--- /dev/null
+/*
+ * mcp4725.c - Support for Microchip MCP4725
+ *
+ * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
+ *
+ * Based on max517 by Roland Stigge <stigge@antcom.de>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
+ * (7-bit I2C slave address 0x60, the three LSBs can be configured in
+ * hardware)
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#include <linux/iio/dac/mcp4725.h>
+
+#define MCP4725_DRV_NAME "mcp4725"
+
+struct mcp4725_data {
+ struct i2c_client *client;
+ u16 vref_mv;
+ u16 dac_value;
+ bool powerdown;
+ unsigned powerdown_mode;
+};
+
+static int mcp4725_suspend(struct device *dev)
+{
+ struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
+ to_i2c_client(dev)));
+ u8 outbuf[2];
+
+ outbuf[0] = (data->powerdown_mode + 1) << 4;
+ outbuf[1] = 0;
+ data->powerdown = true;
+
+ return i2c_master_send(data->client, outbuf, 2);
+}
+
+static int mcp4725_resume(struct device *dev)
+{
+ struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
+ to_i2c_client(dev)));
+ u8 outbuf[2];
+
+ /* restore previous DAC value */
+ outbuf[0] = (data->dac_value >> 8) & 0xf;
+ outbuf[1] = data->dac_value & 0xff;
+ data->powerdown = false;
+
+ return i2c_master_send(data->client, outbuf, 2);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
+#define MCP4725_PM_OPS (&mcp4725_pm_ops)
+#else
+#define MCP4725_PM_OPS NULL
+#endif
+
+static ssize_t mcp4725_store_eeprom(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct mcp4725_data *data = iio_priv(indio_dev);
+ int tries = 20;
+ u8 inoutbuf[3];
+ bool state;
+ int ret;
+
+ ret = strtobool(buf, &state);
+ if (ret < 0)
+ return ret;
+
+ if (!state)
+ return 0;
+
+ inoutbuf[0] = 0x60; /* write EEPROM */
+ inoutbuf[1] = data->dac_value >> 4;
+ inoutbuf[2] = (data->dac_value & 0xf) << 4;
+
+ ret = i2c_master_send(data->client, inoutbuf, 3);
+ if (ret < 0)
+ return ret;
+ else if (ret != 3)
+ return -EIO;
+
+ /* wait for write complete, takes up to 50ms */
+ while (tries--) {
+ msleep(20);
+ ret = i2c_master_recv(data->client, inoutbuf, 3);
+ if (ret < 0)
+ return ret;
+ else if (ret != 3)
+ return -EIO;
+
+ if (inoutbuf[0] & 0x80)
+ break;
+ }
+
+ if (tries < 0) {
+ dev_err(&data->client->dev,
+ "mcp4725_store_eeprom() failed, incomplete\n");
+ return -EIO;
+ }
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
+
+static struct attribute *mcp4725_attributes[] = {
+ &iio_dev_attr_store_eeprom.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group mcp4725_attribute_group = {
+ .attrs = mcp4725_attributes,
+};
+
+static const char * const mcp4725_powerdown_modes[] = {
+ "1kohm_to_gnd",
+ "100kohm_to_gnd",
+ "500kohm_to_gnd"
+};
+
+static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct mcp4725_data *data = iio_priv(indio_dev);
+
+ return data->powerdown_mode;
+}
+
+static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, unsigned mode)
+{
+ struct mcp4725_data *data = iio_priv(indio_dev);
+
+ data->powerdown_mode = mode;
+
+ return 0;
+}
+
+static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private, const struct iio_chan_spec *chan, char *buf)
+{
+ struct mcp4725_data *data = iio_priv(indio_dev);
+
+ return sprintf(buf, "%d\n", data->powerdown);
+}
+
+static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private, const struct iio_chan_spec *chan,
+ const char *buf, size_t len)
+{
+ struct mcp4725_data *data = iio_priv(indio_dev);
+ bool state;
+ int ret;
+
+ ret = strtobool(buf, &state);
+ if (ret)
+ return ret;
+
+ if (state)
+ ret = mcp4725_suspend(&data->client->dev);
+ else
+ ret = mcp4725_resume(&data->client->dev);
+ if (ret < 0)
+ return ret;
+
+ return len;
+}
+
+static const struct iio_enum mcp4725_powerdown_mode_enum = {
+ .items = mcp4725_powerdown_modes,
