root/drivers/iio/health/afe4403.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * AFE4403 Heart Rate Monitors and Low-Cost Pulse Oximeters
 *
 * Copyright (C) 2015-2016 Texas Instruments Incorporated - https://www.ti.com/
 *      Andrew F. Davis <afd@ti.com>
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>
#include <linux/sysfs.h>
#include <linux/regulator/consumer.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>

#include <linux/unaligned.h>

#include "afe440x.h"

#define AFE4403_DRIVER_NAME             "afe4403"

/* AFE4403 Registers */
#define AFE4403_TIAGAIN                 0x20
#define AFE4403_TIA_AMB_GAIN            0x21

enum afe4403_fields {
        /* Gains */
        F_RF_LED1, F_CF_LED1,
        F_RF_LED, F_CF_LED,

        /* LED Current */
        F_ILED1, F_ILED2,

        /* sentinel */
        F_MAX_FIELDS
};

static const struct reg_field afe4403_reg_fields[] = {
        /* Gains */
        [F_RF_LED1]     = REG_FIELD(AFE4403_TIAGAIN, 0, 2),
        [F_CF_LED1]     = REG_FIELD(AFE4403_TIAGAIN, 3, 7),
        [F_RF_LED]      = REG_FIELD(AFE4403_TIA_AMB_GAIN, 0, 2),
        [F_CF_LED]      = REG_FIELD(AFE4403_TIA_AMB_GAIN, 3, 7),
        /* LED Current */
        [F_ILED1]       = REG_FIELD(AFE440X_LEDCNTRL, 0, 7),
        [F_ILED2]       = REG_FIELD(AFE440X_LEDCNTRL, 8, 15),
};

/**
 * struct afe4403_data - AFE4403 device instance data
 * @spi: SPI device handle
 * @regmap: Register map of the device
 * @fields: Register fields of the device
 * @regulator: Pointer to the regulator for the IC
 * @trig: IIO trigger for this device
 * @irq: ADC_RDY line interrupt number
 * @buffer: Used to construct data layout to push into IIO buffer.
 */
struct afe4403_data {
        struct spi_device *spi;
        struct regmap *regmap;
        struct regmap_field *fields[F_MAX_FIELDS];
        struct regulator *regulator;
        struct iio_trigger *trig;
        int irq;
        /* Ensure suitable alignment for timestamp */
        s32 buffer[8] __aligned(8);
};

enum afe4403_chan_id {
        LED2 = 1,
        ALED2,
        LED1,
        ALED1,
        LED2_ALED2,
        LED1_ALED1,
};

static const unsigned int afe4403_channel_values[] = {
        [LED2] = AFE440X_LED2VAL,
        [ALED2] = AFE440X_ALED2VAL,
        [LED1] = AFE440X_LED1VAL,
        [ALED1] = AFE440X_ALED1VAL,
        [LED2_ALED2] = AFE440X_LED2_ALED2VAL,
        [LED1_ALED1] = AFE440X_LED1_ALED1VAL,
};

static const unsigned int afe4403_channel_leds[] = {
        [LED2] = F_ILED2,
        [LED1] = F_ILED1,
};

static const struct iio_chan_spec afe4403_channels[] = {
        /* ADC values */
        AFE440X_INTENSITY_CHAN(LED2, 0),
        AFE440X_INTENSITY_CHAN(ALED2, 0),
        AFE440X_INTENSITY_CHAN(LED1, 0),
        AFE440X_INTENSITY_CHAN(ALED1, 0),
        AFE440X_INTENSITY_CHAN(LED2_ALED2, 0),
        AFE440X_INTENSITY_CHAN(LED1_ALED1, 0),
        /* LED current */
        AFE440X_CURRENT_CHAN(LED2),
        AFE440X_CURRENT_CHAN(LED1),
};

static const struct afe440x_val_table afe4403_res_table[] = {
        { 500000 }, { 250000 }, { 100000 }, { 50000 },
        { 25000 }, { 10000 }, { 1000000 }, { 0 },
};
AFE440X_TABLE_ATTR(in_intensity_resistance_available, afe4403_res_table);

