* 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)
- *
- * writing the DAC value to EEPROM is not supported
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/err.h>
+#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
struct i2c_client *client;
u16 vref_mv;
u16 dac_value;
+ bool powerdown;
+ unsigned powerdown_mode;
};
-#ifdef CONFIG_PM_SLEEP
static int mcp4725_suspend(struct device *dev)
{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct mcp4725_data *data = iio_priv(indio_dev);
u8 outbuf[2];
- outbuf[0] = 0x3 << 4; /* power-down bits, 500 kOhm resistor */
+ outbuf[0] = (data->powerdown_mode + 1) << 4;
outbuf[1] = 0;
+ data->powerdown = true;
return i2c_master_send(to_i2c_client(dev), 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(to_i2c_client(dev), 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,
+ },
+ IIO_ENUM("powerdown_mode", false, &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,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
.scan_type = IIO_ST('u', 12, 16, 0),
+ .ext_info = mcp4725_ext_info,
};
static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
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,
};
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");
- err = -EINVAL;
- goto exit;
+ return -EINVAL;
}
- indio_dev = iio_device_alloc(sizeof(*data));
- if (indio_dev == NULL) {
- err = -ENOMEM;
- goto exit;
- }
+ 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;
err = i2c_master_recv(client, inbuf, 3);
if (err < 0) {
dev_err(&client->dev, "failed to read DAC value");
- goto exit_free_device;
+ 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);
err = iio_device_register(indio_dev);
if (err)
- goto exit_free_device;
+ return err;
dev_info(&client->dev, "MCP4725 DAC registered\n");
return 0;
-
-exit_free_device:
- iio_device_free(indio_dev);
-exit:
- return err;
}
static int mcp4725_remove(struct i2c_client *client)
{
- struct iio_dev *indio_dev = i2c_get_clientdata(client);
-
- iio_device_unregister(indio_dev);
- iio_device_free(indio_dev);
-
+ iio_device_unregister(i2c_get_clientdata(client));
return 0;
}
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