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path: root/drivers/iio/addac/stx104.c
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Diffstat (limited to 'drivers/iio/addac/stx104.c')
-rw-r--r--drivers/iio/addac/stx104.c402
1 files changed, 402 insertions, 0 deletions
diff --git a/drivers/iio/addac/stx104.c b/drivers/iio/addac/stx104.c
new file mode 100644
index 000000000000..48a91a95e597
--- /dev/null
+++ b/drivers/iio/addac/stx104.c
@@ -0,0 +1,402 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * IIO driver for the Apex Embedded Systems STX104
+ * Copyright (C) 2016 William Breathitt Gray
+ */
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/gpio/driver.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/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#define STX104_OUT_CHAN(chan) { \
+ .type = IIO_VOLTAGE, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .indexed = 1, \
+ .output = 1 \
+}
+#define STX104_IN_CHAN(chan, diff) { \
+ .type = IIO_VOLTAGE, \
+ .channel = chan, \
+ .channel2 = chan, \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN) | \
+ BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .indexed = 1, \
+ .differential = diff \
+}
+
+#define STX104_NUM_OUT_CHAN 2
+
+#define STX104_EXTENT 16
+
+static unsigned int base[max_num_isa_dev(STX104_EXTENT)];
+static unsigned int num_stx104;
+module_param_hw_array(base, uint, ioport, &num_stx104, 0);
+MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
+
+/**
+ * struct stx104_reg - device register structure
+ * @ssr_ad: Software Strobe Register and ADC Data
+ * @achan: ADC Channel
+ * @dio: Digital I/O
+ * @dac: DAC Channels
+ * @cir_asr: Clear Interrupts and ADC Status
+ * @acr: ADC Control
+ * @pccr_fsh: Pacer Clock Control and FIFO Status MSB
+ * @acfg: ADC Configuration
+ */
+struct stx104_reg {
+ u16 ssr_ad;
+ u8 achan;
+ u8 dio;
+ u16 dac[2];
+ u8 cir_asr;
+ u8 acr;
+ u8 pccr_fsh;
+ u8 acfg;
+};
+
+/**
+ * struct stx104_iio - IIO device private data structure
+ * @chan_out_states: channels' output states
+ * @reg: I/O address offset for the device registers
+ */
+struct stx104_iio {
+ unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
+ struct stx104_reg __iomem *reg;
+};
+
+/**
+ * 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;
+ u8 __iomem *base;
+ unsigned int out_state;
+};
+
+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);
+ struct stx104_reg __iomem *const reg = priv->reg;
+ unsigned int adc_config;
+ int adbu;
+ int gain;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_HARDWAREGAIN:
+ /* get gain configuration */
+ adc_config = ioread8(&reg->acfg);
+ gain = adc_config & 0x3;
+
+ *val = 1 << gain;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_RAW:
+ if (chan->output) {
+ *val = priv->chan_out_states[chan->channel];
+ return IIO_VAL_INT;
+ }
+
+ /* select ADC channel */
+ iowrite8(chan->channel | (chan->channel << 4), &reg->achan);
+
+ /* trigger ADC sample capture by writing to the 8-bit
+ * Software Strobe Register and wait for completion
+ */
+ iowrite8(0, &reg->ssr_ad);
+ while (ioread8(&reg->cir_asr) & BIT(7));
+
+ *val = ioread16(&reg->ssr_ad);
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_OFFSET:
+ /* get ADC bipolar/unipolar configuration */
+ adc_config = ioread8(&reg->acfg);
+ adbu = !(adc_config & BIT(2));
+
+ *val = -32768 * adbu;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ /* get ADC bipolar/unipolar and gain configuration */
+ adc_config = ioread8(&reg->acfg);
+ adbu = !(adc_config & BIT(2));
+ gain = adc_config & 0x3;
+
+ *val = 5;
+ *val2 = 15 - adbu + gain;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ }
+
+ return -EINVAL;
+}
+
+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);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_HARDWAREGAIN:
+ /* Only four gain states (x1, x2, x4, x8) */
+ switch (val) {
+ case 1:
+ iowrite8(0, &priv->reg->acfg);
+ break;
+ case 2:
+ iowrite8(1, &priv->reg->acfg);
+ break;
+ case 4:
+ iowrite8(2, &priv->reg->acfg);
+ break;
+ case 8:
+ iowrite8(3, &priv->reg->acfg);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+ case IIO_CHAN_INFO_RAW:
