Re: [PATCHv4] iio: adc: add driver for MCP3204/08 12-bit ADC
From: Jonathan Cameron
Date: Mon May 06 2013 - 12:05:03 EST
On 05/03/2013 11:00 AM, Lars-Peter Clausen wrote:
> On 05/03/2013 11:58 AM, Oskar Andero wrote:
>> 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.
>>
>> Cc: Jonathan Cameron <jic23@xxxxxxxxx>
>> Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
>> Signed-off-by: Oskar Andero <oskar.andero@xxxxxxxxx>
>
> Reviewed-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Nice driver. Thanks Oskar and thanks Lars-Peter
for your review work on this. Applied to the togreg
branch of iio.git. Note this branch will be rebased
before I send Greg a pull request (nature of where we
are in the cycle!).
Jonathan
>
>> ---
>> drivers/iio/adc/Kconfig | 10 ++
>> drivers/iio/adc/Makefile | 1 +
>> drivers/iio/adc/mcp320x.c | 257 ++++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 268 insertions(+)
>> create mode 100644 drivers/iio/adc/mcp320x.c
>>
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index ab0767e6..93129ec 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -133,6 +133,16 @@ config MAX1363
>> max11646, max11647) Provides direct access via sysfs and buffered
>> 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
>> tristate "Texas Instruments ADC081C021/027"
>> depends on I2C
>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>> index 0a825be..8f475d3 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -14,6 +14,7 @@ obj-$(CONFIG_AT91_ADC) += at91_adc.o
>> obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
>> obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
>> obj-$(CONFIG_MAX1363) += max1363.o
>> +obj-$(CONFIG_MCP320X) += mcp320x.o
>> obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>> obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
>> obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
>> diff --git a/drivers/iio/adc/mcp320x.c b/drivers/iio/adc/mcp320x.c
>> new file mode 100644
>> index 0000000..ebc0159
>> --- /dev/null
>> +++ b/drivers/iio/adc/mcp320x.c
>> @@ -0,0 +1,257 @@
>> +/*
>> + * Copyright (C) 2013 Oskar Andero <oskar.andero@xxxxxxxxx>
>> + *
>> + * 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@xxxxxxxxx>");
>> +MODULE_DESCRIPTION("Microchip Technology MCP3204/08");
>> +MODULE_LICENSE("GPL v2");
>
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