488 lines
11 KiB
C
488 lines
11 KiB
C
/*
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* AD7816 digital temperature sensor driver supporting AD7816/7/8
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*
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* Copyright 2010 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later.
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*/
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#include <linux/interrupt.h>
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#include <linux/gpio.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/list.h>
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#include <linux/spi/spi.h>
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#include <linux/module.h>
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#include "../iio.h"
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#include "../sysfs.h"
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/*
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* AD7816 config masks
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*/
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#define AD7816_FULL 0x1
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#define AD7816_PD 0x2
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#define AD7816_CS_MASK 0x7
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#define AD7816_CS_MAX 0x4
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/*
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* AD7816 temperature masks
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*/
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#define AD7816_VALUE_OFFSET 6
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#define AD7816_BOUND_VALUE_BASE 0x8
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#define AD7816_BOUND_VALUE_MIN -95
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#define AD7816_BOUND_VALUE_MAX 152
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#define AD7816_TEMP_FLOAT_OFFSET 2
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#define AD7816_TEMP_FLOAT_MASK 0x3
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/*
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* struct ad7816_chip_info - chip specifc information
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*/
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struct ad7816_chip_info {
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struct spi_device *spi_dev;
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u16 rdwr_pin;
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u16 convert_pin;
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u16 busy_pin;
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u8 oti_data[AD7816_CS_MAX+1];
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u8 channel_id; /* 0 always be temperature */
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u8 mode;
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};
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/*
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* ad7816 data access by SPI
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*/
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static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data)
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{
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struct spi_device *spi_dev = chip->spi_dev;
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int ret = 0;
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gpio_set_value(chip->rdwr_pin, 1);
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gpio_set_value(chip->rdwr_pin, 0);
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ret = spi_write(spi_dev, &chip->channel_id, sizeof(chip->channel_id));
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if (ret < 0) {
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dev_err(&spi_dev->dev, "SPI channel setting error\n");
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return ret;
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}
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gpio_set_value(chip->rdwr_pin, 1);
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if (chip->mode == AD7816_PD) { /* operating mode 2 */
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gpio_set_value(chip->convert_pin, 1);
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gpio_set_value(chip->convert_pin, 0);
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} else { /* operating mode 1 */
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gpio_set_value(chip->convert_pin, 0);
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gpio_set_value(chip->convert_pin, 1);
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}
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while (gpio_get_value(chip->busy_pin))
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cpu_relax();
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gpio_set_value(chip->rdwr_pin, 0);
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gpio_set_value(chip->rdwr_pin, 1);
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ret = spi_read(spi_dev, (u8 *)data, sizeof(*data));
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if (ret < 0) {
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dev_err(&spi_dev->dev, "SPI data read error\n");
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return ret;
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}
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*data = be16_to_cpu(*data);
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return ret;
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}
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static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
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{
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struct spi_device *spi_dev = chip->spi_dev;
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int ret = 0;
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gpio_set_value(chip->rdwr_pin, 1);
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gpio_set_value(chip->rdwr_pin, 0);
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ret = spi_write(spi_dev, &data, sizeof(data));
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if (ret < 0)
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dev_err(&spi_dev->dev, "SPI oti data write error\n");
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return ret;
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}
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static ssize_t ad7816_show_mode(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7816_chip_info *chip = iio_priv(dev_info);
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if (chip->mode)
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return sprintf(buf, "power-save\n");
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else
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return sprintf(buf, "full\n");
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}
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static ssize_t ad7816_store_mode(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t len)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7816_chip_info *chip = iio_priv(dev_info);
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if (strcmp(buf, "full")) {
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gpio_set_value(chip->rdwr_pin, 1);
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chip->mode = AD7816_FULL;
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} else {
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gpio_set_value(chip->rdwr_pin, 0);
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chip->mode = AD7816_PD;
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}
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return len;
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}
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static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR,
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ad7816_show_mode,
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ad7816_store_mode,
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0);
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static ssize_t ad7816_show_available_modes(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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return sprintf(buf, "full\npower-save\n");
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}
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static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes, NULL, 0);
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static ssize_t ad7816_show_channel(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7816_chip_info *chip = iio_priv(dev_info);
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return sprintf(buf, "%d\n", chip->channel_id);
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}
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static ssize_t ad7816_store_channel(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t len)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7816_chip_info *chip = iio_priv(dev_info);
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unsigned long data;
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int ret;
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ret = strict_strtoul(buf, 10, &data);
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if (ret)