+ if (chan->output) {
+ /* DAC can only accept up to a 16-bit value */
+ if ((unsigned int)val > 65535)
+ return -EINVAL;
+
+ priv->chan_out_states[chan->channel] = val;
+ iowrite16(val, &priv->reg->dac[chan->channel]);
+
+ return 0;
+ }
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info stx104_info = {
+ .read_raw = stx104_read_raw,
+ .write_raw = stx104_write_raw
+};
+
+/* single-ended input channels configuration */
+static const struct iio_chan_spec stx104_channels_sing[] = {
+ STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
+ STX104_IN_CHAN(0, 0), STX104_IN_CHAN(1, 0), STX104_IN_CHAN(2, 0),
+ STX104_IN_CHAN(3, 0), STX104_IN_CHAN(4, 0), STX104_IN_CHAN(5, 0),
+ STX104_IN_CHAN(6, 0), STX104_IN_CHAN(7, 0), STX104_IN_CHAN(8, 0),
+ STX104_IN_CHAN(9, 0), STX104_IN_CHAN(10, 0), STX104_IN_CHAN(11, 0),
+ STX104_IN_CHAN(12, 0), STX104_IN_CHAN(13, 0), STX104_IN_CHAN(14, 0),
+ STX104_IN_CHAN(15, 0)
+};
+/* differential input channels configuration */
+static const struct iio_chan_spec stx104_channels_diff[] = {
+ STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
+ STX104_IN_CHAN(0, 1), STX104_IN_CHAN(1, 1), STX104_IN_CHAN(2, 1),
+ STX104_IN_CHAN(3, 1), STX104_IN_CHAN(4, 1), STX104_IN_CHAN(5, 1),
+ STX104_IN_CHAN(6, 1), STX104_IN_CHAN(7, 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 !!(ioread8(stx104gpio->base) & BIT(offset));
+}
+
+static int stx104_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
+ unsigned long *bits)
+{
+ struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
+
+ *bits = ioread8(stx104gpio->base);
+
+ return 0;
+}
+
+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;
+
+ iowrite8(stx104gpio->out_state, stx104gpio->base);
+
+ spin_unlock_irqrestore(&stx104gpio->lock, flags);
+}
+
+#define STX104_NGPIO 8
+static const char *stx104_names[STX104_NGPIO] = {
+ "DIN0", "DIN1", "DIN2", "DIN3", "DOUT0", "DOUT1", "DOUT2", "DOUT3"
+};
+
+static void stx104_gpio_set_multiple(struct gpio_chip *chip,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
+ unsigned long flags;
+
+ /* verify masked GPIO are output */
+ if (!(*mask & 0xF0))
+ return;
+
+ *mask >>= 4;
+ *bits >>= 4;
+
+ spin_lock_irqsave(&stx104gpio->lock, flags);
+
+ stx104gpio->out_state &= ~*mask;
+ stx104gpio->out_state |= *mask & *bits;
+ iowrite8(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;
+ 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;
+
+ 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;
+ }
+
+ priv = iio_priv(indio_dev);
+ priv->reg = devm_ioport_map(dev, base[id], STX104_EXTENT);
+ if (!priv->reg)
+ return -ENOMEM;
+
+ indio_dev->info = &stx104_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ /* determine if differential inputs */
+ if (ioread8(&priv->reg->cir_asr) & BIT(5)) {
+ indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
+ indio_dev->channels = stx104_channels_diff;
+ } else {
+ indio_dev->num_channels = ARRAY_SIZE(stx104_channels_sing);
+ indio_dev->channels = stx104_channels_sing;
+ }
+
+ indio_dev->name = dev_name(dev);
+
+ /* configure device for software trigger operation */
+ iowrite8(0, &priv->reg->acr);
+
+ /* initialize gain setting to x1 */
+ iowrite8(0, &priv->reg->acfg);
+
+ /* initialize DAC output to 0V */
+ iowrite16(0, &priv->reg->dac[0]);
+ iowrite16(0, &priv->reg->dac[1]);
+
+ stx104gpio->chip.label = dev_name(dev);
+ stx104gpio->chip.parent = dev;
+ stx104gpio->chip.owner = THIS_MODULE;
+ stx104gpio->chip.base = -1;
+ stx104gpio->chip.ngpio = STX104_NGPIO;
+ stx104gpio->chip.names = stx104_names;
+ 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.get_multiple = stx104_gpio_get_multiple;
+ stx104gpio->chip.set = stx104_gpio_set;
+ stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
+ stx104gpio->base = &priv->reg->dio;
+ stx104gpio->out_state = 0x0;
+
+ spin_lock_init(&stx104gpio->lock);
+
+ err = devm_gpiochip_add_data(dev, &stx104gpio->chip, stx104gpio);
+ if (err) {
+ dev_err(dev, "GPIO registering failed (%d)\n", err);
+ return err;
+ }
+
+ 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 IIO driver");
+MODULE_LICENSE("GPL v2");