This revision solves various problems of the previous one. Most important is locking of the chip configuration during updates and the use of devm_* API. For each channel there are now two sysfs attributes, so you can read the raw value or the scaled one. To Peter: Chip versions differs in address assignment (MCP3422 has a fixed address) and channel number (MCP3423 has 2 channels, MCP3424 has 4) but the chip manages internally the lack of channels (it remaps non exixtent channels to the existent ones) so I opted to keep the driver clean and implemented all the four channels. Signed-off-by: Angelo Compagnucci <angelo.compagnucci@xxxxxxxxx> --- drivers/iio/adc/Kconfig | 10 ++ drivers/iio/adc/Makefile | 1 + drivers/iio/adc/mcp3422.c | 420 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 431 insertions(+) create mode 100644 drivers/iio/adc/mcp3422.c diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index f725b45..e9879e6 100644 --- a/drivers/iio/adc/Kconfig +++ b/drivers/iio/adc/Kconfig @@ -145,6 +145,16 @@ config MCP320X This driver can also be built as a module. If so, the module will be called mcp320x. +config MCP3422 + tristate "Microchip Technology MCP3422/3/4 driver" + depends on I2C + help + Say yes here to build support for Microchip Technology's MCP3422, + MCP3423 or MCP3424 analog to digital converters. + + This driver can also be built as a module. If so, the module will be + called mcp3422. + config NAU7802 tristate "Nuvoton NAU7802 ADC driver" depends on I2C diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index 2a4324e..9772e3b 100644 --- a/drivers/iio/adc/Makefile +++ b/drivers/iio/adc/Makefile @@ -16,6 +16,7 @@ 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-$(CONFIG_MCP3422) += mcp3422.o obj-$(CONFIG_NAU7802) += nau7802.o obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o diff --git a/drivers/iio/adc/mcp3422.c b/drivers/iio/adc/mcp3422.c new file mode 100644 index 0000000..c6058da --- /dev/null +++ b/drivers/iio/adc/mcp3422.c @@ -0,0 +1,420 @@ +/* + * mcp3422.c - driver for the Microchip mcp3422/3/4 chip family + * + * Copyright (C) 2013, Angelo Compagnucci + * Author: Angelo Compagnucci <angelo.compagnucci@xxxxxxxxx> + * + * Datasheet: http://ww1.microchip.com/downloads/en/devicedoc/22088b.pdf + * + * This driver exports the value of analog input voltage to sysfs, the + * voltage unit is nV. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/sysfs.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +/* Masks */ +#define MCP3422_CHANNEL_MASK 0x60 +#define MCP3422_PGA_MASK 0x03 +#define MCP3422_SRATE_MASK 0x0C +#define MCP3422_SRATE_240 0x0 +#define MCP3422_SRATE_60 0x1 +#define MCP3422_SRATE_15 0x2 +#define MCP3422_SRATE_3 0x3 +#define MCP3422_PGA_1 0 +#define MCP3422_PGA_2 1 +#define MCP3422_PGA_4 2 +#define MCP3422_PGA_8 3 +#define MCP3422_CONT_SAMPLING 0x10 + +#define MCP3422_CHANNEL(config) ((((config) & MCP3422_CHANNEL_MASK) >> 5) + 1) +#define MCP3422_PGA(config) ((config) & MCP3422_PGA_MASK) +#define MCP3422_SAMPLE_RATE(config) (((config) & MCP3422_SRATE_MASK) >> 2) + +#define MCP3422_CHANNEL_VALUE(value) (((value - 1) << 5) & MCP3422_CHANNEL_MASK) +#define MCP3422_PGA_VALUE(value) ((value) & MCP3422_PGA_MASK) +#define MCP3422_SAMPLE_RATE_VALUE(value) ((value << 2) & MCP3422_SRATE_MASK) + +#define VREF 2048 + +#define MCP3422_CHAN(index) \ + { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = index, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \ + | BIT(IIO_CHAN_INFO_SCALE), \ + } + +/* LSB is in nV to eliminate floating point */ +static const u32 rates_to_lsb[] = {1000000, 250000, 62500, 15625}; + +/* + * Client data (each client gets its own) + */ +struct