| Message ID | 1491488454-22468-4-git-send-email-jacopo+renesas@jmondi.org (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
On 06/04/17 15:20, Jacopo Mondi wrote: > Add iio driver for Maxim max9611 and max9612 current-sense amplifiers > with 12-bits ADC interface. > > Datasheet publicly available at: > https://datasheets.maximintegrated.com/en/ds/MAX9611-MAX9612.pdf > > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org> Applied to the togreg branch of iio.git and and pushed out as testing to see if the various tests can find anything we have all missed! Jonathan > --- > > Output of iio_info on Salvator-X board for max9611 chip installed on > VDD_0.8 lines. > The VDD_0.8 line powers the CPU cluster and on-board RAM. > > iio:device0: max9611 > 5 channels found: > voltage0: (input) > 1 channel-specific attributes found: > attr 0: input value: 4.085000000 > voltage1: (input) > 3 channel-specific attributes found: > attr 0: scale value: 14 > attr 1: offset value: 1 > attr 2: raw value: 59 > power: (input) > 2 channel-specific attributes found: > attr 0: shunt_resistor value: 5.000 > attr 1: input value: 663.404000000 > current: (input) > 2 channel-specific attributes found: > attr 0: shunt_resistor value: 5.000 > attr 1: input value: 817.000000000 > temp: (input) > 2 channel-specific attributes found: > attr 0: scale value: 480.076812289 > attr 1: raw value: 59 > > The collected information represent: > > * voltage0 (current sense voltage) Vcsa > voltage drop between RS+ and RS- input = 4,085 mV > * voltage1: (common input voltage) Vcim > voltage at RS+ input = (59 - 1) * 14 = 812 mV > * current flowing on shunt resistor (Icsa) > = Vcsa / Rshunt = 817 mA > * power load on the sensed line (Pload) > = Vcim * Icsa = 663 m > * die temperature = (57 * 480.07) = 27360 milli Celsius > > --- > drivers/iio/adc/Kconfig | 10 + > drivers/iio/adc/Makefile | 1 + > drivers/iio/adc/max9611.c | 585 ++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 596 insertions(+) > create mode 100644 drivers/iio/adc/max9611.c > > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig > index dedae7a..82f2e7b8 100644 > --- a/drivers/iio/adc/Kconfig > +++ b/drivers/iio/adc/Kconfig > @@ -354,6 +354,16 @@ config MAX1363 > To compile this driver as a module, choose M here: the module will be > called max1363. > > +config MAX9611 > + tristate "Maxim max9611/max9612 ADC driver" > + depends on I2C > + help > + Say yes here to build support for Maxim max9611/max9612 current sense > + amplifier with 12-bits ADC interface. > + > + To compile this driver as a module, choose M here: the module will be > + called max9611. > + > config MCP320X > tristate "Microchip Technology MCP3x01/02/04/08" > depends on SPI > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile > index d001262..149f979 100644 > --- a/drivers/iio/adc/Makefile > +++ b/drivers/iio/adc/Makefile > @@ -34,6 +34,7 @@ obj-$(CONFIG_LTC2485) += ltc2485.o > obj-$(CONFIG_MAX1027) += max1027.o > obj-$(CONFIG_MAX11100) += max11100.o > obj-$(CONFIG_MAX1363) += max1363.o > +obj-$(CONFIG_MAX9611) += max9611.o > obj-$(CONFIG_MCP320X) += mcp320x.o > obj-$(CONFIG_MCP3422) += mcp3422.o > obj-$(CONFIG_MEDIATEK_MT6577_AUXADC) += mt6577_auxadc.o > diff --git a/drivers/iio/adc/max9611.c b/drivers/iio/adc/max9611.c > new file mode 100644 > index 0000000..f0b47fa > --- /dev/null > +++ b/drivers/iio/adc/max9611.c > @@ -0,0 +1,585 @@ > +/* > + * iio/adc/max9611.c > + * > + * Maxim max9611/max9612 high side current sense amplifier with > + * 12-bit ADC interface. > + * > + * Copyright (C) 2017 Jacopo Mondi > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + */ > + > +/* > + * This driver supports input common-mode voltage, current-sense > + * amplifier with programmable gains and die temperature reading from > + * Maxim max9611/max9612. > + * > + * Op-amp, analog comparator, and watchdog functionalities are not > + * supported by this driver. > + */ > + > +#include <linux/delay.h> > +#include <linux/i2c.h> > +#include <linux/iio/iio.h> > +#include <linux/iio/sysfs.h> > +#include <linux/module.h> > +#include <linux/of_device.h> > + > +#define DRIVER_NAME "max9611" > + > +/* max9611 register addresses */ > +#define MAX9611_REG_CSA_DATA 0x00 > +#define MAX9611_REG_RS_DATA 0x02 > +#define MAX9611_REG_TEMP_DATA 0x08 > +#define MAX9611_REG_CTRL1 0x0a > +#define MAX9611_REG_CTRL2 0x0b > + > +/* max9611 REG1 mux configuration options */ > +#define MAX9611_MUX_MASK GENMASK(3, 0) > +#define MAX9611_MUX_SENSE_1x 0x00 > +#define MAX9611_MUX_SENSE_4x 0x01 > +#define MAX9611_MUX_SENSE_8x 0x02 > +#define MAX9611_INPUT_VOLT 0x03 > +#define