From f17b77d6cfbc0d130ba9d57b89e8579ff43a3350 Mon Sep 17 00:00:00 2001 From: Peter Meerwald Date: Sun, 23 Jun 2013 22:30:00 +0100 Subject: [PATCH] iio: add store_eeprom to mcp4725 dac driver Signed-off-by: Peter Meerwald Signed-off-by: Jonathan Cameron --- 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 a612ec766d96..cb9db90f0a21 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 #include #include #include +#include #include #include @@ -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, }; -- 2.20.1