The GPIO interface offers 16 GPIOs. 6 are read/write, and 10 are
read-only.
Signed-off-by: frank zago <frank@xxxxxxxx>
---
MAINTAINERS | 1 +
drivers/gpio/Kconfig | 10 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-ch341.c | 385 ++++++++++++++++++++++++++++++++++++++
include/linux/mfd/ch341.h | 8 +
5 files changed, 405 insertions(+)
create mode 100644 drivers/gpio/gpio-ch341.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 628eeaa9bf68..8b93f6192704 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21479,6 +21479,7 @@ WINCHIPHEAD CH341 I2C/GPIO MFD DRIVER
M: Frank Zago <frank@xxxxxxxx>
L: linux-usb@xxxxxxxxxxxxxxx
S: Maintained
+F: drivers/gpio/gpio-ch341.c
F: drivers/mfd/ch341-core.c
F: include/linux/mfd/ch341.h
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index b01961999ced..473b6e7226ca 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1653,6 +1653,16 @@ endmenu
menu "USB GPIO expanders"
depends on USB
+config GPIO_CH341
+ tristate "CH341 USB to GPIO support"
+ select MFD_CH341
+ help
+ If you say yes to this option, GPIO support will be included for the
+ WCH CH341, a USB to I2C/SPI/GPIO interface.
+
+ This driver can also be built as a module. If so, the module
+ will be called gpio-ch341.
+
config GPIO_VIPERBOARD
tristate "Viperboard GPIO a & b support"
depends on MFD_VIPERBOARD
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 14352f6dfe8e..beef802cbfb1 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_GPIO_BD9571MWV) += gpio-bd9571mwv.o
obj-$(CONFIG_GPIO_BRCMSTB) += gpio-brcmstb.o
obj-$(CONFIG_GPIO_BT8XX) += gpio-bt8xx.o
obj-$(CONFIG_GPIO_CADENCE) += gpio-cadence.o
+obj-$(CONFIG_GPIO_CH341) += gpio-ch341.o
obj-$(CONFIG_GPIO_CLPS711X) += gpio-clps711x.o
obj-$(CONFIG_GPIO_SNPS_CREG) += gpio-creg-snps.o
obj-$(CONFIG_GPIO_CRYSTAL_COVE) += gpio-crystalcove.o
diff --git a/drivers/gpio/gpio-ch341.c b/drivers/gpio/gpio-ch341.c
new file mode 100644
index 000000000000..233dfe1f2ae8
--- /dev/null
+++ b/drivers/gpio/gpio-ch341.c
@@ -0,0 +1,385 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * GPIO cell driver for the CH341A and CH341B chips.
+ *
+ * Copyright 2022, Frank Zago
+ * Copyright (c) 2017 Gunar Schorcht (gunar@xxxxxxxxxxxx)
+ * Copyright (c) 2016 Tse Lun Bien
+ * Copyright (c) 2014 Marco Gittler
+ * Copyright (c) 2006-2007 Till Harbaum (Till@xxxxxxxxxxx)
+ */
+
+/*
+ * Notes.
+ *
+ * For the CH341, 0=IN, 1=OUT, but for the GPIO subsystem, 1=IN and
+ * 0=OUT. Translation happens in a couple places.
+ */
+
+#include <linux/gpio/driver.h>
+#include <linux/kernel.h>
+#include <linux/mfd/ch341.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/usb.h>
+
+#define CH341_GPIO_NUM_PINS 16 /* Number of GPIO pins */
+
+/* GPIO chip commands */
+#define CH341_PARA_CMD_STS 0xA0 /* Get pins status */
+#define CH341_CMD_UIO_STREAM 0xAB /* pin IO stream command */
+
+#define CH341_CMD_UIO_STM_OUT 0x80 /* pin IO interface OUT command (D0~D5) */
+#define CH341_CMD_UIO_STM_DIR 0x40 /* pin IO interface DIR command (D0~D5) */
+#define CH341_CMD_UIO_STM_END 0x20 /* pin IO interface END command */
+
+#define CH341_USB_MAX_INTR_SIZE 8
+
+struct ch341_gpio {
+ struct gpio_chip gpio;
+ struct mutex gpio_lock;
+ u16 gpio_dir; /* 1 bit per pin, 0=IN, 1=OUT. */
+ u16 gpio_last_read; /* last GPIO values read */
+ u16 gpio_last_written; /* last GPIO values written */
+ union {
+ u8 gpio_buf[SEG_SIZE];
+ __le16 gpio_buf_status;
+ };
+
+ struct urb *irq_urb;
+ struct usb_anchor irq_urb_out;
+ u8 irq_buf[CH341_USB_MAX_INTR_SIZE];
+ struct irq_chip irq_chip;
+
+ struct ch341_ddata *ddata;
+};
+
+/*
+ * Masks to describe the 16 GPIOs. Pins D0 to D5 (mapped to GPIOs 0 to
+ * 5) can do input/output, but the other pins are input-only.
