--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* ad7949.c - Analog Devices ADC driver 14/16 bits 4/8 channels
+ *
+ * Copyright (C) 2018 CMC NV
+ *
+ * http://www.analog.com/media/en/technical-documentation/data-sheets/AD7949.pdf
+ */
+
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#define AD7949_MASK_CHANNEL_SEL GENMASK(9, 7)
+#define AD7949_MASK_TOTAL GENMASK(13, 0)
+#define AD7949_OFFSET_CHANNEL_SEL 7
+#define AD7949_CFG_READ_BACK 0x1
+#define AD7949_CFG_REG_SIZE_BITS 14
+
+enum {
+ ID_AD7949 = 0,
+ ID_AD7682,
+ ID_AD7689,
+};
+
+struct ad7949_adc_spec {
+ u8 num_channels;
+ u8 resolution;
+};
+
+static const struct ad7949_adc_spec ad7949_adc_spec[] = {
+ [ID_AD7949] = { .num_channels = 8, .resolution = 14 },
+ [ID_AD7682] = { .num_channels = 4, .resolution = 16 },
+ [ID_AD7689] = { .num_channels = 8, .resolution = 16 },
+};
+
+/**
+ * struct ad7949_adc_chip - AD ADC chip
+ * @lock: protects write sequences
+ * @vref: regulator generating Vref
+ * @iio_dev: reference to iio structure
+ * @spi: reference to spi structure
+ * @resolution: resolution of the chip
+ * @cfg: copy of the configuration register
+ * @current_channel: current channel in use
+ * @buffer: buffer to send / receive data to / from device
+ */
+struct ad7949_adc_chip {
+ struct mutex lock;
+ struct regulator *vref;
+ struct iio_dev *indio_dev;
+ struct spi_device *spi;
+ u8 resolution;
+ u16 cfg;
+ unsigned int current_channel;
+ u32 buffer ____cacheline_aligned;
+};
+
+static bool ad7949_spi_cfg_is_read_back(struct ad7949_adc_chip *ad7949_adc)
+{
+ if (!(ad7949_adc->cfg & AD7949_CFG_READ_BACK))
+ return true;
+
+ return false;
+}
+
+static int ad7949_spi_bits_per_word(struct ad7949_adc_chip *ad7949_adc)
+{
+ int ret = ad7949_adc->resolution;
+
+ if (ad7949_spi_cfg_is_read_back(ad7949_adc))
+ ret += AD7949_CFG_REG_SIZE_BITS;
+
+ return ret;
+}
+
+static int ad7949_spi_write_cfg(struct ad7949_adc_chip *ad7949_adc, u16 val,
+ u16 mask)
+{
+ int ret;
+ int bits_per_word = ad7949_spi_bits_per_word(ad7949_adc);
+ int shift = bits_per_word - AD7949_CFG_REG_SIZE_BITS;
+ struct spi_message msg;
+ struct spi_transfer tx[] = {
+ {
+ .tx_buf = &ad7949_adc->buffer,
+ .len = 4,
+ .bits_per_word = bits_per_word,
+ },
+ };
+
+ ad7949_adc->cfg = (val & mask) | (ad7949_adc->cfg & ~mask);
+ ad7949_adc->buffer = ad7949_adc->cfg << shift;
+ spi_message_init_with_transfers(&msg, tx, 1);
+ ret = spi_sync(ad7949_adc->spi, &msg);
+
+ /*
+ * This delay is to avoid a new request before the required time to
+ * send a new command to the device
+ */
+ udelay(2);
+ return ret;
+}
+
+static int ad7949_spi_read_channel(struct ad7949_adc_chip *ad7949_adc, int *val,
+ unsigned int channel)
+{
+ int ret;
+ int bits_per_word = ad7949_spi_bits_per_word(ad7949_adc);
+ int mask = GENMASK(ad7949_adc->resolution, 0);
+ struct spi_message msg;
+ struct spi_transfer tx[] = {
+ {
+ .rx_buf = &ad7949_adc->buffer,
+ .len = 4,
+ .bits_per_word = bits_per_word,
+ },
+ };
+
+ ret = ad7949_spi_write_cfg(ad7949_adc,
+ channel << AD7949_OFFSET_CHANNEL_SEL,
+ AD7949_MASK_CHANNEL_SEL);
+ if (ret)
+ return ret;
+
+ ad7949_adc->buffer = 0;
+ spi_message_init_with_transfers(&msg, tx, 1);
+ ret = spi_sync(ad7949_adc->spi, &msg);
+ if (ret)
+ return ret;
+
+ /*
+ * This delay is to avoid a new request before the required time to
+ * send a new command to the device
+ */
+ udelay(2);
+
+ ad7949_adc->current_channel = channel;
+
+ if (ad7949_spi_cfg_is_read_back(ad7949_adc))
+ *val = (ad7949_adc->buffer >> AD7949_CFG_REG_SIZE_BITS) & mask;
+ else
+ *val = ad7949_adc->buffer & mask;
+
+ return 0;
+}
+
+#define AD7949_ADC_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), \
+}
+
+static const struct iio_chan_spec ad7949_adc_channels[] = {
+ AD7949_ADC_CHANNEL(0),
+ AD7949_ADC_CHANNEL(1),
+ AD7949_ADC_CHANNEL(2),
+ AD7949_ADC_CHANNEL(3),
+ AD7949_ADC_CHANNEL(4),
+ AD7949_ADC_CHANNEL(5),
+ AD7949_ADC_CHANNEL(6),
+ AD7949_ADC_CHANNEL(7),
+};
+
+static int ad7949_spi_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev);
+ int ret;
+
+ if (!val)
+ return -EINVAL;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&ad7949_adc->lock);
