The ADS1100 is a 16-bit ADC (at 8 samples per second). The ADS1000 is similar, but has a fixed data rate. Signed-off-by: Mike Looijmans <mike.looijmans@xxxxxxxx> --- Changes in v4: Use post-increment Formatting fixes (commas, indents, empty line) Use 'ffs' and explain gain formula Use dev_set_drvdata/dev_get_drvdata for pm_ methods Use units.h for micro-to-milli conversion Changes in v3: Add #include linux/bitfield.h and linux/bits.h Changes in v2: Remove "driver for" from title Use proper PM_RUNTIME macros Fix indents Use dev_err_probe() Unsigned index and post-increment Use GENMASK and FIELD_GET remove ads1100_set_conv_mode remove Kconfig BUFFER dependencies remove unused #include Set SCALE instead of HARDWAREGAIN Use devm_add_action_or_reset drivers/iio/adc/Kconfig | 10 + drivers/iio/adc/Makefile | 1 + drivers/iio/adc/ti-ads1100.c | 442 +++++++++++++++++++++++++++++++++++ 3 files changed, 453 insertions(+) create mode 100644 drivers/iio/adc/ti-ads1100.c diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index 63f80d747cbd..257efb25a92e 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -1207,6 +1207,16 @@ config TI_ADS1015 This driver can also be built as a module. If so, the module will be called ti-ads1015. +config TI_ADS1100 + tristate "Texas Instruments ADS1100 and ADS1000 ADC" + depends on I2C + help + If you say yes here you get support for Texas Instruments ADS1100 and + ADS1000 ADC chips. + + This driver can also be built as a module. If so, the module will be + called ti-ads1100. + config TI_ADS7950 tristate "Texas Instruments ADS7950 ADC driver" depends on SPI && GPIOLIB diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index 4ef41a7dfac6..61ef600fab99 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -107,6 +107,7 @@ obj-$(CONFIG_TI_ADC108S102) += ti-adc108s102.o obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o +obj-$(CONFIG_TI_ADS1100) += ti-ads1100.o obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o obj-$(CONFIG_TI_ADS8344) += ti-ads8344.o obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o diff --git a/drivers/iio/adc/ti-ads1100.c b/drivers/iio/adc/ti-ads1100.c new file mode 100644 index 000000000000..2189634dccbf --- /dev/null +++ b/drivers/iio/adc/ti-ads1100.c @@ -0,0 +1,442 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ADS1100 - Texas Instruments Analog-to-Digital Converter + * + * Copyright (c) 2023, Topic Embedded Products + * + * Datasheet: https://www.ti.com/lit/gpn/ads1100 + * IIO driver for ADS1100 and ADS1000 ADC 16-bit I2C + */ + +#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/i2c.h> +#include <linux/mutex.h> +#include <linux/property.h> +#include <linux/pm_runtime.h> +#include <linux/regulator/consumer.h> +#include <linux/units.h> + +#include <linux/iio/iio.h> +#include <linux/iio/types.h> + +/* The ADS1100 has a single byte config register */ + +/* Conversion in progress bit */ +#define ADS1100_CFG_ST_BSY BIT(7) +/* Single conversion bit */ +#define ADS1100_CFG_SC BIT(4) +/* Data rate */ +#define ADS1100_DR_MASK GENMASK(3, 2) +/* Gain */ +#define ADS1100_PGA_MASK GENMASK(1, 0) + +#define ADS1100_CONTINUOUS 0 +#define ADS1100_SINGLESHOT ADS1100_CFG_SC + +#define ADS1100_SLEEP_DELAY_MS 2000 + +static const int ads1100_data_rate[] = {128, 32, 16, 8}; +static const int ads1100_data_rate_bits[] = {12, 14, 