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return -EINVAL;
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if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
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dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
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data, dev_info->name);
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return -EINVAL;
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} else if (strcmp(dev_info->name, "ad7818") == 0 && data > 1) {
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dev_err(&chip->spi_dev->dev,
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"Invalid channel id %lu for ad7818.\n", data);
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return -EINVAL;
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} else if (strcmp(dev_info->name, "ad7816") == 0 && data > 0) {
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dev_err(&chip->spi_dev->dev,
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"Invalid channel id %lu for ad7816.\n", data);
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return -EINVAL;
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}
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chip->channel_id = data;
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return len;
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}
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static IIO_DEVICE_ATTR(channel, S_IRUGO | S_IWUSR,
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ad7816_show_channel,
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ad7816_store_channel,
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0);
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static ssize_t ad7816_show_value(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7816_chip_info *chip = iio_priv(dev_info);
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u16 data;
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s8 value;
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int ret;
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ret = ad7816_spi_read(chip, &data);
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if (ret)
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return -EIO;
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data >>= AD7816_VALUE_OFFSET;
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if (chip->channel_id == 0) {
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value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
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data &= AD7816_TEMP_FLOAT_MASK;
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if (value < 0)
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data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data;
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return sprintf(buf, "%d.%.2d\n", value, data * 25);
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} else
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return sprintf(buf, "%u\n", data);
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}
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static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0);
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static struct attribute *ad7816_attributes[] = {
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&iio_dev_attr_available_modes.dev_attr.attr,
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&iio_dev_attr_mode.dev_attr.attr,
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&iio_dev_attr_channel.dev_attr.attr,
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&iio_dev_attr_value.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group ad7816_attribute_group = {
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.attrs = ad7816_attributes,
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};
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/*
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* temperature bound events
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*/
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#define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP, \
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0, \
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IIO_EV_TYPE_THRESH, \
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IIO_EV_DIR_FALLING)
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static irqreturn_t ad7816_event_handler(int irq, void *private)
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{
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iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI, iio_get_time_ns());
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return IRQ_HANDLED;
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}
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static ssize_t ad7816_show_oti(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7816_chip_info *chip = iio_priv(dev_info);
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int value;
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if (chip->channel_id > AD7816_CS_MAX) {
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dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
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return -EINVAL;
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} else if (chip->channel_id == 0) {
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value = AD7816_BOUND_VALUE_MIN +
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(chip->oti_data[chip->channel_id] -
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AD7816_BOUND_VALUE_BASE);
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return sprintf(buf, "%d\n", value);
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} else
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return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]);
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}
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static inline ssize_t ad7816_set_oti(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t len)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct ad7816_chip_info *chip = iio_priv(dev_info);
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long value;
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u8 data;
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int ret;
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ret = strict_strtol(buf, 10, &value);
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if (chip->channel_id > AD7816_CS_MAX) {
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dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
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return -EINVAL;
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} else if (chip->channel_id == 0) {
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if (ret || value < AD7816_BOUND_VALUE_MIN ||
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value > AD7816_BOUND_VALUE_MAX)
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return -EINVAL;
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data = (u8)(value - AD7816_BOUND_VALUE_MIN +
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AD7816_BOUND_VALUE_BASE);
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} else {
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if (ret || value < AD7816_BOUND_VALUE_BASE || value > 255)
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return -EINVAL;
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data = (u8)value;
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}
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ret = ad7816_spi_write(chip, data);
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if (ret)
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return -EIO;
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chip->oti_data[chip->channel_id] = data;
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return len;
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}
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static IIO_DEVICE_ATTR(oti, S_IRUGO | S_IWUSR,
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ad7816_show_oti, ad7816_set_oti, 0);
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static struct attribute *ad7816_event_attributes[] = {
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&iio_dev_attr_oti.dev_attr.attr,
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NULL,
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};
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static struct attribute_group ad7816_event_attribute_group = {
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.attrs = ad7816_event_attributes,
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.name = "events",
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};
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static const struct iio_info ad7816_info = {
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.attrs = &ad7816_attribute_group,
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.event_attrs = &ad7816_event_attribute_group,
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.driver_module = THIS_MODULE,
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};
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/*
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* device probe and remove
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*/
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static int __devinit ad7816_probe(struct spi_device *spi_dev)
