| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * MAX1117/MAX1118/MAX1119 8-bit, dual-channel ADCs driver |
| * |
| * Copyright (c) 2017 Akinobu Mita <akinobu.mita@gmail.com> |
| * |
| * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1117-MAX1119.pdf |
| * |
| * SPI interface connections |
| * |
| * SPI MAXIM |
| * Master Direction MAX1117/8/9 |
| * ------ --------- ----------- |
| * nCS --> CNVST |
| * SCK --> SCLK |
| * MISO <-- DOUT |
| * ------ --------- ----------- |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/spi/spi.h> |
| #include <linux/iio/iio.h> |
| #include <linux/iio/buffer.h> |
| #include <linux/iio/triggered_buffer.h> |
| #include <linux/iio/trigger_consumer.h> |
| #include <linux/regulator/consumer.h> |
| |
| enum max1118_id { |
| max1117, |
| max1118, |
| max1119, |
| }; |
| |
| struct max1118 { |
| struct spi_device *spi; |
| struct mutex lock; |
| struct regulator *reg; |
| |
| u8 data ____cacheline_aligned; |
| }; |
| |
| #define MAX1118_CHANNEL(ch) \ |
| { \ |
| .type = IIO_VOLTAGE, \ |
| .indexed = 1, \ |
| .channel = (ch), \ |
| .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
| .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ |
| .scan_index = ch, \ |
| .scan_type = { \ |
| .sign = 'u', \ |
| .realbits = 8, \ |
| .storagebits = 8, \ |
| }, \ |
| } |
| |
| static const struct iio_chan_spec max1118_channels[] = { |
| MAX1118_CHANNEL(0), |
| MAX1118_CHANNEL(1), |
| IIO_CHAN_SOFT_TIMESTAMP(2), |
| }; |
| |
| static int max1118_read(struct spi_device *spi, int channel) |
| { |
| struct iio_dev *indio_dev = spi_get_drvdata(spi); |
| struct max1118 *adc = iio_priv(indio_dev); |
| struct spi_transfer xfers[] = { |
| /* |
| * To select CH1 for conversion, CNVST pin must be brought high |
| * and low for a second time. |
| */ |
| { |
| .len = 0, |
| .delay_usecs = 1, /* > CNVST Low Time 100 ns */ |
| .cs_change = 1, |
| }, |
| /* |
| * The acquisition interval begins with the falling edge of |
| * CNVST. The total acquisition and conversion process takes |
| * <7.5us. |
| */ |
| { |
| .len = 0, |
| .delay_usecs = 8, |
| }, |
| { |
| .rx_buf = &adc->data, |
| .len = 1, |
| }, |
| }; |
| int ret; |
| |
| if (channel == 0) |
| ret = spi_sync_transfer(spi, xfers + 1, 2); |
| else |
| ret = spi_sync_transfer(spi, xfers, 3); |
| |
| if (ret) |
| return ret; |
| |
| return adc->data; |
| } |
| |
| static int max1118_get_vref_mV(struct spi_device *spi) |
| { |
| struct iio_dev *indio_dev = spi_get_drvdata(spi); |
| struct max1118 *adc = iio_priv(indio_dev); |
| const struct spi_device_id *id = spi_get_device_id(spi); |
| int vref_uV; |
| |
| switch (id->driver_data) { |
| case max1117: |
| return 2048; |
| case max1119: |
| return 4096; |
| case max1118: |
| vref_uV = regulator_get_voltage(adc->reg); |
| if (vref_uV < 0) |
| return vref_uV; |
| return vref_uV / 1000; |
| } |
| |
| return -ENODEV; |
| } |
| |
| static int max1118_read_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, |
| int *val, int *val2, long mask) |
| { |
| struct max1118 *adc = iio_priv(indio_dev); |
| |
| switch (mask) { |
| case IIO_CHAN_INFO_RAW: |
| mutex_lock(&adc->lock); |
| *val = max1118_read(adc->spi, chan->channel); |
| mutex_unlock(&adc->lock); |
| if (*val < 0) |
| return *val; |
| |
| return IIO_VAL_INT; |
| case IIO_CHAN_INFO_SCALE: |
| *val = max1118_get_vref_mV(adc->spi); |
| if (*val < 0) |
| return *val; |
| *val2 = 8; |
| |
| return IIO_VAL_FRACTIONAL_LOG2; |
| } |
| |
| return -EINVAL; |
| } |
| |
| static const struct iio_info max1118_info = { |
| .read_raw = max1118_read_raw, |
| }; |
| |
| static irqreturn_t max1118_trigger_handler(int irq, void *p) |
| { |
| struct iio_poll_func *pf = p; |
| struct iio_dev *indio_dev = pf->indio_dev; |
