--- /dev/null
+/*
+ * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
+ *
+ * Driver for Microchip Technology's MCP3204 and MCP3208 ADC chips.
+ * Datasheet can be found here:
+ * http://ww1.microchip.com/downloads/en/devicedoc/21298c.pdf
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
+
+#define MCP_SINGLE_ENDED (1 << 3)
+#define MCP_START_BIT (1 << 4)
+
+enum {
+ mcp3204,
+ mcp3208,
+};
+
+struct mcp320x {
+ struct spi_device *spi;
+ struct spi_message msg;
+ struct spi_transfer transfer[2];
+
+ u8 tx_buf;
+ u8 rx_buf[2];
+
+ struct regulator *reg;
+ struct mutex lock;
+};
+
+static int mcp320x_adc_conversion(struct mcp320x *adc, u8 msg)
+{
+ int ret;
+
+ adc->tx_buf = msg;
+ ret = spi_sync(adc->spi, &adc->msg);
+ if (ret < 0)
+ return ret;
+
+ return ((adc->rx_buf[0] & 0x3f) << 6) |
+ (adc->rx_buf[1] >> 2);
+}
+
+static int mcp320x_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *channel, int *val,
+ int *val2, long mask)
+{
+ struct mcp320x *adc = iio_priv(indio_dev);
+ int ret = -EINVAL;
+
+ mutex_lock(&adc->lock);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (channel->differential)
+ ret = mcp320x_adc_conversion(adc,
+ MCP_START_BIT | channel->address);
+ else
+ ret = mcp320x_adc_conversion(adc,
+ MCP_START_BIT | MCP_SINGLE_ENDED |
+ channel->address);
+ if (ret < 0)
+ goto out;
+
+ *val = ret;
+ ret = IIO_VAL_INT;
+ break;
+
+ case IIO_CHAN_INFO_SCALE:
+ /* Digital output code = (4096 * Vin) / Vref */
+ ret = regulator_get_voltage(adc->reg);
+ if (ret < 0)
+ goto out;
+
+ *val = ret / 1000;
+ *val2 = 12;
+ ret = IIO_VAL_FRACTIONAL_LOG2;
+ break;
+
+ default:
+ break;
+ }
+
+out:
+ mutex_unlock(&adc->lock);
+
+ return ret;
+}
+
+#define MCP320X_VOLTAGE_CHANNEL(num) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = (num), \
+ .address = (num), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
+ }
+
+#define MCP320X_VOLTAGE_CHANNEL_DIFF(num) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = (num * 2), \
+ .channel2 = (num * 2 + 1), \
+ .address = (num * 2), \
+ .differential = 1, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
+ }
+
+static const struct iio_chan_spec mcp3204_channels[] = {
+ MCP320X_VOLTAGE_CHANNEL(0),
+ MCP320X_VOLTAGE_CHANNEL(1),
+ MCP320X_VOLTAGE_CHANNEL(2),
+ MCP320X_VOLTAGE_CHANNEL(3),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(0),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(1),
+};
+
+static const struct iio_chan_spec mcp3208_channels[] = {
+ MCP320X_VOLTAGE_CHANNEL(0),
+ MCP320X_VOLTAGE_CHANNEL(1),
+ MCP320X_VOLTAGE_CHANNEL(2),
+ MCP320X_VOLTAGE_CHANNEL(3),
+ MCP320X_VOLTAGE_CHANNEL(4),
+ MCP320X_VOLTAGE_CHANNEL(5),
+ MCP320X_VOLTAGE_CHANNEL(6),
+ MCP320X_VOLTAGE_CHANNEL(7),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(0),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(1),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(2),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(3),
+};
+
+static const struct iio_info mcp320x_info = {
+ .read_raw = mcp320x_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+struct mcp3208_chip_info {
+ const struct iio_chan_spec *channels;
+ unsigned int num_channels;
+};
+
+static const struct mcp3208_chip_info mcp3208_chip_infos[] = {
+ [mcp3204] = {
+ .channels = mcp3204_channels,
+ .num_channels = ARRAY_SIZE(mcp3204_channels)
+ },
+ [mcp3208] = {
+ .channels = mcp3208_channels,
+ .num_channels = ARRAY_SIZE(mcp3208_channels)
+ },
+};
+
+static int mcp320x_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct mcp320x *adc;
+ const struct mcp3208_chip_info *chip_info;
+ int ret;
+
+ indio_dev = iio_device_alloc(sizeof(*adc));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ adc = iio_priv(indio_dev);
+ adc->spi = spi;
+
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &mcp320x_info;
+
+ chip_info = &mcp3208_chip_infos[spi_get_device_id(spi)->driver_data];
+ indio_dev->channels = chip_info->channels;
+ indio_dev->num_channels = chip_info->num_channels;
+
+ adc->transfer[0].tx_buf = &adc->tx_buf;
+ adc->transfer[0].len = sizeof(adc->tx_buf);
+ adc->transfer[1].rx_buf = adc->rx_buf;
+ adc->transfer[1].len = sizeof(adc->rx_buf);
+
+ spi_message_init_with_transfers(&adc->msg, adc->transfer,
+ ARRAY_SIZE(adc->transfer));
+
+ adc->reg = regulator_get(&spi->dev, "vref");
+ if (IS_ERR(adc->reg)) {
+ ret = PTR_ERR(adc->reg);
+ goto iio_free;
+ }
+
+ ret = regulator_enable(adc->reg);
+ if (ret < 0)
+ goto reg_free;
+
+ mutex_init(&adc->lock);
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0)
+ goto reg_disable;
+
+ return 0;
+
+reg_disable:
+ regulator_disable(adc->reg);
+reg_free:
+ regulator_put(adc->reg);
+iio_free:
+ iio_device_free(indio_dev);
+
+ return ret;
+}
+
+static int mcp320x_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct mcp320x *adc = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ regulator_disable(adc->reg);
+ regulator_put(adc->reg);
+ iio_device_free(indio_dev);
+
+ return 0;
+}
+
+static const struct spi_device_id mcp320x_id[] = {
+ { "mcp3204", mcp3204 },
+ { "mcp3208", mcp3208 },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, mcp320x_id);
+
+static struct spi_driver mcp320x_driver = {
+ .driver = {
+ .name = "mcp320x",
+ .owner = THIS_MODULE,
+ },
+ .probe = mcp320x_probe,
+ .remove = mcp320x_remove,
+ .id_table = mcp320x_id,
+};
+module_spi_driver(mcp320x_driver);
+
+MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
+MODULE_DESCRIPTION("Microchip Technology MCP3204/08");
+MODULE_LICENSE("GPL v2");
projects / GitHub / MotorolaMobilityLLC / kernel-slsi.git / commitdiff