static const struct afe440x_val_table afe4403_cap_table[] = {
        { 0, 5000 }, { 0, 10000 }, { 0, 20000 }, { 0, 25000 },
        { 0, 30000 }, { 0, 35000 }, { 0, 45000 }, { 0, 50000 },
        { 0, 55000 }, { 0, 60000 }, { 0, 70000 }, { 0, 75000 },
        { 0, 80000 }, { 0, 85000 }, { 0, 95000 }, { 0, 100000 },
        { 0, 155000 }, { 0, 160000 }, { 0, 170000 }, { 0, 175000 },
        { 0, 180000 }, { 0, 185000 }, { 0, 195000 }, { 0, 200000 },
        { 0, 205000 }, { 0, 210000 }, { 0, 220000 }, { 0, 225000 },
        { 0, 230000 }, { 0, 235000 }, { 0, 245000 }, { 0, 250000 },
};
AFE440X_TABLE_ATTR(in_intensity_capacitance_available, afe4403_cap_table);

static ssize_t afe440x_show_register(struct device *dev,
                                     struct device_attribute *attr,
                                     char *buf)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct afe4403_data *afe = iio_priv(indio_dev);
        struct afe440x_attr *afe440x_attr = to_afe440x_attr(attr);
        unsigned int reg_val;
        int vals[2];
        int ret;

        ret = regmap_field_read(afe->fields[afe440x_attr->field], &reg_val);
        if (ret)
                return ret;

        if (reg_val >= afe440x_attr->table_size)
                return -EINVAL;

        vals[0] = afe440x_attr->val_table[reg_val].integer;
        vals[1] = afe440x_attr->val_table[reg_val].fract;

        return iio_format_value(buf, IIO_VAL_INT_PLUS_MICRO, 2, vals);
}

static ssize_t afe440x_store_register(struct device *dev,
                                      struct device_attribute *attr,
                                      const char *buf, size_t count)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct afe4403_data *afe = iio_priv(indio_dev);
        struct afe440x_attr *afe440x_attr = to_afe440x_attr(attr);
        int val, integer, fract, ret;

        ret = iio_str_to_fixpoint(buf, 100000, &integer, &fract);
        if (ret)
                return ret;

        for (val = 0; val < afe440x_attr->table_size; val++)
                if (afe440x_attr->val_table[val].integer == integer &&
                    afe440x_attr->val_table[val].fract == fract)
                        break;
        if (val == afe440x_attr->table_size)
                return -EINVAL;

        ret = regmap_field_write(afe->fields[afe440x_attr->field], val);
        if (ret)
                return ret;

        return count;
}

static AFE440X_ATTR(in_intensity1_resistance, F_RF_LED, afe4403_res_table);
static AFE440X_ATTR(in_intensity1_capacitance, F_CF_LED, afe4403_cap_table);

static AFE440X_ATTR(in_intensity2_resistance, F_RF_LED, afe4403_res_table);
static AFE440X_ATTR(in_intensity2_capacitance, F_CF_LED, afe4403_cap_table);

static AFE440X_ATTR(in_intensity3_resistance, F_RF_LED1, afe4403_res_table);
static AFE440X_ATTR(in_intensity3_capacitance, F_CF_LED1, afe4403_cap_table);

static AFE440X_ATTR(in_intensity4_resistance, F_RF_LED1, afe4403_res_table);
static AFE440X_ATTR(in_intensity4_capacitance, F_CF_LED1, afe4403_cap_table);

static struct attribute *afe440x_attributes[] = {
        &dev_attr_in_intensity_resistance_available.attr,
        &dev_attr_in_intensity_capacitance_available.attr,
        &afe440x_attr_in_intensity1_resistance.dev_attr.attr,
        &afe440x_attr_in_intensity1_capacitance.dev_attr.attr,
        &afe440x_attr_in_intensity2_resistance.dev_attr.attr,
        &afe440x_attr_in_intensity2_capacitance.dev_attr.attr,
        &afe440x_attr_in_intensity3_resistance.dev_attr.attr,
        &afe440x_attr_in_intensity3_capacitance.dev_attr.attr,
        &afe440x_attr_in_intensity4_resistance.dev_attr.attr,
        &afe440x_attr_in_intensity4_capacitance.dev_attr.attr,
        NULL
};

static const struct attribute_group afe440x_attribute_group = {
        .attrs = afe440x_attributes
};

static int afe4403_read(struct afe4403_data *afe, unsigned int reg, u32 *val)
{
        u8 tx[4] = {AFE440X_CONTROL0, 0x0, 0x0, AFE440X_CONTROL0_READ};
        u8 rx[3];
        int ret;

