Signed-off-by: Peter Meerwald <pmeerw@xxxxxxxxxx>
---
drivers/iio/dac/mcp4725.c | 64 +++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 62 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c
index a612ec7..cb9db90 100644
--- a/drivers/iio/dac/mcp4725.c
+++ b/drivers/iio/dac/mcp4725.c
@@ -12,14 +12,13 @@
* 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>
@@ -64,6 +63,66 @@ static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
#define MCP4725_PM_OPS NULL
#endif
+static int 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 struct iio_chan_spec mcp4725_channel = {
.type = IIO_VOLTAGE,
.indexed = 1,
@@ -138,6 +197,7 @@ static int mcp4725_write_raw(struct iio_dev *indio_dev,
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,
};
--
1.8.3.1
--
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