MAX9611_MUX_TEMP 0x06 > + > +/* max9611 voltage (both csa and input) helper macros */ > +#define MAX9611_VOLTAGE_SHIFT 0x04 > +#define MAX9611_VOLTAGE_RAW(_r) ((_r) >> MAX9611_VOLTAGE_SHIFT) > + > +/* > + * max9611 current sense amplifier voltage output: > + * LSB and offset values depends on selected gain (1x, 4x, 8x) > + * > + * GAIN LSB (nV) OFFSET (LSB steps) > + * 1x 107500 1 > + * 4x 26880 1 > + * 8x 13440 3 > + * > + * The complete formula to calculate current sense voltage is: > + * (((adc_read >> 4) - offset) / ((1 / LSB) * 10^-3) > + */ > +#define MAX9611_CSA_1X_LSB_nV 107500 > +#define MAX9611_CSA_4X_LSB_nV 26880 > +#define MAX9611_CSA_8X_LSB_nV 13440 > + > +#define MAX9611_CSA_1X_OFFS_RAW 1 > +#define MAX9611_CSA_4X_OFFS_RAW 1 > +#define MAX9611_CSA_8X_OFFS_RAW 3 > + > +/* > + * max9611 common input mode (CIM): LSB is 14mV, with 14mV offset at 25 C > + * > + * The complete formula to calculate input common voltage is: > + * (((adc_read >> 4) * 1000) - offset) / (1 / 14 * 1000) > + */ > +#define MAX9611_CIM_LSB_mV 14 > +#define MAX9611_CIM_OFFSET_RAW 1 > + > +/* > + * max9611 temperature reading: LSB is 480 milli degrees Celsius > + * > + * The complete formula to calculate temperature is: > + * ((adc_read >> 7) * 1000) / (1 / 480 * 1000) > + */ > +#define MAX9611_TEMP_MAX_POS 0x7f80 > +#define MAX9611_TEMP_MAX_NEG 0xff80 > +#define MAX9611_TEMP_MIN_NEG 0xd980 > +#define MAX9611_TEMP_MASK GENMASK(7, 15) > +#define MAX9611_TEMP_SHIFT 0x07 > +#define MAX9611_TEMP_RAW(_r) ((_r) >> MAX9611_TEMP_SHIFT) > +#define MAX9611_TEMP_SCALE_NUM 1000000 > +#define MAX9611_TEMP_SCALE_DIV 2083 > + > +struct max9611_dev { > + struct device *dev; > + struct i2c_client *i2c_client; > + struct mutex lock; > + unsigned int shunt_resistor_uohm; > +}; > + > +enum max9611_conf_ids { > + CONF_SENSE_1x, > + CONF_SENSE_4x, > + CONF_SENSE_8x, > + CONF_IN_VOLT, > + CONF_TEMP, > +}; > + > +/** > + * max9611_mux_conf - associate ADC mux configuration with register address > + * where data shall be read from > + */ > +static const unsigned int max9611_mux_conf[][2] = { > + /* CONF_SENSE_1x */ > + { MAX9611_MUX_SENSE_1x, MAX9611_REG_CSA_DATA }, > + /* CONF_SENSE_4x */ > + { MAX9611_MUX_SENSE_4x, MAX9611_REG_CSA_DATA }, > + /* CONF_SENSE_8x */ > + { MAX9611_MUX_SENSE_8x, MAX9611_REG_CSA_DATA }, > + /* CONF_IN_VOLT */ > + { MAX9611_INPUT_VOLT, MAX9611_REG_RS_DATA }, > + /* CONF_TEMP */ > + { MAX9611_MUX_TEMP, MAX9611_REG_TEMP_DATA }, > +}; > + > +enum max9611_csa_gain { > + CSA_GAIN_1x, > + CSA_GAIN_4x, > + CSA_GAIN_8x, > +}; > + > +enum max9611_csa_gain_params { > + CSA_GAIN_LSB_nV, > + CSA_GAIN_OFFS_RAW, > +}; > + > +/** > + * max9611_csa_gain_conf - associate gain multiplier with LSB and > + * offset values. > + * > + * Group together parameters associated with configurable gain > + * on current sense amplifier path to ADC interface. > + * Current sense read routine adjusts gain until it gets a meaningful > + * value; use this structure to retrieve the correct LSB and offset values. > + */ > +static const unsigned int max9611_gain_conf[][2] = { > + { /* [0] CSA_GAIN_1x */ > + MAX9611_CSA_1X_LSB_nV, > + MAX9611_CSA_1X_OFFS_RAW, > + }, > + { /* [1] CSA_GAIN_4x */ > + MAX9611_CSA_4X_LSB_nV, > + MAX9611_CSA_4X_OFFS_RAW, > + }, > + { /* [2] CSA_GAIN_8x */ > + MAX9611_CSA_8X_LSB_nV, > + MAX9611_CSA_8X_OFFS_RAW, > + }, > +}; > + > +enum max9611_chan_addrs { > + MAX9611_CHAN_VOLTAGE_INPUT, > + MAX9611_CHAN_VOLTAGE_SENSE, > + MAX9611_CHAN_TEMPERATURE, > + MAX9611_CHAN_CURRENT_LOAD, > + MAX9611_CHAN_POWER_LOAD, > +}; > + > +static const struct iio_chan_spec max9611_channels[] = { > + { > + .type = IIO_TEMP, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > + BIT(IIO_CHAN_INFO_SCALE), > + .address = MAX9611_CHAN_TEMPERATURE, > + }, > + { > + .type = IIO_VOLTAGE, > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), > + .address = MAX9611_CHAN_VOLTAGE_SENSE, > + .indexed = 1, > + .channel = 0, > + }, > + { > + .type = IIO_VOLTAGE, > + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > + BIT(IIO_CHAN_INFO_SCALE) | > + BIT(IIO_CHAN_INFO_OFFSET), > + .address = MAX9611_CHAN_VOLTAGE_INPUT, > + .indexed = 1, > + .channel = 1, > + }, > + { > + .type = IIO_CURRENT, > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), > + .address = MAX9611_CHAN_CURRENT_LOAD, > + }, > + { > + .type = IIO_POWER, > + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), > + .address = MAX9611_CHAN_POWER_LOAD > + }, > +}; > + > +/** > + * max9611_read_single() - read a single value from ADC interface > + * > + * Data registers are 16 bit long, spread between two 8 bit registers > + * with