+ */
+static const u16 pin_can_output = 0b111111;
+
+/* Only GPIO 10 (INT# line) has hardware interrupt */
+#define CH341_GPIO_INT_LINE 10
+
+/* Send a command and get a reply if requested */
+static int gpio_transfer(struct ch341_gpio *dev, int out_len, int in_len)
+{
+ struct ch341_ddata *ddata = dev->ddata;
+ int actual;
+ int ret;
+
+ mutex_lock(&ddata->usb_lock);
+
+ ret = usb_bulk_msg(ddata->usb_dev,
+ usb_sndbulkpipe(ddata->usb_dev, ddata->ep_out),
+ dev->gpio_buf, out_len,
+ &actual, DEFAULT_TIMEOUT_MS);
+ if (ret < 0)
+ goto out_unlock;
+
+ if (in_len == 0)
+ goto out_unlock;
+
+ ret = usb_bulk_msg(ddata->usb_dev,
+ usb_rcvbulkpipe(ddata->usb_dev, ddata->ep_in),
+ dev->gpio_buf, SEG_SIZE, &actual, DEFAULT_TIMEOUT_MS);
+
+out_unlock:
+ mutex_unlock(&ddata->usb_lock);
+
+ if (ret < 0)
+ return ret;
+
+ return actual;
+}
+
+/* Read the GPIO line status. */
+static int read_inputs(struct ch341_gpio *dev)
+{
+ int ret;
+
+ mutex_lock(&dev->gpio_lock);
+
+ dev->gpio_buf[0] = CH341_PARA_CMD_STS;
+
+ ret = gpio_transfer(dev, 1, 1);
+
+ /*
+ * The status command returns 6 bytes of data. Byte 0 has
+ * status for lines 0 to 7, and byte 1 is lines 8 to 15. The
+ * 3rd has the status for the SCL/SDA/SCK pins. The 4th byte
+ * might have some remaining pin status. Byte 5 and 6 content
+ * is unknown.
+ */
+ if (ret == 6)
+ dev->gpio_last_read = le16_to_cpu(dev->gpio_buf_status);
+ else
+ ret = -EIO;
+
+ mutex_unlock(&dev->gpio_lock);
+
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int ch341_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct ch341_gpio *dev = gpiochip_get_data(chip);
+ int ret;
+
+ ret = read_inputs(dev);
+ if (ret)
+ return ret;
+
+ return !!(dev->gpio_last_read & BIT(offset));
+}
+
+static int ch341_gpio_get_multiple(struct gpio_chip *chip,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct ch341_gpio *dev = gpiochip_get_data(chip);
+ int ret;
+
+ ret = read_inputs(dev);
+ if (ret)
+ return ret;
+
+ *bits = dev->gpio_last_read & *mask;
+
+ return 0;
+}
+
+static void write_outputs(struct ch341_gpio *dev)
+{
+ mutex_lock(&dev->gpio_lock);
+
+ /* Only the first 6 lines can output. */
+ dev->gpio_buf[0] = CH341_CMD_UIO_STREAM;
+ dev->gpio_buf[1] = CH341_CMD_UIO_STM_DIR | (dev->gpio_dir & pin_can_output);
+ dev->gpio_buf[2] = CH341_CMD_UIO_STM_OUT |
+ (dev->gpio_last_written & dev->gpio_dir & pin_can_output);
+ dev->gpio_buf[3] = CH341_CMD_UIO_STM_END;
+
+ gpio_transfer(dev, 4, 0);
+
+ mutex_unlock(&dev->gpio_lock);
+}
+
+static void ch341_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+ struct ch341_gpio *dev = gpiochip_get_data(chip);
+
+ if (value)
+ dev->gpio_last_written |= BIT(offset);
+ else
+ dev->gpio_last_written &= ~BIT(offset);
+
+ write_outputs(dev);
+}
+
+static void ch341_gpio_set_multiple(struct gpio_chip *chip,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct ch341_gpio *dev = gpiochip_get_data(chip);
+
+ dev->gpio_last_written = (dev->gpio_last_written & ~*mask) | (*bits & *mask);
+
+ write_outputs(dev);
+}
+
+static int ch341_gpio_get_direction(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ struct ch341_gpio *dev = gpiochip_get_data(chip);
+
+ return !(dev->gpio_dir & BIT(offset));
+}
+
+static int ch341_gpio_direction_input(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ struct ch341_gpio *dev = gpiochip_get_data(chip);
+
+ dev->gpio_dir &= ~BIT(offset);
+
+ write_outputs(dev);
+
+ return 0;
+}
+
+static int ch341_gpio_direction_output(struct gpio_chip *chip,
+ unsigned int offset, int value)
+{
+ struct ch341_gpio *dev = gpiochip_get_data(chip);
+ u16 mask = BIT(offset);
+
+ if (!(pin_can_output & mask))
+ return -EINVAL;
+
+ dev->gpio_dir |= mask;
+
+ ch341_gpio_set(chip, offset, value);
+
+ return 0;
+}
+
+static void ch341_complete_intr_urb(struct urb *urb)
+{
+ struct ch341_gpio *dev = urb->context;
+ int ret;
+
+ if (urb->status) {
+ usb_unanchor_urb(dev->irq_urb);
+ } else {
+ /*
+ * Data is 8 bytes. Byte 0 might be the length of
+ * significant data, which is 3 more bytes. Bytes 1
+ * and 2, and possibly 3, are the pin status. The byte
+ * order is different than for the GET_STATUS
+ * command. Byte 1 is GPIOs 8 to 15, and byte 2 is
+ * GPIOs 0 to 7.
+ */
+
+ handle_nested_irq(irq_find_mapping(dev->gpio.irq.domain,
+ CH341_GPIO_INT_LINE));
+
+ ret = usb_submit_urb(dev->irq_urb, GFP_ATOMIC);
+ if (ret)
+ usb_unanchor_urb(dev->irq_urb);
+ }
+}
+
+static int ch341_gpio_irq_set_type(struct irq_data *data, unsigned int flow_type)
+{
+ const unsigned long offset = irqd_to_hwirq(data);
+
+ if (offset != CH341_GPIO_INT_LINE || flow_type != IRQ_TYPE_EDGE_RISING)
+ return -EINVAL;
+
+ return 0;
+}
+
+static void ch341_gpio_irq_enable(struct irq_data *data)
+{
+ struct ch341_gpio *dev = irq_data_get_irq_chip_data(data);
+ int ret;
+
+ /*
+ * The URB might have just been unlinked in
+ * ch341_gpio_irq_disable, but the completion handler hasn't
+ * been called yet.
