>From some researches, this driver was available from the IC
constructor site, but for older kernel versions. From there, decided
to add a much simplier mainline version, written from sratch.
This initial simple version is implemented without any flow control,
tested mainly at 115200, but all standard baud rates are supported
and applied as per serial terminal setting.
Signed-off-by: Angelo Dureghello <angelo.dureghello@xxxxxxxxxxx>
---
drivers/usb/serial/Kconfig | 9 +
drivers/usb/serial/Makefile | 1 +
drivers/usb/serial/xr21v1412.c | 361 +++++++++++++++++++++++++++++++++
3 files changed, 371 insertions(+)
create mode 100644 drivers/usb/serial/xr21v1412.c
diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index 4007fa25a8ff..5f215a736618 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -644,6 +644,15 @@ config USB_SERIAL_UPD78F0730
To compile this driver as a module, choose M here: the
module will be called upd78f0730.
+config USB_SERIAL_XR21V1412
+ tristate "USB MaxLinear XR21V1412 serial driver"
+ help
+ Say Y here if you want to use the MaxLinear XR21V1412
+ serial driver.
+
+ To compile this driver as a module, choose M here: the
+ module will be called xr21v1412.
+
config USB_SERIAL_DEBUG
tristate "USB Debugging Device"
help
diff --git a/drivers/usb/serial/Makefile b/drivers/usb/serial/Makefile
index 2d491e434f11..8b4afcc44b46 100644
--- a/drivers/usb/serial/Makefile
+++ b/drivers/usb/serial/Makefile
@@ -62,4 +62,5 @@ obj-$(CONFIG_USB_SERIAL_VISOR) += visor.o
obj-$(CONFIG_USB_SERIAL_WISHBONE) += wishbone-serial.o
obj-$(CONFIG_USB_SERIAL_WHITEHEAT) += whiteheat.o
obj-$(CONFIG_USB_SERIAL_XIRCOM) += keyspan_pda.o
+obj-$(CONFIG_USB_SERIAL_XR21V1412) += xr21v1412.o
obj-$(CONFIG_USB_SERIAL_XSENS_MT) += xsens_mt.o
diff --git a/drivers/usb/serial/xr21v1412.c b/drivers/usb/serial/xr21v1412.c
new file mode 100644
index 000000000000..9c9ace46bc41
--- /dev/null
+++ b/drivers/usb/serial/xr21v1412.c
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MaxLinear XR21V1412 USB to serial adaptor driver
+ *
+ * Copyright (C) 2020 Angelo Dureghello <angelo.dureghello@xxxxxxxxxxx>
+ *
+ * This driver has been started looking into ch341.c and f81232.c
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+
+/*
+ * The internal register set of the XR21V1412 consists of 3 different
+ * blocks of registers:
+ * UART Manager,
+ * UART registers,
+ * UART miscellaneous.
+ */
+
+#define index(reg, block) ((block << 8) | reg)
+
+#define REG_BLOCK_UART_A 0x0
+#define REG_BLOCK_UART_B 0x1
+#define REG_BLOCK_UART_MGR 0x4
+#define REG_BLOCK_I2C_EE 0x65
+#define REG_BLOCK_UART_CUSTOM 0x66
+
+#define REQ_CDC_ACM 35
+#define REQ_SET_REG 0
+#define REQ_GETN_REG 1
+
+#define REQ_TYPE_XR_SET_REG 0x40
+
+#define FIFO_ENABLE_CHA 0x10
+#define FIFO_ENABLE_CHB 0x11
+#define FIFO_ENABLE_TX BIT(0)
+#define FIFO_ENABLE_RX BIT(1)
+
+#define REG_UART_ENABLE 0x03
+#define REG_UART_DIV0 0x04
+#define REG_UART_DIV1 0x05
+#define REG_UART_DIV2 0x06
+#define REG_UART_TXCLOCK_MASK0 0x07
+#define REG_UART_TXCLOCK_MASK1 0x08
+#define REG_UART_RXCLOCK_MASK0 0x09
+#define REG_UART_RXCLOCK_MASK1 0x0a
+#define REG_UART_CHAR_FMT 0x0b
+
+#define REG_SET_RETRY 2
+
+#define REG_DIV0_MASK GENMASK(7, 0)
+#define REG_DIV1_MASK GENMASK(15, 8)
+#define REG_DIV2_MASK GENMASK(18, 16)
+#define REG_DIV0(x) (x & REG_DIV0_MASK)
+#define REG_DIV1(x) ((x & REG_DIV1_MASK) >> 8)
+#define REG_DIV2(x) ((x & REG_DIV2_MASK) >> 16)
+
+#define INT_OSC 48000000
+
+#define CLKM_TABLE_ENTRIES 32
+#define CLKM_TX 0
+#define CLKM_RX_ODD 1
+#define CLKM_RX_EVEN 2
+#define CLKM_ENTRIES 3
+
+#define PARITY_NONE 0
+#define PARITY_ODD 1
+#define PARITY_EVEN 2
+
+#define DEFAULT_BAUDRATE 115200
+#define DEFAULT_DATA_BITS 8
+#define DEFAULT_PARITY PARITY_NONE
+#define DEFAULT_STOP_BITS 1