15, 16}; + +struct ads1100_data { + struct i2c_client *client; + struct regulator *reg_vdd; + struct mutex lock; + int scale_avail[2 * 4]; /* 4 gain settings */ + u8 config; + bool supports_data_rate; /* Only the ADS1100 can select the rate */ +}; + +static const struct iio_chan_spec ads1100_channel = { + .type = IIO_VOLTAGE, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_all = + BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_SAMP_FREQ), + .info_mask_shared_by_all_available = + BIT(IIO_CHAN_INFO_SCALE) | + BIT(IIO_CHAN_INFO_SAMP_FREQ), + .scan_type = { + .sign = 's', + .realbits = 16, + .storagebits = 16, + .endianness = IIO_CPU, + }, + .datasheet_name = "AIN", +}; + +static int ads1100_set_config_bits(struct ads1100_data *data, u8 mask, u8 value) +{ + int ret; + u8 config = (data->config & ~mask) | (value & mask); + + if (data->config == config) + return 0; /* Already done */ + + ret = i2c_master_send(data->client, &config, 1); + if (ret < 0) + return ret; + + data->config = config; + return 0; +}; + +static int ads1100_data_bits(struct ads1100_data *data) +{ + return ads1100_data_rate_bits[FIELD_GET(ADS1100_DR_MASK, data->config)]; +} + +static int ads1100_get_adc_result(struct ads1100_data *data, int chan, int *val) +{ + int ret; + __be16 buffer; + s16 value; + + if (chan != 0) + return -EINVAL; + + ret = pm_runtime_resume_and_get(&data->client->dev); + if (ret < 0) + return ret; + + ret = i2c_master_recv(data->client, (char *)&buffer, sizeof(buffer)); + + pm_runtime_mark_last_busy(&data->client->dev); + pm_runtime_put_autosuspend(&data->client->dev); + + if (ret < 0) { + dev_err(&data->client->dev, "I2C read fail: %d\n", ret); + return ret; + } + + /* Value is always 16-bit 2's complement */ + value = be16_to_cpu(buffer); + /* Shift result to compensate for bit resolution vs. sample rate */ + value <<= 16 - ads1100_data_bits(data); + *val = sign_extend32(value, 15); + + return 0; +} + +static int ads1100_set_scale(struct ads1100_data *data, int val, int val2) +{ + int microvolts; + int gain; + int regval; + + /* With Vdd between 2.7 and 5V, the scale is always below 1 */ + if (val) + return -EINVAL; + + if (!val2) + return -EINVAL; + + microvolts = regulator_get_voltage(data->reg_vdd); + /* + * val2 is in 'micro' units, n = val2 / 1000000 + * result must be millivolts, d = microvolts / 1000 + * the full-scale value is d/n, corresponds to 2^15, + * hence the gain = (d / n) >> 15, factoring out the 1000 and moving the + * bitshift so everything fits in 32-bits yields this formula. + */ + gain = ((microvolts + BIT(14)) >> 15) * 1000 / val2; + if (gain <= 0 || gain > 8) + return -EINVAL; + + regval = ffs(gain) - 1; + ads1100_set_config_bits(data, ADS1100_PGA_MASK, regval); + return 0; +} + +static int ads1100_set_data_rate(struct ads1100_data *data, int chan, int rate) +{ + unsigned int i; + unsigned int size; + + size = data->supports_data_rate ? ARRAY_SIZE(ads1100_data_rate) : 1; + for (i = 0; i < size; i++) { + if (ads1100_data_rate[i] == rate) + return ads1100_set_config_bits( + data, ADS1100_DR_MASK, + FIELD_PREP(ADS1100_DR_MASK, i)); + } + + return -EINVAL; +} + +static int ads1100_get_vdd_millivolts(struct ads1100_data *data) +{ + return regulator_get_voltage(data->reg_vdd) / (MICRO / MILLI); +} + +static void ads1100_calc_scale_avail(struct ads1100_data *data) +{ + int millivolts = ads1100_get_vdd_millivolts(data); + unsigned int i; + + for (i = 0; i < ARRAY_SIZE(data->scale_avail) / 2; i++) { + data->scale_avail[i * 2 + 0] = millivolts; + data->scale_avail[i * 2 + 1] = 15 + i; + } +} + +static int ads1100_read_avail(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int **vals, int *type, int *length, + long mask) +{ + struct ads1100_data *data = iio_priv(indio_dev); + + if (chan->type != IIO_VOLTAGE) + return -EINVAL; + + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + *type = IIO_VAL_INT; + *vals = ads1100_data_rate; + if (data->supports_data_rate) + *length = ARRAY_SIZE(ads1100_data_rate); + else + *length = 1; + return IIO_AVAIL_LIST; + case IIO_CHAN_INFO_SCALE: + *type = IIO_VAL_FRACTIONAL_LOG2; + *vals = data->scale_avail; + *length = ARRAY_SIZE(data->scale_avail); + return IIO_AVAIL_LIST; + default: + return -EINVAL; + } +} + +static int ads1100_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + int ret; + struct ads1100_data *data = iio_priv(indio_dev); + + mutex_lock(&data->lock); + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + break; + + ret = ads1100_get_adc_result(data, chan->address, val); + if (ret >= 0) + ret = IIO_VAL_INT; + iio_device_release_direct_mode(indio_dev); + break; + case IIO_CHAN_INFO_SCALE: + /* full-scale is the supply voltage in millivolts */ + *val = ads1100_get_vdd_millivolts(data); + *val2 = 15 + FIELD_GET(ADS1100_PGA_MASK, data->config); + ret = IIO_VAL_FRACTIONAL_LOG2; + break; + case IIO_CHAN_INFO_SAMP_FREQ: + *val = ads1100_data_rate[FIELD_GET(ADS1100_DR_MASK, + data->config)]; + ret = IIO_VAL_INT; + break; + default: + ret = -EINVAL; + break; + } + mutex_unlock(&data->lock); + + return ret; +} + +static int ads1100_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int val, + int val2, long mask) +{ + struct ads1100_data *data = iio_priv(indio_dev); + int ret; + + mutex_lock(&data->lock); + switch (mask) { + case IIO_CHAN_INFO_SCALE: + ret = ads1100_set_scale(data, val, val2); + break; + case IIO_CHAN_INFO_SAMP_FREQ: + ret = ads1100_set_data_rate(data, chan->address, val); + break; + default: + ret = -EINVAL; + break; + } + mutex_unlock(&data->lock); + + return ret; +} + +static const struct iio_info ads1100_info = { + .read_avail = ads1100_read_avail, + .read_raw = ads1100_read_raw, + .write_raw = ads1100_write_raw, +}; + +static int ads1100_setup(struct ads1100_data *data) +{ + int ret; + u8 buffer[3]; + + /* Setup continuous sampling mode at 8sps */ + buffer[0] = ADS1100_DR_MASK | ADS1100_CONTINUOUS; + ret = i2c_master_send(data->client, buffer, 1); + if (ret < 0) + return ret; + + ret = i2c_master_recv(data->client, buffer, sizeof(buffer)); + if (ret < 0) + return ret; + + /* Config register returned in third byte, strip away the busy status */ + data->config = buffer[2] & ~ADS1100_CFG_ST_BSY; + + /* Detect the sample rate capability by checking the DR bits */ + data->supports_data_rate = FIELD_GET(ADS1100_DR_MASK, buffer[2]) != 0; + + return 0; +} + +static void ads1100_reg_disable(void *reg) +{ + regulator_disable(reg); +} + +static void ads1100_disable_continuous(void *data) +{ + ads1100_set_config_bits(data, ADS1100_CFG_SC, ADS1100_SINGLESHOT); +} + +static int ads1100_probe(struct i2c_client *client) +{ + struct iio_dev *indio_dev; + struct ads1100_data *data; + struct device *dev = &client->dev; + int ret; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + dev_set_drvdata(dev, data); + data->client = client; + mutex_init(&data->lock); + + indio_dev->name = "ads1100"; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = &ads1100_channel; + indio_dev->num_channels = 1; + indio_dev->info = &ads1100_info; + + data->reg_vdd = devm_regulator_get(dev, "vdd"); + if (IS_ERR(data->reg_vdd)) + return dev_err_probe(dev, PTR_ERR(data->reg_vdd), + "Failed to get vdd regulator\n"); + + ret = regulator_enable(data->reg_vdd); + if (ret < 0) + return dev_err_probe(dev, PTR_ERR(data->reg_vdd), + "Failed to enable vdd regulator\n"); + + ret = devm_add_action_or_reset(dev, ads1100_reg_disable, data->reg_vdd); + if (ret) + return ret; + + ret = ads1100_setup(data); + if (ret) + return dev_err_probe(dev, ret, + "Failed to communicate with device\n"); + + ret = devm_add_action_or_reset(dev, ads1100_disable_continuous, data); + if (ret) + return ret; + + ads1100_calc_scale_avail(data); + + pm_runtime_set_autosuspend_delay(dev, ADS1100_SLEEP_DELAY_MS); + pm_runtime_use_autosuspend(dev); + pm_runtime_set_active(dev); + ret = devm_pm_runtime_enable(dev); + if (ret) + return dev_err_probe(dev, ret, "Failed to enable pm_runtime\n"); + + ret = devm_iio_device_register(dev, indio_dev); + if (ret) + return dev_err_probe(dev, ret, + "Failed to register IIO device\n"); + + return 0; +} + +static int ads1100_runtime_suspend(struct device *dev) +{ + struct ads1100_data *data = dev_get_drvdata(dev); + + ads1100_set_config_bits(data, ADS1100_CFG_SC, ADS1100_SINGLESHOT); + regulator_disable(data->reg_vdd); + + return 0; +} + +static int ads1100_runtime_resume(struct device *dev) +{ + struct ads1100_data *data = dev_get_drvdata(dev); + int ret; + + ret = regulator_enable(data->reg_vdd); + if (ret) { + dev_err(&data->client->dev, "Failed to enable Vdd\n"); + return ret; + } + + /* + * We'll always change the mode bit in the config register, so there is + * no need here to "force" a write to the config register. If the device + * has been power-cycled, we'll re-write its config register now. + */ + return ads1100_set_config_bits(data, ADS1100_CFG_SC, ADS1100_CONTINUOUS); +} + +static DEFINE_RUNTIME_DEV_PM_OPS(ads1100_pm_ops, + ads1100_runtime_suspend, + ads1100_runtime_resume, + NULL); + +static const struct i2c_device_id ads1100_id[] = { + { "ads1100" }, + { "ads1000" }, + {} +}; +MODULE_DEVICE_TABLE(i2c, ads1100_id); + +static const struct of_device_id ads1100_of_match[] = { + { .compatible = "ti,ads1100" }, + { .compatible = "ti,ads1000" }, + {} +}; +MODULE_DEVICE_TABLE(of, ads1100_of_match); + +static struct i2c_driver ads1100_driver = { + .driver = { + .name = "ads1100", + .of_match_table = ads1100_of_match, + .pm = pm_ptr(&ads1100_pm_ops), + }, + .probe_new = ads1100_probe, + .id_table = ads1100_id, +}; +module_i2c_driver(ads1100_driver); + +MODULE_AUTHOR("Mike Looijmans <mike.looijmans@xxxxxxxx>"); +MODULE_DESCRIPTION("Texas Instruments ADS1100 ADC driver"); +MODULE_LICENSE("GPL"); -- 2.17.1 Met vriendelijke groet / kind regards, Mike Looijmans System Expert TOPIC Embedded Products B.V. Materiaalweg 4, 5681 RJ Best The Netherlands T: +31 (0) 499 33 69 69 E: mike.looijmans@xxxxxxxxxxxxxxxxx W: www.topic.nl Please consider the environment before printing this e-mail
