diff options
Diffstat (limited to 'drivers/iio/adc/ti-ads1298.c')
| -rw-r--r-- | drivers/iio/adc/ti-ads1298.c | 771 |
1 files changed, 771 insertions, 0 deletions
diff --git a/drivers/iio/adc/ti-ads1298.c b/drivers/iio/adc/ti-ads1298.c new file mode 100644 index 0000000000..1d1eaba3d6 --- /dev/null +++ b/drivers/iio/adc/ti-ads1298.c @@ -0,0 +1,771 @@ +// SPDX-License-Identifier: GPL-2.0 +/* TI ADS1298 chip family driver + * Copyright (C) 2023 - 2024 Topic Embedded Products + */ + +#include <linux/bitfield.h> +#include <linux/cleanup.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/gpio/consumer.h> +#include <linux/log2.h> +#include <linux/math.h> +#include <linux/module.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> +#include <linux/slab.h> +#include <linux/spi/spi.h> +#include <linux/units.h> + +#include <linux/iio/iio.h> +#include <linux/iio/buffer.h> +#include <linux/iio/kfifo_buf.h> + +#include <asm/unaligned.h> + +/* Commands */ +#define ADS1298_CMD_WAKEUP 0x02 +#define ADS1298_CMD_STANDBY 0x04 +#define ADS1298_CMD_RESET 0x06 +#define ADS1298_CMD_START 0x08 +#define ADS1298_CMD_STOP 0x0a +#define ADS1298_CMD_RDATAC 0x10 +#define ADS1298_CMD_SDATAC 0x11 +#define ADS1298_CMD_RDATA 0x12 +#define ADS1298_CMD_RREG 0x20 +#define ADS1298_CMD_WREG 0x40 + +/* Registers */ +#define ADS1298_REG_ID 0x00 +#define ADS1298_MASK_ID_FAMILY GENMASK(7, 3) +#define ADS1298_MASK_ID_CHANNELS GENMASK(2, 0) +#define ADS1298_ID_FAMILY_ADS129X 0x90 +#define ADS1298_ID_FAMILY_ADS129XR 0xd0 + +#define ADS1298_REG_CONFIG1 0x01 +#define ADS1298_MASK_CONFIG1_HR BIT(7) +#define ADS1298_MASK_CONFIG1_DR GENMASK(2, 0) +#define ADS1298_SHIFT_DR_HR 6 +#define ADS1298_SHIFT_DR_LP 7 +#define ADS1298_LOWEST_DR 0x06 + +#define ADS1298_REG_CONFIG2 0x02 +#define ADS1298_MASK_CONFIG2_RESERVED BIT(6) +#define ADS1298_MASK_CONFIG2_WCT_CHOP BIT(5) +#define ADS1298_MASK_CONFIG2_INT_TEST BIT(4) +#define ADS1298_MASK_CONFIG2_TEST_AMP BIT(2) +#define ADS1298_MASK_CONFIG2_TEST_FREQ_DC GENMASK(1, 0) +#define ADS1298_MASK_CONFIG2_TEST_FREQ_SLOW 0 +#define ADS1298_MASK_CONFIG2_TEST_FREQ_FAST BIT(0) + +#define ADS1298_REG_CONFIG3 0x03 +#define ADS1298_MASK_CONFIG3_PWR_REFBUF BIT(7) +#define ADS1298_MASK_CONFIG3_RESERVED BIT(6) +#define ADS1298_MASK_CONFIG3_VREF_4V BIT(5) + +#define ADS1298_REG_LOFF 0x04 +#define ADS1298_REG_CHnSET(n) (0x05 + n) +#define ADS1298_MASK_CH_PD BIT(7) +#define ADS1298_MASK_CH_PGA GENMASK(6, 4) +#define ADS1298_MASK_CH_MUX GENMASK(2, 0) + +#define ADS1298_REG_LOFF_STATP 0x12 +#define ADS1298_REG_LOFF_STATN 0x13 +#define ADS1298_REG_CONFIG4 0x17 +#define ADS1298_MASK_CONFIG4_SINGLE_SHOT BIT(3) + +#define ADS1298_REG_WCT1 0x18 +#define ADS1298_REG_WCT2 0x19 + +#define ADS1298_MAX_CHANNELS 8 +#define ADS1298_BITS_PER_SAMPLE 24 +#define ADS1298_CLK_RATE_HZ 2048000 +#define ADS1298_CLOCKS_TO_USECS(x) \ + (DIV_ROUND_UP((x) * MICROHZ_PER_HZ, ADS1298_CLK_RATE_HZ)) +/* + * Read/write register commands require 4 clocks to decode, for speeds above + * 2x the clock rate, this would require extra time between the command byte and + * the data. Much simpler is to just