        /* Enable reading from the device */
        ret = spi_write_then_read(afe->spi, tx, 4, NULL, 0);
        if (ret)
                return ret;

        ret = spi_write_then_read(afe->spi, &reg, 1, rx, sizeof(rx));
        if (ret)
                return ret;

        *val = get_unaligned_be24(&rx[0]);

        /* Disable reading from the device */
        tx[3] = AFE440X_CONTROL0_WRITE;
        ret = spi_write_then_read(afe->spi, tx, 4, NULL, 0);
        if (ret)
                return ret;

        return 0;
}

static int afe4403_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
{
        struct afe4403_data *afe = iio_priv(indio_dev);
        unsigned int reg, field;
        int ret;

        switch (chan->type) {
        case IIO_INTENSITY:
                switch (mask) {
                case IIO_CHAN_INFO_RAW:
                        reg = afe4403_channel_values[chan->address];
                        ret = afe4403_read(afe, reg, val);
                        if (ret)
                                return ret;
                        return IIO_VAL_INT;
                }
                break;
        case IIO_CURRENT:
                switch (mask) {
                case IIO_CHAN_INFO_RAW:
                        field = afe4403_channel_leds[chan->address];
                        ret = regmap_field_read(afe->fields[field], val);
                        if (ret)
                                return ret;
                        return IIO_VAL_INT;
                case IIO_CHAN_INFO_SCALE:
                        *val = 0;
                        *val2 = 800000;
                        return IIO_VAL_INT_PLUS_MICRO;
                }
                break;
        default:
                break;
        }

        return -EINVAL;
}

static int afe4403_write_raw(struct iio_dev *indio_dev,
                             struct iio_chan_spec const *chan,
                             int val, int val2, long mask)
{
        struct afe4403_data *afe = iio_priv(indio_dev);
        unsigned int field = afe4403_channel_leds[chan->address];

        switch (chan->type) {
        case IIO_CURRENT:
                switch (mask) {
                case IIO_CHAN_INFO_RAW:
                        return regmap_field_write(afe->fields[field], val);
                }
                break;
        default:
                break;
        }

        return -EINVAL;
}

static const struct iio_info afe4403_iio_info = {
        .attrs = &afe440x_attribute_group,
        .read_raw = afe4403_read_raw,
        .write_raw = afe4403_write_raw,
};

static irqreturn_t afe4403_trigger_handler(int irq, void *private)
{
        struct iio_poll_func *pf = private;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct afe4403_data *afe = iio_priv(indio_dev);
        int ret, bit, i = 0;
        u8 tx[4] = {AFE440X_CONTROL0, 0x0, 0x0, AFE440X_CONTROL0_READ};
        u8 rx[3];

        /* Enable reading from the device */
        ret = spi_write_then_read(afe->spi, tx, 4, NULL, 0);
        if (ret)
                goto err;

        iio_for_each_active_channel(indio_dev, bit) {
                ret = spi_write_then_read(afe->spi,
                                          &afe4403_channel_values[bit], 1,
                                          rx, sizeof(rx));
                if (ret)
                        goto err;

                afe->buffer[i++] = get_unaligned_be24(&rx[0]);
        }

        /* Disable reading from the device */
        tx[3] = AFE440X_CONTROL0_WRITE;
        ret = spi_write_then_read(afe->spi, tx, 4, NULL, 0);
        if (ret)
                goto err;

        iio_push_to_buffers_with_timestamp(indio_dev, afe->buffer,
                                           pf->timestamp);
err:
        iio_trigger_notify_done(indio_dev->trig);

        return IRQ_HANDLED;
}

static void afe4403_regulator_disable(void *data)
{
        struct regulator *regulator = data;