+ ret = ad7949_spi_read_channel(ad7949_adc, val, chan->channel);
+ mutex_unlock(&ad7949_adc->lock);
+
+ if (ret < 0)
+ return ret;
+
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ ret = regulator_get_voltage(ad7949_adc->vref);
+ if (ret < 0)
+ return ret;
+
+ *val = ret / 5000;
+ return IIO_VAL_INT;
+ }
+
+ return -EINVAL;
+}
+
+static int ad7949_spi_reg_access(struct iio_dev *indio_dev,
+ unsigned int reg, unsigned int writeval,
+ unsigned int *readval)
+{
+ struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev);
+ int ret = 0;
+
+ if (readval)
+ *readval = ad7949_adc->cfg;
+ else
+ ret = ad7949_spi_write_cfg(ad7949_adc,
+ writeval & AD7949_MASK_TOTAL, AD7949_MASK_TOTAL);
+
+ return ret;
+}
+
+static const struct iio_info ad7949_spi_info = {
+ .read_raw = ad7949_spi_read_raw,
+ .debugfs_reg_access = ad7949_spi_reg_access,
+};
+
+static int ad7949_spi_init(struct ad7949_adc_chip *ad7949_adc)
+{
+ int ret;
+ int val;
+
+ /* Sequencer disabled, CFG readback disabled, IN0 as default channel */
+ ad7949_adc->current_channel = 0;
+ ret = ad7949_spi_write_cfg(ad7949_adc, 0x3C79, AD7949_MASK_TOTAL);
+
+ /*
+ * Do two dummy conversions to apply the first configuration setting.
+ * Required only after the start up of the device.
+ */
+ ad7949_spi_read_channel(ad7949_adc, &val, ad7949_adc->current_channel);
+ ad7949_spi_read_channel(ad7949_adc, &val, ad7949_adc->current_channel);
+
+ return ret;
+}
+
+static int ad7949_spi_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ const struct ad7949_adc_spec *spec;
+ struct ad7949_adc_chip *ad7949_adc;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*ad7949_adc));
+ if (!indio_dev) {
+ dev_err(dev, "can not allocate iio device\n");
+ return -ENOMEM;
+ }
+
+ indio_dev->dev.parent = dev;
+ indio_dev->dev.of_node = dev->of_node;
+ indio_dev->info = &ad7949_spi_info;
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = ad7949_adc_channels;
+ spi_set_drvdata(spi, indio_dev);
+
+ ad7949_adc = iio_priv(indio_dev);
+ ad7949_adc->indio_dev = indio_dev;
+ ad7949_adc->spi = spi;
+
+ spec = &ad7949_adc_spec[spi_get_device_id(spi)->driver_data];
+ indio_dev->num_channels = spec->num_channels;
+ ad7949_adc->resolution = spec->resolution;
+
+ ad7949_adc->vref = devm_regulator_get(dev, "vref");
+ if (IS_ERR(ad7949_adc->vref)) {
+ dev_err(dev, "fail to request regulator\n");
+ return PTR_ERR(ad7949_adc->vref);
+ }
+
+ ret = regulator_enable(ad7949_adc->vref);
+ if (ret < 0) {
+ dev_err(dev, "fail to enable regulator\n");
+ return ret;
+ }
+
+ mutex_init(&ad7949_adc->lock);
+
+ ret = ad7949_spi_init(ad7949_adc);
+ if (ret) {
+ dev_err(dev, "enable to init this device: %d\n", ret);
+ goto err;
+ }
+
+ ret = iio_device_register(indio_dev);
+ if (ret) {
+ dev_err(dev, "fail to register iio device: %d\n", ret);
+ goto err;
+ }
+
+ return 0;
+
+err:
+ mutex_destroy(&ad7949_adc->lock);
+ regulator_disable(ad7949_adc->vref);
+
+ return ret;
+}
+
+static int ad7949_spi_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct ad7949_adc_chip *ad7949_adc = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ mutex_destroy(&ad7949_adc->lock);
+ regulator_disable(ad7949_adc->vref);
+
+ return 0;
+}
+
+static const struct of_device_id ad7949_spi_of_id[] = {
+ { .compatible = "adi,ad7949" },
+ { .compatible = "adi,ad7682" },
+ { .compatible = "adi,ad7689" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ad7949_spi_of_id);
+
+static const struct spi_device_id ad7949_spi_id[] = {
+ { "ad7949", ID_AD7949 },
+ { "ad7682", ID_AD7682 },
+ { "ad7689", ID_AD7689 },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, ad7949_spi_id);
+
+static struct spi_driver ad7949_spi_driver = {
+ .driver = {
+ .name = "ad7949",
+ .of_match_table = ad7949_spi_of_id,
+ },
+ .probe = ad7949_spi_probe,
+ .remove = ad7949_spi_remove,
+ .id_table = ad7949_spi_id,
+};
+module_spi_driver(ad7949_spi_driver);
+
+MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@essensium.com>");
+MODULE_DESCRIPTION("Analog Devices 14/16-bit 8-channel ADC driver");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-starfive.git / commitdiff