limit the SPI transfer speed while doing + * register access. + */ +#define ADS1298_SPI_BUS_SPEED_SLOW ADS1298_CLK_RATE_HZ +/* For reading and writing registers, we need a 3-byte buffer */ +#define ADS1298_SPI_CMD_BUFFER_SIZE 3 +/* Outputs status word and 'n' 24-bit samples, plus the command byte */ +#define ADS1298_SPI_RDATA_BUFFER_SIZE(n) (((n) + 1) * 3 + 1) +#define ADS1298_SPI_RDATA_BUFFER_SIZE_MAX \ + ADS1298_SPI_RDATA_BUFFER_SIZE(ADS1298_MAX_CHANNELS) + +struct ads1298_private { + const struct ads1298_chip_info *chip_info; + struct spi_device *spi; + struct regulator *reg_avdd; + struct regulator *reg_vref; + struct clk *clk; + struct regmap *regmap; + struct completion completion; + struct iio_trigger *trig; + struct spi_transfer rdata_xfer; + struct spi_message rdata_msg; + spinlock_t irq_busy_lock; /* Handshake between SPI and DRDY irqs */ + /* + * rdata_xfer_busy increments when a DRDY occurs and decrements when SPI + * completion is reported. Hence its meaning is: + * 0 = Waiting for DRDY interrupt + * 1 = SPI transfer in progress + * 2 = DRDY during SPI transfer, start another transfer on completion + * >2 = Multiple DRDY during transfer, lost rdata_xfer_busy - 2 samples + */ + unsigned int rdata_xfer_busy; + + /* Temporary storage for demuxing data after SPI transfer */ + u32 bounce_buffer[ADS1298_MAX_CHANNELS]; + + /* For synchronous SPI exchanges (read/write registers) */ + u8 cmd_buffer[ADS1298_SPI_CMD_BUFFER_SIZE] __aligned(IIO_DMA_MINALIGN); + + /* Buffer used for incoming SPI data */ + u8 rx_buffer[ADS1298_SPI_RDATA_BUFFER_SIZE_MAX]; + /* Contains the RDATA command and zeroes to clock out */ + u8 tx_buffer[ADS1298_SPI_RDATA_BUFFER_SIZE_MAX]; +}; + +/* Three bytes per sample in RX buffer, starting at offset 4 */ +#define ADS1298_OFFSET_IN_RX_BUFFER(index) (3 * (index) + 4) + +#define ADS1298_CHAN(index) \ +{ \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = index, \ + .address = ADS1298_OFFSET_IN_RX_BUFFER(index), \ + .info_mask_separate = \ + BIT(IIO_CHAN_INFO_RAW) | \ + BIT(IIO_CHAN_INFO_SCALE), \ + .info_mask_shared_by_all = \ + BIT(IIO_CHAN_INFO_SAMP_FREQ) | \ + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \ + .scan_index = index, \ + .scan_type = { \ + .sign = 's', \ + .realbits = ADS1298_BITS_PER_SAMPLE, \ + .storagebits = 32, \ + .endianness = IIO_CPU, \ + }, \ +} + +static const struct iio_chan_spec ads1298_channels[] = { + ADS1298_CHAN(0), + ADS1298_CHAN(1), + ADS1298_CHAN(2), + ADS1298_CHAN(3), + ADS1298_CHAN(4), + ADS1298_CHAN(5), + ADS1298_CHAN(6), + ADS1298_CHAN(7), +}; + +static int ads1298_write_cmd(struct ads1298_private *priv, u8 command) +{ + struct spi_transfer xfer = { + .tx_buf = priv->cmd_buffer, + .rx_buf = priv->cmd_buffer, + .len = 1, + .speed_hz = ADS1298_SPI_BUS_SPEED_SLOW, + .delay = { + .value = 2, + .unit = SPI_DELAY_UNIT_USECS, + }, + }; + + priv->cmd_buffer[0] = command; + + return spi_sync_transfer(priv->spi, &xfer, 1); +} + +static int ads1298_read_one(struct ads1298_private *priv, int chan_index) +{ + int ret; + + /* Enable the channel */ + ret = regmap_update_bits(priv->regmap, ADS1298_REG_CHnSET(chan_index), + ADS1298_MASK_CH_PD, 0); + if (ret) + return ret; + + /* Enable single-shot mode, so we don't need to send a STOP */ + ret = regmap_update_bits(priv->regmap, ADS1298_REG_CONFIG4, + ADS1298_MASK_CONFIG4_SINGLE_SHOT, + ADS1298_MASK_CONFIG4_SINGLE_SHOT); + if (ret) + return ret; + + reinit_completion(&priv->completion); + + ret = ads1298_write_cmd(priv, ADS1298_CMD_START); + if (ret < 0) { + dev_err(&priv->spi->dev, "CMD_START error: %d\n", ret); + return ret; + } + + /* Cannot take longer than 40ms (250Hz) */ + ret = wait_for_completion_timeout(&priv->completion, msecs_to_jiffies(50)); + if (!ret) + return -ETIMEDOUT; + + return 0; +} + +static int ads1298_get_samp_freq(struct ads1298_private *priv, int *val) +{ + unsigned long rate; + unsigned int cfg; + int ret; + + ret = regmap_read(priv->regmap, ADS1298_REG_CONFIG1, &cfg); + if (ret) + return ret; + + if (priv->clk) + rate = clk_get_rate(priv->clk); + else + rate = ADS1298_CLK_RATE_HZ; + if (!rate) + return -EINVAL; + + /* Data rate shift depends on HR/LP mode */ + if (cfg & ADS1298_MASK_CONFIG1_HR) + rate >>= ADS1298_SHIFT_DR_HR; + else + rate >>= ADS1298_SHIFT_DR_LP; + + *val = rate >> (cfg & ADS1298_MASK_CONFIG1_DR); + + return IIO_VAL_INT; +} + +static int ads1298_set_samp_freq(struct ads1298_private *priv, int val) +{ + unsigned long rate; + unsigned int factor; + unsigned int cfg; + + if (priv->clk) + rate = clk_get_rate(priv->clk); + else + rate = ADS1298_CLK_RATE_HZ; + if (!rate) + return -EINVAL; + if (val <= 0) + return -EINVAL; + + factor = (rate >> ADS1298_SHIFT_DR_HR) / val; + if (factor >= BIT(ADS1298_SHIFT_DR_LP)) + cfg = ADS1298_LOWEST_DR; + else if (factor) + cfg = ADS1298_MASK_CONFIG1_HR | ilog2(factor); /* Use HR mode */ + else + cfg = ADS1298_MASK_CONFIG1_HR; /* Fastest possible */ + + return regmap_update_bits(priv->regmap, ADS1298_REG_CONFIG1, + ADS1298_MASK_CONFIG1_HR | ADS1298_MASK_CONFIG1_DR, + cfg); +} + +static const u8 ads1298_pga_settings[] = { 6, 1, 2, 3, 4, 8, 12 }; + +static int ads1298_get_scale(struct ads1298_private *priv, + int channel, int *val, int *val2) +{ + int ret; + unsigned int regval; + u8 gain; + + if (priv->reg_vref) { + ret = regulator_get_voltage(priv->reg_vref); + if (ret < 0) + return ret; + + *val = ret / MILLI; /* Convert to millivolts */ + } else { + ret = regmap_read(priv->regmap, ADS1298_REG_CONFIG3, ®val); + if (ret) + return ret; + + /* Refererence in millivolts */ + *val = regval & ADS1298_MASK_CONFIG3_VREF_4V ? 4000 : 2400; + } + + ret = regmap_read(priv->regmap, ADS1298_REG_CHnSET(channel), ®val); + if (ret) + return ret; + + gain = ads1298_pga_settings[FIELD_GET(ADS1298_MASK_CH_PGA, regval)]; + *val /= gain; /* Full scale is VREF / gain */ + + *val2 = ADS1298_BITS_PER_SAMPLE - 1; /* Signed, hence the -1 */ + + return IIO_VAL_FRACTIONAL_LOG2; +} + +static int ads1298_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct ads1298_private *priv = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + + ret = ads1298_read_one(priv, chan->scan_index); + + iio_device_release_direct_mode(indio_dev); + + if (ret) + return ret; + + *val = sign_extend32(get_unaligned_be24(priv->rx_buffer + chan->address), + ADS1298_BITS_PER_SAMPLE - 1); + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + return ads1298_get_scale(priv, chan->channel, val, val2); + case IIO_CHAN_INFO_SAMP_FREQ: + return ads1298_get_samp_freq(priv, val); + case IIO_CHAN_INFO_OVERSAMPLING_RATIO: + ret = regmap_read(priv->regmap, ADS1298_REG_CONFIG1, val); + if (ret) + return ret; + + *val = 16 << (*val & ADS1298_MASK_CONFIG1_DR); + return IIO_VAL_INT; + default: + return -EINVAL; + } +} + +static int ads1298_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int val, + int val2, long mask) +{ + struct ads1298_private *priv = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_SAMP_FREQ: + return ads1298_set_samp_freq(priv, val); + default: + return -EINVAL; + } +} + +static int ads1298_reg_write(void *context, unsigned int reg, unsigned int val) +{ + struct ads1298_private *priv = context; + struct spi_transfer reg_write_xfer = { + .tx_buf = priv->cmd_buffer, + .rx_buf = priv->cmd_buffer, + .len = 3, + .speed_hz = ADS1298_SPI_BUS_SPEED_SLOW, + .delay = { + .value = 2, + .unit = SPI_DELAY_UNIT_USECS, + }, + }; + + priv->cmd_buffer[0] = ADS1298_CMD_WREG | reg; + priv->cmd_buffer[1] = 0; /* Number of registers to be written - 1 */ + priv->cmd_buffer[2] = val; + + return spi_sync_transfer(priv->spi, ®_write_xfer, 1); +} + +static int ads1298_reg_read(void *context, unsigned int reg, unsigned int *val) +{ + struct ads1298_private *priv = context; + struct spi_transfer reg_read_xfer = { + .tx_buf = priv->cmd_buffer, + .rx_buf = priv->cmd_buffer, + .len = 3, + .speed_hz = ADS1298_SPI_BUS_SPEED_SLOW, + .delay = { + .value = 2, + .unit = SPI_DELAY_UNIT_USECS, + }, + }; + int ret; + + priv->cmd_buffer[0] = ADS1298_CMD_RREG | reg; + priv->cmd_buffer[1] = 0; /* Number of registers to be read - 1 */ + priv->cmd_buffer[2] = 0; + + ret = spi_sync_transfer(priv->spi, ®_read_xfer, 1); + if (ret) + return ret; + + *val = priv->cmd_buffer[2]; + + return 0; +} + +static int ads1298_reg_access(struct iio_dev *indio_dev, unsigned int reg, + unsigned int writeval, unsigned int *readval) +{ + struct ads1298_private *priv = iio_priv(indio_dev); + + if (readval) + return regmap_read(priv->regmap, reg, readval); + + return regmap_write(priv->regmap, reg, writeval); +} + +static void ads1298_rdata_unmark_busy(struct ads1298_private *priv) +{ + /* Notify we're no longer waiting for the SPI transfer to complete */ + guard(spinlock_irqsave)(&priv->irq_busy_lock); + priv->rdata_xfer_busy = 0; +} + +static int ads1298_update_scan_mode(struct iio_dev *indio_dev, + const unsigned long *scan_mask) +{ + struct ads1298_private *priv = iio_priv(indio_dev); + unsigned int val; + int ret; + int i; + + /* Make the interrupt routines start with a clean slate */ + ads1298_rdata_unmark_busy(priv); + + /* Configure power-down bits to match scan mask */ + for (i = 0; i < indio_dev->num_channels; i++) { + val = test_bit(i, scan_mask) ? 