diff options
Diffstat (limited to 'drivers/iio/adc/ti-ads7950.c')
| -rw-r--r-- | drivers/iio/adc/ti-ads7950.c | 531 |
1 files changed, 531 insertions, 0 deletions
diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c new file mode 100644 index 000000000..c9cd7e5c1 --- /dev/null +++ b/drivers/iio/adc/ti-ads7950.c @@ -0,0 +1,531 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Texas Instruments ADS7950 SPI ADC driver + * + * Copyright 2016 David Lechner <david@lechnology.com> + * + * Based on iio/ad7923.c: + * Copyright 2011 Analog Devices Inc + * Copyright 2012 CS Systemes d'Information + * + * And also on hwmon/ads79xx.c + * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com/ + * Nishanth Menon + */ + +#include <linux/acpi.h> +#include <linux/bitops.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/slab.h> +#include <linux/spi/spi.h> + +#include <linux/iio/buffer.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> + +/* + * In case of ACPI, we use the 5000 mV as default for the reference pin. + * Device tree users encode that via the vref-supply regulator. + */ +#define TI_ADS7950_VA_MV_ACPI_DEFAULT 5000 + +#define TI_ADS7950_CR_MANUAL BIT(12) +#define TI_ADS7950_CR_WRITE BIT(11) +#define TI_ADS7950_CR_CHAN(ch) ((ch) << 7) +#define TI_ADS7950_CR_RANGE_5V BIT(6) + +#define TI_ADS7950_MAX_CHAN 16 + +#define TI_ADS7950_TIMESTAMP_SIZE (sizeof(int64_t) / sizeof(__be16)) + +/* val = value, dec = left shift, bits = number of bits of the mask */ +#define TI_ADS7950_EXTRACT(val, dec, bits) \ + (((val) >> (dec)) & ((1 << (bits)) - 1)) + +struct ti_ads7950_state { + struct spi_device *spi; + struct spi_transfer ring_xfer[TI_ADS7950_MAX_CHAN + 2]; + struct spi_transfer scan_single_xfer[3]; + struct spi_message ring_msg; + struct spi_message scan_single_msg; + + /* Lock to protect the spi xfer buffers */ + struct mutex slock; + + struct regulator *reg; + unsigned int vref_mv; + + unsigned int settings; + + /* + * DMA (thus cache coherency maintenance) requires the + * transfer buffers to live in their own cache lines. + */ + __be16 rx_buf[TI_ADS7950_MAX_CHAN + TI_ADS7950_TIMESTAMP_SIZE] + ____cacheline_aligned; + __be16 tx_buf[TI_ADS7950_MAX_CHAN]; + __be16 single_tx; + __be16 single_rx; + +}; + +struct ti_ads7950_chip_info { + const struct iio_chan_spec *channels; + unsigned int num_channels; +}; + +enum ti_ads7950_id { + TI_ADS7950, + TI_ADS7951, + TI_ADS7952, + TI_ADS7953, + TI_ADS7954, + TI_ADS7955, + TI_ADS7956, + TI_ADS7957, + TI_ADS7958, + TI_ADS7959, + TI_ADS7960, + TI_ADS7961, +}; + +#define TI_ADS7950_V_CHAN(index, bits) \ +{ \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = index, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .address = index, \ + .datasheet_name = "CH##index", \ + .scan_index = index, \ + .scan_type = { \ + .sign = 'u', \ + .realbits = bits, \ + .storagebits = 16, \ + .shift = 12 - (bits), \ + .endianness = IIO_BE, \ + }, \ +} + +#define DECLARE_TI_ADS7950_4_CHANNELS(name, bits) \ +const struct iio_chan_spec name ## _channels[] = { \ + TI_ADS7950_V_CHAN(0, bits), \ + TI_ADS7950_V_CHAN(1, bits), \ + TI_ADS7950_V_CHAN(2, bits), \ + TI_ADS7950_V_CHAN(3, bits), \ + IIO_CHAN_SOFT_TIMESTAMP(4), \ +} + +#define DECLARE_TI_ADS7950_8_CHANNELS(name, bits) \ +const struct iio_chan_spec name ## _channels[] = { \ + TI_ADS7950_V_CHAN(0, bits), \ + TI_ADS7950_V_CHAN(1, bits), \ + TI_ADS7950_V_CHAN(2, bits), \ + TI_ADS7950_V_CHAN(3, bits), \ + TI_ADS7950_V_CHAN(4, bits), \ + TI_ADS7950_V_CHAN(5, bits), \ + TI_ADS7950_V_CHAN(6, bits), \ + TI_ADS7950_V_CHAN(7, bits), \ + IIO_CHAN_SOFT_TIMESTAMP(8), \ +} + +#define DECLARE_TI_ADS7950_12_CHANNELS(name, bits) \ +const struct iio_chan_spec name ## _channels[] = { \ + TI_ADS7950_V_CHAN(0, bits), \ + TI_ADS7950_V_CHAN(1, bits), \ + TI_ADS7950_V_CHAN(2, bits), \ + TI_ADS7950_V_CHAN(3, bits), \ + TI_ADS7950_V_CHAN(4, bits), \ + TI_ADS7950_V_CHAN(5, bits), \ + TI_ADS7950_V_CHAN(6, bits), \ + TI_ADS7950_V_CHAN(7, bits), \ + TI_ADS7950_V_CHAN(8, bits), \ + TI_ADS7950_V_CHAN(9, bits), \ + TI_ADS7950_V_CHAN(10, bits), \ + TI_ADS7950_V_CHAN(11, bits), \ + IIO_CHAN_SOFT_TIMESTAMP(12), \ +} + +#define DECLARE_TI_ADS7950_16_CHANNELS(name, bits) \ +const struct iio_chan_spec name ## _channels[] = { \ + TI_ADS7950_V_CHAN(0, bits), \ + TI_ADS7950_V_CHAN(1, bits), \ + TI_ADS7950_V_CHAN(2, bits), \ + TI_ADS7950_V_CHAN(3, bits), \ + TI_ADS7950_V_CHAN(4, bits), \ + TI_ADS7950_V_CHAN(5, bits), \ + TI_ADS7950_V_CHAN(6, bits), \ + TI_ADS7950_V_CHAN(7, bits), \ + TI_ADS7950_V_CHAN(8, bits), \ + TI_ADS7950_V_CHAN(9, bits), \ + TI_ADS7950_V_CHAN(10, bits), \ + TI_ADS7950_V_CHAN(11, bits), \ + TI_ADS7950_V_CHAN(12, bits), \ + TI_ADS7950_V_CHAN(13, bits), \ + TI_ADS7950_V_CHAN(14, bits), \ + TI_ADS7950_V_CHAN(15, bits), \ + IIO_CHAN_SOFT_TIMESTAMP(16), \ +} + +static DECLARE_TI_ADS7950_4_CHANNELS(ti_ads7950, 12); +static DECLARE_TI_ADS7950_8_CHANNELS(ti_ads7951, 12); +static DECLARE_TI_ADS7950_12_CHANNELS(ti_ads7952, 12); +static DECLARE_TI_ADS7950_16_CHANNELS(ti_ads7953, 12); +static DECLARE_TI_ADS7950_4_CHANNELS(ti_ads7954, 10); +static DECLARE_TI_ADS7950_8_CHANNELS(ti_ads7955, 10); +static DECLARE_TI_ADS7950_12_CHANNELS(ti_ads7956, 10); +static DECLARE_TI_ADS7950_16_CHANNELS(ti_ads7957, 10); +static DECLARE_TI_ADS7950_4_CHANNELS(ti_ads7958, 8); +static DECLARE_TI_ADS7950_8_CHANNELS(ti_ads7959, 8); +static DECLARE_TI_ADS7950_12_CHANNELS(ti_ads7960, 8); +static DECLARE_TI_ADS7950_16_CHANNELS(ti_ads7961, 8); + +static const struct ti_ads7950_chip_info ti_ads7950_chip_info[] = { + [TI_ADS7950] = { + .channels = ti_ads7950_channels, + .num_channels = ARRAY_SIZE(ti_ads7950_channels), + }, + [TI_ADS7951] = { + .channels = ti_ads7951_channels, + .num_channels = ARRAY_SIZE(ti_ads7951_channels), + }, + [TI_ADS7952] = { + .channels = ti_ads7952_channels, + .num_channels = ARRAY_SIZE(ti_ads7952_channels), + }, + [TI_ADS7953] = { + .channels = ti_ads7953_channels, + .num_channels = ARRAY_SIZE(ti_ads7953_channels), + }, + [TI_ADS7954] = { + .channels = ti_ads7954_channels, + .num_channels = ARRAY_SIZE(ti_ads7954_channels), + }, + [TI_ADS7955] = { + .channels = ti_ads7955_channels, + .num_channels = ARRAY_SIZE(ti_ads7955_channels), + }, + [TI_ADS7956] = { + .channels = ti_ads7956_channels, + .num_channels = ARRAY_SIZE(ti_ads7956_channels), + }, + [TI_ADS7957] = { + .channels = ti_ads7957_channels, + .num_channels = ARRAY_SIZE(ti_ads7957_channels), + }, + [TI_ADS7958] = { + .channels = ti_ads7958_channels, + .num_channels = ARRAY_SIZE(ti_ads7958_channels), + }, + [TI_ADS7959] = { + .channels = ti_ads7959_channels, + .num_channels = ARRAY_SIZE(ti_ads7959_channels), + }, + [TI_ADS7960] = { + .channels = ti_ads7960_channels, + .num_channels = ARRAY_SIZE(ti_ads7960_channels), + }, + [TI_ADS7961] = { + .channels = ti_ads7961_channels, + .num_channels = ARRAY_SIZE(ti_ads7961_channels), + }, +}; + +/* + * ti_ads7950_update_scan_mode() setup the spi transfer buffer for the new + * scan mask + */ +static int ti_ads7950_update_scan_mode(struct iio_dev *indio_dev, + const unsigned long *active_scan_mask) +{ + struct ti_ads7950_state *st = iio_priv(indio_dev); + int i, cmd, len; + + len = 0; + for_each_set_bit(i, active_scan_mask, indio_dev->num_channels) { + cmd = TI_ADS7950_CR_WRITE | TI_ADS7950_CR_CHAN(i) | st->settings; + st->tx_buf[len++] = cpu_to_be16(cmd); + } + + /* Data for the 1st channel is not returned until the 3rd transfer */ + len += 2; + for (i = 0; i < len; i++) { + if ((i + 2) < len) + st->ring_xfer[i].tx_buf = &st->tx_buf[i]; + if (i >= 2) + st->ring_xfer[i].rx_buf = &st->rx_buf[i - 2]; + st->ring_xfer[i].len = 2; + st->ring_xfer[i].cs_change = 1; + } + /* make sure last transfer's cs_change is not set */ + st->ring_xfer[len - 1].cs_change = 0; + + spi_message_init_with_transfers(&st->ring_msg, st->ring_xfer, len); + + return 0; +} + +static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct ti_ads7950_state *st = iio_priv(indio_dev); + int ret; + + mutex_lock(&st->slock); + ret = spi_sync(st->spi, &st->ring_msg); + if (ret < 0) + goto out; + + iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf, + iio_get_time_ns(indio_dev)); + +out: + mutex_unlock(&st->slock); + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch) +{ + struct ti_ads7950_state *st = iio_priv(indio_dev); + int ret, cmd; + + mutex_lock(&st->slock); + + cmd = TI_ADS7950_CR_WRITE | TI_ADS7950_CR_CHAN(ch) | st->settings; + st->single_tx = cpu_to_be16(cmd); + + ret = spi_sync(st->spi, &st->scan_single_msg); + if (ret) + goto out; + + ret = be16_to_cpu(st->single_rx); + +out: + mutex_unlock(&st->slock); + + return ret; +} + +static int ti_ads7950_get_range(struct ti_ads7950_state *st) +{ + int vref; + + if (st->vref_mv) { + vref = st->vref_mv; + } else { + vref = regulator_get_voltage(st->reg); + if (vref < 0) + return vref; + + vref /= 1000; + } + + if (st->settings & TI_ADS7950_CR_RANGE_5V) + vref *= 2; + + return vref; +} + +static int ti_ads7950_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long m) +{ + struct ti_ads7950_state *st = iio_priv(indio_dev); + int ret; + + switch (m) { + case IIO_CHAN_INFO_RAW: + ret = ti_ads7950_scan_direct(indio_dev, chan->address); + if (ret < 0) + return ret; + + if (chan->address != TI_ADS7950_EXTRACT(ret, 12, 4)) + return -EIO; + + *val = TI_ADS7950_EXTRACT(ret, chan->scan_type.shift, + chan->scan_type.realbits); + + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + ret = ti_ads7950_get_range(st); + if (ret < 0) + return ret; + + *val = ret; + *val2 = (1 << chan->scan_type.realbits) - 1; + + return IIO_VAL_FRACTIONAL; + } + + return -EINVAL; +} + +static const struct iio_info ti_ads7950_info = { + .read_raw = &ti_ads7950_read_raw, + .update_scan_mode = ti_ads7950_update_scan_mode, +}; + +static int ti_ads7950_probe(struct spi_device *spi) +{ + struct ti_ads7950_state *st; + struct iio_dev *indio_dev; + const struct ti_ads7950_chip_info *info; + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + + spi_set_drvdata(spi, indio_dev); + + st->spi = spi; + st->settings = TI_ADS7950_CR_MANUAL | TI_ADS7950_CR_RANGE_5V; + + info = &ti_ads7950_chip_info[spi_get_device_id(spi)->driver_data]; + + indio_dev->name = spi_get_device_id(spi)->name; + indio_dev->dev.parent = &spi->dev; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = info->channels; + indio_dev->num_channels = info->num_channels; + indio_dev->info = &ti_ads7950_info; + + /* + * Setup default message. The sample is read at the end of the first + * transfer, then it takes one full cycle to convert the sample and one + * more cycle to send the value. The conversion process is driven by + * the SPI clock, which is why we have 3 transfers. The middle one is + * just dummy data sent while the chip is converting the sample that + * was read at the end of the first transfer. + */ + + st->scan_single_xfer[0].tx_buf = &st->single_tx; + st->scan_single_xfer[0].len = 2; + st->scan_single_xfer[0].cs_change = 1; + st->scan_single_xfer[1].tx_buf = &st->single_tx; + st->scan_single_xfer[1].len = 2; + st->scan_single_xfer[1].cs_change = 1; + st->scan_single_xfer[2].rx_buf = &st->single_rx; + st->scan_single_xfer[2].len = 2; + + spi_message_init_with_transfers(&st->scan_single_msg, + st->scan_single_xfer, 3); + + /* Use hard coded value for reference voltage in ACPI case */ + if (ACPI_COMPANION(&spi->dev)) + st->vref_mv = TI_ADS7950_VA_MV_ACPI_DEFAULT; + + mutex_init(&st->slock); + + st->reg = devm_regulator_get(&spi->dev, "vref"); + if (IS_ERR(st->reg)) { + dev_err(&spi->dev, "Failed get get regulator \"vref\"\n"); + ret = PTR_ERR(st->reg); + goto