consecutive addresses. > + * Configure ADC mux first, then read register at address "reg_addr". > + * The smbus_read_word routine asks for 16 bits and the ADC is kind enough > + * to return values from "reg_addr" and "reg_addr + 1" consecutively. > + * Data are transmitted with big-endian ordering: MSB arrives first. > + * > + * @max9611: max9611 device > + * @selector: index for mux and register configuration > + * @raw_val: the value returned from ADC > + */ > +static int max9611_read_single(struct max9611_dev *max9611, > + enum max9611_conf_ids selector, > + u16 *raw_val) > +{ > + int ret; > + > + u8 mux_conf = max9611_mux_conf[selector][0] & MAX9611_MUX_MASK; > + u8 reg_addr = max9611_mux_conf[selector][1]; > + > + /* > + * Keep mutex lock held during read-write to avoid mux register > + * (CTRL1) re-configuration. > + */ > + mutex_lock(&max9611->lock); > + ret = i2c_smbus_write_byte_data(max9611->i2c_client, > + MAX9611_REG_CTRL1, mux_conf); > + if (ret) { > + dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n", > + MAX9611_REG_CTRL1, mux_conf); > + mutex_unlock(&max9611->lock); > + return ret; > + } > + > + /* > + * need a delay here to make register configuration > + * stabilize. 1 msec at least, from empirical testing. > + */ > + usleep_range(1000, 2000); > + > + ret = i2c_smbus_read_word_swapped(max9611->i2c_client, reg_addr); > + if (ret < 0) { > + dev_err(max9611->dev, "i2c read word from 0x%2x failed\n", > + reg_addr); > + mutex_unlock(&max9611->lock); > + return ret; > + } > + > + *raw_val = ret; > + mutex_unlock(&max9611->lock); > + > + return 0; > +} > + > +/** > + * max9611_read_csa_voltage() - read current sense amplifier output voltage > + * > + * Current sense amplifier output voltage is read through a configurable > + * 1x, 4x or 8x gain. > + * Start with plain 1x gain, and adjust gain control properly until a > + * meaningful value is read from ADC output. > + * > + * @max9611: max9611 device > + * @adc_raw: raw value read from ADC output > + * @csa_gain: gain configuration option selector > + */ > +static int max9611_read_csa_voltage(struct max9611_dev *max9611, > + u16 *adc_raw, > + enum max9611_csa_gain *csa_gain) > +{ > + enum max9611_conf_ids gain_selectors[] = { > + CONF_SENSE_1x, > + CONF_SENSE_4x, > + CONF_SENSE_8x > + }; > + unsigned int i; > + int ret; > + > + for (i = 0; i < ARRAY_SIZE(gain_selectors); ++i) { > + ret = max9611_read_single(max9611, gain_selectors[i], adc_raw); > + if (ret) > + return ret; > + > + if (*adc_raw > 0) { > + *csa_gain = gain_selectors[i]; > + return 0; > + } > + } > + > + return -EIO; > +} > + > +static int max9611_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + struct max9611_dev *dev = iio_priv(indio_dev); > + enum max9611_csa_gain gain_selector; > + const unsigned int *csa_gain; > + u16 adc_data; > + int ret; > + > + switch (mask) { > + case IIO_CHAN_INFO_RAW: > + > + switch (chan->address) { > + case MAX9611_CHAN_TEMPERATURE: > + ret = max9611_read_single(dev, CONF_TEMP, > + &adc_data); > + if (ret) > + return -EINVAL; > + > + *val = MAX9611_TEMP_RAW(adc_data); > + return IIO_VAL_INT; > + > + case MAX9611_CHAN_VOLTAGE_INPUT: > + ret = max9611_read_single(dev, CONF_IN_VOLT, > + &adc_data); > + if (ret) > + return -EINVAL; > + > + *val = MAX9611_VOLTAGE_RAW(adc_data); > + return IIO_VAL_INT; > + } > + > + break; > + > + case IIO_CHAN_INFO_OFFSET: > + /* MAX9611_CHAN_VOLTAGE_INPUT */ > + *val = MAX9611_CIM_OFFSET_RAW; > + > + return IIO_VAL_INT; > + > + case IIO_CHAN_INFO_SCALE: > + > + switch (chan->address) { > + case MAX9611_CHAN_TEMPERATURE: > + *val = MAX9611_TEMP_SCALE_NUM; > + *val2 = MAX9611_TEMP_SCALE_DIV; > + > + return IIO_VAL_FRACTIONAL; > + > + case MAX9611_CHAN_VOLTAGE_INPUT: > + *val = MAX9611_CIM_LSB_mV; > + > + return IIO_VAL_INT; > + } > + > + break; > + > + case IIO_CHAN_INFO_PROCESSED: > + > + switch (chan->address) { > + case MAX9611_CHAN_VOLTAGE_SENSE: > + /* > + * processed (mV): (raw - offset) * LSB (nV) / 10^6 > + * > + * Even if max9611 can output raw csa voltage readings, > + * use a produced value as scale depends on gain. > + */ > + ret = max9611_read_csa_voltage(dev, &adc_data, > + &gain_selector); > + if (ret) > + return -EINVAL; > + > + csa_gain = max9611_gain_conf[gain_selector]; > + > + adc_data -= csa_gain[CSA_GAIN_OFFS_RAW]; > + *val = MAX9611_VOLTAGE_RAW(adc_data) * > + csa_gain[CSA_GAIN_LSB_nV]; > + *val2 = 1000000; > + > + return IIO_VAL_FRACTIONAL; > + > + case MAX9611_CHAN_CURRENT_LOAD: > + /* processed (mA): Vcsa (nV) / Rshunt (uOhm) */ > + ret = max9611_read_csa_voltage(dev, &adc_data, > + &gain_selector); > + if (ret) > + return -EINVAL; > + > + csa_gain = max9611_gain_conf[gain_selector]; > + > + adc_data -= csa_gain[CSA_GAIN_OFFS_RAW]; > + *val = MAX9611_VOLTAGE_RAW(adc_data) * > + csa_gain[CSA_GAIN_LSB_nV]; > + *val2 = dev->shunt_resistor_uohm; > + > + return IIO_VAL_FRACTIONAL; > + > + case MAX9611_CHAN_POWER_LOAD: > + /* > + * processed (mW): Vin (mV) * Vcsa (uV) / > + * Rshunt (uOhm) > + */ > + ret = max9611_read_single(dev, CONF_IN_VOLT, > + &adc_data); > + if (ret) > + return -EINVAL; > + > + adc_data -= MAX9611_CIM_OFFSET_RAW; > + *val = MAX9611_VOLTAGE_RAW(adc_data) * > + MAX9611_CIM_LSB_mV; > + > + ret = max9611_read_csa_voltage(dev, &adc_data, > + &gain_selector); > + if (ret) > + return -EINVAL; > + > + csa_gain = max9611_gain_conf[gain_selector]; > + > + /* divide by 10^3 here to avoid 32bit overflow */ > + adc_data -= csa_gain[CSA_GAIN_OFFS_RAW]; > + *val *= MAX9611_VOLTAGE_RAW(adc_data) * > + csa_gain[CSA_GAIN_LSB_nV] / 1000; > + *val2 = dev->shunt_resistor_uohm; > + > + return IIO_VAL_FRACTIONAL; > + } > + > + break; > + } > + > + return -EINVAL; > +} > + > +static ssize_t max9611_shunt_resistor_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + struct max9611_dev *max9611 = iio_priv(dev_to_iio_dev(dev)); > + unsigned int i, r; > + > + i = max9611->shunt_resistor_uohm / 1000; > + r = max9611->shunt_resistor_uohm % 1000; > + > + return sprintf(buf, "%u.%03u\n", i, r); > +} > + > +static IIO_DEVICE_ATTR(in_power_shunt_resistor, 0444, > + max9611_shunt_resistor_show, NULL, 0); > +static IIO_DEVICE_ATTR(in_current_shunt_resistor, 0444, > + max9611_shunt_resistor_show, NULL, 0); > + > +static struct attribute *max9611_attributes[] = { > + &iio_dev_attr_in_power_shunt_resistor.dev_attr.attr, > + &iio_dev_attr_in_current_shunt_resistor.dev_attr.attr, > + NULL, > +}; > + > +static const struct attribute_group max9611_attribute_group = { > + .attrs = max9611_attributes, > +}; > + > +static const struct iio_info indio_info = { > + .driver_module = THIS_MODULE, > + .read_raw = max9611_read_raw, > + .attrs = &max9611_attribute_group, > +}; > + > +static int max9611_init(struct max9611_dev *max9611) > +{ > + struct i2c_client *client = max9611->i2c_client; > + u16 regval; > + int ret; > + > + if (!i2c_check_functionality(client->adapter, > + I2C_FUNC_SMBUS_WRITE_BYTE | > + I2C_FUNC_SMBUS_READ_WORD_DATA)) { > + dev_err(max9611->dev, > + "I2c adapter does not support smbus write_byte or read_word functionalities: aborting probe.\n"); > + return -EINVAL; > + } > + > + /* Make sure die temperature is in range to test communications. */ > + ret = max9611_read_single(max9611, CONF_TEMP, ®val); > + if (ret) > + return ret; > + > + regval = ret & MAX9611_TEMP_MASK; > + > + if ((regval > MAX9611_TEMP_MAX_POS && > + regval < MAX9611_TEMP_MIN_NEG) || > + regval > MAX9611_TEMP_MAX_NEG) { > + dev_err(max9611->dev, > + "Invalid value received from ADC 0x%4x: aborting\n", > + regval); > + return -EIO; > + } > + > + /* Mux shall be zeroed back before applying other configurations */ > + ret = i2c_smbus_write_byte_data(max9611->i2c_client, > + MAX9611_REG_CTRL1, 0); > + if (ret) { > + dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n", > + MAX9611_REG_CTRL1, 0); > + return ret; > + } > + > + ret = i2c_smbus_write_byte_data(max9611->i2c_client, > + MAX9611_REG_CTRL2, 0); > + if (ret) { > + dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n", > + MAX9611_REG_CTRL2, 0); > + return ret; > + } > + usleep_range(1000, 2000); > + > + return 0; > +} > + > +static const struct of_device_id max9611_of_table[] = { > + {.compatible = "maxim,max9611", .data = "max9611"}, > + {.compatible = "maxim,max9612", .data = "max9612"}, > + { }, > +}; > + > +MODULE_DEVICE_TABLE(of, max9611_of_table); > +static int max9611_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + const char * const shunt_res_prop = "shunt-resistor-micro-ohms"; > + const struct device_node *of_node = client->dev.of_node; > + const struct of_device_id *of_id = > + of_match_device(max9611_of_table, &client->dev); > + struct max9611_dev *max9611; > + struct iio_dev *indio_dev; > + unsigned int of_shunt; > + int ret; > + > + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*max9611)); > + if (IS_ERR(indio_dev)) > + return PTR_ERR(indio_dev); > + > + i2c_set_clientdata(client, indio_dev); > + > + max9611 = iio_priv(indio_dev); > + max9611->dev = &client->dev; > + max9611->i2c_client = client; > + mutex_init(&max9611->lock); > + > + ret = of_property_read_u32(of_node, shunt_res_prop, &of_shunt); > + if (ret) { > + dev_err(&client->dev, > + "Missing %s property for %s node\n", > + shunt_res_prop, of_node->full_name); > + return