+ .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
+ .get = mcp4725_get_powerdown_mode,
+ .set = mcp4725_set_powerdown_mode,
+};
+
+static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
+ {
+ .name = "powerdown",
+ .read = mcp4725_read_powerdown,
+ .write = mcp4725_write_powerdown,
+ .shared = IIO_SEPARATE,
+ },
+ IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4725_powerdown_mode_enum),
+ IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum),
+ { },
+};
+
+static const struct iio_chan_spec mcp4725_channel = {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .output = 1,
+ .channel = 0,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+ .ext_info = mcp4725_ext_info,
+};
+
+static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
+{
+ struct mcp4725_data *data = iio_priv(indio_dev);
+ u8 outbuf[2];
+ int ret;
+
+ if (val >= (1 << 12) || val < 0)
+ return -EINVAL;
+
+ outbuf[0] = (val >> 8) & 0xf;
+ outbuf[1] = val & 0xff;
+
+ ret = i2c_master_send(data->client, outbuf, 2);
+ if (ret < 0)
+ return ret;
+ else if (ret != 2)
+ return -EIO;
+ else
+ return 0;
+}
+
+static int mcp4725_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct mcp4725_data *data = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ *val = data->dac_value;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = data->vref_mv;
+ *val2 = 12;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ }
+ return -EINVAL;
+}
+
+static int mcp4725_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct mcp4725_data *data = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = mcp4725_set_value(indio_dev, val);
+ data->dac_value = val;
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+static const struct iio_info mcp4725_info = {
+ .read_raw = mcp4725_read_raw,
+ .write_raw = mcp4725_write_raw,
+ .attrs = &mcp4725_attribute_group,
+ .driver_module = THIS_MODULE,
+};
+
+static int mcp4725_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct mcp4725_data *data;
+ struct iio_dev *indio_dev;
+ struct mcp4725_platform_data *platform_data = client->dev.platform_data;
+ u8 inbuf[3];
+ u8 pd;
+ int err;
+
+ if (!platform_data || !platform_data->vref_mv) {
+ dev_err(&client->dev, "invalid platform data");
+ return -EINVAL;
+ }
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+ if (indio_dev == NULL)
+ return -ENOMEM;
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ data->client = client;
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &mcp4725_info;
+ indio_dev->channels = &mcp4725_channel;
+ indio_dev->num_channels = 1;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ data->vref_mv = platform_data->vref_mv;
+
+ /* read current DAC value */
+ err = i2c_master_recv(client, inbuf, 3);
+ if (err < 0) {
+ dev_err(&client->dev, "failed to read DAC value");
+ return err;
+ }
+ pd = (inbuf[0] >> 1) & 0x3;
+ data->powerdown = pd > 0 ? true : false;
+ data->powerdown_mode = pd ? pd-1 : 2; /* 500kohm_to_gnd */
+ data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
+
+ return iio_device_register(indio_dev);
+}
+
+static int mcp4725_remove(struct i2c_client *client)
+{
+ iio_device_unregister(i2c_get_clientdata(client));
+ return 0;
+}
+
+static const struct i2c_device_id mcp4725_id[] = {
+ { "mcp4725", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, mcp4725_id);
+
+static struct i2c_driver mcp4725_driver = {
+ .driver = {
+ .name = MCP4725_DRV_NAME,
+ .pm = MCP4725_PM_OPS,
+ },
+ .probe = mcp4725_probe,
+ .remove = mcp4725_remove,
+ .id_table = mcp4725_id,
+};
+module_i2c_driver(mcp4725_driver);
+
+MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
+MODULE_DESCRIPTION("MCP4725 12-bit DAC");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff