From cf35ad61aca2c0c8983fa1e140c901f6588aba7e Mon Sep 17 00:00:00 2001 From: Peter Meerwald Date: Fri, 8 Jun 2012 18:06:45 +0200 Subject: [PATCH] iio: add mcp4725 I2C DAC driver v5: * fix warnings (Jonathan Cameron) v4: * remove unused indio_dev pointer in mcp4725_data (Jonathan Cameron) * use u16 instead of unsigned short in mcp4725_data (Jonathan Cameron) * #include mcp4725.h from linux/iio/dac/ v3: * move from staging to drivers/iio * switch to chan_spec * dev_get_drvdata() -> dev_to_iio_dev() * annotate probe() and remove() with __devinit and __devexit v2 (based on comments from Jonathan Cameron and Lars-Peter Clausen): * did NOT switch to chan_spec yet * rebase to staging-next tree, update iio header locations * dropped dac.h #include, not needed * strict_strtol() -> kstrtol() * call iio_device_unregister() in remove() * everything in one patch Signed-off-by: Peter Meerwald Acked-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/iio/dac/Kconfig | 11 ++ drivers/iio/dac/Makefile | 1 + drivers/iio/dac/mcp4725.c | 227 ++++++++++++++++++++++++++++++++++++++++ include/linux/iio/dac/mcp4725.h | 16 +++ 4 files changed, 255 insertions(+) create mode 100644 drivers/iio/dac/mcp4725.c create mode 100644 include/linux/iio/dac/mcp4725.h diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig index a626f03..92fb3a0 100644 --- a/drivers/iio/dac/Kconfig +++ b/drivers/iio/dac/Kconfig @@ -118,4 +118,15 @@ config MAX517 This driver can also be built as a module. If so, the module will be called max517. +config MCP4725 + tristate "MCP4725 DAC driver" + depends on I2C + ---help--- + Say Y here if you want to build a driver for the Microchip + MCP 4725 12-bit digital-to-analog converter (DAC) with I2C + interface. + + To compile this driver as a module, choose M here: the module + will be called mcp4725. + endmenu diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile index 8ab1d26..9ea3cee 100644 --- a/drivers/iio/dac/Makefile +++ b/drivers/iio/dac/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_AD5764) += ad5764.o obj-$(CONFIG_AD5791) += ad5791.o obj-$(CONFIG_AD5686) += ad5686.o obj-$(CONFIG_MAX517) += max517.o +obj-$(CONFIG_MCP4725) += mcp4725.o diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c new file mode 100644 index 0000000..e0e168b --- /dev/null +++ b/drivers/iio/dac/mcp4725.c @@ -0,0 +1,227 @@ +/* + * mcp4725.c - Support for Microchip MCP4725 + * + * Copyright (C) 2012 Peter Meerwald + * + * Based on max517 by Roland Stigge + * + * 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) + * + * writing the DAC value to EEPROM is not supported + */ + +#include +#include +#include +#include + +#include +#include + +#include + +#define MCP4725_DRV_NAME "mcp4725" + +struct mcp4725_data { + struct i2c_client *client; + u16 vref_mv; + u16 dac_value; +}; + +#ifdef CONFIG_PM_SLEEP +static int mcp4725_suspend(struct device *dev) +{ + u8 outbuf[2]; + + outbuf[0] = 0x3 << 4; /* power-down bits, 500 kOhm resistor */ + outbuf[1] = 0; + + return i2c_master_send(to_i2c_client(dev), outbuf, 2); +} + +static int mcp4725_resume(struct device *dev) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct mcp4725_data *data = iio_priv(indio_dev); + u8 outbuf[2]; + + /* restore previous DAC value */ + outbuf[0] = (data->dac_value >> 8) & 0xf; + outbuf[1] = data->dac_value & 0xff; + + return i2c_master_send(to_i2c_client(dev), outbuf, 2); +} + +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 const struct iio_chan_spec mcp4725_channel = { + .type = IIO_VOLTAGE, + .indexed = 1, + .output = 1, + .channel = 0, + .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | + IIO_CHAN_INFO_SCALE_SHARED_BIT, + .scan_type = IIO_ST('u', 12, 16, 0), +}; + +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); + unsigned long scale_uv; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + *val = data->dac_value; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + scale_uv = (data->vref_mv * 1000) >> 12; + *val = scale_uv / 1000000; + *val2 = scale_uv % 1000000; + return IIO_VAL_INT_PLUS_MICRO; + } + 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, + .driver_module = THIS_MODULE, +}; + +static int __devinit 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]; + int err; + + if (!platform_data || !platform_data->vref_mv) { + dev_err(&client->dev, "invalid platform data"); + err = -EINVAL; + goto exit; + } + + indio_dev = iio_device_alloc(sizeof(*data)); + if (indio_dev == NULL) { + err = -ENOMEM; + goto exit; + } + 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"); + goto exit_free_device; + } + data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4); + + err = iio_device_register(indio_dev); + if (err) + goto exit_free_device; + + dev_info(&client->dev, "MCP4725 DAC registered\n"); + + return 0; + +exit_free_device: + iio_device_free(indio_dev); +exit: + return err; +} + +static int __devexit 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); + + 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 = __devexit_p(mcp4725_remove), + .id_table = mcp4725_id, +}; +module_i2c_driver(mcp4725_driver); + +MODULE_AUTHOR("Peter Meerwald "); +MODULE_DESCRIPTION("MCP4725 12-bit DAC"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/iio/dac/mcp4725.h b/include/linux/iio/dac/mcp4725.h new file mode 100644 index 0000000..91530e6 --- /dev/null +++ b/include/linux/iio/dac/mcp4725.h @@ -0,0 +1,16 @@ +/* + * MCP4725 DAC driver + * + * Copyright (C) 2012 Peter Meerwald + * + * Licensed under the GPL-2 or later. + */ + +#ifndef IIO_DAC_MCP4725_H_ +#define IIO_DAC_MCP4725_H_ + +struct mcp4725_platform_data { + u16 vref_mv; +}; + +#endif /* IIO_DAC_MCP4725_H_ */ -- 2.7.4