diff options
Diffstat (limited to 'drivers/iio/adc/ad_sigma_delta.c')
| -rw-r--r-- | drivers/iio/adc/ad_sigma_delta.c | 679 |
1 files changed, 679 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c new file mode 100644 index 000000000..7e2192870 --- /dev/null +++ b/drivers/iio/adc/ad_sigma_delta.c @@ -0,0 +1,679 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Support code for Analog Devices Sigma-Delta ADCs + * + * Copyright 2012 Analog Devices Inc. + * Author: Lars-Peter Clausen <lars@metafoo.de> + */ + +#include <linux/align.h> +#include <linux/interrupt.h> +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/spi/spi.h> +#include <linux/err.h> +#include <linux/module.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/buffer.h> +#include <linux/iio/trigger.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/iio/adc/ad_sigma_delta.h> + +#include <asm/unaligned.h> + + +#define AD_SD_COMM_CHAN_MASK 0x3 + +#define AD_SD_REG_COMM 0x00 +#define AD_SD_REG_DATA 0x03 + +/** + * ad_sd_set_comm() - Set communications register + * + * @sigma_delta: The sigma delta device + * @comm: New value for the communications register + */ +void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm) +{ + /* Some variants use the lower two bits of the communications register + * to select the channel */ + sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK; +} +EXPORT_SYMBOL_NS_GPL(ad_sd_set_comm, IIO_AD_SIGMA_DELTA); + +/** + * ad_sd_write_reg() - Write a register + * + * @sigma_delta: The sigma delta device + * @reg: Address of the register + * @size: Size of the register (0-3) + * @val: Value to write to the register + * + * Returns 0 on success, an error code otherwise. + **/ +int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg, + unsigned int size, unsigned int val) +{ + uint8_t *data = sigma_delta->tx_buf; + struct spi_transfer t = { + .tx_buf = data, + .len = size + 1, + .cs_change = sigma_delta->keep_cs_asserted, + }; + struct spi_message m; + int ret; + + data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm; + + switch (size) { + case 3: + put_unaligned_be24(val, &data[1]); + break; + case 2: + put_unaligned_be16(val, &data[1]); + break; + case 1: + data[1] = val; + break; + case 0: + break; + default: + return -EINVAL; + } + + spi_message_init(&m); + spi_message_add_tail(&t, &m); + + if (sigma_delta->bus_locked) + ret = spi_sync_locked(sigma_delta->spi, &m); + else + ret = spi_sync(sigma_delta->spi, &m); + + return ret; +} +EXPORT_SYMBOL_NS_GPL(ad_sd_write_reg, IIO_AD_SIGMA_DELTA); + +static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta, + unsigned int reg, unsigned int size, uint8_t *val) +{ + uint8_t *data = sigma_delta->tx_buf; + int ret; + struct spi_transfer t[] = { + { + .tx_buf = data, + .len = 1, + }, { + .rx_buf = val, + .len = size, + .cs_change = sigma_delta->bus_locked, + }, + }; + struct spi_message m; + + spi_message_init(&m); + + if (sigma_delta->info->has_registers) { + data[0] = reg << sigma_delta->info->addr_shift; + data[0] |= sigma_delta->info->read_mask; + data[0] |= sigma_delta->comm; + spi_message_add_tail(&t[0], &m); + } + spi_message_add_tail(&t[1], &m); + + if (sigma_delta->bus_locked) + ret = spi_sync_locked(sigma_delta->spi, &m); + else + ret = spi_sync(sigma_delta->spi, &m); + + return ret; +} + +/** + * ad_sd_read_reg() - Read a register + * + * @sigma_delta: The sigma delta device + * @reg: Address of the register + * @size: Size of the register (1-4) + * @val: Read value + * + * Returns 0 on success, an error code otherwise. + **/ +int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, + unsigned int reg, unsigned int size, unsigned int *val) +{ + int ret; + + ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->rx_buf); + if (ret < 0) + goto out; + + switch (size) { + case 4: + *val = get_unaligned_be32(sigma_delta->rx_buf); + break; + case 3: + *val = get_unaligned_be24(sigma_delta->rx_buf); + break; + case 2: + *val = get_unaligned_be16(sigma_delta->rx_buf); + break; + case 1: + *val = sigma_delta->rx_buf[0]; + break; + default: + ret = -EINVAL; + break; + } + +out: + return ret; +} +EXPORT_SYMBOL_NS_GPL(ad_sd_read_reg, IIO_AD_SIGMA_DELTA); + +/** + * ad_sd_reset() - Reset the serial interface + * + * @sigma_delta: The sigma delta device + * @reset_length: Number of SCLKs with DIN = 1 + * + * Returns 0 on success, an error code otherwise. + **/ +int ad_sd_reset(struct ad_sigma_delta *sigma_delta, + unsigned int reset_length) +{ + uint8_t *buf; + unsigned int size; + int ret; + + size = DIV_ROUND_UP(reset_length, 8); + buf = kcalloc(size, sizeof(*buf), GFP_KERNEL); + if (!buf) + return -ENOMEM; + + memset(buf, 0xff, size); + ret = spi_write(sigma_delta->spi, buf, size); + kfree(buf); + + return ret; +} +EXPORT_SYMBOL_NS_GPL(ad_sd_reset, IIO_AD_SIGMA_DELTA); + +int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta, + unsigned int mode, unsigned int channel) +{ + int ret; + unsigned long timeout; + + ret = ad_sigma_delta_set_channel(sigma_delta, channel); + if (ret) + return ret; + + spi_bus_lock(sigma_delta->spi->master); + sigma_delta->bus_locked = true; + sigma_delta->keep_cs_asserted = true; + reinit_completion(&sigma_delta->completion); + + ret = ad_sigma_delta_set_mode(sigma_delta, mode); + if (ret < 0) + goto out; + + sigma_delta->irq_dis = false; + enable_irq(sigma_delta->spi->irq); + timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ); + if (timeout == 0) { + sigma_delta->irq_dis = true; + disable_irq_nosync(sigma_delta->spi->irq); + ret = -EIO; + } else { + ret = 0; + } +out: + sigma_delta->keep_cs_asserted = false; + ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); + sigma_delta->bus_locked = false; + spi_bus_unlock(sigma_delta->spi->master); + + return ret; +} +EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate, IIO_AD_SIGMA_DELTA); + +/** + * ad_sd_calibrate_all() - Performs channel calibration + * @sigma_delta: The sigma delta device + * @cb: Array of channels and calibration type to perform + * @n: Number of items in cb + * + * Returns 0 on success, an error code otherwise. + **/ +int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta, + const struct ad_sd_calib_data *cb, unsigned int n) +{ + unsigned int i; + int ret; + + for (i = 0; i < n; i++) { + ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel); + if (ret) + return ret; + } + + return 0; +} +EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate_all, IIO_AD_SIGMA_DELTA); + +/** + * ad_sigma_delta_single_conversion() - Performs a single data conversion + * @indio_dev: The IIO device + * @chan: The conversion is done for this channel + * @val: Pointer to the location where to store the read value + * + * Returns: 0 on success, an error value otherwise. + */ +int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev, + const struct iio_chan_spec *chan, int *val) +{ + struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); + unsigned int sample, raw_sample; + unsigned int data_reg; + int ret = 0; + + ret = iio_device_claim_direct_mode(indio_dev); + if (ret) + return ret; + + ad_sigma_delta_set_channel(sigma_delta, chan->address); + + spi_bus_lock(sigma_delta->spi->master); + sigma_delta->bus_locked = true; + sigma_delta->keep_cs_asserted = true; + reinit_completion(&sigma_delta->completion); + + ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE); + + sigma_delta->irq_dis = false; + enable_irq(sigma_delta->spi->irq); + ret = wait_for_completion_interruptible_timeout( + &sigma_delta->completion, HZ); + + if (ret == 0) + ret = -EIO; + if (ret < 0) + goto out; + + if (sigma_delta->info->data_reg != 0) + data_reg = sigma_delta->info->data_reg; + else + data_reg = AD_SD_REG_DATA; + + ret = ad_sd_read_reg(sigma_delta, data_reg, + DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8), + &raw_sample); + +out: + if (!sigma_delta->irq_dis) { + disable_irq_nosync(sigma_delta->spi->irq); + sigma_delta->irq_dis = true; + } + + sigma_delta->keep_cs_asserted = false; + ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); + sigma_delta->bus_locked = false; + spi_bus_unlock(sigma_delta->spi->master); + iio_device_release_direct_mode(indio_dev); + + if (ret) + return ret; + + sample = raw_sample >> chan->scan_type.shift; + sample &= (1 << chan->scan_type.realbits) - 1; + *val = sample; + + ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample); + if (ret) + return ret; + + return IIO_VAL_INT; +} +EXPORT_SYMBOL_NS_GPL(ad_sigma_delta_single_conversion, IIO_AD_SIGMA_DELTA); + +static int ad_sd_buffer_postenable(struct iio_dev *indio_dev) +{ + struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); + unsigned int i, slot, samples_buf_size; + unsigned int channel; + uint8_t *samples_buf; + int ret; + + if (sigma_delta->num_slots == 1) { + channel = find_first_bit(indio_dev->active_scan_mask, + indio_dev->masklength); + ret = ad_sigma_delta_set_channel(sigma_delta, + indio_dev->channels[channel].address); + if (ret) + return