// SPDX-License-Identifier: GPL-2.0-only /* * ADC0831/ADC0832/ADC0834/ADC0838 8-bit ADC driver * * Copyright (c) 2016 Akinobu Mita * * Datasheet: http://www.ti.com/lit/ds/symlink/adc0832-n.pdf */ #include #include #include #include #include #include #include #include enum { adc0831, adc0832, adc0834, adc0838, }; struct adc0832 { struct spi_device *spi; struct regulator *reg; struct mutex lock; u8 mux_bits; u8 tx_buf[2] ____cacheline_aligned; u8 rx_buf[2]; }; #define ADC0832_VOLTAGE_CHANNEL(chan) \ { \ .type = IIO_VOLTAGE, \ .indexed = 1, \ .channel = chan, \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ .scan_index = chan, \ .scan_type = { \ .sign = 'u', \ .realbits = 8, \ .storagebits = 8, \ }, \ } #define ADC0832_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \ { \ .type = IIO_VOLTAGE, \ .indexed = 1, \ .channel = (chan1), \ .channel2 = (chan2), \ .differential = 1, \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ .scan_index = si, \ .scan_type = { \ .sign = 'u', \ .realbits = 8, \ .storagebits = 8, \ }, \ } static const struct iio_chan_spec adc0831_channels[] = { ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 0), IIO_CHAN_SOFT_TIMESTAMP(1), }; static const struct iio_chan_spec adc0832_channels[] = { ADC0832_VOLTAGE_CHANNEL(0), ADC0832_VOLTAGE_CHANNEL(1), ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 2), ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 3), IIO_CHAN_SOFT_TIMESTAMP(4), }; static const struct iio_chan_spec adc0834_channels[] = { ADC0832_VOLTAGE_CHANNEL(0), ADC0832_VOLTAGE_CHANNEL(1), ADC0832_VOLTAGE_CHANNEL(2), ADC0832_VOLTAGE_CHANNEL(3), ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 4), ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 5), ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 6), ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 7), IIO_CHAN_SOFT_TIMESTAMP(8), }; static const struct iio_chan_spec adc0838_channels[] = { ADC0832_VOLTAGE_CHANNEL(0), ADC0832_VOLTAGE_CHANNEL(1), ADC0832_VOLTAGE_CHANNEL(2), ADC0832_VOLTAGE_CHANNEL(3), ADC0832_VOLTAGE_CHANNEL(4), ADC0832_VOLTAGE_CHANNEL(5), ADC0832_VOLTAGE_CHANNEL(6), ADC0832_VOLTAGE_CHANNEL(7), ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 8), ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 9), ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 10), ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 11), ADC0832_VOLTAGE_CHANNEL_DIFF(4, 5, 12), ADC0832_VOLTAGE_CHANNEL_DIFF(5, 4, 13), ADC0832_VOLTAGE_CHANNEL_DIFF(6, 7, 14), ADC0832_VOLTAGE_CHANNEL_DIFF(7, 6, 15), IIO_CHAN_SOFT_TIMESTAMP(16), }; static int adc0831_adc_conversion(struct adc0832 *adc) { struct spi_device *spi = adc->spi; int ret; ret = spi_read(spi, &adc->rx_buf, 2); if (ret) return ret; /* * Skip TRI-STATE and a leading zero */ return (adc->rx_buf[0] << 2 & 0xff) | (adc->rx_buf[1] >> 6); } static int adc0832_adc_conversion(struct adc0832 *adc, int channel, bool differential) { struct spi_device *spi = adc->spi; struct spi_transfer xfer = { .tx_buf = adc->tx_buf, .rx_buf = adc->rx_buf, .len = 2, }; int ret; if (!adc->mux_bits) return adc0831_adc_conversion(adc); /* start bit */ adc->tx_buf[0] = 1 << (adc->mux_bits + 1); /* single-ended or differential */ adc->tx_buf[0] |= differential ? 