From: Roland Stigge <stigge@xxxxxxxxx> IIO Driver for Maxim MAX517, MAX518 and MAX519 DAC Signed-off-by: Roland Stigge <stigge@xxxxxxxxx> Acked-by: Jonathan Cameron <jic23@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx> --- drivers/staging/iio/Documentation/dac/max517 | 41 ++++ drivers/staging/iio/dac/Kconfig | 10 + drivers/staging/iio/dac/Makefile | 1 + drivers/staging/iio/dac/max517.c | 293 ++++++++++++++++++++++++++ drivers/staging/iio/dac/max517.h | 19 ++ 5 files changed, 364 insertions(+), 0 deletions(-) create mode 100644 drivers/staging/iio/Documentation/dac/max517 create mode 100644 drivers/staging/iio/dac/max517.c create mode 100644 drivers/staging/iio/dac/max517.h diff --git a/drivers/staging/iio/Documentation/dac/max517 b/drivers/staging/iio/Documentation/dac/max517 new file mode 100644 index 0000000..e60ec2f --- /dev/null +++ b/drivers/staging/iio/Documentation/dac/max517 @@ -0,0 +1,41 @@ +Kernel driver max517 +==================== + +Supported chips: + * Maxim MAX517, MAX518, MAX519 + Prefix: 'max517' + Datasheet: Publicly available at the Maxim website + http://www.maxim-ic.com/ + +Author: + Roland Stigge <stigge@xxxxxxxxx> + +Description +----------- + +The Maxim MAX517/518/519 is an 8-bit DAC on the I2C bus. The following table +shows the different feature sets of the variants MAX517, MAX518 and MAX519: + +Feature MAX517 MAX518 MAX519 +-------------------------------------------------------------------------- +One output channel X +Two output channels X X +Simultaneous output updates X X +Supply voltage as reference X +Separate reference input X +Reference input for each DAC X + +Via the iio sysfs interface, there are three attributes available: out1_raw, +out2_raw and out12_raw. With out1_raw and out2_raw, the current output values +(0..255) of the DACs can be written to the device. out12_raw can be used to set +both output channel values simultaneously. + +With MAX517, only out1_raw is available. + +Via out1_scale (and where appropriate, out2_scale), the current scaling factor +in mV can be read. + +When the operating system goes to a power down state, the Power Down function +of the chip is activated, reducing the supply current to 4uA. + +On power-up, the device is in 0V-output state. diff --git a/drivers/staging/iio/dac/Kconfig b/drivers/staging/iio/dac/Kconfig index 9191bd2..2120904 100644 --- a/drivers/staging/iio/dac/Kconfig +++ b/drivers/staging/iio/dac/Kconfig @@ -19,3 +19,13 @@ config AD5446 To compile this driver as a module, choose M here: the module will be called ad5446. + +config MAX517 + tristate "Maxim MAX517/518/519 DAC driver" + depends on I2C && EXPERIMENTAL + help + If you say yes here you get support for the Maxim chips MAX517, + MAX518 and MAX519 (I2C 8-Bit DACs with rail-to-rail outputs). + + This driver can also be built as a module. If so, the module + will be called max517. diff --git a/drivers/staging/iio/dac/Makefile b/drivers/staging/iio/dac/Makefile index 7cf331b..1197aef 100644 --- a/drivers/staging/iio/dac/Makefile +++ b/drivers/staging/iio/dac/Makefile @@ -4,3 +4,4 @@ obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o obj-$(CONFIG_AD5446) += ad5446.o +obj-$(CONFIG_MAX517) += max517.o diff --git a/drivers/staging/iio/dac/max517.c b/drivers/staging/iio/dac/max517.c new file mode 100644 index 0000000..4974e70 --- /dev/null +++ b/drivers/staging/iio/dac/max517.c @@ -0,0 +1,293 @@ +/* + * max517.c - Support for Maxim MAX517, MAX518 and MAX519 + * + * Copyright (C) 2010, 2011 Roland Stigge <stigge@xxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/jiffies.h> +#include <linux/i2c.h> +#include <linux/err.h> + +#include "../iio.h" +#include "dac.h" + +#include "max517.h" + +#define MAX517_DRV_NAME "max517" + +/* Commands */ +#define COMMAND_CHANNEL0 0x00 +#define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */ +#define COMMAND_PD 0x08 /* Power Down */ + +enum max517_device_ids { + ID_MAX517, + ID_MAX518, + ID_MAX519, +}; + +struct max517_data { + struct iio_dev *indio_dev; + unsigned short vref_mv[2]; +}; + +/* + * channel: bit 0: channel 1 + * bit 1: channel 2 + * (this way, it's possible to set both channels at once) + */ +static ssize_t max517_set_value(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count, int channel) +{ + struct i2c_client *client = to_i2c_client(dev); + u8 outbuf[4]; /* 1x or 2x command + value */ + int outbuf_size = 0; + int res; + long val; + + res = strict_strtol(buf, 10, &val); + + if (res) + return res; + + if (val < 0 || val > 255) + return -EINVAL; + + if (channel & 1) { + outbuf[outbuf_size++] = COMMAND_CHANNEL0; + outbuf[outbuf_size++] = val; + } + if (channel & 2) { + outbuf[outbuf_size++] = COMMAND_CHANNEL1; + outbuf[outbuf_size++] = val; + } + + /* + * At this point, there are always 1 or 2 two-byte commands in + * outbuf. With 2 commands, the device can set two outputs + * simultaneously, latching the values upon the end of the I2C + * transfer. + */ + + res = i2c_master_send(client, outbuf, outbuf_size); + if (res < 0) + return res; + + return count; +} + +static ssize_t max517_set_value_1(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return max517_set_value(dev, attr, buf, count, 1); +} +static IIO_DEV_ATTR_OUT_RAW(1, max517_set_value_1, 0); + +static ssize_t max517_set_value_2(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return max517_set_value(dev, attr, buf, count, 2); +} +static IIO_DEV_ATTR_OUT_RAW(2, max517_set_value_2, 1); + +static ssize_t max517_set_value_both(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + return max517_set_value(dev, attr, buf, count, 3); +} +static IIO_DEVICE_ATTR_NAMED(out1and2_raw, out1&2_raw, S_IWUSR, NULL, + max517_set_value_both, -1); + +static ssize_t max517_show_scale(struct device *dev, + struct device_attribute *attr, + char *buf, int channel) +{ + struct iio_dev *dev_info = dev_get_drvdata(dev); + struct max517_data *data = iio_dev_get_devdata(dev_info); + /* Corresponds to Vref / 2^(bits) */ + unsigned int scale_uv = (data->vref_mv[channel - 1] * 1000) >> 8; + + return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000); +} + +static ssize_t max517_show_scale1(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return max517_show_scale(dev, attr, buf, 1); +} +static IIO_DEVICE_ATTR(out1_scale, S_IRUGO, max517_show_scale1, NULL, 0); + +static ssize_t max517_show_scale2(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return max517_show_scale(dev, attr, buf, 2); +} +static IIO_DEVICE_ATTR(out2_scale, S_IRUGO, max517_show_scale2, NULL, 0); + +/* On MAX517 variant, we have two outputs */ +static struct attribute *max517_attributes[] = { + &iio_dev_attr_out1_raw.dev_attr.attr, + &iio_dev_attr_out1_scale.dev_attr.attr, + NULL +}; + +static struct attribute_group max517_attribute_group = { + .attrs = max517_attributes, +}; + +/* On MAX518 and MAX518 variant, we have two outputs */ +static struct attribute *max518_attributes[] = { + &iio_dev_attr_out1_raw.dev_attr.attr, + &iio_dev_attr_out1_scale.dev_attr.attr, + &iio_dev_attr_out2_raw.dev_attr.attr, + &iio_dev_attr_out2_scale.dev_attr.attr, + &iio_dev_attr_out1and2_raw.dev_attr.attr, + NULL +}; + +static struct attribute_group max518_attribute_group = { + .attrs = max518_attributes, +}; + +static int max517_suspend(struct i2c_client *client, pm_message_t mesg) +{ + u8 outbuf = COMMAND_PD; + + return i2c_master_send(client, &outbuf, 1); +} + +static int max517_resume(struct i2c_client *client) +{ + u8 outbuf = 0; + + return i2c_master_send(client, &outbuf, 1); +} + +static int max517_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct max517_data *data; + struct max517_platform_data *platform_data = client->dev.platform_data; + int err; + + data = kzalloc(sizeof(struct max517_data), GFP_KERNEL); + if (!data) { + err = -ENOMEM; + goto exit; + } + + i2c_set_clientdata(client, data); + + data->indio_dev = iio_allocate_device(); + if (data->indio_dev == NULL) { + err = -ENOMEM; + goto exit_free_data; + } + + /* establish that the iio_dev is a child of the i2c device */ + data->indio_dev->dev.parent = &client->dev; + + /* reduced attribute set for MAX517 */ + if (id->driver_data == ID_MAX517) + data->indio_dev->attrs = &max517_attribute_group; + else + data->indio_dev->attrs = &max518_attribute_group; + data->indio_dev->dev_data = (void *)(data); + data->indio_dev->driver_module = THIS_MODULE; + data->indio_dev->modes = INDIO_DIRECT_MODE; + + /* + * Reference voltage on MAX518 and default is 5V, else take vref_mv + * from platform_data + */ + if (id->driver_data == ID_MAX518 || !platform_data) { + data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */ + } else { + data->vref_mv[0] = platform_data->vref_mv[0]; + data->vref_mv[1] = platform_data->vref_mv[1]; + } + + err = iio_device_register(data->indio_dev); + if (err) + goto exit_free_device; + + dev_info(&client->dev, "DAC registered\n"); + + return 0; + +exit_free_device: + iio_free_device(data->indio_dev); +exit_free_data: + kfree(data); +exit: + return err; +} + +static int max517_remove(struct i2c_client *client) +{ + struct max517_data *data = i2c_get_clientdata(client); + + iio_free_device(data->indio_dev); + kfree(data); + + return 0; +} + +static const struct i2c_device_id max517_id[] = { + { "max517", ID_MAX517 }, + { "max518", ID_MAX518 }, + { "max519", ID_MAX519 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, max517_id); + +static struct i2c_driver max517_driver = { + .driver = { + .name = MAX517_DRV_NAME, + }, + .probe = max517_probe, + .remove = max517_remove, + .suspend = max517_suspend, + .resume = max517_resume, + .id_table = max517_id, +}; + +static int __init max517_init(void) +{ + return i2c_add_driver(&max517_driver); +} + +static void __exit max517_exit(void) +{ + i2c_del_driver(&max517_driver); +} + +MODULE_AUTHOR("Roland Stigge <stigge@xxxxxxxxx>"); +MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC"); +MODULE_LICENSE("GPL"); + +module_init(max517_init); +module_exit(max517_exit); diff --git a/drivers/staging/iio/dac/max517.h b/drivers/staging/iio/dac/max517.h new file mode 100644 index 0000000..8106cf2 --- /dev/null +++ b/drivers/staging/iio/dac/max517.h @@ -0,0 +1,19 @@ +/* + * MAX517 DAC driver + * + * Copyright 2011 Roland Stigge <stigge@xxxxxxxxx> + * + * Licensed under the GPL-2 or later. + */ +#ifndef IIO_DAC_MAX517_H_ +#define IIO_DAC_MAX517_H_ + +/* + * TODO: struct max517_platform_data needs to go into include/linux/iio + */ + +struct max517_platform_data { + u16 vref_mv[2]; +}; + +#endif /* IIO_DAC_MAX517_H_ */ -- 1.7.4.1 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