ret; + slot = 1; + } else { + /* + * At this point update_scan_mode already enabled the required channels. + * For sigma-delta sequencer drivers with multiple slots, an update_scan_mode + * implementation is mandatory. + */ + slot = 0; + for_each_set_bit(i, indio_dev->active_scan_mask, indio_dev->masklength) { + sigma_delta->slots[slot] = indio_dev->channels[i].address; + slot++; + } + } + + sigma_delta->active_slots = slot; + sigma_delta->current_slot = 0; + + if (sigma_delta->active_slots > 1) { + ret = ad_sigma_delta_append_status(sigma_delta, true); + if (ret) + return ret; + } + + samples_buf_size = ALIGN(slot * indio_dev->channels[0].scan_type.storagebits, 8); + samples_buf_size += sizeof(int64_t); + samples_buf = devm_krealloc(&sigma_delta->spi->dev, sigma_delta->samples_buf, + samples_buf_size, GFP_KERNEL); + if (!samples_buf) + return -ENOMEM; + + sigma_delta->samples_buf = samples_buf; + + spi_bus_lock(sigma_delta->spi->master); + sigma_delta->bus_locked = true; + sigma_delta->keep_cs_asserted = true; + + ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS); + if (ret) + goto err_unlock; + + sigma_delta->irq_dis = false; + enable_irq(sigma_delta->spi->irq); + + return 0; + +err_unlock: + spi_bus_unlock(sigma_delta->spi->master); + + return ret; +} + +static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev) +{ + struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); + + reinit_completion(&sigma_delta->completion); + wait_for_completion_timeout(&sigma_delta->completion, HZ); + + if (!sigma_delta->irq_dis) { + disable_irq_nosync(sigma_delta->spi->irq); + sigma_delta->irq_dis = true; + } + + sigma_delta->keep_cs_asserted = false; + ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE); + + if (sigma_delta->status_appended) + ad_sigma_delta_append_status(sigma_delta, false); + + ad_sigma_delta_disable_all(sigma_delta); + sigma_delta->bus_locked = false; + return spi_bus_unlock(sigma_delta->spi->master); +} + +static irqreturn_t ad_sd_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); + uint8_t *data = sigma_delta->rx_buf; + unsigned int transfer_size; + unsigned int sample_size; + unsigned int sample_pos; + unsigned int status_pos; + unsigned int reg_size; + unsigned int data_reg; + + reg_size = indio_dev->channels[0].scan_type.realbits + + indio_dev->channels[0].scan_type.shift; + reg_size = DIV_ROUND_UP(reg_size, 8); + + if (sigma_delta->info->data_reg != 0) + data_reg = sigma_delta->info->data_reg; + else + data_reg = AD_SD_REG_DATA; + + /* Status word will be appended to the sample during transfer */ + if (sigma_delta->status_appended) + transfer_size = reg_size + 1; + else + transfer_size = reg_size; + + switch (reg_size) { + case 4: + case 2: + case 1: + status_pos = reg_size; + ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[0]); + break; + case 3: + /* + * Data array after transfer will look like (if status is appended): + * data[] = { [0][sample][sample][sample][status] } + * Keeping the first byte 0 shifts the status postion by 1 byte to the right. + */ + status_pos = reg_size + 1; + + /* We store 24 bit samples in a 32 bit word. Keep the upper + * byte set to zero. */ + ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[1]); + break; + } + + /* + * For devices sampling only one channel at + * once, there is no need for sample number tracking. + */ + if (sigma_delta->active_slots == 1) { + iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp); + goto irq_handled; + } + + if (sigma_delta->status_appended) { + u8 converted_channel; + + converted_channel = data[status_pos] & sigma_delta->info->status_ch_mask; + if (converted_channel != sigma_delta->slots[sigma_delta->current_slot]) { + /* + * Desync occurred during continuous sampling of multiple channels. + * Drop this incomplete sample and start from first channel again. + */ + + sigma_delta->current_slot = 0; + goto irq_handled; + } + } + + sample_size = indio_dev->channels[0].scan_type.storagebits / 8; + sample_pos = sample_size * sigma_delta->current_slot; + memcpy(&sigma_delta->samples_buf[sample_pos], data, sample_size); + sigma_delta->current_slot++; + + if (sigma_delta->current_slot == sigma_delta->active_slots) { + sigma_delta->current_slot = 0; + iio_push_to_buffers_with_timestamp(indio_dev, sigma_delta->samples_buf, + pf->timestamp); + } + +irq_handled: + iio_trigger_notify_done(indio_dev->trig); + sigma_delta->irq_dis = false; + enable_irq(sigma_delta->spi->irq); + + return IRQ_HANDLED; +} + +static