From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> The Texas Instruments ADS7924 is a 4 channels, 12-bit analog to digital converter (ADC) with an I2C interface. Datasheet: https://www.ti.com/lit/gpn/ads7924 Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> --- MAINTAINERS | 7 + drivers/iio/adc/Kconfig | 11 + drivers/iio/adc/Makefile | 1 + drivers/iio/adc/ti-ads7924.c | 474 +++++++++++++++++++++++++++++++++++ 4 files changed, 493 insertions(+) create mode 100644 drivers/iio/adc/ti-ads7924.c diff --git a/MAINTAINERS b/MAINTAINERS index f61eb221415b..1a22d2124ad5 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20774,6 +20774,13 @@ M: Robert Richter <rric@xxxxxxxxxx> S: Odd Fixes F: drivers/gpio/gpio-thunderx.c +TI ADS7924 ADC DRIVER +M: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> +L: linux-iio@xxxxxxxxxxxxxxx +S: Supported +F: Documentation/devicetree/bindings/iio/adc/ti,ads7924.yaml +F: drivers/iio/adc/ti-ads7924.c + TI AM437X VPFE DRIVER M: "Lad, Prabhakar" <prabhakar.csengg@xxxxxxxxx> L: linux-media@xxxxxxxxxxxxxxx diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index 63f80d747cbd..5bf4bf16df80 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -1207,6 +1207,17 @@ config TI_ADS1015 This driver can also be built as a module. If so, the module will be called ti-ads1015. +config TI_ADS7924 + tristate "Texas Instruments ADS7924 ADC" + depends on I2C + select REGMAP_I2C + help + If you say yes here you get support for Texas Instruments ADS7924 + 4 channels, 12-bit I2C ADC chip. + + This driver can also be built as a module. If so, the module will be + called ti-ads7924. + 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..6b2a2b4ad9ce 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-$(CONFIG_TI_ADS7924) += ti-ads7924.o obj-$(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-ads7924.c b/drivers/iio/adc/ti-ads7924.c new file mode 100644 index 000000000000..c24fae4ef8e0 --- /dev/null +++ b/drivers/iio/adc/ti-ads7924.c @@ -0,0 +1,474 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * IIO driver for Texas Instruments ADS7924 ADC, 12-bit, 4-Channels, I2C + * + * Author: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> + * Copyright 2022 DimOnOff + * + * based on iio/adc/ti-ads1015.c + * Copyright (c) 2016, Intel Corporation. + * + * Datasheet: https://www.ti.com/lit/gpn/ads7924 + */ + +#include <linux/bitfield.h> +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/init.h> +#include <linux/irq.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> + +#include <linux/iio/iio.h> +#include <linux/iio/types.h> + +#define ADS7924_CHANNELS 4 +#define ADS7924_BITS 12 +#define ADS7924_DATA_SHIFT 4 + +/* Registers. */ +#define ADS7924_MODECNTRL_REG 0x00 +#define ADS7924_INTCNTRL_REG 0x01 +#define ADS7924_DATA0_U_REG 0x02 +#define ADS7924_DATA0_L_REG 0x03 +#define ADS7924_DATA1_U_REG 0x04 +#define ADS7924_DATA1_L_REG 0x05 +#define ADS7924_DATA2_U_REG 0x06 +#define ADS7924_DATA2_L_REG 0x07 +#define ADS7924_DATA3_U_REG 0x08 +#define ADS7924_DATA3_L_REG 0x09 +#define ADS7924_ULR0_REG 0x0A +#define ADS7924_LLR0_REG 0x0B +#define ADS7924_ULR1_REG 0x0C +#define ADS7924_LLR1_REG 0x0D +#define ADS7924_ULR2_REG 0x0E +#define ADS7924_LLR2_REG 0x0F +#define ADS7924_ULR3_REG 0x10 +#define ADS7924_LLR3_REG 0x11 +#define ADS7924_INTCONFIG_REG 0x12 +#define ADS7924_SLPCONFIG_REG 0x13 +#define ADS7924_ACQCONFIG_REG 0x14 +#define ADS7924_PWRCONFIG_REG 0x15 +#define ADS7924_RESET_REG 0x16 + +/* + * Register address INC bit: when set to '1', the register address is + * automatically incremented after every register read which allows convenient + * reading of multiple