ret; > + } > + max9611->shunt_resistor_uohm = of_shunt; > + > + ret = max9611_init(max9611); > + if (ret) > + return ret; > + > + indio_dev->dev.parent = &client->dev; > + indio_dev->dev.of_node = client->dev.of_node; > + indio_dev->name = of_id->data; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->info = &indio_info; > + indio_dev->channels = max9611_channels; > + indio_dev->num_channels = ARRAY_SIZE(max9611_channels); > + > + return devm_iio_device_register(&client->dev, indio_dev); > +} > + > +static struct i2c_driver max9611_driver = { > + .driver = { > + .name = DRIVER_NAME, > + .owner = THIS_MODULE, > + .of_match_table = max9611_of_table, > + }, > + .probe = max9611_probe, > +}; > +module_i2c_driver(max9611_driver); > + > +MODULE_AUTHOR("Jacopo Mondi <jacopo+renesas@jmondi.org>"); > +MODULE_DESCRIPTION("Maxim max9611/12 current sense amplifier with 12bit ADC"); > +MODULE_LICENSE("GPL v2"); > -- > 2.7.4 >
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index dedae7a..82f2e7b8 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -354,6 +354,16 @@ config MAX1363 To compile this driver as a module, choose M here: the module will be called max1363. +config MAX9611 + tristate "Maxim max9611/max9612 ADC driver" + depends on I2C + help + Say yes here to build support for Maxim max9611/max9612 current sense + amplifier with 12-bits ADC interface. + + To compile this driver as a module, choose M here: the module will be + called max9611. + config MCP320X tristate "Microchip Technology MCP3x01/02/04/08" depends on SPI diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index d001262..149f979 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_LTC2485) += ltc2485.o obj-$(CONFIG_MAX1027) += max1027.o obj-$(CONFIG_MAX11100) += max11100.o obj-$(CONFIG_MAX1363) += max1363.o +obj-$(CONFIG_MAX9611) += max9611.o obj-$(CONFIG_MCP320X) += mcp320x.o obj-$(CONFIG_MCP3422) += mcp3422.o obj-$(CONFIG_MEDIATEK_MT6577_AUXADC) += mt6577_auxadc.o diff --git a/drivers/iio/adc/max9611.c b/drivers/iio/adc/max9611.c new file mode 100644 index 0000000..f0b47fa --- /dev/null +++ b/drivers/iio/adc/max9611.c @@ -0,0 +1,585 @@ +/* + * iio/adc/max9611.c + * + * Maxim max9611/max9612 high side current sense amplifier with + * 12-bit ADC interface. + * + * Copyright (C) 2017 Jacopo Mondi + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +/* + * This driver supports input common-mode voltage, current-sense + * amplifier with programmable gains and die temperature reading from + * Maxim max9611/max9612. + * + * Op-amp, analog comparator, and watchdog functionalities are not + * supported by this driver. + */ + +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/module.h> +#include <linux/of_device.h> + +#define DRIVER_NAME "max9611" + +/* max9611 register addresses */ +#define MAX9611_REG_CSA_DATA 0x00 +#define MAX9611_REG_RS_DATA 0x02 +#define MAX9611_REG_TEMP_DATA 0x08 +#define MAX9611_REG_CTRL1 0x0a +#define MAX9611_REG_CTRL2 0x0b + +/* max9611 REG1 mux configuration options */ +#define MAX9611_MUX_MASK GENMASK(3, 0) +#define MAX9611_MUX_SENSE_1x 0x00 +#define MAX9611_MUX_SENSE_4x 0x01 +#define MAX9611_MUX_SENSE_8x 0x02 +#define MAX9611_INPUT_VOLT 0x03 +#define MAX9611_MUX_TEMP 0x06 + +/* max9611 voltage (both csa and input) helper macros */ +#define MAX9611_VOLTAGE_SHIFT 0x04 +#define MAX9611_VOLTAGE_RAW(_r) ((_r) >> MAX9611_VOLTAGE_SHIFT) + +/* + * max9611 current sense amplifier voltage output: + * LSB and offset values depends on selected gain (1x, 4x, 8x) + * + * GAIN LSB (nV) OFFSET (LSB steps) + * 1x 107500 1 + * 4x 26880 1 + * 8x 13440 3 + * + * The complete formula to calculate current sense voltage is: + * (((adc_read >> 4) - offset) / ((1 / LSB) * 10^-3) + */ +#define MAX9611_CSA_1X_LSB_nV 107500 +#define MAX9611_CSA_4X_LSB_nV 26880 +#define MAX9611_CSA_8X_LSB_nV 13440 + +#define MAX9611_CSA_1X_OFFS_RAW 1 +#define MAX9611_CSA_4X_OFFS_RAW 1 +#define MAX9611_CSA_8X_OFFS_RAW 3 + +/* + * max9611 common input mode (CIM): LSB is 14mV, with 14mV offset at 25 C + * + * The complete formula to calculate input common voltage is: + * (((adc_read >> 4) * 1000) - offset) / (1 / 14 * 1000) + */ +#define MAX9611_CIM_LSB_mV 14 +#define MAX9611_CIM_OFFSET_RAW 1 + +/* + * max9611 temperature reading: LSB is 480 milli degrees Celsius + * + * The complete formula to calculate temperature is: + * ((adc_read >> 7) * 1000) / (1 / 480 * 1000) + */ +#define MAX9611_TEMP_MAX_POS 0x7f80 +#define MAX9611_TEMP_MAX_NEG 0xff80 +#define MAX9611_TEMP_MIN_NEG 0xd980 +#define MAX9611_TEMP_MASK GENMASK(7, 15) +#define MAX9611_TEMP_SHIFT 0x07 +#define