error_destroy_mutex; + } + + ret = regulator_enable(st->reg); + if (ret) { + dev_err(&spi->dev, "Failed to enable regulator \"vref\"\n"); + goto error_destroy_mutex; + } + + ret = iio_triggered_buffer_setup(indio_dev, NULL, + &ti_ads7950_trigger_handler, NULL); + if (ret) { + dev_err(&spi->dev, "Failed to setup triggered buffer\n"); + goto error_disable_reg; + } + + ret = iio_device_register(indio_dev); + if (ret) { + dev_err(&spi->dev, "Failed to register iio device\n"); + goto error_cleanup_ring; + } + + return 0; + +error_cleanup_ring: + iio_triggered_buffer_cleanup(indio_dev); +error_disable_reg: + regulator_disable(st->reg); +error_destroy_mutex: + mutex_destroy(&st->slock); + + return ret; +} + +static int ti_ads7950_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = spi_get_drvdata(spi); + struct ti_ads7950_state *st = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + iio_triggered_buffer_cleanup(indio_dev); + regulator_disable(st->reg); + mutex_destroy(&st->slock); + + return 0; +} + +static const struct spi_device_id ti_ads7950_id[] = { + { "ads7950", TI_ADS7950 }, + { "ads7951", TI_ADS7951 }, + { "ads7952", TI_ADS7952 }, + { "ads7953", TI_ADS7953 }, + { "ads7954", TI_ADS7954 }, + { "ads7955", TI_ADS7955 }, + { "ads7956", TI_ADS7956 }, + { "ads7957", TI_ADS7957 }, + { "ads7958", TI_ADS7958 }, + { "ads7959", TI_ADS7959 }, + { "ads7960", TI_ADS7960 }, + { "ads7961", TI_ADS7961 }, + { } +}; +MODULE_DEVICE_TABLE(spi, ti_ads7950_id); + +static const struct of_device_id ads7950_of_table[] = { + { .compatible = "ti,ads7950", .data = &ti_ads7950_chip_info[TI_ADS7950] }, + { .compatible = "ti,ads7951", .data = &ti_ads7950_chip_info[TI_ADS7951] }, + { .compatible = "ti,ads7952", .data = &ti_ads7950_chip_info[TI_ADS7952] }, + { .compatible = "ti,ads7953", .data = &ti_ads7950_chip_info[TI_ADS7953] }, + { .compatible = "ti,ads7954", .data = &ti_ads7950_chip_info[TI_ADS7954] }, + { .compatible = "ti,ads7955", .data = &ti_ads7950_chip_info[TI_ADS7955] }, + { .compatible = "ti,ads7956", .data = &ti_ads7950_chip_info[TI_ADS7956] }, + { .compatible = "ti,ads7957", .data = &ti_ads7950_chip_info[TI_ADS7957] }, + { .compatible = "ti,ads7958", .data = &ti_ads7950_chip_info[TI_ADS7958] }, + { .compatible = "ti,ads7959", .data = &ti_ads7950_chip_info[TI_ADS7959] }, + { .compatible = "ti,ads7960", .data = &ti_ads7950_chip_info[TI_ADS7960] }, + { .compatible = "ti,ads7961", .data = &ti_ads7950_chip_info[TI_ADS7961] }, + { }, +}; +MODULE_DEVICE_TABLE(of, ads7950_of_table); + +static struct spi_driver ti_ads7950_driver = { + .driver = { + .name = "ads7950", + .of_match_table = ads7950_of_table, + }, + .probe = ti_ads7950_probe, + .remove = ti_ads7950_remove, + .id_table = ti_ads7950_id, +}; +module_spi_driver(ti_ads7950_driver); + +MODULE_AUTHOR("David Lechner <david@lechnology.com>"); +MODULE_DESCRIPTION("TI TI_ADS7950 ADC"); +MODULE_LICENSE("GPL v2"); |