+
+static const int mask_lookup_table[CLKM_TABLE_ENTRIES][CLKM_ENTRIES] = {
+ {0x0000, 0x0000, 0x0000},
+ {0x0000, 0x0000, 0x0000},
+ {0x0100, 0x0000, 0x0100},
+ {0x0020, 0x0400, 0x0020},
+ {0x0010, 0x0100, 0x0010},
+ {0x0208, 0x0040, 0x0208},
+ {0x0104, 0x0820, 0x0108},
+ {0x0844, 0x0210, 0x0884},
+ {0x0444, 0x0110, 0x0444},
+ {0x0122, 0x0888, 0x0224},
+ {0x0912, 0x0448, 0x0924},
+ {0x0492, 0x0248, 0x0492},
+ {0x0252, 0x0928, 0x0292},
+ {0x094A, 0x04A4, 0x0A52},
+ {0x052A, 0x0AA4, 0x054A},
+ {0x0AAA, 0x0954, 0x04AA},
+ {0x0AAA, 0x0554, 0x0AAA},
+ {0x0555, 0x0AD4, 0x05AA},
+ {0x0B55, 0x0AB4, 0x055A},
+ {0x06B5, 0x05AC, 0x0B56},
+ {0x05B5, 0x0D6C, 0x06D6},
+ {0x0B6D, 0x0B6A, 0x0DB6},
+ {0x076D, 0x06DA, 0x0BB6},
+ {0x0EDD, 0x0DDA, 0x076E},
+ {0x0DDD, 0x0BBA, 0x0EEE},
+ {0x07BB, 0x0F7A, 0x0DDE},
+ {0x0F7B, 0x0EF6, 0x07DE},
+ {0x0DF7, 0x0BF6, 0x0F7E},
+ {0x07F7, 0x0FEE, 0x0EFE},
+ {0x0FDF, 0x0FBE, 0x07FE},
+ {0x0F7F, 0x0EFE, 0x0FFE},
+ {0x0FFF, 0x0FFE, 0x0FFD},
+};
+
+struct xr21v1412_private {
+ int baudrate;
+ u8 parity;
+ u8 data_bits;
+ u8 stop_bits;
+};
+
+static const struct usb_device_id id_table[] = {
+ { USB_DEVICE(0x04e2, 0x1412) },
+ { },
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+static u8 xr21v1412_interface_num(struct usb_serial *serial)
+{
+ struct usb_host_interface *cur_altsetting;
+
+ cur_altsetting = serial->interface->cur_altsetting;
+
+ return cur_altsetting->desc.bInterfaceNumber;
+}
+
+static int xr21v1412_xr_set_register(struct usb_device *udev, u16 reg, u16 val)
+{
+ int retry = REG_SET_RETRY;
+ int status, size;
+
+ while (retry--) {
+ status = usb_control_msg(udev,
+ usb_sndctrlpipe(udev, 0),
+ REQ_SET_REG,
+ REQ_TYPE_XR_SET_REG,
+ val & 0xff,
+ reg,
+ 0,
+ 0,
+ USB_CTRL_SET_TIMEOUT);
+ if (status < 0) {
+ status = usb_translate_errors(status);
+ if (status == -EIO)
+ continue;
+ } else if (status != size) {
+ /* Retry on short transfers */
+ status = -EIO;
+ continue;
+ } else {
+ status = 0;
+ }
+
+ break;
+ }
+
+ if (status) {
+ dev_err(&udev->dev, "failed to set register 0x%x: %d\n",
+ reg, status);
+ }
+
+ return status;
+}
+
+static inline int xr21v1412_get_clock_divisor(int baudrate)
+{
+ return (INT_OSC / baudrate);
+}
+
+static inline int xr21v1412_get_mask_table_idx(int baudrate, int clock_divisor)
+{
+ uint32_t value;
+
+ value = (INT_OSC * 10) / (baudrate / 10);
+ value -= (clock_divisor * 100);
+ value = value * 32 / 100;
+
+ return value;
+}
+
+static void xr21v1412_configure_port(struct usb_serial_port *port)
+{
+ struct xr21v1412_private *priv = usb_get_serial_port_data(port);
+ struct usb_device *udev = port->serial->dev;
+ int block, fifo_enable, clock_divisor, table_index, char_fmt;
+ u8 div0, div1, div2;
+ u16 mask_rx, mask_tx;
+
+ block = xr21v1412_interface_num(port->serial) >> 1;
+
+ fifo_enable = (block == 0) ? FIFO_ENABLE_CHA : FIFO_ENABLE_CHB;
+
+ xr21v1412_xr_set_register(udev,
+ index(fifo_enable, REG_BLOCK_UART_MGR),
+ FIFO_ENABLE_TX);
+ xr21v1412_xr_set_register(udev, index(REG_UART_ENABLE, block), 0x3);
+ xr21v1412_xr_set_register(udev,
+ index(fifo_enable, REG_BLOCK_UART_MGR),
+ FIFO_ENABLE_TX | FIFO_ENABLE_RX);
+
+ clock_divisor = xr21v1412_get_clock_divisor(priv->baudrate);
+
+ div0 = REG_DIV0(clock_divisor);
+ div1 = REG_DIV1(clock_divisor);
+ div2 = REG_DIV2(clock_divisor);
+
+ xr21v1412_xr_set_register(udev, index(REG_UART_DIV0, block), div0);
+ xr21v1412_xr_set_register(udev, index(REG_UART_DIV1, block), div1);
+ xr21v1412_xr_set_register(udev, index(REG_UART_DIV2, block), div2);
+
+ table_index = xr21v1412_get_mask_table_idx(priv->baudrate,
+ clock_divisor);
+
+ if (table_index > CLKM_TABLE_ENTRIES - 1)
+ table_index = CLKM_TABLE_ENTRIES - 1;
+
+ mask_tx = mask_lookup_table[table_index][CLKM_TX];
+ mask_rx = (clock_divisor & 1) ?
