diff options
Diffstat (limited to 'kernel/drivers/staging/iio/adc/ad7816.c')
| -rw-r--r-- | kernel/drivers/staging/iio/adc/ad7816.c | 446 |
1 files changed, 446 insertions, 0 deletions
diff --git a/kernel/drivers/staging/iio/adc/ad7816.c b/kernel/drivers/staging/iio/adc/ad7816.c new file mode 100644 index 000000000..48b1c3740 --- /dev/null +++ b/kernel/drivers/staging/iio/adc/ad7816.c @@ -0,0 +1,446 @@ +/* + * AD7816 digital temperature sensor driver supporting AD7816/7/8 + * + * Copyright 2010 Analog Devices Inc. + * + * Licensed under the GPL-2 or later. + */ + +#include <linux/interrupt.h> +#include <linux/gpio.h> +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/sysfs.h> +#include <linux/list.h> +#include <linux/spi/spi.h> +#include <linux/module.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/iio/events.h> + +/* + * AD7816 config masks + */ +#define AD7816_FULL 0x1 +#define AD7816_PD 0x2 +#define AD7816_CS_MASK 0x7 +#define AD7816_CS_MAX 0x4 + +/* + * AD7816 temperature masks + */ +#define AD7816_VALUE_OFFSET 6 +#define AD7816_BOUND_VALUE_BASE 0x8 +#define AD7816_BOUND_VALUE_MIN -95 +#define AD7816_BOUND_VALUE_MAX 152 +#define AD7816_TEMP_FLOAT_OFFSET 2 +#define AD7816_TEMP_FLOAT_MASK 0x3 + + +/* + * struct ad7816_chip_info - chip specific information + */ + +struct ad7816_chip_info { + struct spi_device *spi_dev; + u16 rdwr_pin; + u16 convert_pin; + u16 busy_pin; + u8 oti_data[AD7816_CS_MAX+1]; + u8 channel_id; /* 0 always be temperature */ + u8 mode; +}; + +/* + * ad7816 data access by SPI + */ +static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data) +{ + struct spi_device *spi_dev = chip->spi_dev; + int ret = 0; + + gpio_set_value(chip->rdwr_pin, 1); + gpio_set_value(chip->rdwr_pin, 0); + ret = spi_write(spi_dev, &chip->channel_id, sizeof(chip->channel_id)); + if (ret < 0) { + dev_err(&spi_dev->dev, "SPI channel setting error\n"); + return ret; + } + gpio_set_value(chip->rdwr_pin, 1); + + + if (chip->mode == AD7816_PD) { /* operating mode 2 */ + gpio_set_value(chip->convert_pin, 1); + gpio_set_value(chip->convert_pin, 0); + } else { /* operating mode 1 */ + gpio_set_value(chip->convert_pin, 0); + gpio_set_value(chip->convert_pin, 1); + } + + while (gpio_get_value(chip->busy_pin)) + cpu_relax(); + + gpio_set_value(chip->rdwr_pin, 0); + gpio_set_value(chip->rdwr_pin, 1); + ret = spi_read(spi_dev, (u8 *)data, sizeof(*data)); + if (ret < 0) { + dev_err(&spi_dev->dev, "SPI data read error\n"); + return ret; + } + + *data = be16_to_cpu(*data); + + return ret; +} + +static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data) +{ + struct spi_device *spi_dev = chip->spi_dev; + int ret = 0; + + gpio_set_value(chip->rdwr_pin, 1); + gpio_set_value(chip->rdwr_pin, 0); + ret = spi_write(spi_dev, &data, sizeof(data)); + if (ret < 0) + dev_err(&spi_dev->dev, "SPI oti data write error\n"); + + return ret; +} + +static ssize_t ad7816_show_mode(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7816_chip_info *chip = iio_priv(indio_dev); + + if (chip->mode) + return sprintf(buf, "power-save\n"); + return sprintf(buf, "full\n"); +} + +static ssize_t ad7816_store_mode(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7816_chip_info *chip = iio_priv(indio_dev); + + if (strcmp(buf, "full")) { + gpio_set_value(chip->rdwr_pin, 1); + chip->mode = AD7816_FULL; + } else { + gpio_set_value(chip->rdwr_pin, 0); + chip->mode = AD7816_PD; + } + + return len; +} + +static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR, + ad7816_show_mode, + ad7816_store_mode, + 