提交 f5ce4a7a 编写于 作者: O Oskar Andero 提交者: Jonathan Cameron

iio: adc: add driver for MCP3204/08 12-bit ADC

This adds support for Microchip's 12 bit AD converters MCP3204 and
MCP3208. These chips communicates over SPI and supports single-ended
and pseudo-differential configurations.
Signed-off-by: NOskar Andero <oskar.andero@gmail.com>
Reviewed-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
上级 735ae539
...@@ -133,6 +133,16 @@ config MAX1363 ...@@ -133,6 +133,16 @@ config MAX1363
max11646, max11647) Provides direct access via sysfs and buffered max11646, max11647) Provides direct access via sysfs and buffered
data via the iio dev interface. data via the iio dev interface.
config MCP320X
tristate "Microchip Technology MCP3204/08"
depends on SPI
help
Say yes here to build support for Microchip Technology's MCP3204 or
MCP3208 analog to digital converter.
This driver can also be built as a module. If so, the module will be
called mcp320x.
config TI_ADC081C config TI_ADC081C
tristate "Texas Instruments ADC081C021/027" tristate "Texas Instruments ADC081C021/027"
depends on I2C depends on I2C
......
...@@ -14,6 +14,7 @@ obj-$(CONFIG_AT91_ADC) += at91_adc.o ...@@ -14,6 +14,7 @@ obj-$(CONFIG_AT91_ADC) += at91_adc.o
obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
obj-$(CONFIG_MAX1363) += max1363.o obj-$(CONFIG_MAX1363) += max1363.o
obj-$(CONFIG_MCP320X) += mcp320x.o
obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
/*
* 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");
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