// SPDX-License-Identifier: GPL-2.0-only /* * TI tlc4541 ADC Driver * * Copyright (C) 2017 Phil Reid * * Datasheets can be found here: * https://www.ti.com/lit/gpn/tlc3541 * https://www.ti.com/lit/gpn/tlc4541 * * The tlc4541 requires 24 clock cycles to start a transfer. * Conversion then takes 2.94us to complete before data is ready * Data is returned MSB first. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include struct tlc4541_state { struct spi_device *spi; struct regulator *reg; struct spi_transfer scan_single_xfer[3]; struct spi_message scan_single_msg; /* * DMA (thus cache coherency maintenance) may require the * transfer buffers to live in their own cache lines. * 2 bytes data + 6 bytes padding + 8 bytes timestamp when * call iio_push_to_buffers_with_timestamp. */ __be16 rx_buf[8] __aligned(IIO_DMA_MINALIGN); }; struct tlc4541_chip_info { const struct iio_chan_spec *channels; unsigned int num_channels; }; enum tlc4541_id { TLC3541, TLC4541, }; #define TLC4541_V_CHAN(bits, bitshift) { \ .type = IIO_VOLTAGE, \ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ .scan_type = { \ .sign = 'u', \ .realbits = (bits), \ .storagebits = 16, \ .shift = (bitshift), \ .endianness = IIO_BE, \ }, \ } #define DECLARE_TLC4541_CHANNELS(name, bits, bitshift) \ const struct iio_chan_spec name ## _channels[] = { \ TLC4541_V_CHAN(bits, bitshift), \ IIO_CHAN_SOFT_TIMESTAMP(1), \ } static DECLARE_TLC4541_CHANNELS(tlc3541, 14, 2); static DECLARE_TLC4541_CHANNELS(tlc4541, 16, 0); static const struct tlc4541_chip_info tlc4541_chip_info[] = { [TLC3541] = { .channels = tlc3541_channels, .num_channels = ARRAY_SIZE(tlc3541_channels), }, [TLC4541] = { .channels = tlc4541_channels, .num_channels = ARRAY_SIZE(tlc4541_channels), }, }; static irqreturn_t tlc4541_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; struct iio_dev *indio_dev = pf->indio_dev; struct tlc4541_state *st = iio_priv(indio_dev); int ret; ret = spi_sync(st->spi, &st->scan_single_msg); if (ret < 0) goto done; iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf, iio_get_time_ns(indio_dev)); done: iio_trigger_notify_done(indio_dev->trig); return IRQ_HANDLED; } static int tlc4541_get_range(struct tlc4541_state *st) { int vref; vref = regulator_get_voltage(st->reg); if (vref < 0) return vref; vref /= 1000; return vref; } static int tlc4541_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long m) { int ret = 0; struct tlc4541_state *st = iio_priv(indio_dev); switch (m) { case IIO_CHAN_INFO_RAW: ret = iio_device_claim_direct_mode(indio_dev); if (ret) return ret; ret = spi_sync(st->spi, &st->scan_single_msg); iio_device_release_direct_mode(indio_dev); if (ret < 0) return ret; *val = be16_to_cpu(st->rx_buf[0]); *val = *val >> chan->scan_type.shift; *val &= GENMASK(chan->scan_type.realbits - 1, 0); return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: ret = tlc4541_get_range(st); if (ret < 0) return ret; *val = ret; *val2 = chan->scan_type.realbits; return IIO_VAL_FRACTIONAL_LOG2; } return -EINVAL; } static const struct iio_info tlc4541_info = { .read_raw = &tlc4541_read_raw, }; static int tlc4541_probe(struct spi_device *spi) { struct tlc4541_state *st; struct iio_dev *indio_dev; const struct tlc4541_chip_info *info; int ret; int8_t device_init = 0; indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); if (indio_dev == NULL) return -ENOMEM; st = iio_priv(indio_dev); spi_set_drvdata(spi, indio_dev); st->spi = spi; info = &tlc4541_chip_info[spi_get_device_id(spi)->driver_data]; indio_dev->name = spi_get_device_id(spi)->name; indio_dev->modes = INDIO_DIRECT_MODE; indio_dev->channels = info->channels; indio_dev->num_channels = info->num_channels; indio_dev->info = &tlc4541_info; /* perform reset */ spi_write(spi, &device_init, 1); /* Setup default message */ st->scan_single_xfer[0].rx_buf = &st->rx_buf[0]; st->scan_single_xfer[0].len = 3; st->scan_single_xfer[1].delay.value = 3; st->scan_single_xfer[1].delay.unit = SPI_DELAY_UNIT_NSECS; st->scan_single_xfer[2].rx_buf = &st->rx_buf[0]; st->scan_single_xfer[2].len = 2; spi_message_init_with_transfers(&st->scan_single_msg, st->scan_single_xfer, 3); st->reg = devm_regulator_get(&spi->dev, "vref"); if (IS_ERR(st->reg)) return PTR_ERR(st->reg); ret = regulator_enable(st->reg); if (ret) return ret; ret = iio_triggered_buffer_setup(indio_dev, NULL, &tlc4541_trigger_handler, NULL); if (ret) goto error_disable_reg; ret = iio_device_register(indio_dev); if (ret) goto error_cleanup_buffer; return 0; error_cleanup_buffer: iio_triggered_buffer_cleanup(indio_dev); error_disable_reg: regulator_disable(st->reg); return ret; } static void tlc4541_remove(struct spi_device *spi) { struct iio_dev *indio_dev = spi_get_drvdata(spi); struct tlc4541_state *st = iio_priv(indio_dev); iio_device_unregister(indio_dev); iio_triggered_buffer_cleanup(indio_dev); regulator_disable(st->reg); } static const struct of_device_id tlc4541_dt_ids[] = { { .compatible = "ti,tlc3541", }, { .compatible = "ti,tlc4541", }, { } }; MODULE_DEVICE_TABLE(of, tlc4541_dt_ids); static const struct spi_device_id tlc4541_id[] = { { "tlc3541", TLC3541 }, { "tlc4541", TLC4541 }, { } }; MODULE_DEVICE_TABLE(spi, tlc4541_id); static struct spi_driver tlc4541_driver = { .driver = { .name = "tlc4541", .of_match_table = tlc4541_dt_ids, }, .probe = tlc4541_probe, .remove = tlc4541_remove, .id_table = tlc4541_id, }; module_spi_driver(tlc4541_driver); MODULE_AUTHOR("Phil Reid "); MODULE_DESCRIPTION("Texas Instruments TLC4541 ADC"); MODULE_LICENSE("GPL v2");