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Diffstat (limited to 'drivers/iio/adc/mcp320x.c')
-rw-r--r--drivers/iio/adc/mcp320x.c530
1 files changed, 530 insertions, 0 deletions
diff --git a/drivers/iio/adc/mcp320x.c b/drivers/iio/adc/mcp320x.c
new file mode 100644
index 000000000..f3b81798b
--- /dev/null
+++ b/drivers/iio/adc/mcp320x.c
@@ -0,0 +1,530 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
+ * Copyright (C) 2014 Rose Technology
+ * Allan Bendorff Jensen <abj@rosetechnology.dk>
+ * Soren Andersen <san@rosetechnology.dk>
+ *
+ * Driver for following ADC chips from Microchip Technology's:
+ * 10 Bit converter
+ * MCP3001
+ * MCP3002
+ * MCP3004
+ * MCP3008
+ * ------------
+ * 12 bit converter
+ * MCP3201
+ * MCP3202
+ * MCP3204
+ * MCP3208
+ * ------------
+ * 13 bit converter
+ * MCP3301
+ * ------------
+ * 22 bit converter
+ * MCP3550
+ * MCP3551
+ * MCP3553
+ *
+ * Datasheet can be found here:
+ * https://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf mcp3001
+ * https://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf mcp3002
+ * https://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf mcp3004/08
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf mcp3201
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf mcp3202
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf mcp3204/08
+ * https://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf mcp3301
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21950D.pdf mcp3550/1/3
+ */
+
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
+
+enum {
+ mcp3001,
+ mcp3002,
+ mcp3004,
+ mcp3008,
+ mcp3201,
+ mcp3202,
+ mcp3204,
+ mcp3208,
+ mcp3301,
+ mcp3550_50,
+ mcp3550_60,
+ mcp3551,
+ mcp3553,
+};
+
+struct mcp320x_chip_info {
+ const struct iio_chan_spec *channels;
+ unsigned int num_channels;
+ unsigned int resolution;
+ unsigned int conv_time; /* usec */
+};
+
+/**
+ * struct mcp320x - Microchip SPI ADC instance
+ * @spi: SPI slave (parent of the IIO device)
+ * @msg: SPI message to select a channel and receive a value from the ADC
+ * @transfer: SPI transfers used by @msg
+ * @start_conv_msg: SPI message to start a conversion by briefly asserting CS
+ * @start_conv_transfer: SPI transfer used by @start_conv_msg
+ * @reg: regulator generating Vref
+ * @lock: protects read sequences
+ * @chip_info: ADC properties
+ * @tx_buf: buffer for @transfer[0] (not used on single-channel converters)
+ * @rx_buf: buffer for @transfer[1]
+ */
+struct mcp320x {
+ struct spi_device *spi;
+ struct spi_message msg;
+ struct spi_transfer transfer[2];
+ struct spi_message start_conv_msg;
+ struct spi_transfer start_conv_transfer;
+
+ struct regulator *reg;
+ struct mutex lock;
+ const struct mcp320x_chip_info *chip_info;
+
+ u8 tx_buf __aligned(IIO_DMA_MINALIGN);
+ u8 rx_buf[4];
+};
+
+static int mcp320x_channel_to_tx_data(int device_index,
+ const unsigned int channel, bool differential)
+{
+ int start_bit = 1;
+
+ switch (device_index) {
+ case mcp3002:
+ case mcp3202:
+ return ((start_bit << 4) | (!differential << 3) |
+ (channel << 2));
+ case mcp3004:
+ case mcp3204:
+ case mcp3008:
+ case mcp3208:
+ return ((start_bit << 6) | (!differential << 5) |
+ (channel << 2));
+ default:
+ return -EINVAL;
+ }
+}
+
+static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
+ bool differential, int device_index, int *val)
+{
+ int ret;
+
+ if (adc->chip_info->conv_time) {
+ ret = spi_sync(adc->spi, &adc->start_conv_msg);
+ if (ret < 0)
+ return ret;
+
+ usleep_range(adc->chip_info->conv_time,
+ adc->chip_info->conv_time + 100);
+ }
+
+ memset(&adc->rx_buf, 0, sizeof(adc->rx_buf));
+ if (adc->chip_info->num_channels > 1)
+ adc->tx_buf = mcp320x_channel_to_tx_data(device_index, channel,
+ differential);
+
+ ret = spi_sync(adc->spi, &adc->msg);
+ if (ret < 0)
+ return ret;
+
+ switch (device_index) {
+ case mcp3001:
+ *val = (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
+ return 0;
+ case mcp3002:
+ case mcp3004:
+ case mcp3008:
+ *val = (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
+ return 0;
+ case mcp3201:
+ *val = (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
+ return 0;
+ case mcp3202:
+ case mcp3204:
+ case mcp3208:
+ *val = (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
+ return 0;
+ case mcp3301:
+ *val = sign_extend32((adc->rx_buf[0] & 0x1f) << 8
+ | adc->rx_buf[1], 12);
+ return 0;
+ case mcp3550_50:
+ case mcp3550_60:
+ case mcp3551:
+ case mcp3553: {
+ u32 raw = be32_to_cpup((__be32 *)adc->rx_buf);
+
+ if (!(adc->spi->mode & SPI_CPOL))
+ raw <<= 1; /* strip Data Ready bit in SPI mode 0,0 */
+
+ /*
+ * If the input is within -vref and vref, bit 21 is the sign.