0 : ADS1298_MASK_CH_PD; + ret = regmap_update_bits(priv->regmap, ADS1298_REG_CHnSET(i), + ADS1298_MASK_CH_PD, val); + if (ret) + return ret; + } + + return 0; +} + +static const struct iio_info ads1298_info = { + .read_raw = &ads1298_read_raw, + .write_raw = &ads1298_write_raw, + .update_scan_mode = &ads1298_update_scan_mode, + .debugfs_reg_access = &ads1298_reg_access, +}; + +static void ads1298_rdata_release_busy_or_restart(struct ads1298_private *priv) +{ + guard(spinlock_irqsave)(&priv->irq_busy_lock); + + if (priv->rdata_xfer_busy > 1) { + /* + * DRDY interrupt occurred before SPI completion. Start a new + * SPI transaction now to retrieve the data that wasn't latched + * into the ADS1298 chip's transfer buffer yet. + */ + spi_async(priv->spi, &priv->rdata_msg); + /* + * If more than one DRDY took place, there was an overrun. Since + * the sample is already lost, reset the counter to 1 so that + * we will wait for a DRDY interrupt after this SPI transaction. + */ + priv->rdata_xfer_busy = 1; + } else { + /* No pending data, wait for DRDY */ + priv->rdata_xfer_busy = 0; + } +} + +/* Called from SPI completion interrupt handler */ +static void ads1298_rdata_complete(void *context) +{ + struct iio_dev *indio_dev = context; + struct ads1298_private *priv = iio_priv(indio_dev); + int scan_index; + u32 *bounce = priv->bounce_buffer; + + if (!iio_buffer_enabled(indio_dev)) { + /* + * for a single transfer mode we're kept in direct_mode until + * completion, avoiding a race with buffered IO. + */ + ads1298_rdata_unmark_busy(priv); + complete(&priv->completion); + return; + } + + /* Demux the channel data into our bounce buffer */ + for_each_set_bit(scan_index, indio_dev->active_scan_mask, + indio_dev->masklength) { + const struct iio_chan_spec *scan_chan = + &indio_dev->channels[scan_index]; + const u8 *data = priv->rx_buffer + scan_chan->address; + + *bounce++ = get_unaligned_be24(data); + } + + /* rx_buffer can be overwritten from this point on */ + ads1298_rdata_release_busy_or_restart(priv); + + iio_push_to_buffers(indio_dev, priv->bounce_buffer); +} + +static irqreturn_t ads1298_interrupt(int irq, void *dev_id) +{ + struct iio_dev *indio_dev = dev_id; + struct ads1298_private *priv = iio_priv(indio_dev); + unsigned int wasbusy; + + guard(spinlock_irqsave)(&priv->irq_busy_lock); + + wasbusy = priv->rdata_xfer_busy++; + /* When no SPI transfer in transit, start one now */ + if (!wasbusy) + spi_async(priv->spi, &priv->rdata_msg); + + return IRQ_HANDLED; +}; + +static int ads1298_buffer_postenable(struct iio_dev *indio_dev) +{ + struct ads1298_private *priv = iio_priv(indio_dev); + int ret; + + /* Disable single-shot mode */ + ret = regmap_update_bits(priv->regmap, ADS1298_REG_CONFIG4, + ADS1298_MASK_CONFIG4_SINGLE_SHOT, 0); + if (ret) + return ret; + + return ads1298_write_cmd(priv, ADS1298_CMD_START); +} + +static int ads1298_buffer_predisable(struct iio_dev *indio_dev) +{ + struct ads1298_private *priv = iio_priv(indio_dev); + + return ads1298_write_cmd(priv, ADS1298_CMD_STOP); +} + +static const struct iio_buffer_setup_ops ads1298_setup_ops = { + .postenable = &ads1298_buffer_postenable, + .predisable = &ads1298_buffer_predisable, +}; + +static