--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * FTDI MPSSE GPIO support
+ *
+ * Based on code by Anatolij Gustschin
+ *
+ * Copyright (C) 2024 Mary Strodl <mstrodl@csh.rit.edu>
+ */
+
+#include <linux/cleanup.h>
+#include <linux/gpio/driver.h>
+#include <linux/mutex.h>
+#include <linux/usb.h>
+
+struct mpsse_priv {
+ struct gpio_chip gpio;
+ struct usb_device *udev; /* USB device encompassing all MPSSEs */
+ struct usb_interface *intf; /* USB interface for this MPSSE */
+ u8 intf_id; /* USB interface number for this MPSSE */
+ struct work_struct irq_work; /* polling work thread */
+ struct mutex irq_mutex; /* lock over irq_data */
+ atomic_t irq_type[16]; /* pin -> edge detection type */
+ atomic_t irq_enabled;
+ int id;
+
+ u8 gpio_outputs[2]; /* Output states for GPIOs [L, H] */
+ u8 gpio_dir[2]; /* Directions for GPIOs [L, H] */
+
+ u8 *bulk_in_buf; /* Extra recv buffer to grab status bytes */
+
+ struct usb_endpoint_descriptor *bulk_in;
+ struct usb_endpoint_descriptor *bulk_out;
+
+ struct mutex io_mutex; /* sync I/O with disconnect */
+};
+
+struct bulk_desc {
+ bool tx; /* direction of bulk transfer */
+ u8 *data; /* input (tx) or output (rx) */
+ int len; /* Length of `data` if tx, or length of */
+ /* Data to read if rx */
+ int len_actual; /* Length successfully transferred */
+ int timeout;
+};
+
+static const struct usb_device_id gpio_mpsse_table[] = {
+ { USB_DEVICE(0x0c52, 0xa064) }, /* SeaLevel Systems, Inc. */
+ { } /* Terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, gpio_mpsse_table);
+
+static DEFINE_IDA(gpio_mpsse_ida);
+
+/* MPSSE commands */
+#define SET_BITS_CMD 0x80
+#define GET_BITS_CMD 0x81
+
+#define SET_BITMODE_REQUEST 0x0B
+#define MODE_MPSSE (2 << 8)
+#define MODE_RESET 0
+
+/* Arbitrarily decided. This could probably be much less */
+#define MPSSE_WRITE_TIMEOUT 5000
+#define MPSSE_READ_TIMEOUT 5000
+
+/* 1 millisecond, also pretty arbitrary */
+#define MPSSE_POLL_INTERVAL 1000
+
+static int mpsse_bulk_xfer(struct usb_interface *intf, struct bulk_desc *desc)
+{
+ struct mpsse_priv *priv = usb_get_intfdata(intf);
+ struct usb_device *udev = priv->udev;
+ unsigned int pipe;
+ int ret;
+
+ if (desc->tx)
+ pipe = usb_sndbulkpipe(udev, priv->bulk_out->bEndpointAddress);
+ else
+ pipe = usb_rcvbulkpipe(udev, priv->bulk_in->bEndpointAddress);
+
+ ret = usb_bulk_msg(udev, pipe, desc->data, desc->len,
+ &desc->len_actual, desc->timeout);
+ if (ret)
+ dev_dbg(&udev->dev, "mpsse: bulk transfer failed: %d\n", ret);
+
+ return ret;
+}
+
+static int mpsse_write(struct usb_interface *intf,
+ u8 *buf, size_t len)
+{
+ int ret;
+ struct bulk_desc desc;
+
+ desc.len_actual = 0;
+ desc.tx = true;
+ desc.data = buf;
+ desc.len = len;
+ desc.timeout = MPSSE_WRITE_TIMEOUT;
+
+ ret = mpsse_bulk_xfer(intf, &desc);
+
+ return ret;
+}
+
+static int mpsse_read(struct usb_interface *intf, u8 *buf, size_t len)
+{
+ int ret;
+ struct bulk_desc desc;
+ struct mpsse_priv *priv = usb_get_intfdata(intf);
+
+ desc.len_actual = 0;
+ desc.tx = false;
+ desc.data = priv->bulk_in_buf;
+ /* Device sends 2 additional status bytes, read len + 2 */
+ desc.len = min_t(size_t, len + 2, usb_endpoint_maxp(priv->bulk_in));
+ desc.timeout = MPSSE_READ_TIMEOUT;
+
+ ret = mpsse_bulk_xfer(intf, &desc);
+ if (ret)
+ return ret;
+
+ /* Did we get enough data? */
+ if (desc.len_actual < desc.len)