| struct max1118 *adc = iio_priv(indio_dev); |
| u8 data[16] = { }; /* 2x 8-bit ADC data + padding + 8 bytes timestamp */ |
| int scan_index; |
| int i = 0; |
| |
| mutex_lock(&adc->lock); |
| |
| 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]; |
| int ret = max1118_read(adc->spi, scan_chan->channel); |
| |
| if (ret < 0) { |
| dev_warn(&adc->spi->dev, |
| "failed to get conversion data\n"); |
| goto out; |
| } |
| |
| data[i] = ret; |
| i++; |
| } |
| iio_push_to_buffers_with_timestamp(indio_dev, data, |
| iio_get_time_ns(indio_dev)); |
| out: |
| mutex_unlock(&adc->lock); |
| |
| iio_trigger_notify_done(indio_dev->trig); |
| |
| return IRQ_HANDLED; |
| } |
| |
| static int max1118_probe(struct spi_device *spi) |
| { |
| struct iio_dev *indio_dev; |
| struct max1118 *adc; |
| const struct spi_device_id *id = spi_get_device_id(spi); |
| int ret; |
| |
| indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); |
| if (!indio_dev) |
| return -ENOMEM; |
| |
| adc = iio_priv(indio_dev); |
| adc->spi = spi; |
| mutex_init(&adc->lock); |
| |
| if (id->driver_data == max1118) { |
| adc->reg = devm_regulator_get(&spi->dev, "vref"); |
| if (IS_ERR(adc->reg)) { |
| dev_err(&spi->dev, "failed to get vref regulator\n"); |
| return PTR_ERR(adc->reg); |
| } |
| ret = regulator_enable(adc->reg); |
| if (ret) |
| return ret; |
| } |
| |
| spi_set_drvdata(spi, indio_dev); |
| |
| indio_dev->name = spi_get_device_id(spi)->name; |
| indio_dev->dev.parent = &spi->dev; |
| indio_dev->info = &max1118_info; |
| indio_dev->modes = INDIO_DIRECT_MODE; |
| indio_dev->channels = max1118_channels; |
| indio_dev->num_channels = ARRAY_SIZE(max1118_channels); |
| |
| /* |
| * To reinitiate a conversion on CH0, it is necessary to allow for a |
| * conversion to be complete and all of the data to be read out. Once |
| * a conversion has been completed, the MAX1117/MAX1118/MAX1119 will go |
| * into AutoShutdown mode until the next conversion is initiated. |
| */ |
| max1118_read(spi, 0); |
| |
| ret = iio_triggered_buffer_setup(indio_dev, NULL, |
| max1118_trigger_handler, NULL); |
| if (ret) |
| goto err_reg_disable; |
| |
| ret = iio_device_register(indio_dev); |
| if (ret) |
| goto err_buffer_cleanup; |
| |
| return 0; |
| |
| err_buffer_cleanup: |
| iio_triggered_buffer_cleanup(indio_dev); |
| err_reg_disable: |
| if (id->driver_data == max1118) |
| regulator_disable(adc->reg); |
| |
| return ret; |
| } |
| |
| static int max1118_remove(struct spi_device *spi) |
| { |
| struct iio_dev *indio_dev = spi_get_drvdata(spi); |
| struct max1118 *adc = iio_priv(indio_dev); |
| const struct spi_device_id *id = spi_get_device_id(spi); |
| |
| iio_device_unregister(indio_dev); |
| iio_triggered_buffer_cleanup(indio_dev); |
| if (id->driver_data == max1118) |
| return regulator_disable(adc->reg); |
| |
| return 0; |
| } |
| |
| static const struct spi_device_id max1118_id[] = { |
| { "max1117", max1117 }, |
| { "max1118", max1118 }, |
| { "max1119", max1119 }, |
| {} |
| }; |
| MODULE_DEVICE_TABLE(spi, max1118_id); |
| |
| #ifdef CONFIG_OF |
| |
| static const struct of_device_id max1118_dt_ids[] = { |
| { .compatible = "maxim,max1117" }, |
| { .compatible = "maxim,max1118" }, |
| { .compatible = "maxim,max1119" }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(of, max1118_dt_ids); |
| |
| #endif |
| |
| static struct spi_driver max1118_spi_driver = { |
| .driver = { |
| .name = "max1118", |
| .of_match_table = of_match_ptr(max1118_dt_ids), |
| }, |
| .probe = max1118_probe, |
| .remove = max1118_remove, |
| .id_table = max1118_id, |
| }; |
| module_spi_driver(max1118_spi_driver); |
| |
| MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); |
| MODULE_DESCRIPTION("MAXIM MAX1117/MAX1118/MAX1119 ADCs driver"); |
| MODULE_LICENSE("GPL v2"); |