+ mask_lookup_table[table_index][CLKM_RX_ODD] :
+ mask_lookup_table[table_index][CLKM_RX_EVEN];
+
+ xr21v1412_xr_set_register(udev, index(REG_UART_TXCLOCK_MASK0, block),
+ mask_tx & 0xff);
+ xr21v1412_xr_set_register(udev, index(REG_UART_TXCLOCK_MASK1, block),
+ mask_tx >> 8);
+ xr21v1412_xr_set_register(udev, index(REG_UART_RXCLOCK_MASK0, block),
+ mask_rx & 0xff);
+ xr21v1412_xr_set_register(udev, index(REG_UART_RXCLOCK_MASK1, block),
+ mask_rx >> 8);
+
+ char_fmt = priv->data_bits;
+ char_fmt |= priv->parity << 4;
+ char_fmt |= (priv->stop_bits - 1) << 7;
+
+ xr21v1412_xr_set_register(udev, index(REG_UART_CHAR_FMT, block),
+ char_fmt);
+}
+
+static int xr21v1412_port_probe(struct usb_serial_port *port)
+{
+ struct xr21v1412_private *priv;
+
+ if (!port->bulk_in_size || !port->bulk_out_size)
+ return -ENODEV;
+
+ priv = kzalloc(sizeof(struct xr21v1412_private), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->baudrate = DEFAULT_BAUDRATE;
+ priv->data_bits = DEFAULT_DATA_BITS;
+ priv->stop_bits = DEFAULT_STOP_BITS;
+ priv->parity = DEFAULT_PARITY;
+
+ usb_set_serial_port_data(port, priv);
+
+ xr21v1412_configure_port(port);
+
+ return 0;
+}
+
+static int xr21v1412_port_remove(struct usb_serial_port *port)
+{
+ struct xr21v1412_private *priv;
+
+ priv = usb_get_serial_port_data(port);
+ kfree(priv);
+
+ return 0;
+}
+
+static void xr21v1412_set_termios(struct tty_struct *tty,
+ struct usb_serial_port *port,
+ struct ktermios *old_termios)
+{
+ struct xr21v1412_private *priv = usb_get_serial_port_data(port);
+
+ /* Redundant changes may cause the chip to lose bytes */
+ if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
+ return;
+
+ priv->baudrate = tty_get_baud_rate(tty);
+
+ switch (C_CSIZE(tty)) {
+ case CS7:
+ priv->data_bits = 7;
+ break;
+ case CS8:
+ default:
+ priv->data_bits = 8;
+ break;
+ }
+
+ if (C_PARENB(tty)) {
+ priv->parity = (C_PARODD(tty) == 0) ?
+ PARITY_EVEN : PARITY_ODD;
+ } else {
+ priv->parity = PARITY_NONE;
+ }
+
+ priv->stop_bits = (C_CSTOPB(tty)) ? 2 : 1;
+
+ xr21v1412_configure_port(port);
+}
+
+static int xr21v1412_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+ int result;
+
+ result = usb_serial_generic_open(tty, port);
+ if (result) {
+ usb_kill_urb(port->interrupt_in_urb);
+ return result;
+ }
+
+ /* Setup termios */
+ if (tty)
+ xr21v1412_set_termios(tty, port, NULL);
+
+ return 0;
+}
+
+static void xr21v1412_close(struct usb_serial_port *port)
+{
+ usb_serial_generic_close(port);
+ usb_kill_urb(port->interrupt_in_urb);
+}
+
+static struct usb_serial_driver xr21v1412_device = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "xr21v1412",
+ },
+ .id_table = id_table,
+ .num_ports = 1,
+ .open = xr21v1412_open,
+ .close = xr21v1412_close,
+ .set_termios = xr21v1412_set_termios,
+ .port_probe = xr21v1412_port_probe,
+ .port_remove = xr21v1412_port_remove,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+ &xr21v1412_device, NULL,
+};
+
+module_usb_serial_driver(serial_drivers, id_table);
+
+MODULE_DESCRIPTION("MaxLinear XR21V1412 USB to serial driver");
+MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
2.26.2