+ return -EIO;
+
+ memcpy(buf, desc.data + 2, desc.len_actual - 2);
+
+ return ret;
+}
+
+static int gpio_mpsse_set_bank(struct mpsse_priv *priv, u8 bank)
+{
+ int ret;
+ u8 tx_buf[3] = {
+ SET_BITS_CMD | (bank << 1),
+ priv->gpio_outputs[bank],
+ priv->gpio_dir[bank],
+ };
+
+ ret = mpsse_write(priv->intf, tx_buf, 3);
+
+ return ret;
+}
+
+static int gpio_mpsse_get_bank(struct mpsse_priv *priv, u8 bank)
+{
+ int ret;
+ u8 buf = GET_BITS_CMD | (bank << 1);
+
+ ret = mpsse_write(priv->intf, &buf, 1);
+ if (ret)
+ return ret;
+
+ ret = mpsse_read(priv->intf, &buf, 1);
+ if (ret)
+ return ret;
+
+ return buf;
+}
+
+static void gpio_mpsse_set_multiple(struct gpio_chip *chip, unsigned long *mask,
+ unsigned long *bits)
+{
+ unsigned long i, bank, bank_mask, bank_bits;
+ int ret;
+ struct mpsse_priv *priv = gpiochip_get_data(chip);
+
+ guard(mutex)(&priv->io_mutex);
+ for_each_set_clump8(i, bank_mask, mask, chip->ngpio) {
+ bank = i / 8;
+
+ if (bank_mask) {
+ bank_bits = bitmap_get_value8(bits, i);
+ /* Zero out pins we want to change */
+ priv->gpio_outputs[bank] &= ~bank_mask;
+ /* Set pins we care about */
+ priv->gpio_outputs[bank] |= bank_bits & bank_mask;
+
+ ret = gpio_mpsse_set_bank(priv, bank);
+ if (ret)
+ dev_err(&priv->intf->dev,
+ "Couldn't set values for bank %ld!",
+ bank);
+ }
+ }
+}
+
+static int gpio_mpsse_get_multiple(struct gpio_chip *chip, unsigned long *mask,
+ unsigned long *bits)
+{
+ unsigned long i, bank, bank_mask;
+ int ret;
+ struct mpsse_priv *priv = gpiochip_get_data(chip);
+
+ guard(mutex)(&priv->io_mutex);
+ for_each_set_clump8(i, bank_mask, mask, chip->ngpio) {
+ bank = i / 8;
+
+ if (bank_mask) {
+ ret = gpio_mpsse_get_bank(priv, bank);
+ if (ret < 0)
+ return ret;
+
+ bitmap_set_value8(bits, ret & bank_mask, i);
+ }
+ }
+
+ return 0;
+}
+
+static int gpio_mpsse_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ int err;
+ unsigned long mask = 0, bits = 0;
+
+ __set_bit(offset, &mask);
+ err = gpio_mpsse_get_multiple(chip, &mask, &bits);
+ if (err)
+ return err;
+
+ /* == is not guaranteed to give 1 if true */
+ if (bits)
+ return 1;
+ else
+ return 0;
+}
+
+static void gpio_mpsse_gpio_set(struct gpio_chip *chip, unsigned int offset,
+ int value)
+{
+ unsigned long mask = 0, bits = 0;
+
+ __set_bit(offset, &mask);
+ if (value)
+ __set_bit(offset, &bits);
+
+ gpio_mpsse_set_multiple(chip, &mask, &bits);
+}
+
+static int gpio_mpsse_direction_output(struct gpio_chip *chip,
+ unsigned int offset, int value)
+{
+ struct mpsse_priv *priv = gpiochip_get_data(chip);
+ int bank = (offset & 8) >> 3;
+ int bank_offset = offset & 7;
+
+ scoped_guard(mutex, &priv->io_mutex)
+ priv->gpio_dir[bank] |= BIT(bank_offset);
+
+ gpio_mpsse_gpio_set(chip, offset, value);
+
+ return 0;
+}
+
+static int gpio_mpsse_direction_input(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ struct mpsse_priv *priv = gpiochip_get_data(chip);
+ int bank = (offset & 8) >> 3;
+ int bank_offset = offset & 7;
+
+ guard(mutex)(&priv->io_mutex);
+ priv->gpio_dir[bank] &= ~BIT(bank_offset);
+ gpio_mpsse_set_bank(priv, bank);
+
+ return 0;
+}
+
+static int gpio_mpsse_get_direction(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ int ret;
+ int bank = (offset & 8) >> 3;
+ int bank_offset = offset & 7;
+ struct mpsse_priv *priv = gpiochip_get_data(chip);
+