        regulator_disable(regulator);
}

#define AFE4403_TIMING_PAIRS                    \
        { AFE440X_LED2STC,      0x000050 },     \
        { AFE440X_LED2ENDC,     0x0003e7 },     \
        { AFE440X_LED1LEDSTC,   0x0007d0 },     \
        { AFE440X_LED1LEDENDC,  0x000bb7 },     \
        { AFE440X_ALED2STC,     0x000438 },     \
        { AFE440X_ALED2ENDC,    0x0007cf },     \
        { AFE440X_LED1STC,      0x000820 },     \
        { AFE440X_LED1ENDC,     0x000bb7 },     \
        { AFE440X_LED2LEDSTC,   0x000000 },     \
        { AFE440X_LED2LEDENDC,  0x0003e7 },     \
        { AFE440X_ALED1STC,     0x000c08 },     \
        { AFE440X_ALED1ENDC,    0x000f9f },     \
        { AFE440X_LED2CONVST,   0x0003ef },     \
        { AFE440X_LED2CONVEND,  0x0007cf },     \
        { AFE440X_ALED2CONVST,  0x0007d7 },     \
        { AFE440X_ALED2CONVEND, 0x000bb7 },     \
        { AFE440X_LED1CONVST,   0x000bbf },     \
        { AFE440X_LED1CONVEND,  0x009c3f },     \
        { AFE440X_ALED1CONVST,  0x000fa7 },     \
        { AFE440X_ALED1CONVEND, 0x001387 },     \
        { AFE440X_ADCRSTSTCT0,  0x0003e8 },     \
        { AFE440X_ADCRSTENDCT0, 0x0003eb },     \
        { AFE440X_ADCRSTSTCT1,  0x0007d0 },     \
        { AFE440X_ADCRSTENDCT1, 0x0007d3 },     \
        { AFE440X_ADCRSTSTCT2,  0x000bb8 },     \
        { AFE440X_ADCRSTENDCT2, 0x000bbb },     \
        { AFE440X_ADCRSTSTCT3,  0x000fa0 },     \
        { AFE440X_ADCRSTENDCT3, 0x000fa3 },     \
        { AFE440X_PRPCOUNT,     0x009c3f },     \
        { AFE440X_PDNCYCLESTC,  0x001518 },     \
        { AFE440X_PDNCYCLEENDC, 0x00991f }

static const struct reg_sequence afe4403_reg_sequences[] = {
        AFE4403_TIMING_PAIRS,
        { AFE440X_CONTROL1, AFE440X_CONTROL1_TIMEREN },
        { AFE4403_TIAGAIN, AFE440X_TIAGAIN_ENSEPGAIN },
};

static const struct regmap_range afe4403_yes_ranges[] = {
        regmap_reg_range(AFE440X_LED2VAL, AFE440X_LED1_ALED1VAL),
};

static const struct regmap_access_table afe4403_volatile_table = {
        .yes_ranges = afe4403_yes_ranges,
        .n_yes_ranges = ARRAY_SIZE(afe4403_yes_ranges),
};

static const struct regmap_config afe4403_regmap_config = {
        .reg_bits = 8,
        .val_bits = 24,

        .max_register = AFE440X_PDNCYCLEENDC,
        .cache_type = REGCACHE_MAPLE,
        .volatile_table = &afe4403_volatile_table,
};

static const struct of_device_id afe4403_of_match[] = {
        { .compatible = "ti,afe4403", },
        { }
};
MODULE_DEVICE_TABLE(of, afe4403_of_match);

static int afe4403_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = spi_get_drvdata(to_spi_device(dev));
        struct afe4403_data *afe = iio_priv(indio_dev);
        int ret;

        ret = regmap_set_bits(afe->regmap, AFE440X_CONTROL2,
                              AFE440X_CONTROL2_PDN_AFE);
        if (ret)
                return ret;

        ret = regulator_disable(afe->regulator);
        if (ret) {
                dev_err(dev, "Unable to disable regulator\n");
                return ret;
        }

        return 0;
}

static int afe4403_resume(struct device *dev)
{
        struct iio_dev *indio_dev = spi_get_drvdata(to_spi_device(dev));
        struct afe4403_data *afe = iio_priv(indio_dev);
        int ret;

        ret = regulator_enable(afe->regulator);
        if (ret) {
                dev_err(dev, "Unable to enable regulator\n");
                return ret;
        }

        ret = regmap_clear_bits(afe->regmap, AFE440X_CONTROL2,
                                AFE440X_CONTROL2_PDN_AFE);
        if (ret)
                return ret;