registers. Set INC to '0' when reading a single register. + */ +#define ADS7924_AUTO_INCREMENT_BIT BIT(7) + +#define ADS7924_MODECNTRL_MODE_MASK GENMASK(7, 2) + +#define ADS7924_MODECNTRL_SEL_MASK GENMASK(1, 0) + +#define ADS7924_CFG_INTPOL_BIT 1 +#define ADS7924_CFG_INTTRIG_BIT 0 + +#define ADS7924_CFG_INTPOL_MASK BIT(ADS7924_CFG_INTPOL_BIT) +#define ADS7924_CFG_INTTRIG_MASK BIT(ADS7924_CFG_INTTRIG_BIT) + +/* Interrupt pin polarity */ +#define ADS7924_CFG_INTPOL_LOW 0 +#define ADS7924_CFG_INTPOL_HIGH 1 + +/* Interrupt pin signaling */ +#define ADS7924_CFG_INTTRIG_LEVEL 0 +#define ADS7924_CFG_INTTRIG_EDGE 1 + +/* Mode control values */ +#define ADS7924_MODECNTRL_IDLE 0x00 +#define ADS7924_MODECNTRL_AWAKE 0x20 +#define ADS7924_MODECNTRL_MANUAL_SINGLE 0x30 +#define ADS7924_MODECNTRL_MANUAL_SCAN 0x32 +#define ADS7924_MODECNTRL_AUTO_SINGLE 0x31 +#define ADS7924_MODECNTRL_AUTO_SCAN 0x33 +#define ADS7924_MODECNTRL_AUTO_SINGLE_SLEEP 0x39 +#define ADS7924_MODECNTRL_AUTO_SCAN_SLEEP 0x3B +#define ADS7924_MODECNTRL_AUTO_BURST_SLEEP 0x3F + +#define ADS7924_ACQTIME_MASK GENMASK(4, 0) + +#define ADS7924_PWRUPTIME_MASK GENMASK(4, 0) + +/* + * The power-up time is allowed to elapse whenever the device has been shutdown + * in idle mode. Power-up time can allow external circuits, such as an + * operational amplifier, between the MUXOUT and ADCIN pins to turn on. + * The nominal time programmed by the PUTIME[4:0] register bits is given by: + * t PU = PWRUPTIME[4:0] × 2 μs + * If a power-up time is not required, set the bits to '0' to effectively bypass. + */ +#define ADS7924_PWRUPTIME_US 0 /* Bypass (0us). */ + +/* + * Acquisition Time according to ACQTIME[4:0] register bits. + * The Acquisition Time is given by: + * t ACQ = (ACQTIME[4:0] × 2 μs) + 6 μs + * Using default value of 0 for ACQTIME[4:0] results in a minimum acquisition + * time of 6us. + */ +#define ADS7924_ACQTIME_US 6 + +/* The conversion time is always 4μs and cannot be programmed by the user. */ +#define ADS7924_CONVTIME_US 4 + +#define ADS7924_TOTAL_CONVTIME_US (ADS7924_PWRUPTIME_US + ADS7924_ACQTIME_US + \ + ADS7924_CONVTIME_US) + +#define ADS7924_V_CHAN(_chan, _addr) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = _chan, \ + .address = _addr, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .datasheet_name = "AIN"#_chan, \ +} + +struct ads7924_data { + struct device *dev; + struct regmap *regmap; + struct regulator *vref_reg; + + /* GPIO descriptor for device hard-reset pin. */ + struct gpio_desc *reset_gpio; + + /* + * Protects ADC ops, e.g: concurrent sysfs/buffered + * data reads, configuration updates + */ + struct mutex lock; + + /* + * Set to true when the ADC is switched to the continuous-conversion + * mode and exits from a power-down state. This flag is used to avoid + * getting the stale result from the conversion register. + */ + bool conv_invalid; +}; + +static bool ads7924_is_writeable_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case ADS7924_MODECNTRL_REG: + case ADS7924_INTCNTRL_REG: + case ADS7924_ULR0_REG: + case ADS7924_LLR0_REG: + case ADS7924_ULR1_REG: + case ADS7924_LLR1_REG: + case ADS7924_ULR2_REG: + case ADS7924_LLR2_REG: + case ADS7924_ULR3_REG: + case ADS7924_LLR3_REG: + case ADS7924_INTCONFIG_REG: + case ADS7924_SLPCONFIG_REG: + case ADS7924_ACQCONFIG_REG: + case ADS7924_PWRCONFIG_REG: + case ADS7924_RESET_REG: + return true; + default: + return false; + } +} + +static const struct regmap_config ads7924_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = ADS7924_RESET_REG, + .writeable_reg = ads7924_is_writeable_reg, +}; + +static const struct iio_chan_spec