+ * Up to 12% overrange or underrange are allowed, in which case
+ * bit 23 is the sign and bit 0 to 21 is the value.
+ */
+ raw >>= 8;
+ if (raw & BIT(22) && raw & BIT(23))
+ return -EIO; /* cannot have overrange AND underrange */
+ else if (raw & BIT(22))
+ raw &= ~BIT(22); /* overrange */
+ else if (raw & BIT(23) || raw & BIT(21))
+ raw |= GENMASK(31, 22); /* underrange or negative */
+
+ *val = (s32)raw;
+ return 0;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+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;
+ int device_index = 0;
+
+ mutex_lock(&adc->lock);
+
+ device_index = spi_get_device_id(adc->spi)->driver_data;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = mcp320x_adc_conversion(adc, channel->address,
+ channel->differential, device_index, val);
+ if (ret < 0)
+ goto out;
+
+ ret = IIO_VAL_INT;
+ break;
+
+ case IIO_CHAN_INFO_SCALE:
+ ret = regulator_get_voltage(adc->reg);
+ if (ret < 0)
+ goto out;
+
+ /* convert regulator output voltage to mV */
+ *val = ret / 1000;
+ *val2 = adc->chip_info->resolution;
+ ret = IIO_VAL_FRACTIONAL_LOG2;
+ 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(chan1, chan2) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = (chan1), \
+ .channel2 = (chan2), \
+ .address = (chan1), \
+ .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 mcp3201_channels[] = {
+ MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
+};
+
+static const struct iio_chan_spec mcp3202_channels[] = {
+ MCP320X_VOLTAGE_CHANNEL(0),
+ MCP320X_VOLTAGE_CHANNEL(1),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
+};
+
+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, 1),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
+};
+
+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, 1),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(4, 5),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(5, 4),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(6, 7),
+ MCP320X_VOLTAGE_CHANNEL_DIFF(7, 6),
+};
+
+static const struct iio_info mcp320x_info = {
+ .read_raw = mcp320x_read_raw,
+};
+
+static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
+ [mcp3001] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 10
+ },
+ [mcp3002] = {
+ .channels = mcp3202_channels,
+ .num_channels = ARRAY_SIZE(mcp3202_channels),
+ .resolution = 10
+ },
+ [mcp3004] = {
+ .channels = mcp3204_channels,
+ .num_channels = ARRAY_SIZE(mcp3204_channels),
+ .resolution = 10
+ },
+ [mcp3008] = {
+ .channels = mcp3208_channels,
+ .num_channels = ARRAY_SIZE(mcp3208_channels),
+ .resolution = 10
+ },
+ [mcp3201] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 12
+ },
+ [mcp3202] = {
+ .channels = mcp3202_channels,
+ .num_channels = ARRAY_SIZE(mcp3202_channels),
+ .resolution = 12
+ },
+ [mcp3204] = {
+ .channels = mcp3204_channels,
+ .num_channels = ARRAY_SIZE(mcp3204_channels),
+ .resolution = 12
+ },
+ [mcp3208] = {
+ .channels = mcp3208_channels,
+ .num_channels = ARRAY_SIZE(mcp3208_channels),
+ .resolution = 12
+ },
+ [mcp3301] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 13
+ },
+ [mcp3550_50] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 21,
+ /* 2% max deviation + 144 clock periods to exit shutdown */
+ .conv_time = 80000 * 1.02 + 144000 / 102.4,
+ },
+ [mcp3550_60] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 21,
+ .conv_time = 66670 * 1.02 + 144000 / 122.88,
+ },
+ [mcp3551] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 21,
+ .conv_time = 73100 * 1.02 + 144000 / 112.64,
+ },
+ [mcp3553] = {
+ .channels = mcp3201_channels,
+ .num_channels = ARRAY_SIZE(mcp3201_channels),
+ .resolution = 21,
+ .conv_time = 16670 * 1.02 + 144000 / 122.88,
+ },
+};
+
+static int mcp320x_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct mcp320x *adc;
+ const struct mcp320x_chip_info *chip_info;