mcp3422 { + struct i2c_client *i2c; + u8 config; + struct mutex lock; +}; + +static int mcp3422_update_config(struct mcp3422 *adc, u8 newconfig) +{ + u8 buf; + int ret; + + mutex_lock(&adc->lock); + + buf = newconfig; + ret = i2c_master_send(adc->i2c, &buf, 1); + if (ret > 0) + adc->config = buf; + + mutex_unlock(&adc->lock); + + return ret; +} + +static int mcp3422_read(struct mcp3422 *adc, int *value, u8 *config) +{ + int ret = 0; + u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config); + u8 buf[4] = {'\0', '\0', '\0', '\0'}; + + *value = 0; + + if (sample_rate == MCP3422_SRATE_3) { + ret = i2c_master_recv(adc->i2c, buf, 4); + *value += (s8)buf[0]; + *value <<= 16; + *value |= buf[1] << 8; + *value |= buf[2]; + *config = buf[3]; + if (*value == 0xFFFFFFFF) + *value = 0; + } else { + ret = i2c_master_recv(adc->i2c, buf, 3); + *value += (s8)buf[0]; + *value <<= 8; + *value |= buf[1]; + *config = buf[2]; + } + + return ret; +} + +static int mcp3422_read_channel(struct mcp3422 *adc, + struct iio_chan_spec const *channel, int *value) +{ + int ret, mtime = 0; + u8 config = 0; + u8 req_channel = channel->channel; + + if (req_channel != MCP3422_CHANNEL(adc->config)) { + config = adc->config; + config &= ~MCP3422_CHANNEL_MASK; + config |= MCP3422_CHANNEL_VALUE(req_channel); + mcp3422_update_config(adc, config); + switch (MCP3422_SAMPLE_RATE(config)) { + case MCP3422_SRATE_240: + mtime = 1000 / 240; + break; + case MCP3422_SRATE_60: + mtime = 1000 / 60; + break; + case MCP3422_SRATE_15: + mtime = 1000 / 15; + break; + case MCP3422_SRATE_3: + mtime = 1000 / 3; + break; + } + msleep(mtime); + } + + ret = mcp3422_read(adc, value, &config); + return ret; +} + +static int mcp3422_read_raw(struct iio_dev *iio, + struct iio_chan_spec const *channel, int *val1, + int *val2, long mask) +{ + struct mcp3422 *adc = iio_priv(iio); + int err, temp = 0; + + u8 sample_rate = MCP3422_SAMPLE_RATE(adc->config); + u8 pga = MCP3422_PGA(adc->config); + + err = mcp3422_read_channel(adc, channel, &temp); + if (err < 0) + return err; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + *val1 = temp; + + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + + temp = (temp * rates_to_lsb[sample_rate]) + / (pga ? 1 << pga : 1); + + *val1 = temp / 1000000000; + *val2 = temp % 1000000000; + + return IIO_VAL_INT_PLUS_NANO; + + default: + break; + } + + return -EINVAL; +} + +static ssize_t mcp3422_set_sample_rate(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct iio_dev *iio = i2c_get_clientdata(client); + struct mcp3422 *adc = iio_priv(iio); + u8 value = 0; + u8 config = adc->config; + + if (kstrtou8(buf, 10, &value) < 0) + return -EINVAL; + + switch (value) { + case 240: + value = MCP3422_SRATE_240; + break; + case 60: + value = MCP3422_SRATE_60; + break; + case 15: + value = MCP3422_SRATE_15; + break; + case 3: + value = MCP3422_SRATE_3; + break; + default: + return -EINVAL; + } + + config &= ~MCP3422_SRATE_MASK; + config |= MCP3422_SAMPLE_RATE_VALUE(value); + + mcp3422_update_config(adc, config); + + return count; +} + +static ssize_t mcp3422_get_sample_rate(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + struct iio_dev *iio = i2c_get_clientdata(client); + struct mcp3422 *adc = iio_priv(iio); + u8 value = 0; + + switch (MCP3422_SAMPLE_RATE(adc->config)) { + case 0: + value = 240; + break; + case 1: + value = 60; + break; + case 2: + value = 15; + break; + case 3: + value = 3; + break; + } + + return sprintf(buf, "%d\n", value); +} + +static ssize_t mcp3422_set_pga(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + struct iio_dev *iio = i2c_get_clientdata(client); + struct mcp3422 *adc = iio_priv(iio); + u8 value = 0; + u8 