ads7924_channels[] = { + ADS7924_V_CHAN(0, ADS7924_DATA0_U_REG), + ADS7924_V_CHAN(1, ADS7924_DATA1_U_REG), + ADS7924_V_CHAN(2, ADS7924_DATA2_U_REG), + ADS7924_V_CHAN(3, ADS7924_DATA3_U_REG), +}; + +static int ads7924_get_adc_result(struct ads7924_data *data, + struct iio_chan_spec const *chan, int *val) +{ + int ret; + __be16 be_val; + + if (chan->channel < 0 || chan->channel >= ADS7924_CHANNELS) + return -EINVAL; + + if (data->conv_invalid) { + int conv_time; + + conv_time = ADS7924_TOTAL_CONVTIME_US; + /* Allow 10% for internal clock inaccuracy. */ + conv_time += conv_time / 10; + usleep_range(conv_time, conv_time + 1); + data->conv_invalid = false; + } + + ret = regmap_raw_read(data->regmap, ADS7924_AUTO_INCREMENT_BIT | + chan->address, &be_val, sizeof(be_val)); + if (ret) + return ret; + + *val = be16_to_cpu(be_val) >> ADS7924_DATA_SHIFT; + + return 0; +} + +static int ads7924_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + int ret, vref_uv; + struct ads7924_data *data = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&data->lock); + ret = ads7924_get_adc_result(data, chan, val); + mutex_unlock(&data->lock); + if (ret < 0) + return ret; + + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + vref_uv = regulator_get_voltage(data->vref_reg); + if (vref_uv < 0) + return -EINVAL; + + *val = vref_uv / 1000; /* Convert reg voltage to mV */ + *val2 = ADS7924_BITS; + return IIO_VAL_FRACTIONAL_LOG2; + default: + return -EINVAL; + } +} + +static const struct iio_info ads7924_info = { + .read_raw = ads7924_read_raw, +}; + +static int ads7924_get_channels_config(struct i2c_client *client, + struct iio_dev *indio_dev) +{ + struct ads7924_data *priv = iio_priv(indio_dev); + struct device *dev = priv->dev; + struct fwnode_handle *node; + int num_channels = 0; + + device_for_each_child_node(dev, node) { + u32 pval; + unsigned int channel; + + if (fwnode_property_read_u32(node, "reg", &pval)) { + dev_err(dev, "invalid reg on %pfw\n", node); + continue; + } + + channel = pval; + if (channel >= ADS7924_CHANNELS) { + dev_err(dev, "invalid channel index %d on %pfw\n", + channel, node); + continue; + } + + num_channels++; + } + + if (num_channels <= 0) + return -EINVAL; + + return 0; +} + +static int ads7924_set_conv_mode(struct ads7924_data *data, int mode) +{ + int ret; + unsigned int mode_field; + struct device *dev = data->dev; + + /* + * When switching between modes, be sure to first select the Awake mode + * and then switch to the desired mode. This procedure ensures the + * internal control logic is properly synchronized. + */ + if (mode != ADS7924_MODECNTRL_IDLE) { + mode_field = FIELD_PREP(ADS7924_MODECNTRL_MODE_MASK, + ADS7924_MODECNTRL_AWAKE); + + ret = regmap_update_bits(data->regmap, ADS7924_MODECNTRL_REG, + ADS7924_MODECNTRL_MODE_MASK, + mode_field); + if (ret) { + dev_warn(dev, "failed to set awake mode (%pe)\n", + ERR_PTR(ret)); + return ret; + } + } + + mode_field = FIELD_PREP(ADS7924_MODECNTRL_MODE_MASK, mode); + + ret = regmap_update_bits(data->regmap, ADS7924_MODECNTRL_REG, + ADS7924_MODECNTRL_MODE_MASK, mode_field); + if (ret) + dev_warn(dev, "failed to set mode %d (%pe)\n", mode, + ERR_PTR(ret)); + + return ret; +} + +static int ads7924_reset(struct iio_dev *indio_dev) +{ + struct ads7924_data *data = iio_priv(indio_dev); + + if (data->reset_gpio) { + gpiod_set_value(data->reset_gpio, 1); /* Assert. */ + /* Educated guess: assert time not specified in datasheet... */ + mdelay(100); + gpiod_set_value(data->reset_gpio, 0); /* Deassert. */ + return 0; + } + + /* + * A write of 10101010 to this register will generate a + * software reset of the ADS7924. + */ + return regmap_write(data->regmap, ADS7924_RESET_REG, 