/* * 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 #include #include #include #include #include #include #include #include #include #include #include #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; }; /** * struct stx104_gpio - GPIO device private data structure * @chip: instance of the gpio_chip * @lock: synchronization lock to prevent I/O race conditions * @base: base port address of the GPIO device * @out_state: output bits state */ struct stx104_gpio { struct gpio_chip chip; spinlock_t lock; unsigned int base; unsigned int out_state; }; /** * struct stx104_dev - STX104 device private data structure * @indio_dev: IIO device * @chip: instance of the gpio_chip */ struct stx104_dev { struct iio_dev *indio_dev; struct gpio_chip *chip; }; 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_gpio_get_direction(struct gpio_chip *chip, unsigned int offset) { /* GPIO 0-3 are input only, while the rest are output only */ if (offset < 4) return 1; return 0; } static int stx104_gpio_direction_input(struct gpio_chip *chip, unsigned int offset) { if (offset >= 4) return -EINVAL; return 0; } static int stx104_gpio_direction_output(struct gpio_chip *chip, unsigned int offset, int value) { if (offset < 4) return -EINVAL; chip->set(chip, offset, value); return 0; } static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset) { struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip); if (offset >= 4) return -EINVAL; return !!(inb(stx104gpio->base) & BIT(offset)); } static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset, int value) { struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip); const unsigned int mask = BIT(offset) >> 4; unsigned long flags; if (offset < 4) return; spin_lock_irqsave(&stx104gpio->lock, flags); if (value) stx104gpio->out_state |= mask; else stx104gpio->out_state &= ~mask; outb(stx104gpio->out_state, stx104gpio->base); spin_unlock_irqrestore(&stx104gpio->lock, flags); } static int stx104_probe(struct device *dev, unsigned int id) { struct iio_dev *indio_dev; struct stx104_iio *priv; struct stx104_gpio *stx104gpio; struct stx104_dev *stx104dev; int err; indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); if (!indio_dev) return -ENOMEM; stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL); if (!stx104gpio) return -ENOMEM; stx104dev = devm_kzalloc(dev, sizeof(*stx104dev), GFP_KERNEL); if (!stx104dev) 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); stx104gpio->chip.label = dev_name(dev); stx104gpio->chip.parent = dev; stx104gpio->chip.owner = THIS_MODULE; stx104gpio->chip.base = -1; stx104gpio->chip.ngpio = 8; stx104gpio->chip.get_direction = stx104_gpio_get_direction; stx104gpio->chip.direction_input = stx104_gpio_direction_input; stx104gpio->chip.direction_output = stx104_gpio_direction_output; stx104gpio->chip.get = stx104_gpio_get; stx104gpio->chip.set = stx104_gpio_set; stx104gpio->base = base[id] + 3; stx104gpio->out_state = 0x0; spin_lock_init(&stx104gpio->lock); stx104dev->indio_dev = indio_dev; stx104dev->chip = &stx104gpio->chip; dev_set_drvdata(dev, stx104dev); err = gpiochip_add_data(&stx104gpio->chip, stx104gpio); if (err) { dev_err(dev, "GPIO registering failed (%d)\n", err); return err; } err = iio_device_register(indio_dev); if (err) { dev_err(dev, "IIO device registering failed (%d)\n", err); gpiochip_remove(&stx104gpio->chip); return err; } return 0; } static int stx104_remove(struct device *dev, unsigned int id) { struct stx104_dev *const stx104dev = dev_get_drvdata(dev); iio_device_unregister(stx104dev->indio_dev); gpiochip_remove(stx104dev->chip); return 0; } static struct isa_driver stx104_driver = { .probe = stx104_probe, .driver = { .name = "stx104" }, .remove = stx104_remove }; module_isa_driver(stx104_driver, num_stx104); MODULE_AUTHOR("William Breathitt Gray "); MODULE_DESCRIPTION("Apex Embedded Systems STX104 DAC driver"); MODULE_LICENSE("GPL v2");