0); + +static ssize_t ad7816_show_available_modes(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return sprintf(buf, "full\npower-save\n"); +} + +static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes, + NULL, 0); + +static ssize_t ad7816_show_channel(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7816_chip_info *chip = iio_priv(indio_dev); + + return sprintf(buf, "%d\n", chip->channel_id); +} + +static ssize_t ad7816_store_channel(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7816_chip_info *chip = iio_priv(indio_dev); + unsigned long data; + int ret; + + ret = kstrtoul(buf, 10, &data); + if (ret) + return ret; + + if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) { + dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n", + data, indio_dev->name); + return -EINVAL; + } else if (strcmp(indio_dev->name, "ad7818") == 0 && data > 1) { + dev_err(&chip->spi_dev->dev, + "Invalid channel id %lu for ad7818.\n", data); + return -EINVAL; + } else if (strcmp(indio_dev->name, "ad7816") == 0 && data > 0) { + dev_err(&chip->spi_dev->dev, + "Invalid channel id %lu for ad7816.\n", data); + return -EINVAL; + } + + chip->channel_id = data; + + return len; +} + +static IIO_DEVICE_ATTR(channel, S_IRUGO | S_IWUSR, + ad7816_show_channel, + ad7816_store_channel, + 0); + + +static ssize_t ad7816_show_value(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7816_chip_info *chip = iio_priv(indio_dev); + u16 data; + s8 value; + int ret; + + ret = ad7816_spi_read(chip, &data); + if (ret) + return -EIO; + + data >>= AD7816_VALUE_OFFSET; + + if (chip->channel_id == 0) { + value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103); + data &= AD7816_TEMP_FLOAT_MASK; + if (value < 0) + data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data; + return sprintf(buf, "%d.%.2d\n", value, data * 25); + } + return sprintf(buf, "%u\n", data); +} + +static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0); + +static struct attribute *ad7816_attributes[] = { + &iio_dev_attr_available_modes.dev_attr.attr, + &iio_dev_attr_mode.dev_attr.attr, + &iio_dev_attr_channel.dev_attr.attr, + &iio_dev_attr_value.dev_attr.attr, + NULL, +}; + +static const struct attribute_group ad7816_attribute_group = { + .attrs = ad7816_attributes, +}; + +/* + * temperature bound events + */ + +#define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP, \ + 0, \ + IIO_EV_TYPE_THRESH, \ + IIO_EV_DIR_FALLING) + +static irqreturn_t ad7816_event_handler(int irq, void *private) +{ + iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI, iio_get_time_ns()); + return IRQ_HANDLED; +} + +static ssize_t ad7816_show_oti(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7816_chip_info *chip = iio_priv(indio_dev); + int value; + + if (chip->channel_id > AD7816_CS_MAX) { + dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id); + return -EINVAL; + } else if (chip->channel_id == 0) { + value = AD7816_BOUND_VALUE_MIN + + (chip->oti_data[chip->channel_id] - + AD7816_BOUND_VALUE_BASE); + return sprintf(buf, "%d\n", value); + } + return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]); +} + +static inline ssize_t ad7816_set_oti(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct ad7816_chip_info *chip = iio_priv(indio_dev); + long value; + u8 data; + int ret; + + ret = kstrtol(buf, 10, &value); + if (ret) + return ret; + + if (chip->channel_id > AD7816_CS_MAX) { + dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id); + return -EINVAL; + } else if (chip->channel_id == 0) { + if (ret || value < AD7816_BOUND_VALUE_MIN || + value > AD7816_BOUND_VALUE_MAX) + return -EINVAL; + + data = (u8)(value - AD7816_BOUND_VALUE_MIN + + AD7816_BOUND_VALUE_BASE); + } else { + if (ret || value < AD7816_BOUND_VALUE_BASE || value > 255) + return -EINVAL; + + data = (u8)value; + } + + ret = ad7816_spi_write(chip, data); + if (ret) + return -EIO; + + chip->oti_data[chip->channel_id] = data; + + return len; +} + +static IIO_DEVICE_ATTR(oti, S_IRUGO | S_IWUSR, + ad7816_show_oti, ad7816_set_oti, 0); + +static struct attribute *ad7816_event_attributes[] = { + &iio_dev_attr_oti.dev_attr.attr, + NULL, +}; + +static struct attribute_group ad7816_event_attribute_group = { + .attrs = ad7816_event_attributes, + .name = "events", +}; + +static const struct iio_info ad7816_info = { + .attrs = &ad7816_attribute_group, + .event_attrs = &ad7816_event_attribute_group, + .driver_module = THIS_MODULE, +}; + +/* + * device probe and remove + */ + +static int ad7816_probe(struct spi_device *spi_dev) +{ + struct ad7816_chip_info *chip; + struct iio_dev *indio_dev; + unsigned short *pins = spi_dev->dev.platform_data; + int ret = 0; + int i; + + if (!pins) { + dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n"); + return -EINVAL; + } + + indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip)); + if (!indio_dev) + return -ENOMEM; + chip = iio_priv(indio_dev); + /* this is only used for device removal purposes */ + dev_set_drvdata(&spi_dev->dev, indio_dev); + + chip->spi_dev = spi_dev; + for (i = 0; i <= AD7816_CS_MAX; i++) + chip->oti_data[i] = 203; + chip->rdwr_pin = pins[0]; + chip->convert_pin = pins[1]; + chip->busy_pin = pins[2]; + + ret = devm_gpio_request(&spi_dev->dev, chip->rdwr_pin, + spi_get_device_id(spi_dev)->name); + if (ret) { + dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n", + chip->rdwr_pin); + return ret; + } + gpio_direction_input(chip->rdwr_pin); + ret = devm_gpio_request(&spi_dev->dev, chip->convert_pin, + spi_get_device_id(spi_dev)->name); + if (ret) { + dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n", + chip->convert_pin); + return ret; + } + gpio_direction_input(chip->convert_pin); + ret = devm_gpio_request(&spi_dev->dev, chip->busy_pin, + spi_get_device_id(spi_dev)->name); + if (ret) { + dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n", + chip->busy_pin); + return ret; + } + gpio_direction_input(chip->busy_pin); + + indio_dev->name = spi_get_device_id(spi_dev)->name; + indio_dev->dev.parent = &spi_dev->dev; + indio_dev->info = &ad7816_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + if (spi_dev->irq) { + /* Only low trigger is supported in ad7816/7/8 */ + ret = devm_request_threaded_irq(&spi_dev->dev, spi_dev->irq, + NULL, + &ad7816_event_handler, + IRQF_TRIGGER_LOW | IRQF_ONESHOT, + indio_dev->name, + indio_dev); + if (ret) + return ret; + } + + ret = devm_iio_device_register(&spi_dev->dev, indio_dev); + if (ret) + return ret; + + dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n", + indio_dev->name); + + return 0; +} + +static const struct spi_device_id ad7816_id[] = { + { "ad7816", 0 }, + { "ad7817", 0 }, + { "ad7818", 0 }, + {} +}; + +MODULE_DEVICE_TABLE(spi, ad7816_id); + +static struct spi_driver ad7816_driver = { + .driver = { + .name = "ad7816", + .owner = THIS_MODULE, + }, + .probe = ad7816_probe, + .id_table = ad7816_id, +}; +module_spi_driver(ad7816_driver); + +MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); +MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver"); +MODULE_LICENSE("GPL v2"); |