On 18/10/16 18:43, Tomas Novotny wrote: > From: Tomas Novotny <tomas@xxxxxxxxxx> > > MCP47x6 chip supports selection of a voltage reference (VDD, VREF buffered > or unbuffered). MCP4725 doesn't have this feature thus the eventual setting > is ignored and user is warned. > > The setting is stored only in the volatile memory of the chip. You need to > manually store it to the EEPROM of the chip via 'store_eeprom' sysfs entry. > > Signed-off-by: Tomas Novotny <tomas@xxxxxxxxxx> Something odd happened and this patch wouldn't apply without some manual intervention. Please check the result in the testing branch of iio.git. Thanks, Jonathan > --- > drivers/iio/dac/mcp4725.c | 97 ++++++++++++++++++++++++++++++++++++++--- > include/linux/iio/dac/mcp4725.h | 11 +++++ > 2 files changed, 102 insertions(+), 6 deletions(-) > > diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c > index e481f38..83d431f 100644 > --- a/drivers/iio/dac/mcp4725.c > +++ b/drivers/iio/dac/mcp4725.c > @@ -27,12 +27,20 @@ > > #define MCP4725_DRV_NAME "mcp4725" > > +#define MCP472X_REF_VDD 0x00 > +#define MCP472X_REF_VREF_UNBUFFERED 0x02 > +#define MCP472X_REF_VREF_BUFFERED 0x03 > + > struct mcp4725_data { > struct i2c_client *client; > + int id; > + unsigned ref_mode; > + bool vref_buffered; > u16 dac_value; > bool powerdown; > unsigned powerdown_mode; > struct regulator *vdd_reg; > + struct regulator *vref_reg; > }; > > static int mcp4725_suspend(struct device *dev) > @@ -87,6 +95,7 @@ static ssize_t mcp4725_store_eeprom(struct device *dev, > return 0; > > inoutbuf[0] = 0x60; /* write EEPROM */ > + inoutbuf[0] |= data->ref_mode << 3; > inoutbuf[1] = data->dac_value >> 4; > inoutbuf[2] = (data->dac_value & 0xf) << 4; > > @@ -279,6 +288,28 @@ static int mcp4725_set_value(struct iio_dev *indio_dev, int val) > return 0; > } > > +static int mcp4726_set_cfg(struct iio_dev *indio_dev) > +{ > + struct mcp4725_data *data = iio_priv(indio_dev); > + u8 outbuf[3]; > + int ret; > + > + outbuf[0] = 0x40; > + outbuf[0] |= data->ref_mode << 3; > + if (data->powerdown) > + outbuf[0] |= data->powerdown << 1; > + outbuf[1] = data->dac_value >> 4; > + outbuf[2] = (data->dac_value & 0xf) << 4; > + > + ret = i2c_master_send(data->client, outbuf, 3); > + if (ret < 0) > + return ret; > + else if (ret != 3) > + 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) > @@ -291,7 +322,11 @@ static int mcp4725_read_raw(struct iio_dev *indio_dev, > *val = data->dac_value; > return IIO_VAL_INT; > case IIO_CHAN_INFO_SCALE: > - ret = regulator_get_voltage(data->vdd_reg); > + if (data->ref_mode == MCP472X_REF_VDD) > + ret = regulator_get_voltage(data->vdd_reg); > + else > + ret = regulator_get_voltage(data->vref_reg); > + > if (ret < 0) > return ret; > > @@ -335,8 +370,9 @@ static int mcp4725_probe(struct i2c_client *client, > struct mcp4725_data *data; > struct iio_dev *indio_dev; > struct mcp4725_platform_data *pdata = dev_get_platdata(&client->dev); > - u8 inbuf[3]; > + u8 inbuf[4]; > u8 pd; > + u8 ref; > int err; > > if (!pdata) { > @@ -350,6 +386,26 @@ static int mcp4725_probe(struct i2c_client *client, > data = iio_priv(indio_dev); > i2c_set_clientdata(client, indio_dev); > data->client = client; > + data->id = id->driver_data; > + > + if (data->id == MCP4725 && pdata->use_vref) { > + dev_err(&client->dev, > + "external reference is unavailable on MCP4725"); > + return -EINVAL; > + } > + > + if (!pdata->use_vref && pdata->vref_buffered) { > + dev_err(&client->dev, > + "buffering is unavailable on the internal reference"); > + return -EINVAL; > + } > + > + if (!pdata->use_vref) > + data->ref_mode = MCP472X_REF_VDD; > + else > + data->ref_mode = pdata->vref_buffered ? > + MCP472X_REF_VREF_BUFFERED : > + MCP472X_REF_VREF_UNBUFFERED; > > data->vdd_reg = devm_regulator_get(&client->dev, "vdd"); > if (IS_ERR(data->vdd_reg)) > @@ -359,6 +415,18 @@ static int mcp4725_probe(struct i2c_client *client, > if (err) > return err; > > + if (pdata->use_vref) { > + data->vref_reg = devm_regulator_get(&client->dev, "vref"); > + if (IS_ERR(data->vref_reg)) { > + err = PTR_ERR(data->vdd_reg); > + goto err_disable_vdd_reg; > + } > + > + err = regulator_enable(data->vref_reg); > + if (err) > + goto err_disable_vdd_reg; > + } > + > indio_dev->dev.parent = &client->dev; > indio_dev->name = id->name; > indio_dev->info = &mcp4725_info; > @@ -366,23 +434,38 @@ static int mcp4725_probe(struct i2c_client *client, > indio_dev->num_channels = 1; > indio_dev->modes = INDIO_DIRECT_MODE; > > - /* read current DAC value */ > - err = i2c_master_recv(client, inbuf, 3); > + /* read current DAC value and settings */ > + err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4); > if (err < 0) { > dev_err(&client->dev, "failed to read DAC value"); > - goto err_disable_vdd_reg; > + goto err_disable_vref_reg; > } > pd = (inbuf[0] >> 1) & 0x3; > data->powerdown = pd > 0 ? true : false; > data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */ > data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4); > + if (data->id == MCP4726) > + ref = (inbuf[3] >> 3) & 0x3; > + > + if (data->id == MCP4726 && ref != data->ref_mode) { > + dev_info(&client->dev, > + "voltage reference mode differs (conf: %u, eeprom: %u), setting %u", > + data->ref_mode, ref, data->ref_mode); > + err = mcp4726_set_cfg(indio_dev); > + if (err < 0) > + goto err_disable_vref_reg; > + } > > err = iio_device_register(indio_dev); > if (err) > - goto err_disable_vdd_reg; > + goto err_disable_vref_reg; > > return 0; > > +err_disable_vref_reg: > + if (data->vref_reg) > + regulator_disable(data->vref_reg); > + > err_disable_vdd_reg: > regulator_disable(data->vdd_reg); > > @@ -396,6 +479,8 @@ static int mcp4725_remove(struct i2c_client *client) > > iio_device_unregister(indio_dev); > > + if (data->vref_reg) > + regulator_disable(data->vref_reg); > regulator_disable(data->vdd_reg); > > return 0; > diff --git a/include/linux/iio/dac/mcp4725.h b/include/linux/iio/dac/mcp4725.h > index 7c062e8..628b2cf 100644 > --- a/include/linux/iio/dac/mcp4725.h > +++ b/include/linux/iio/dac/mcp4725.h > @@ -9,7 +9,18 @@ > #ifndef IIO_DAC_MCP4725_H_ > #define IIO_DAC_MCP4725_H_ > > +/** > + * struct mcp4725_platform_data - MCP4725/6 DAC specific data. > + * @use_vref: Whether an external reference voltage on Vref pin should be used. > + * Additional vref-supply must be specified when used. > + * @vref_buffered: Controls buffering of the external reference voltage. > + * > + * Vref related settings are available only on MCP4756. See > + * Documentation/devicetree/bindings/iio/dac/mcp4725.txt for more information. > + */ > struct mcp4725_platform_data { > + bool use_vref; > + bool vref_buffered; > }; > > #endif /* IIO_DAC_MCP4725_H_ */ > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html