MAX9611_TEMP_RAW(_r) ((_r) >> MAX9611_TEMP_SHIFT) +#define MAX9611_TEMP_SCALE_NUM 1000000 +#define MAX9611_TEMP_SCALE_DIV 2083 + +struct max9611_dev { + struct device *dev; + struct i2c_client *i2c_client; + struct mutex lock; + unsigned int shunt_resistor_uohm; +}; + +enum max9611_conf_ids { + CONF_SENSE_1x, + CONF_SENSE_4x, + CONF_SENSE_8x, + CONF_IN_VOLT, + CONF_TEMP, +}; + +/** + * max9611_mux_conf - associate ADC mux configuration with register address + * where data shall be read from + */ +static const unsigned int max9611_mux_conf[][2] = { + /* CONF_SENSE_1x */ + { MAX9611_MUX_SENSE_1x, MAX9611_REG_CSA_DATA }, + /* CONF_SENSE_4x */ + { MAX9611_MUX_SENSE_4x, MAX9611_REG_CSA_DATA }, + /* CONF_SENSE_8x */ + { MAX9611_MUX_SENSE_8x, MAX9611_REG_CSA_DATA }, + /* CONF_IN_VOLT */ + { MAX9611_INPUT_VOLT, MAX9611_REG_RS_DATA }, + /* CONF_TEMP */ + { MAX9611_MUX_TEMP, MAX9611_REG_TEMP_DATA }, +}; + +enum max9611_csa_gain { + CSA_GAIN_1x, + CSA_GAIN_4x, + CSA_GAIN_8x, +}; + +enum max9611_csa_gain_params { + CSA_GAIN_LSB_nV, + CSA_GAIN_OFFS_RAW, +}; + +/** + * max9611_csa_gain_conf - associate gain multiplier with LSB and + * offset values. + * + * Group together parameters associated with configurable gain + * on current sense amplifier path to ADC interface. + * Current sense read routine adjusts gain until it gets a meaningful + * value; use this structure to retrieve the correct LSB and offset values. + */ +static const unsigned int max9611_gain_conf[][2] = { + { /* [0] CSA_GAIN_1x */ + MAX9611_CSA_1X_LSB_nV, + MAX9611_CSA_1X_OFFS_RAW, + }, + { /* [1] CSA_GAIN_4x */ + MAX9611_CSA_4X_LSB_nV, + MAX9611_CSA_4X_OFFS_RAW, + }, + { /* [2] CSA_GAIN_8x */ + MAX9611_CSA_8X_LSB_nV, + MAX9611_CSA_8X_OFFS_RAW, + }, +}; + +enum max9611_chan_addrs { + MAX9611_CHAN_VOLTAGE_INPUT, + MAX9611_CHAN_VOLTAGE_SENSE, + MAX9611_CHAN_TEMPERATURE, + MAX9611_CHAN_CURRENT_LOAD, + MAX9611_CHAN_POWER_LOAD, +}; + +static const struct iio_chan_spec max9611_channels[] = { + { + .type = IIO_TEMP, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE), + .address = MAX9611_CHAN_TEMPERATURE, + }, + { + .type = IIO_VOLTAGE, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + .address = MAX9611_CHAN_VOLTAGE_SENSE, + .indexed = 1, + .channel = 0, + }, + { + .type = IIO_VOLTAGE, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_OFFSET), + .address = MAX9611_CHAN_VOLTAGE_INPUT, + .indexed = 1, + .channel = 1, + }, + { + .type = IIO_CURRENT, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + .address = MAX9611_CHAN_CURRENT_LOAD, + }, + { + .type = IIO_POWER, + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), + .address = MAX9611_CHAN_POWER_LOAD + }, +}; + +/** + * max9611_read_single() - read a single value from ADC interface + * + * Data registers are 16 bit long, spread between two 8 bit registers + * with consecutive addresses. + * Configure ADC mux first, then read register at address "reg_addr". + * The smbus_read_word routine asks for 16 bits and the ADC is kind enough + * to return values from "reg_addr" and "reg_addr + 1" consecutively. + * Data are transmitted with big-endian ordering: MSB arrives first. + * + * @max9611: max9611 device + * @selector: index for mux and register configuration + * @raw_val: the value returned from ADC + */ +static int max9611_read_single(struct max9611_dev *max9611, + enum max9611_conf_ids selector, + u16 *raw_val) +{ + int ret; + + u8 mux_conf = max9611_mux_conf[selector][0] & MAX9611_MUX_MASK; + u8 reg_addr = max9611_mux_conf[selector][1]; + + /* + * Keep mutex lock held during read-write to avoid mux register + * (CTRL1) re-configuration. + */ + mutex_lock(&max9611->lock); + ret = i2c_smbus_write_byte_data(max9611->i2c_client, + MAX9611_REG_CTRL1, mux_conf); + if (ret) { + dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n", + MAX9611_REG_CTRL1, mux_conf); + mutex_unlock(&max9611->lock); + return ret; + } + + /* + * need a delay here to make register configuration + * stabilize. 