+ */
+ if (!usb_wait_anchor_empty_timeout(&dev->irq_urb_out, 5000))
+ usb_kill_anchored_urbs(&dev->irq_urb_out);
+
+ usb_anchor_urb(dev->irq_urb, &dev->irq_urb_out);
+ ret = usb_submit_urb(dev->irq_urb, GFP_KERNEL);
+ if (ret)
+ usb_unanchor_urb(dev->irq_urb);
+}
+
+static void ch341_gpio_irq_disable(struct irq_data *data)
+{
+ struct ch341_gpio *dev = irq_data_get_irq_chip_data(data);
+
+ usb_unlink_urb(dev->irq_urb);
+}
+
+static int ch341_gpio_remove(struct platform_device *pdev)
+{
+ struct ch341_gpio *dev = platform_get_drvdata(pdev);
+
+ usb_kill_anchored_urbs(&dev->irq_urb_out);
+ gpiochip_remove(&dev->gpio);
+ usb_free_urb(dev->irq_urb);
+
+ return 0;
+}
+
+static const struct irq_chip ch341_irqchip = {
+ .name = "CH341",
+ .irq_set_type = ch341_gpio_irq_set_type,
+ .irq_enable = ch341_gpio_irq_enable,
+ .irq_disable = ch341_gpio_irq_disable,
+ .flags = IRQCHIP_IMMUTABLE,
+ GPIOCHIP_IRQ_RESOURCE_HELPERS,
+};
+
+static int ch341_gpio_probe(struct platform_device *pdev)
+{
+ struct ch341_ddata *ddata = dev_get_drvdata(pdev->dev.parent);
+ struct gpio_irq_chip *girq;
+ struct ch341_gpio *dev;
+ struct gpio_chip *gpio;
+ int ret;
+
+ dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+ if (dev == NULL)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, dev);
+ dev->ddata = ddata;
+ mutex_init(&dev->gpio_lock);
+
+ gpio = &dev->gpio;
+ gpio->label = dev_name(&pdev->dev);
+ gpio->parent = &pdev->dev;
+ gpio->owner = THIS_MODULE;
+ gpio->get_direction = ch341_gpio_get_direction;
+ gpio->direction_input = ch341_gpio_direction_input;
+ gpio->direction_output = ch341_gpio_direction_output;
+ gpio->get = ch341_gpio_get;
+ gpio->get_multiple = ch341_gpio_get_multiple;
+ gpio->set = ch341_gpio_set;
+ gpio->set_multiple = ch341_gpio_set_multiple;
+ gpio->base = -1;
+ gpio->ngpio = CH341_GPIO_NUM_PINS;
+ gpio->can_sleep = true;
+
+ girq = &gpio->irq;
+ gpio_irq_chip_set_chip(girq, &ch341_irqchip);
+ girq->handler = handle_simple_irq;
+ girq->default_type = IRQ_TYPE_NONE;
+
+ /* Create an URB for handling interrupt */
+ dev->irq_urb = usb_alloc_urb(0, GFP_KERNEL);
+ if (!dev->irq_urb)
+ return dev_err_probe(&pdev->dev, -ENOMEM, "Cannot allocate the int URB\n");
+
+ usb_fill_int_urb(dev->irq_urb, ddata->usb_dev,
+ usb_rcvintpipe(ddata->usb_dev, ddata->ep_intr),
+ dev->irq_buf, CH341_USB_MAX_INTR_SIZE,
+ ch341_complete_intr_urb, dev, ddata->ep_intr_interval);
+
+ init_usb_anchor(&dev->irq_urb_out);
+
+ ret = gpiochip_add_data(gpio, dev);
+ if (ret) {
+ ret = dev_err_probe(&pdev->dev, ret, "Could not add GPIO\n");
+ goto release_urb;
+ }
+
+ return 0;
+
+release_urb:
+ usb_free_urb(dev->irq_urb);
+
+ return ret;
+}
+
+static struct platform_driver ch341_gpio_driver = {
+ .driver.name = "ch341-gpio",
+ .probe = ch341_gpio_probe,
+ .remove = ch341_gpio_remove,
+};
+module_platform_driver(ch341_gpio_driver);
+
+MODULE_AUTHOR("Frank Zago <frank@xxxxxxxx>");
+MODULE_DESCRIPTION("CH341 USB to GPIO");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ch341-gpio");
diff --git a/include/linux/mfd/ch341.h b/include/linux/mfd/ch341.h
index 44f5da0720bd..804d671fbe45 100644
--- a/include/linux/mfd/ch341.h
+++ b/include/linux/mfd/ch341.h
@@ -4,6 +4,14 @@
#include <linux/mutex.h>
#include <linux/types.h>
+#define DEFAULT_TIMEOUT_MS 1000 /* 1s USB requests timeout */
+
+/*
+ * All commands fit inside a 32-byte segment. There may be several of
+ * these segments in a USB command.
+ */
+#define SEG_SIZE 32
+
struct usb_device;
struct usb_interface;
--
2.32.0