config = adc->config; + + if (kstrtou8(buf, 10, &value) < 0) + return -EINVAL; + + switch (value) { + case 1: + value = MCP3422_PGA_1; + break; + case 2: + value = MCP3422_PGA_2; + break; + case 4: + value = MCP3422_PGA_4; + break; + case 8: + value = MCP3422_PGA_8; + break; + default: + return -EINVAL; + } + + config &= ~MCP3422_PGA_MASK; + config |= MCP3422_PGA_VALUE(value); + + mcp3422_update_config(adc, config); + + return count; +} + +static ssize_t mcp3422_get_pga(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + struct iio_dev *iio = i2c_get_clientdata(client); + struct mcp3422 *adc = iio_priv(iio); + + return sprintf(buf, "%d\n", 1 << MCP3422_PGA(adc->config)); +} + +static IIO_DEV_ATTR_SAMP_FREQ(S_IRUGO | S_IWUSR, + mcp3422_get_sample_rate, + mcp3422_set_sample_rate); +static IIO_DEVICE_ATTR(pga, + S_IRUGO | S_IWUSR, + mcp3422_get_pga, + mcp3422_set_pga, 0); +static IIO_CONST_ATTR(sampling_frequency_available, "240 60 15 3"); +static IIO_CONST_ATTR(pga_available, "1 2 4 8"); + +static struct attribute *mcp3422_attributes[] = { + &iio_dev_attr_sampling_frequency.dev_attr.attr, + &iio_const_attr_sampling_frequency_available.dev_attr.attr, + &iio_dev_attr_pga.dev_attr.attr, + &iio_const_attr_pga_available.dev_attr.attr, + NULL, +}; + +static const struct attribute_group mcp3422_attribute_group = { + .attrs = mcp3422_attributes, +}; + +static const struct iio_chan_spec mcp3422_channels[] = { + MCP3422_CHAN(1), + MCP3422_CHAN(2), + MCP3422_CHAN(3), + MCP3422_CHAN(4), +}; + +static const struct iio_info mcp3422_info = { + .read_raw = mcp3422_read_raw, + .attrs = &mcp3422_attribute_group, + .driver_module = THIS_MODULE, +}; + +static int mcp3422_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct iio_dev *indio_dev; + struct mcp3422 *adc; + int err; + u8 config; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return -ENODEV; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*adc)); + if (!indio_dev) + return -ENOMEM; + + adc = iio_priv(indio_dev); + adc->i2c = client; + + mutex_init(&adc->lock); + + indio_dev->dev.parent = &client->dev; + indio_dev->name = dev_name(&client->dev); + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &mcp3422_info; + + indio_dev->channels = mcp3422_channels; + indio_dev->num_channels = ARRAY_SIZE(mcp3422_channels); + + err = iio_device_register(indio_dev); + if (err < 0) + return err; + + i2c_set_clientdata(client, indio_dev); + + /* meaningful default configuration */ + config = (MCP3422_CONT_SAMPLING + | MCP3422_CHANNEL_VALUE(1) + | MCP3422_PGA_VALUE(MCP3422_PGA_1) + | MCP3422_SAMPLE_RATE_VALUE(MCP3422_SRATE_240)); + mcp3422_update_config(adc, config); + + return 0; +} + +static int mcp3422_remove(struct i2c_client *client) +{ + struct iio_dev *iio = i2c_get_clientdata(client); + + iio_device_unregister(iio); + iio_device_free(iio); + + return 0; +} + +static const struct i2c_device_id mcp3422_id[] = { + { "mcp3422", 2 }, + { "mcp3423", 3 }, + { "mcp3424", 4 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, mcp3422_id); + +#ifdef CONFIG_OF +static const struct of_device_id mcp3422_of_match[] = { + { .compatible = "mcp3422" }, + { } +}; +MODULE_DEVICE_TABLE(of, mcp3422_of_match); +#endif + +static struct i2c_driver mcp3422_driver = { + .driver = { + .name = "mcp3422", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(mcp3422_of_match), + }, + .probe = mcp3422_probe, + .remove = mcp3422_remove, + .id_table = mcp3422_id, +}; +module_i2c_driver(mcp3422_driver); + +MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@xxxxxxxxx>"); +MODULE_DESCRIPTION("Microchip mcp3422/3/4 driver"); +MODULE_LICENSE("GPL v2"); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