0 : (1 << adc->mux_bits); /* odd / sign */ adc->tx_buf[0] |= (channel % 2) << (adc->mux_bits - 1); /* select */ if (adc->mux_bits > 1) adc->tx_buf[0] |= channel / 2; /* align Data output BIT7 (MSB) to 8-bit boundary */ adc->tx_buf[0] <<= 1; ret = spi_sync_transfer(spi, &xfer, 1); if (ret) return ret; return adc->rx_buf[1]; } static int adc0832_read_raw(struct iio_dev *iio, struct iio_chan_spec const *channel, int *value, int *shift, long mask) { struct adc0832 *adc = iio_priv(iio); switch (mask) { case IIO_CHAN_INFO_RAW: mutex_lock(&adc->lock); *value = adc0832_adc_conversion(adc, channel->channel, channel->differential); mutex_unlock(&adc->lock); if (*value < 0) return *value; return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: *value = regulator_get_voltage(adc->reg); if (*value < 0) return *value; /* convert regulator output voltage to mV */ *value /= 1000; *shift = 8; return IIO_VAL_FRACTIONAL_LOG2; } return -EINVAL; } static const struct iio_info adc0832_info = { .read_raw = adc0832_read_raw, }; static irqreturn_t adc0832_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct adc0832 *adc = iio_priv(indio_dev); u8 data[24] = { }; /* 16x 1 byte ADC data + 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 = adc0832_adc_conversion(adc, scan_chan->channel, scan_chan->differential); 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 adc0832_probe(struct spi_device *spi) { struct iio_dev *indio_dev; struct adc0832 *adc; 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); indio_dev->name = spi_get_device_id(spi)->name; indio_dev->dev.parent = &spi->dev; indio_dev->dev.of_node = spi->dev.of_node; indio_dev->info = &adc0832_info; indio_dev->modes = INDIO_DIRECT_MODE; switch (spi_get_device_id(spi)->driver_data) { case adc0831: adc->mux_bits = 0; indio_dev->channels = adc0831_channels; indio_dev->num_channels = ARRAY_SIZE(adc0831_channels); break; case adc0832: adc->mux_bits = 1; indio_dev->channels = adc0832_channels; indio_dev->num_channels = ARRAY_SIZE(adc0832_channels); break; case adc0834: adc->mux_bits = 2; indio_dev->channels = adc0834_channels; indio_dev->num_channels = ARRAY_SIZE(adc0834_channels); break; case adc0838: adc->mux_bits = 3; indio_dev->channels = adc0838_channels; indio_dev->num_channels = ARRAY_SIZE(adc0838_channels); break; default: return -EINVAL; } adc->reg = devm_regulator_get(&spi->dev, "vref"); if (IS_ERR(adc->reg)) return PTR_ERR(adc->reg); ret = regulator_enable(adc->reg); if (ret) return ret; spi_set_drvdata(spi, indio_dev); ret = iio_triggered_buffer_setup(indio_dev, NULL, adc0832_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: regulator_disable(adc->reg); return ret; } static int adc0832_remove(struct spi_device *spi) { struct iio_dev *indio_dev = spi_get_drvdata(spi); struct adc0832 *adc = iio_priv(indio_dev); iio_device_unregister(indio_dev); iio_triggered_buffer_cleanup(indio_dev); regulator_disable(adc->reg); return 0; } #ifdef CONFIG_OF static const struct of_device_id adc0832_dt_ids[] = { { .compatible = "ti,adc0831", }, { .compatible = "ti,adc0832", }, { .compatible = "ti,adc0834", }, { .compatible = "ti,adc0838", }, {} }; MODULE_DEVICE_TABLE(of, adc0832_dt_ids); #endif static const struct spi_device_id adc0832_id[] = { { "adc0831", adc0831 }, { "adc0832", adc0832 }, { "adc0834", adc0834 }, { "adc0838", adc0838 }, {} }; MODULE_DEVICE_TABLE(spi, adc0832_id); static struct spi_driver adc0832_driver = { .driver = { .name = "adc0832", .of_match_table = of_match_ptr(adc0832_dt_ids), }, .probe = adc0832_probe, .remove = adc0832_remove, .id_table = adc0832_id, }; module_spi_driver(adc0832_driver); MODULE_AUTHOR("Akinobu Mita "); MODULE_DESCRIPTION("ADC0831/ADC0832/ADC0834/ADC0838 driver"); MODULE_LICENSE("GPL v2");