1 msec at least, from empirical testing. + */ + usleep_range(1000, 2000); + + ret = i2c_smbus_read_word_swapped(max9611->i2c_client, reg_addr); + if (ret < 0) { + dev_err(max9611->dev, "i2c read word from 0x%2x failed\n", + reg_addr); + mutex_unlock(&max9611->lock); + return ret; + } + + *raw_val = ret; + mutex_unlock(&max9611->lock); + + return 0; +} + +/** + * max9611_read_csa_voltage() - read current sense amplifier output voltage + * + * Current sense amplifier output voltage is read through a configurable + * 1x, 4x or 8x gain. + * Start with plain 1x gain, and adjust gain control properly until a + * meaningful value is read from ADC output. + * + * @max9611: max9611 device + * @adc_raw: raw value read from ADC output + * @csa_gain: gain configuration option selector + */ +static int max9611_read_csa_voltage(struct max9611_dev *max9611, + u16 *adc_raw, + enum max9611_csa_gain *csa_gain) +{ + enum max9611_conf_ids gain_selectors[] = { + CONF_SENSE_1x, + CONF_SENSE_4x, + CONF_SENSE_8x + }; + unsigned int i; + int ret; + + for (i = 0; i < ARRAY_SIZE(gain_selectors); ++i) { + ret = max9611_read_single(max9611, gain_selectors[i], adc_raw); + if (ret) + return ret; + + if (*adc_raw > 0) { + *csa_gain = gain_selectors[i]; + return 0; + } + } + + return -EIO; +} + +static int max9611_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct max9611_dev *dev = iio_priv(indio_dev); + enum max9611_csa_gain gain_selector; + const unsigned int *csa_gain; + u16 adc_data; + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + + switch (chan->address) { + case MAX9611_CHAN_TEMPERATURE: + ret = max9611_read_single(dev, CONF_TEMP, + &adc_data); + if (ret) + return -EINVAL; + + *val = MAX9611_TEMP_RAW(adc_data); + return IIO_VAL_INT; + + case MAX9611_CHAN_VOLTAGE_INPUT: + ret = max9611_read_single(dev, CONF_IN_VOLT, + &adc_data); + if (ret) + return -EINVAL; + + *val = MAX9611_VOLTAGE_RAW(adc_data); + return IIO_VAL_INT; + } + + break; + + case IIO_CHAN_INFO_OFFSET: + /* MAX9611_CHAN_VOLTAGE_INPUT */ + *val = MAX9611_CIM_OFFSET_RAW; + + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + + switch (chan->address) { + case MAX9611_CHAN_TEMPERATURE: + *val = MAX9611_TEMP_SCALE_NUM; + *val2 = MAX9611_TEMP_SCALE_DIV; + + return IIO_VAL_FRACTIONAL; + + case MAX9611_CHAN_VOLTAGE_INPUT: + *val = MAX9611_CIM_LSB_mV; + + return IIO_VAL_INT; + } + + break; + + case IIO_CHAN_INFO_PROCESSED: + + switch (chan->address) { + case MAX9611_CHAN_VOLTAGE_SENSE: + /* + * processed (mV): (raw - offset) * LSB (nV) / 10^6 + * + * Even if max9611 can output raw csa voltage readings, + * use a produced value as scale depends on gain. + */ + ret = max9611_read_csa_voltage(dev, &adc_data, + &gain_selector); + if (ret) + return -EINVAL; + + csa_gain = max9611_gain_conf[gain_selector]; + + adc_data -= csa_gain[CSA_GAIN_OFFS_RAW]; + *val = MAX9611_VOLTAGE_RAW(adc_data) * + csa_gain[CSA_GAIN_LSB_nV]; + *val2 = 1000000; + + return IIO_VAL_FRACTIONAL; + + case MAX9611_CHAN_CURRENT_LOAD: + /* processed (mA): Vcsa (nV) / Rshunt (uOhm) */ + ret = max9611_read_csa_voltage(dev, &adc_data, + &gain_selector); + if (ret) + return -EINVAL; + + csa_gain = max9611_gain_conf[gain_selector]; + + adc_data -= csa_gain[CSA_GAIN_OFFS_RAW]; + *val = MAX9611_VOLTAGE_RAW(adc_data) * + csa_gain[CSA_GAIN_LSB_nV]; + *val2 = dev->shunt_resistor_uohm; + + return IIO_VAL_FRACTIONAL; + + case MAX9611_CHAN_POWER_LOAD: + /* + * processed (mW): Vin (mV) * Vcsa (uV) / + * Rshunt (uOhm) + */ + ret = max9611_read_single(dev, CONF_IN_VOLT, + &adc_data); + if (ret) + return -EINVAL; + + adc_data -= MAX9611_CIM_OFFSET_RAW; + *val = MAX9611_VOLTAGE_RAW(adc_data) * + MAX9611_CIM_LSB_mV; + + ret = max9611_read_csa_voltage(dev, &adc_data, + &gain_selector); + if (ret) + return -EINVAL; + + csa_gain = max9611_gain_conf[gain_selector]; + + /* divide by 10^3 here to avoid 32bit overflow */ + adc_data -= csa_gain[CSA_GAIN_OFFS_RAW]; + *val *= MAX9611_VOLTAGE_RAW(adc_data) * + csa_gain[CSA_GAIN_LSB_nV] / 1000; + *val2 = dev->shunt_resistor_uohm; + + return IIO_VAL_FRACTIONAL; + } + + break; + } + + return -EINVAL; +} + +static ssize_t max9611_shunt_resistor_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct max9611_dev *max9611 = iio_priv(dev_to_iio_dev(dev)); + unsigned int i, r; + + i = max9611->shunt_resistor_uohm / 1000; + r = max9611->shunt_resistor_uohm % 1000; + + return sprintf(buf, "%u.%03u\n", i, r); +} + +static IIO_DEVICE_ATTR(in_power_shunt_resistor, 0444, + max9611_shunt_resistor_show, NULL, 0); +static IIO_DEVICE_ATTR(in_current_shunt_resistor, 0444, + max9611_shunt_resistor_show, NULL, 0); + +static struct attribute *max9611_attributes[] = { + &iio_dev_attr_in_power_shunt_resistor.dev_attr.attr, + &iio_dev_attr_in_current_shunt_resistor.dev_attr.attr, + NULL, +}; + +static const struct attribute_group max9611_attribute_group = { + .attrs = max9611_attributes, +}; + +static const struct iio_info indio_info = { + .driver_module = THIS_MODULE, + .read_raw = max9611_read_raw, + .attrs = &max9611_attribute_group, +}; + +static int max9611_init(struct max9611_dev *max9611) +{ + struct i2c_client *client = max9611->i2c_client; + u16 regval; + int ret; + + if (!i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_WRITE_BYTE | + I2C_FUNC_SMBUS_READ_WORD_DATA)) { + dev_err(max9611->dev, + "I2c adapter does not support smbus write_byte or read_word functionalities: aborting probe.