void ads1298_reg_disable(void *reg) +{ + regulator_disable(reg); +} + +static const struct regmap_range ads1298_regmap_volatile_range[] = { + regmap_reg_range(ADS1298_REG_LOFF_STATP, ADS1298_REG_LOFF_STATN), +}; + +static const struct regmap_access_table ads1298_regmap_volatile = { + .yes_ranges = ads1298_regmap_volatile_range, + .n_yes_ranges = ARRAY_SIZE(ads1298_regmap_volatile_range), +}; + +static const struct regmap_config ads1298_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .reg_read = ads1298_reg_read, + .reg_write = ads1298_reg_write, + .max_register = ADS1298_REG_WCT2, + .volatile_table = &ads1298_regmap_volatile, + .cache_type = REGCACHE_MAPLE, +}; + +static int ads1298_init(struct iio_dev *indio_dev) +{ + struct ads1298_private *priv = iio_priv(indio_dev); + struct device *dev = &priv->spi->dev; + const char *suffix; + unsigned int val; + int ret; + + /* Device initializes into RDATAC mode, which we don't want */ + ret = ads1298_write_cmd(priv, ADS1298_CMD_SDATAC); + if (ret) + return ret; + + ret = regmap_read(priv->regmap, ADS1298_REG_ID, &val); + if (ret) + return ret; + + /* Fill in name and channel count based on what the chip told us */ + indio_dev->num_channels = 4 + 2 * (val & ADS1298_MASK_ID_CHANNELS); + switch (val & ADS1298_MASK_ID_FAMILY) { + case ADS1298_ID_FAMILY_ADS129X: + suffix = ""; + break; + case ADS1298_ID_FAMILY_ADS129XR: + suffix = "r"; + break; + default: + return dev_err_probe(dev, -ENODEV, "Unknown ID: 0x%x\n", val); + } + indio_dev->name = devm_kasprintf(dev, GFP_KERNEL, "ads129%u%s", + indio_dev->num_channels, suffix); + + /* Enable internal test signal, double amplitude, double frequency */ + ret = regmap_write(priv->regmap, ADS1298_REG_CONFIG2, + ADS1298_MASK_CONFIG2_RESERVED | + ADS1298_MASK_CONFIG2_INT_TEST | + ADS1298_MASK_CONFIG2_TEST_AMP | + ADS1298_MASK_CONFIG2_TEST_FREQ_FAST); + if (ret) + return ret; + + val = ADS1298_MASK_CONFIG3_RESERVED; /* Must write 1 always */ + if (!priv->reg_vref) { + /* Enable internal reference */ + val |= ADS1298_MASK_CONFIG3_PWR_REFBUF; + /* Use 4V VREF when power supply is at least 4.4V */ + if (regulator_get_voltage(priv->reg_avdd) >= 4400000) + val |= ADS1298_MASK_CONFIG3_VREF_4V; + } + return regmap_write(priv->regmap, ADS1298_REG_CONFIG3, val); +} + +static int ads1298_probe(struct spi_device *spi) +{ + struct ads1298_private *priv; + struct iio_dev *indio_dev; + struct device *dev = &spi->dev; + struct gpio_desc *reset_gpio; + int ret; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); + if (!indio_dev) + return -ENOMEM; + + priv = iio_priv(indio_dev); + + /* Reset to be asserted before enabling clock and power */ + reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(reset_gpio)) + return dev_err_probe(dev, PTR_ERR(reset_gpio), + "Cannot get reset GPIO\n"); + + /* VREF can be supplied externally, otherwise use internal reference */ + priv->reg_vref = devm_regulator_get_optional(dev, "vref"); + if (IS_ERR(priv->reg_vref)) { + if (PTR_ERR(priv->reg_vref) != -ENODEV) + return dev_err_probe(dev, PTR_ERR(priv->reg_vref), + "Failed to get vref