| /* |
| * DAC driver for the Apex Embedded Systems STX104 |
| * Copyright (C) 2016 William Breathitt Gray |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License, version 2, as |
| * published by the Free Software Foundation. |
| * |
| * 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. |
| */ |
| #include <linux/bitops.h> |
| #include <linux/device.h> |
| #include <linux/errno.h> |
| #include <linux/iio/iio.h> |
| #include <linux/iio/types.h> |
| #include <linux/io.h> |
| #include <linux/ioport.h> |
| #include <linux/isa.h> |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| |
| #define STX104_NUM_CHAN 2 |
| |
| #define STX104_CHAN(chan) { \ |
| .type = IIO_VOLTAGE, \ |
| .channel = chan, \ |
| .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
| .indexed = 1, \ |
| .output = 1 \ |
| } |
| |
| #define STX104_EXTENT 16 |
| |
| static unsigned int base[max_num_isa_dev(STX104_EXTENT)]; |
| static unsigned int num_stx104; |
| module_param_array(base, uint, &num_stx104, 0); |
| MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses"); |
| |
| /** |
| * struct stx104_iio - IIO device private data structure |
| * @chan_out_states: channels' output states |
| * @base: base port address of the IIO device |
| */ |
| struct stx104_iio { |
| unsigned chan_out_states[STX104_NUM_CHAN]; |
| unsigned base; |
| }; |
| |
| static int stx104_read_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, int *val, int *val2, long mask) |
| { |
| struct stx104_iio *const priv = iio_priv(indio_dev); |
| |
| if (mask != IIO_CHAN_INFO_RAW) |
| return -EINVAL; |
| |
| *val = priv->chan_out_states[chan->channel]; |
| |
| return IIO_VAL_INT; |
| } |
| |
| static int stx104_write_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, int val, int val2, long mask) |
| { |
| struct stx104_iio *const priv = iio_priv(indio_dev); |
| const unsigned chan_addr_offset = 2 * chan->channel; |
| |
| if (mask != IIO_CHAN_INFO_RAW) |
| return -EINVAL; |
| |
| priv->chan_out_states[chan->channel] = val; |
| outw(val, priv->base + 4 + chan_addr_offset); |
| |
| return 0; |
| } |
| |
| static const struct iio_info stx104_info = { |
| .driver_module = THIS_MODULE, |
| .read_raw = stx104_read_raw, |
| .write_raw = stx104_write_raw |
| }; |
| |
| static const struct iio_chan_spec stx104_channels[STX104_NUM_CHAN] = { |
| STX104_CHAN(0), |
| STX104_CHAN(1) |
| }; |
| |
| static int stx104_probe(struct device *dev, unsigned int id) |
| { |
| struct iio_dev *indio_dev; |
| struct stx104_iio *priv; |
| |
| indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); |
| if (!indio_dev) |
| return -ENOMEM; |
| |
| if (!devm_request_region(dev, base[id], STX104_EXTENT, |
| dev_name(dev))) { |
| dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", |
| base[id], base[id] + STX104_EXTENT); |
| return -EBUSY; |
| } |
| |
| indio_dev->info = &stx104_info; |
| indio_dev->modes = INDIO_DIRECT_MODE; |
| indio_dev->channels = stx104_channels; |
| indio_dev->num_channels = STX104_NUM_CHAN; |
| indio_dev->name = dev_name(dev); |
| |
| priv = iio_priv(indio_dev); |
| priv->base = base[id]; |
| |
| /* initialize DAC output to 0V */ |
| outw(0, base[id] + 4); |
| outw(0, base[id] + 6); |
| |
| return devm_iio_device_register(dev, indio_dev); |
| } |
| |
| static struct isa_driver stx104_driver = { |
| .probe = stx104_probe, |
| .driver = { |
| .name = "stx104" |
| } |
| }; |
| |
| module_isa_driver(stx104_driver, num_stx104); |
| |
| MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); |
| MODULE_DESCRIPTION("Apex Embedded Systems STX104 DAC driver"); |
| MODULE_LICENSE("GPL v2"); |