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{
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struct ad7816_chip_info *chip;
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struct iio_dev *indio_dev;
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unsigned short *pins = spi_dev->dev.platform_data;
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int ret = 0;
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int i;
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if (!pins) {
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dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n");
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return -EINVAL;
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}
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indio_dev = iio_allocate_device(sizeof(*chip));
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if (indio_dev == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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chip = iio_priv(indio_dev);
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/* this is only used for device removal purposes */
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dev_set_drvdata(&spi_dev->dev, indio_dev);
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chip->spi_dev = spi_dev;
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for (i = 0; i <= AD7816_CS_MAX; i++)
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chip->oti_data[i] = 203;
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chip->rdwr_pin = pins[0];
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chip->convert_pin = pins[1];
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chip->busy_pin = pins[2];
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ret = gpio_request(chip->rdwr_pin, spi_get_device_id(spi_dev)->name);
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if (ret) {
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dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n",
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chip->rdwr_pin);
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goto error_free_device;
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}
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gpio_direction_input(chip->rdwr_pin);
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ret = gpio_request(chip->convert_pin, spi_get_device_id(spi_dev)->name);
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if (ret) {
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dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n",
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chip->convert_pin);
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goto error_free_gpio_rdwr;
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}
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gpio_direction_input(chip->convert_pin);
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ret = gpio_request(chip->busy_pin, spi_get_device_id(spi_dev)->name);
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if (ret) {
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dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
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chip->busy_pin);
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goto error_free_gpio_convert;
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}
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gpio_direction_input(chip->busy_pin);
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indio_dev->name = spi_get_device_id(spi_dev)->name;
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indio_dev->dev.parent = &spi_dev->dev;
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indio_dev->info = &ad7816_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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ret = iio_device_register(indio_dev);
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if (ret)
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goto error_free_gpio;
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if (spi_dev->irq) {
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/* Only low trigger is supported in ad7816/7/8 */
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ret = request_threaded_irq(spi_dev->irq,
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NULL,
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&ad7816_event_handler,
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IRQF_TRIGGER_LOW,
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indio_dev->name,
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indio_dev);
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if (ret)
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goto error_unreg_dev;
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}
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dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
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indio_dev->name);
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return 0;
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error_unreg_dev:
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iio_device_unregister(indio_dev);
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error_free_gpio:
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gpio_free(chip->busy_pin);
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error_free_gpio_convert:
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gpio_free(chip->convert_pin);
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error_free_gpio_rdwr:
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gpio_free(chip->rdwr_pin);
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error_free_device:
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iio_free_device(indio_dev);
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error_ret:
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return ret;
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}
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static int __devexit ad7816_remove(struct spi_device *spi_dev)
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{
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struct iio_dev *indio_dev = dev_get_drvdata(&spi_dev->dev);
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struct ad7816_chip_info *chip = iio_priv(indio_dev);
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dev_set_drvdata(&spi_dev->dev, NULL);
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if (spi_dev->irq)
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free_irq(spi_dev->irq, indio_dev);
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gpio_free(chip->busy_pin);
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gpio_free(chip->convert_pin);
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gpio_free(chip->rdwr_pin);
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iio_device_unregister(indio_dev);
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iio_free_device(indio_dev);
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return 0;
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}
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static const struct spi_device_id ad7816_id[] = {
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{ "ad7816", 0 },
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{ "ad7817", 0 },
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{ "ad7818", 0 },
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{}
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};
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MODULE_DEVICE_TABLE(spi, ad7816_id);
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static struct spi_driver ad7816_driver = {
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.driver = {
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.name = "ad7816",
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.bus = &spi_bus_type,
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.owner = THIS_MODULE,
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},
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.probe = ad7816_probe,
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.remove = __devexit_p(ad7816_remove),
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.id_table = ad7816_id,
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};
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static __init int ad7816_init(void)
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{
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return spi_register_driver(&ad7816_driver);
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}
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static __exit void ad7816_exit(void)
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{
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spi_unregister_driver(&ad7816_driver);
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}
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MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
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MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital"
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" temperature sensor driver");
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MODULE_LICENSE("GPL v2");
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module_init(ad7816_init);
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module_exit(ad7816_exit);
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