\n"); + return -EINVAL; + } + + /* Make sure die temperature is in range to test communications. */ + ret = max9611_read_single(max9611, CONF_TEMP, ®val); + if (ret) + return ret; + + regval = ret & MAX9611_TEMP_MASK; + + if ((regval > MAX9611_TEMP_MAX_POS && + regval < MAX9611_TEMP_MIN_NEG) || + regval > MAX9611_TEMP_MAX_NEG) { + dev_err(max9611->dev, + "Invalid value received from ADC 0x%4x: aborting\n", + regval); + return -EIO; + } + + /* Mux shall be zeroed back before applying other configurations */ + ret = i2c_smbus_write_byte_data(max9611->i2c_client, + MAX9611_REG_CTRL1, 0); + if (ret) { + dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n", + MAX9611_REG_CTRL1, 0); + return ret; + } + + ret = i2c_smbus_write_byte_data(max9611->i2c_client, + MAX9611_REG_CTRL2, 0); + if (ret) { + dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n", + MAX9611_REG_CTRL2, 0); + return ret; + } + usleep_range(1000, 2000); + + return 0; +} + +static const struct of_device_id max9611_of_table[] = { + {.compatible = "maxim,max9611", .data = "max9611"}, + {.compatible = "maxim,max9612", .data = "max9612"}, + { }, +}; + +MODULE_DEVICE_TABLE(of, max9611_of_table); +static int max9611_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + const char * const shunt_res_prop = "shunt-resistor-micro-ohms"; + const struct device_node *of_node = client->dev.of_node; + const struct of_device_id *of_id = + of_match_device(max9611_of_table, &client->dev); + struct max9611_dev *max9611; + struct iio_dev *indio_dev; + unsigned int of_shunt; + int ret; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*max9611)); + if (IS_ERR(indio_dev)) + return PTR_ERR(indio_dev); + + i2c_set_clientdata(client, indio_dev); + + max9611 = iio_priv(indio_dev); + max9611->dev = &client->dev; + max9611->i2c_client = client; + mutex_init(&max9611->lock); + + ret = of_property_read_u32(of_node, shunt_res_prop, &of_shunt); + if (ret) { + dev_err(&client->dev, + "Missing %s property for %s node\n", + shunt_res_prop, of_node->full_name); + return ret; + } + max9611->shunt_resistor_uohm = of_shunt; + + ret = max9611_init(max9611); + if (ret) + return ret; + + indio_dev->dev.parent = &client->dev; + indio_dev->dev.of_node = client->dev.of_node; + indio_dev->name = of_id->data; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &indio_info; + indio_dev->channels = max9611_channels; + indio_dev->num_channels = ARRAY_SIZE(max9611_channels); + + return devm_iio_device_register(&client->dev, indio_dev); +} + +static struct i2c_driver max9611_driver = { + .driver = { + .name = DRIVER_NAME, + .owner = THIS_MODULE, + .of_match_table = max9611_of_table, + }, + .probe = max9611_probe, +}; +module_i2c_driver(max9611_driver); + +MODULE_AUTHOR("Jacopo Mondi <jacopo+renesas@jmondi.org>"); +MODULE_DESCRIPTION("Maxim max9611/12 current sense amplifier with 12bit ADC"); +MODULE_LICENSE("GPL v2");
Add iio driver for Maxim max9611 and max9612 current-sense amplifiers with 12-bits ADC interface. Datasheet publicly available at: https://datasheets.maximintegrated.com/en/ds/MAX9611-MAX9612.pdf Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org> --- Output of iio_info on Salvator-X board for max9611 chip installed on VDD_0.8 lines. The VDD_0.8 line powers the CPU cluster and on-board RAM. iio:device0: max9611 5 channels found: voltage0: (input) 1 channel-specific attributes found: attr 0: input value: 4.085000000 voltage1: (input) 3 channel-specific attributes found: attr 0: scale value: 14 attr 1: offset value: 1 attr 2: raw value: 59 power: (input) 2 channel-specific attributes found: attr 0: shunt_resistor value: 5.000 attr 1: input value: 663.404000000 current: (input) 2 channel-specific attributes found: attr 0: shunt_resistor value: 5.000 attr 1: input value: 817.000000000 temp: (input) 2 channel-specific attributes found: attr 0: scale value: 480.076812289 attr 1: raw value: 59 The collected information represent: * voltage0 (current sense voltage) Vcsa voltage drop between RS+ and RS- input = 4,085 mV * voltage1: (common input voltage) Vcim voltage at RS+ input = (59 - 1) * 14 = 812 mV * current flowing on shunt resistor (Icsa) = Vcsa / Rshunt = 817 mA * power load on the sensed line (Pload) = Vcim * Icsa = 663 m * die temperature = (57 * 480.07) = 27360 milli Celsius --- drivers/iio/adc/Kconfig | 10 + drivers/iio/adc/Makefile | 1 + drivers/iio/adc/max9611.c | 585 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 596 insertions(+) create mode 100644 drivers/iio/adc/max9611.c -- 2.7.4