| Message ID | 20230307065535.7927-2-mike.looijmans@topic.nl (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v5,1/2] dt-bindings: iio: adc: Add TI ADS1100 and ADS1000 | expand |
On Tue, Mar 07, 2023 at 07:55:34AM +0100, Mike Looijmans wrote: > The ADS1100 is a 16-bit ADC (at 8 samples per second). > The ADS1000 is similar, but has a fixed data rate. Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> But see below. > Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl> > > --- > > Changes in v5: > Use scripts/Lindent to auto-format > Use DIV_ROUNDUP_CLOSEST in gain calculation > > 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 | 444 +++++++++++++++++++++++++++++++++++ > 3 files changed, 455 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..ce386c18618f > --- /dev/null > +++ b/drivers/iio/adc/ti-ads1100.c > @@ -0,0 +1,444 @@ > +// 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; > + > + /* 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 = DIV_ROUND_CLOSEST(microvolts, BIT(15)) * MILLI / val2; > + if (gain < BIT(0) || gain > BIT(3)) > + return -EINVAL; > + > + ads1100_set_config_bits(data, ADS1100_PGA_MASK, ffs(gain) - 1); > + 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)); This is better on a single line. > + } > + > + 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@topic.nl>"); > +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@topicproducts.com > W: www.topic.nl > > Please consider the environment before printing this e-mail
On Tue, 7 Mar 2023 14:24:44 +0200 Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > On Tue, Mar 07, 2023 at 07:55:34AM +0100, Mike Looijmans wrote: > > The ADS1100 is a 16-bit ADC (at 8 samples per second). > > The ADS1000 is similar, but has a fixed data rate. > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > But see below. I tidied that up and made a few other trivial whitespace tweaks whilst applying. Applied to the togreg branch of iio.git and pushed out as testing for 0-day to see if it can find anything we missed. Thanks, Jonathan > > > Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl> > > + > > +static int ads1100_set_scale(struct ads1100_data *data, int val, int val2) > > +{ > > + int microvolts; > > + int gain; > > + > > + /* 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 = DIV_ROUND_CLOSEST(microvolts, BIT(15)) * MILLI / val2; > > + if (gain < BIT(0) || gain > BIT(3)) > > + return -EINVAL; > > + > > + ads1100_set_config_bits(data, ADS1100_PGA_MASK, ffs(gain) - 1); I added a blank line here and in one other place for consistency + I like them before simple return statements. > > + 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)); > > This is better on a single line. Fixed up whilst applying. > > > + } > > + > > + return -EINVAL; > > +} > > +
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..ce386c18618f --- /dev/null +++ b/drivers/iio/adc/ti-ads1100.c @@ -0,0 +1,444 @@ +// 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; + + /* 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 = DIV_ROUND_CLOSEST(microvolts, BIT(15)) * MILLI / val2; + if (gain < BIT(0) || gain > BIT(3)) + return -EINVAL; + + ads1100_set_config_bits(data, ADS1100_PGA_MASK, ffs(gain) - 1); + 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@topic.nl>"); +MODULE_DESCRIPTION("Texas Instruments ADS1100 ADC driver"); +MODULE_LICENSE("GPL");
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@topic.nl> --- Changes in v5: Use scripts/Lindent to auto-format Use DIV_ROUNDUP_CLOSEST in gain calculation 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 | 444 +++++++++++++++++++++++++++++++++++ 3 files changed, 455 insertions(+) create mode 100644 drivers/iio/adc/ti-ads1100.c