+ guard(mutex)(&priv->io_mutex);
+ /* MPSSE directions are inverted */
+ if (priv->gpio_dir[bank] & BIT(bank_offset))
+ ret = GPIO_LINE_DIRECTION_OUT;
+ else
+ ret = GPIO_LINE_DIRECTION_IN;
+
+ return ret;
+}
+
+static void gpio_mpsse_poll(struct work_struct *work)
+{
+ unsigned long pin_mask, pin_states, flags;
+ int irq_enabled, offset, err, value, fire_irq,
+ irq, old_value[16], irq_type[16];
+ struct mpsse_priv *priv = container_of(work, struct mpsse_priv,
+ irq_work);
+
+ for (offset = 0; offset < priv->gpio.ngpio; ++offset)
+ old_value[offset] = -1;
+
+ while ((irq_enabled = atomic_read(&priv->irq_enabled))) {
+ usleep_range(MPSSE_POLL_INTERVAL, MPSSE_POLL_INTERVAL + 1000);
+ /* Cleanup will trigger at the end of the loop */
+ guard(mutex)(&priv->irq_mutex);
+
+ pin_mask = 0;
+ pin_states = 0;
+ for (offset = 0; offset < priv->gpio.ngpio; ++offset) {
+ irq_type[offset] = atomic_read(&priv->irq_type[offset]);
+ if (irq_type[offset] != IRQ_TYPE_NONE &&
+ irq_enabled & BIT(offset))
+ pin_mask |= BIT(offset);
+ else
+ old_value[offset] = -1;
+ }
+
+ err = gpio_mpsse_get_multiple(&priv->gpio, &pin_mask,
+ &pin_states);
+ if (err) {
+ dev_err_ratelimited(&priv->intf->dev,
+ "Error polling!\n");
+ continue;
+ }
+
+ /* Check each value */
+ for (offset = 0; offset < priv->gpio.ngpio; ++offset) {
+ if (old_value[offset] == -1)
+ continue;
+
+ fire_irq = 0;
+ value = pin_states & BIT(offset);
+
+ switch (irq_type[offset]) {
+ case IRQ_TYPE_EDGE_RISING:
+ fire_irq = value > old_value[offset];
+ break;
+ case IRQ_TYPE_EDGE_FALLING:
+ fire_irq = value < old_value[offset];
+ break;
+ case IRQ_TYPE_EDGE_BOTH:
+ fire_irq = value != old_value[offset];
+ break;
+ }
+ if (!fire_irq)
+ continue;
+
+ irq = irq_find_mapping(priv->gpio.irq.domain,
+ offset);
+ local_irq_save(flags);
+ generic_handle_irq(irq);
+ local_irq_disable();
+ local_irq_restore(flags);
+ }
+
+ /* Sync back values so we can refer to them next tick */
+ for (offset = 0; offset < priv->gpio.ngpio; ++offset)
+ if (irq_type[offset] != IRQ_TYPE_NONE &&
+ irq_enabled & BIT(offset))
+ old_value[offset] = pin_states & BIT(offset);
+ }
+}
+
+static int gpio_mpsse_set_irq_type(struct irq_data *irqd, unsigned int type)
+{
+ int offset;
+ struct mpsse_priv *priv = irq_data_get_irq_chip_data(irqd);
+
+ offset = irqd->hwirq;
+ atomic_set(&priv->irq_type[offset], type & IRQ_TYPE_EDGE_BOTH);
+
+ return 0;
+}
+
+static void gpio_mpsse_irq_disable(struct irq_data *irqd)
+{
+ struct mpsse_priv *priv = irq_data_get_irq_chip_data(irqd);
+
+ atomic_and(~BIT(irqd->hwirq), &priv->irq_enabled);
+ gpiochip_disable_irq(&priv->gpio, irqd->hwirq);
+}
+
+static void gpio_mpsse_irq_enable(struct irq_data *irqd)
+{
+ struct mpsse_priv *priv = irq_data_get_irq_chip_data(irqd);
+
+ gpiochip_enable_irq(&priv->gpio, irqd->hwirq);
+ /* If no-one else was using the IRQ, enable it */
+ if (!atomic_fetch_or(BIT(irqd->hwirq), &priv->irq_enabled)) {
+ INIT_WORK(&priv->irq_work, gpio_mpsse_poll);
+ schedule_work(&priv->irq_work);
+ }
+}
+
+static const struct irq_chip gpio_mpsse_irq_chip = {
+ .name = "gpio-mpsse-irq",
+ .irq_enable = gpio_mpsse_irq_enable,
+ .irq_disable = gpio_mpsse_irq_disable,
+ .irq_set_type = gpio_mpsse_set_irq_type,
+ .flags = IRQCHIP_IMMUTABLE,
+ GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static void gpio_mpsse_ida_remove(void *data)
