| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Hugo Villeneuve | 1648 | 99.94% | 1 | 50.00% |
| Uwe Kleine-König | 1 | 0.06% | 1 | 50.00% |
| Total | 1649 | 2 |
// SPDX-License-Identifier: GPL-2.0 /* * IIO driver for Texas Instruments ADS7924 ADC, 12-bit, 4-Channels, I2C * * Author: Hugo Villeneuve <hvilleneuve@dimonoff.com> * 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 vref_uv; *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) 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_err(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_err(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 = ads7924_probe, .id_table = ads7924_id, }; module_i2c_driver(ads7924_driver); MODULE_AUTHOR("Hugo Villeneuve <hvilleneuve@dimonoff.com>"); MODULE_DESCRIPTION("Texas Instruments ADS7924 ADC I2C driver"); MODULE_LICENSE("GPL");
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