34408_DCWW_REG, +}; + +struct max34408_adc_model_data { + const char *model_name; + const struct iio_chan_spec *channels; + const int num_channels; +}; + +#define MAX34008_CHANNEL(_index, _address) \ + { \ + .type = IIO_CURRENT, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ + BIT(IIO_CHAN_INFO_SCALE) | \ + BIT(IIO_CHAN_INFO_OFFSET), \ + .channel = (_index), \ + .address = (_address), \ + .indexed = 1, \ + } + +static const struct iio_chan_spec max34408_channels[] = { + MAX34008_CHANNEL(0, MAX34408_ADC1_REG), + MAX34008_CHANNEL(1, MAX34408_ADC2_REG), +}; + +static const struct iio_chan_spec max34409_channels[] = { + MAX34008_CHANNEL(0, MAX34408_ADC1_REG), + MAX34008_CHANNEL(1, MAX34408_ADC2_REG), + MAX34008_CHANNEL(2, MAX34409_ADC3_REG), + MAX34008_CHANNEL(3, MAX34409_ADC4_REG), +}; + +static int max34408_read_adc_avg(struct max34408_data *max34408, + const struct iio_chan_spec *chan, int *val) +{ + unsigned int ctrl; + int rc; + + guard(mutex)(&max34408->lock); + rc = regmap_read(max34408->regmap, MAX34408_CONTROL_REG, (u32 *)&ctrl); + if (rc) + return rc; + + /* set averaging (0b100) default values*/ + rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG, + MAX34408_DEFAULT_AVG); + if (rc) { + dev_err(max34408->dev, + "Error (%d) writing control register\n", rc); + return rc; + } + + rc = regmap_read(max34408->regmap, chan->address, val); + if (rc) + return rc; + + /* back to old values */ + rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG, ctrl); + if (rc) + dev_err(max34408->dev, + "Error (%d) writing control register\n", rc); + + return rc; +} + +static int max34408_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct max34408_data *max34408 = iio_priv(indio_dev); + int rc; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + rc = max34408_read_adc_avg(max34408, chan, val); + if (rc) + return rc; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + /* + * calcluate current for 8bit ADC with Rsense + * value. + * 10 mV * 1000 / Rsense uOhm = max current + * (max current * adc val * 1000) / (2^8 - 1) mA + */ + *val = 10000 / max34408->input_rsense[chan->channel]; + *val2 = 8; + return IIO_VAL_FRACTIONAL_LOG2; + default: + return -EINVAL; + } +} + +static const struct iio_info max34408_info = { + .read_raw = max34408_read_raw, +}; + +static const struct max34408_adc_model_data max34408_model_data = { + .model_name = "max34408", + .channels = max34408_channels, + .num_channels = 2, +}; + +static const struct max34408_adc_model_data max34409_model_data = { + .model_name = "max34409", + .channels = max34409_channels, + .num_channels = 4, +}; + +static int max34408_probe(struct i2c_client *client) +{ + const struct max34408_adc_model_data *model_data; + struct device *dev = &client->dev; + struct max34408_data *max34408; + struct fwnode_handle *node; + struct iio_dev *indio_dev; + struct regmap *regmap; + int rc, i = 0; + + model_data = i2c_get_match_data(client); + if (!model_data) + return -EINVAL; + + regmap = devm_regmap_init_i2c(client, &max34408_regmap_config); + if (IS_ERR(regmap)) { + dev_err_probe(dev, PTR_ERR(regmap), + "regmap_init failed\n"); + return PTR_ERR(regmap); + } + + indio_dev = devm_iio_device_alloc(dev, sizeof(*max34408)); + if (!indio_dev) + return -ENOMEM; + + max34408 = iio_priv(indio_dev); + max34408->regmap = regmap; + max34408->dev = dev; + mutex_init(&max34408->lock); + + device_for_each_child_node(dev, node) { + fwnode_property_read_u32(node, "maxim,rsense-val-micro-ohms", + &max34408->input_rsense[i]); + i++; + } + + /* disable ALERT and averaging */ + rc = regmap_write(max34408->regmap, MAX34408_CONTROL_REG, 0x0); + if (rc) + return rc; + + indio_dev->channels = model_data->channels; + indio_dev->num_channels = model_data->num_channels; + indio_dev->name = model_data->model_name; + + indio_dev->info = &max34408_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct of_device_id max34408_of_match[] = { + { + .compatible = "maxim,max34408", + .data = &max34408_model_data, + }, + { + .compatible = "maxim,max34409", + .data = &max34409_model_data, + }, + {} +}; +MODULE_DEVICE_TABLE(of, max34408_of_match); + +static const struct i2c_device_id max34408_id[] = { + { "max34408", (kernel_ulong_t)&max34408_model_data }, + { "max34409", (kernel_ulong_t)&max34409_model_data }, + {} +}; +MODULE_DEVICE_TABLE(i2c, max34408_id); + +static struct i2c_driver max34408_driver = { + .driver = { + .name = "max34408", + .of_match_table = max34408_of_match, + }, + .probe = max34408_probe, + .id_table = max34408_id, +}; +module_i2c_driver(max34408_driver); + +MODULE_AUTHOR("Ivan Mikhaylov <fr0st61te@gmail.com>"); +MODULE_DESCRIPTION("Maxim MAX34408/34409 ADC driver"); +MODULE_LICENSE("GPL"); |