+ int ret, device_index;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ adc = iio_priv(indio_dev);
+ adc->spi = spi;
+
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &mcp320x_info;
+ spi_set_drvdata(spi, indio_dev);
+
+ device_index = spi_get_device_id(spi)->driver_data;
+ chip_info = &mcp320x_chip_infos[device_index];
+ indio_dev->channels = chip_info->channels;
+ indio_dev->num_channels = chip_info->num_channels;
+
+ adc->chip_info = chip_info;
+
+ 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 = DIV_ROUND_UP(chip_info->resolution, 8);
+
+ if (chip_info->num_channels == 1)
+ /* single-channel converters are rx only (no MOSI pin) */
+ spi_message_init_with_transfers(&adc->msg,
+ &adc->transfer[1], 1);
+ else
+ spi_message_init_with_transfers(&adc->msg, adc->transfer,
+ ARRAY_SIZE(adc->transfer));
+
+ switch (device_index) {
+ case mcp3550_50:
+ case mcp3550_60:
+ case mcp3551:
+ case mcp3553:
+ /* rx len increases from 24 to 25 bit in SPI mode 0,0 */
+ if (!(spi->mode & SPI_CPOL))
+ adc->transfer[1].len++;
+
+ /* conversions are started by asserting CS pin for 8 usec */
+ adc->start_conv_transfer.delay.value = 8;
+ adc->start_conv_transfer.delay.unit = SPI_DELAY_UNIT_USECS;
+ spi_message_init_with_transfers(&adc->start_conv_msg,
+ &adc->start_conv_transfer, 1);
+
+ /*
+ * If CS was previously kept low (continuous conversion mode)
+ * and then changed to high, the chip is in shutdown.
+ * Sometimes it fails to wake from shutdown and clocks out
+ * only 0xffffff. The magic sequence of performing two
+ * conversions without delay between them resets the chip
+ * and ensures all subsequent conversions succeed.
+ */
+ mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
+ mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
+ }
+
+ 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 < 0)
+ return ret;
+
+ mutex_init(&adc->lock);
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0)
+ goto reg_disable;
+
+ return 0;
+
+reg_disable:
+ regulator_disable(adc->reg);
+
+ return ret;
+}
+
+static void 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);
+}
+
+static const struct of_device_id mcp320x_dt_ids[] = {
+ /* NOTE: The use of compatibles with no vendor prefix is deprecated. */
+ { .compatible = "mcp3001" },
+ { .compatible = "mcp3002" },
+ { .compatible = "mcp3004" },
+ { .compatible = "mcp3008" },
+ { .compatible = "mcp3201" },
+ { .compatible = "mcp3202" },
+ { .compatible = "mcp3204" },
+ { .compatible = "mcp3208" },
+ { .compatible = "mcp3301" },
+ { .compatible = "microchip,mcp3001" },
+ { .compatible = "microchip,mcp3002" },
+ { .compatible = "microchip,mcp3004" },
+ { .compatible = "microchip,mcp3008" },
+ { .compatible = "microchip,mcp3201" },
+ { .compatible = "microchip,mcp3202" },
+ { .compatible = "microchip,mcp3204" },
+ { .compatible = "microchip,mcp3208" },
+ { .compatible = "microchip,mcp3301" },
+ { .compatible = "microchip,mcp3550-50" },
+ { .compatible = "microchip,mcp3550-60" },
+ { .compatible = "microchip,mcp3551" },
+ { .compatible = "microchip,mcp3553" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
+
+static const struct spi_device_id mcp320x_id[] = {
+ { "mcp3001", mcp3001 },
+ { "mcp3002", mcp3002 },
+ { "mcp3004", mcp3004 },
+ { "mcp3008", mcp3008 },
+ { "mcp3201", mcp3201 },
+ { "mcp3202", mcp3202 },
+ { "mcp3204", mcp3204 },
+ { "mcp3208", mcp3208 },
+ { "mcp3301", mcp3301 },
+ { "mcp3550-50", mcp3550_50 },
+ { "mcp3550-60", mcp3550_60 },
+ { "mcp3551", mcp3551 },
+ { "mcp3553", mcp3553 },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, mcp320x_id);
+
+static struct spi_driver mcp320x_driver = {
+ .driver = {
+ .name = "mcp320x",
+ .of_match_table = mcp320x_dt_ids,
+ },
+ .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 MCP3x01/02/04/08 and MCP3550/1/3");
+MODULE_LICENSE("GPL v2");
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-24 07:12:43 +0000