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(afe4403_pm_ops, afe4403_suspend,
                                afe4403_resume);

static int afe4403_probe(struct spi_device *spi)
{
        struct device *dev = &spi->dev;
        struct iio_dev *indio_dev;
        struct afe4403_data *afe;
        int i, ret;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*afe));
        if (!indio_dev)
                return -ENOMEM;

        afe = iio_priv(indio_dev);
        spi_set_drvdata(spi, indio_dev);

        afe->spi = spi;
        afe->irq = spi->irq;

        afe->regmap = devm_regmap_init_spi(spi, &afe4403_regmap_config);
        if (IS_ERR(afe->regmap)) {
                dev_err(dev, "Unable to allocate register map\n");
                return PTR_ERR(afe->regmap);
        }

        for (i = 0; i < F_MAX_FIELDS; i++) {
                afe->fields[i] = devm_regmap_field_alloc(dev, afe->regmap,
                                                         afe4403_reg_fields[i]);
                if (IS_ERR(afe->fields[i])) {
                        dev_err(dev, "Unable to allocate regmap fields\n");
                        return PTR_ERR(afe->fields[i]);
                }
        }

        afe->regulator = devm_regulator_get(dev, "tx_sup");
        if (IS_ERR(afe->regulator))
                return dev_err_probe(dev, PTR_ERR(afe->regulator),
                                     "Unable to get regulator\n");

        ret = regulator_enable(afe->regulator);
        if (ret) {
                dev_err(dev, "Unable to enable regulator\n");
                return ret;
        }
        ret = devm_add_action_or_reset(dev, afe4403_regulator_disable, afe->regulator);
        if (ret) {
                dev_err(dev, "Unable to add regulator disable action\n");
                return ret;
        }

        ret = regmap_write(afe->regmap, AFE440X_CONTROL0,
                           AFE440X_CONTROL0_SW_RESET);
        if (ret) {
                dev_err(dev, "Unable to reset device\n");
                return ret;
        }

        ret = regmap_multi_reg_write(afe->regmap, afe4403_reg_sequences,
                                     ARRAY_SIZE(afe4403_reg_sequences));
        if (ret) {
                dev_err(dev, "Unable to set register defaults\n");
                return ret;
        }

        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = afe4403_channels;
        indio_dev->num_channels = ARRAY_SIZE(afe4403_channels);
        indio_dev->name = AFE4403_DRIVER_NAME;
        indio_dev->info = &afe4403_iio_info;

        if (afe->irq > 0) {
                afe->trig = devm_iio_trigger_alloc(dev,
                                                   "%s-dev%d",
                                                   indio_dev->name,
                                                   iio_device_id(indio_dev));
                if (!afe->trig)
                        return -ENOMEM;

                iio_trigger_set_drvdata(afe->trig, indio_dev);

                ret = devm_iio_trigger_register(dev, afe->trig);
                if (ret) {
                        dev_err(dev, "Unable to register IIO trigger\n");
                        return ret;
                }

                ret = devm_request_irq(dev, afe->irq,
                                       iio_trigger_generic_data_rdy_poll,
                                       IRQF_NO_THREAD, AFE4403_DRIVER_NAME,
                                       afe->trig);
                if (ret) {
                        dev_err(dev, "Unable to request IRQ\n");
                        return ret;
                }
        }

        ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
                                              &iio_pollfunc_store_time,
                                              afe4403_trigger_handler, NULL);
        if (ret) {
                dev_err(dev, "Unable to setup buffer\n");
                return ret;
        }

        ret = devm_iio_device_register(dev, indio_dev);
        if (ret) {
                dev_err(dev, "Unable to register IIO device\n");
                return ret;
        }

        return 0;
}

static const struct spi_device_id afe4403_ids[] = {
        { "afe4403", 0 },
        { }
};
MODULE_DEVICE_TABLE(spi, afe4403_ids);

static struct spi_driver afe4403_spi_driver = {
        .driver = {
                .name = AFE4403_DRIVER_NAME,
                .of_match_table = afe4403_of_match,
                .pm = pm_sleep_ptr(&afe4403_pm_ops),
        },
        .probe = afe4403_probe,
        .id_table = afe4403_ids,
};
module_spi_driver(afe4403_spi_driver);

MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
MODULE_DESCRIPTION("TI AFE4403 Heart Rate Monitor and Pulse Oximeter AFE");
MODULE_LICENSE("GPL v2");