0b10101010); +}; + +static void ads7924_reg_disable(void *data) +{ + regulator_disable(data); +} + +static void ads7924_set_idle_mode(void *data) +{ + ads7924_set_conv_mode(data, ADS7924_MODECNTRL_IDLE); +} + +static int ads7924_probe(struct i2c_client *client) +{ + struct iio_dev *indio_dev; + struct ads7924_data *data; + struct device *dev = &client->dev; + int ret; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) + return dev_err_probe(dev, -ENOMEM, + "failed to allocate iio device\n"); + + data = iio_priv(indio_dev); + + data->dev = dev; + + /* Initialize the reset GPIO as output with an initial value of 0. */ + data->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); + if (IS_ERR(data->reset_gpio)) + return dev_err_probe(dev, PTR_ERR(data->reset_gpio), + "failed to get request reset GPIO\n"); + + mutex_init(&data->lock); + + indio_dev->name = "ads7924"; + indio_dev->modes = INDIO_DIRECT_MODE; + + indio_dev->channels = ads7924_channels; + indio_dev->num_channels = ARRAY_SIZE(ads7924_channels); + indio_dev->info = &ads7924_info; + + ret = ads7924_get_channels_config(client, indio_dev); + if (ret < 0) + return dev_err_probe(dev, ret, + "failed to get channels configuration\n"); + + data->regmap = devm_regmap_init_i2c(client, &ads7924_regmap_config); + if (IS_ERR(data->regmap)) + return dev_err_probe(dev, PTR_ERR(data->regmap), + "failed to init regmap\n"); + + data->vref_reg = devm_regulator_get(dev, "vref"); + if (IS_ERR(data->vref_reg)) + return dev_err_probe(dev, PTR_ERR(data->vref_reg), + "failed to get vref regulator\n"); + + ret = regulator_enable(data->vref_reg); + if (ret) + return dev_err_probe(dev, ret, + "failed to enable regulator\n"); + + ret = devm_add_action_or_reset(dev, ads7924_reg_disable, data->vref_reg); + if (ret) + return dev_err_probe(dev, ret, + "failed to add regulator disable action\n"); + + ret = ads7924_reset(indio_dev); + if (ret < 0) + return dev_err_probe(dev, ret, + "failed to reset device\n"); + + ret = ads7924_set_conv_mode(data, ADS7924_MODECNTRL_AUTO_SCAN); + if (ret) + return dev_err_probe(dev, ret, + "failed to set conversion mode\n"); + + ret = devm_add_action_or_reset(dev, ads7924_set_idle_mode, data); + if (ret) + return dev_err_probe(dev, ret, + "failed to add idle mode action\n"); + + /* Use minimum signal acquire time. */ + ret = regmap_update_bits(data->regmap, ADS7924_ACQCONFIG_REG, + ADS7924_ACQTIME_MASK, + FIELD_PREP(ADS7924_ACQTIME_MASK, 0)); + if (ret < 0) + return dev_err_probe(dev, ret, + "failed to configure signal acquire time\n"); + + /* Disable power-up time. */ + ret = regmap_update_bits(data->regmap, ADS7924_PWRCONFIG_REG, + ADS7924_PWRUPTIME_MASK, + FIELD_PREP(ADS7924_PWRUPTIME_MASK, 0)); + if (ret < 0) + return dev_err_probe(dev, ret, + "failed to configure power-up time\n"); + + data->conv_invalid = true; + + ret = devm_iio_device_register(dev, indio_dev); + if (ret < 0) + return dev_err_probe(dev, ret, + "failed to register IIO device\n"); + + return 0; +} + +static const struct i2c_device_id ads7924_id[] = { + { "ads7924", 0 }, + {} +}; +MODULE_DEVICE_TABLE(i2c, ads7924_id); + +static const struct of_device_id ads7924_of_match[] = { + { .compatible = "ti,ads7924", }, + {} +}; +MODULE_DEVICE_TABLE(of, ads7924_of_match); + +static struct i2c_driver ads7924_driver = { + .driver = { + .name = "ads7924", + .of_match_table = ads7924_of_match, + }, + .probe_new = ads7924_probe, + .id_table = ads7924_id, +}; + +module_i2c_driver(ads7924_driver); + +MODULE_AUTHOR("Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>"); +MODULE_DESCRIPTION("Texas Instruments ADS7924 ADC I2C driver"); +MODULE_LICENSE("GPL"); -- 2.30.2