bool ad_sd_validate_scan_mask(struct iio_dev *indio_dev, const unsigned long *mask) +{ + struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); + + return bitmap_weight(mask, indio_dev->masklength) <= sigma_delta->num_slots; +} + +static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = { + .postenable = &ad_sd_buffer_postenable, + .postdisable = &ad_sd_buffer_postdisable, + .validate_scan_mask = &ad_sd_validate_scan_mask, +}; + +static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private) +{ + struct ad_sigma_delta *sigma_delta = private; + + complete(&sigma_delta->completion); + disable_irq_nosync(irq); + sigma_delta->irq_dis = true; + iio_trigger_poll(sigma_delta->trig); + + return IRQ_HANDLED; +} + +/** + * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices + * @indio_dev: The IIO device + * @trig: The new trigger + * + * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta + * device, -EINVAL otherwise. + */ +int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig) +{ + struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); + + if (sigma_delta->trig != trig) + return -EINVAL; + + return 0; +} +EXPORT_SYMBOL_NS_GPL(ad_sd_validate_trigger, IIO_AD_SIGMA_DELTA); + +static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_dev) +{ + struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); + int ret; + + if (dev != &sigma_delta->spi->dev) { + dev_err(dev, "Trigger parent should be '%s', got '%s'\n", + dev_name(dev), dev_name(&sigma_delta->spi->dev)); + return -EFAULT; + } + + sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name, + iio_device_id(indio_dev)); + if (sigma_delta->trig == NULL) + return -ENOMEM; + + init_completion(&sigma_delta->completion); + + sigma_delta->irq_dis = true; + + /* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */ + irq_set_status_flags(sigma_delta->spi->irq, IRQ_DISABLE_UNLAZY); + + ret = devm_request_irq(dev, sigma_delta->spi->irq, + ad_sd_data_rdy_trig_poll, + sigma_delta->info->irq_flags | IRQF_NO_AUTOEN, + indio_dev->name, + sigma_delta); + if (ret) + return ret; + + iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); + + ret = devm_iio_trigger_register(dev, sigma_delta->trig); + if (ret) + return ret; + + /* select default trigger */ + indio_dev->trig = iio_trigger_get(sigma_delta->trig); + + return 0; +} + +/** + * devm_ad_sd_setup_buffer_and_trigger() - Device-managed buffer & trigger setup + * @dev: Device object to which to bind the life-time of the resources attached + * @indio_dev: The IIO device + */ +int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indio_dev) +{ + struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev); + int ret; + + sigma_delta->slots = devm_kcalloc(dev, sigma_delta->num_slots, + sizeof(*sigma_delta->slots), GFP_KERNEL); + if (!sigma_delta->slots) + return -ENOMEM; + + ret = devm_iio_triggered_buffer_setup(dev, indio_dev, + &iio_pollfunc_store_time, + &ad_sd_trigger_handler, + &ad_sd_buffer_setup_ops); + if (ret) + return ret; + + return devm_ad_sd_probe_trigger(dev, indio_dev); +} +EXPORT_SYMBOL_NS_GPL(devm_ad_sd_setup_buffer_and_trigger, IIO_AD_SIGMA_DELTA); + +/** + * ad_sd_init() - Initializes a ad_sigma_delta struct + * @sigma_delta: The ad_sigma_delta device + * @indio_dev: The IIO device which the Sigma Delta device is used for + * @spi: The SPI device for the ad_sigma_delta device + * @info: Device specific callbacks and options + * + * This function needs to be called before any other operations are performed on + * the ad_sigma_delta struct. + */ +int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev, + struct spi_device *spi, const struct ad_sigma_delta_info *info) +{ + sigma_delta->spi = spi; + sigma_delta->info = info; + + /* If the field is unset in ad_sigma_delta_info, asume there can only be 1 slot. */ + if (!info->num_slots) + sigma_delta->num_slots = 1; + else + sigma_delta->num_slots = info->num_slots; + + if (sigma_delta->num_slots > 1) { + if (!indio_dev->info->update_scan_mode) { + dev_err(&spi->dev, "iio_dev lacks update_scan_mode().\n"); + return -EINVAL; + } + + if (!info->disable_all) { + dev_err(&spi->dev, "ad_sigma_delta_info lacks disable_all().\n"); + return -EINVAL; + } + } + + iio_device_set_drvdata(indio_dev, sigma_delta); + + return 0; +} +EXPORT_SYMBOL_NS_GPL(ad_sd_init, IIO_AD_SIGMA_DELTA); + +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); +MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs"); +MODULE_LICENSE("GPL v2"); |