+{
+ struct mpsse_priv *priv = data;
+
+ ida_simple_remove(&gpio_mpsse_ida, priv->id);
+}
+
+static int gpio_mpsse_probe(struct usb_interface *interface,
+ const struct usb_device_id *id)
+{
+ struct mpsse_priv *priv;
+ struct device *dev;
+ int err;
+
+ dev = &interface->dev;
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->udev = usb_get_dev(interface_to_usbdev(interface));
+ priv->intf = interface;
+ priv->intf_id = interface->cur_altsetting->desc.bInterfaceNumber;
+
+ priv->id = ida_simple_get(&gpio_mpsse_ida, 0, 0, GFP_KERNEL);
+ if (priv->id < 0)
+ return priv->id;
+
+ err = devm_add_action_or_reset(dev, gpio_mpsse_ida_remove, priv);
+ if (err)
+ return err;
+
+ devm_mutex_init(dev, &priv->io_mutex);
+ devm_mutex_init(dev, &priv->irq_mutex);
+
+ priv->gpio.label = devm_kasprintf(dev, GFP_KERNEL,
+ "gpio-mpsse.%d.%d",
+ priv->id, priv->intf_id);
+ if (!priv->gpio.label)
+ return -ENOMEM;
+
+ priv->gpio.owner = THIS_MODULE;
+ priv->gpio.parent = interface->usb_dev;
+ priv->gpio.get_direction = gpio_mpsse_get_direction;
+ priv->gpio.direction_input = gpio_mpsse_direction_input;
+ priv->gpio.direction_output = gpio_mpsse_direction_output;
+ priv->gpio.get = gpio_mpsse_gpio_get;
+ priv->gpio.set = gpio_mpsse_gpio_set;
+ priv->gpio.get_multiple = gpio_mpsse_get_multiple;
+ priv->gpio.set_multiple = gpio_mpsse_set_multiple;
+ priv->gpio.base = -1;
+ priv->gpio.ngpio = 16;
+ priv->gpio.offset = priv->intf_id * priv->gpio.ngpio;
+ priv->gpio.can_sleep = 1;
+
+ err = usb_find_common_endpoints(interface->cur_altsetting,
+ &priv->bulk_in, &priv->bulk_out,
+ NULL, NULL);
+ if (err)
+ return err;
+
+ priv->bulk_in_buf = devm_kmalloc(dev, usb_endpoint_maxp(priv->bulk_in),
+ GFP_KERNEL);
+ if (!priv->bulk_in_buf)
+ return -ENOMEM;
+
+ usb_set_intfdata(interface, priv);
+
+ /* Reset mode, needed to correctly enter MPSSE mode */
+ err = usb_control_msg(priv->udev, usb_sndctrlpipe(priv->udev, 0),
+ SET_BITMODE_REQUEST,
+ USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+ MODE_RESET, priv->intf_id + 1, NULL, 0,
+ USB_CTRL_SET_TIMEOUT);
+ if (err)
+ return err;
+
+ /* Enter MPSSE mode */
+ err = usb_control_msg(priv->udev, usb_sndctrlpipe(priv->udev, 0),
+ SET_BITMODE_REQUEST,
+ USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+ MODE_MPSSE, priv->intf_id + 1, NULL, 0,
+ USB_CTRL_SET_TIMEOUT);
+ if (err)
+ return err;
+
+ gpio_irq_chip_set_chip(&priv->gpio.irq, &gpio_mpsse_irq_chip);
+
+ priv->gpio.irq.parent_handler = NULL;
+ priv->gpio.irq.num_parents = 0;
+ priv->gpio.irq.parents = NULL;
+ priv->gpio.irq.default_type = IRQ_TYPE_NONE;
+ priv->gpio.irq.handler = handle_simple_irq;
+
+ err = devm_gpiochip_add_data(dev, &priv->gpio, priv);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static void gpio_mpsse_disconnect(struct usb_interface *intf)
+{
+ struct mpsse_priv *priv = usb_get_intfdata(intf);
+
+ priv->intf = NULL;
+ usb_set_intfdata(intf, NULL);
+ usb_put_dev(priv->udev);
+}
+
+static struct usb_driver gpio_mpsse_driver = {
+ .name = "gpio-mpsse",
+ .probe = gpio_mpsse_probe,
+ .disconnect = gpio_mpsse_disconnect,
+ .id_table = gpio_mpsse_table,
+};
+
+module_usb_driver(gpio_mpsse_driver);
+
+MODULE_AUTHOR("Mary Strodl <mstrodl@csh.rit.edu>");
+MODULE_DESCRIPTION("MPSSE GPIO driver");
+MODULE_LICENSE("GPL");
projects / linux-2.6-microblaze.git / commitdiff