// 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 #include #include #include #include #include #include #include #include #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: /* * calculate 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 "); MODULE_DESCRIPTION("Maxim MAX34408/34409 ADC driver"); MODULE_LICENSE("GPL");