regulator\n"); + + priv->reg_vref = NULL; + } else { + ret = regulator_enable(priv->reg_vref); + if (ret) + return ret; + + ret = devm_add_action_or_reset(dev, ads1298_reg_disable, priv->reg_vref); + if (ret) + return ret; + } + + priv->clk = devm_clk_get_optional_enabled(dev, "clk"); + if (IS_ERR(priv->clk)) + return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to get clk\n"); + + priv->reg_avdd = devm_regulator_get(dev, "avdd"); + if (IS_ERR(priv->reg_avdd)) + return dev_err_probe(dev, PTR_ERR(priv->reg_avdd), + "Failed to get avdd regulator\n"); + + ret = regulator_enable(priv->reg_avdd); + if (ret) + return dev_err_probe(dev, ret, "Failed to enable avdd regulator\n"); + + ret = devm_add_action_or_reset(dev, ads1298_reg_disable, priv->reg_avdd); + if (ret) + return ret; + + priv->spi = spi; + init_completion(&priv->completion); + spin_lock_init(&priv->irq_busy_lock); + priv->regmap = devm_regmap_init(dev, NULL, priv, &ads1298_regmap_config); + if (IS_ERR(priv->regmap)) + return PTR_ERR(priv->regmap); + + indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE; + indio_dev->channels = ads1298_channels; + indio_dev->info = &ads1298_info; + + if (reset_gpio) { + /* + * Deassert reset now that clock and power are active. + * Minimum reset pulsewidth is 2 clock cycles. + */ + fsleep(ADS1298_CLOCKS_TO_USECS(2)); + gpiod_set_value_cansleep(reset_gpio, 0); + } else { + ret = ads1298_write_cmd(priv, ADS1298_CMD_RESET); + if (ret) + return dev_err_probe(dev, ret, "RESET failed\n"); + } + /* Wait 18 clock cycles for reset command to complete */ + fsleep(ADS1298_CLOCKS_TO_USECS(18)); + + ret = ads1298_init(indio_dev); + if (ret) + return dev_err_probe(dev, ret, "Init failed\n"); + + priv->tx_buffer[0] = ADS1298_CMD_RDATA; + priv->rdata_xfer.tx_buf = priv->tx_buffer; + priv->rdata_xfer.rx_buf = priv->rx_buffer; + priv->rdata_xfer.len = ADS1298_SPI_RDATA_BUFFER_SIZE(indio_dev->num_channels); + /* Must keep CS low for 4 clocks */ + priv->rdata_xfer.delay.value = 2; + priv->rdata_xfer.delay.unit = SPI_DELAY_UNIT_USECS; + spi_message_init_with_transfers(&priv->rdata_msg, &priv->rdata_xfer, 1); + priv->rdata_msg.complete = &ads1298_rdata_complete; + priv->rdata_msg.context = indio_dev; + + ret = devm_request_irq(dev, spi->irq, &ads1298_interrupt, + IRQF_TRIGGER_FALLING, indio_dev->name, + indio_dev); + if (ret) + return ret; + + ret = devm_iio_kfifo_buffer_setup(dev, indio_dev, &ads1298_setup_ops); + if (ret) + return ret; + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct spi_device_id ads1298_id[] = { + { "ads1298" }, + { } +}; +MODULE_DEVICE_TABLE(spi, ads1298_id); + +static const struct of_device_id ads1298_of_table[] = { + { .compatible = "ti,ads1298" }, + { } +}; +MODULE_DEVICE_TABLE(of, ads1298_of_table); + +static struct spi_driver ads1298_driver = { + .driver = { + .name = "ads1298", + .of_match_table = ads1298_of_table, + }, + .probe = ads1298_probe, + .id_table = ads1298_id, +}; +module_spi_driver(ads1298_driver); + +MODULE_AUTHOR("Mike Looijmans <mike.looijmans@topic.nl>"); +MODULE_DESCRIPTION("TI ADS1298 ADC"); +MODULE_LICENSE("GPL"); |