// SPDX-License-Identifier: GPL-2.0 /* * Copyright 2007, Frank A Kingswood <[email protected]> * Copyright 2007, Werner Cornelius <[email protected]> * Copyright 2009, Boris Hajduk <[email protected]> * * ch341.c implements a serial port driver for the Winchiphead CH341. * * The CH341 device can be used to implement an RS232 asynchronous * serial port, an IEEE-1284 parallel printer port or a memory-like * interface. In all cases the CH341 supports an I2C interface as well. * This driver only supports the asynchronous serial interface. */ #include <linux/kernel.h> #include <linux/tty.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/usb.h> #include <linux/usb/serial.h> #include <linux/serial.h> #include <asm/unaligned.h> #define DEFAULT_BAUD_RATE … #define DEFAULT_TIMEOUT … /* flags for IO-Bits */ #define CH341_BIT_RTS … #define CH341_BIT_DTR … /******************************/ /* interrupt pipe definitions */ /******************************/ /* always 4 interrupt bytes */ /* first irq byte normally 0x08 */ /* second irq byte base 0x7d + below */ /* third irq byte base 0x94 + below */ /* fourth irq byte normally 0xee */ /* second interrupt byte */ #define CH341_MULT_STAT … /* status returned in third interrupt answer byte, inverted in data from irq */ #define CH341_BIT_CTS … #define CH341_BIT_DSR … #define CH341_BIT_RI … #define CH341_BIT_DCD … #define CH341_BITS_MODEM_STAT … /* Break support - the information used to implement this was gleaned from * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato. */ #define CH341_REQ_READ_VERSION … #define CH341_REQ_WRITE_REG … #define CH341_REQ_READ_REG … #define CH341_REQ_SERIAL_INIT … #define CH341_REQ_MODEM_CTRL … #define CH341_REG_BREAK … #define CH341_REG_PRESCALER … #define CH341_REG_DIVISOR … #define CH341_REG_LCR … #define CH341_REG_LCR2 … #define CH341_NBREAK_BITS … #define CH341_LCR_ENABLE_RX … #define CH341_LCR_ENABLE_TX … #define CH341_LCR_MARK_SPACE … #define CH341_LCR_PAR_EVEN … #define CH341_LCR_ENABLE_PAR … #define CH341_LCR_STOP_BITS_2 … #define CH341_LCR_CS8 … #define CH341_LCR_CS7 … #define CH341_LCR_CS6 … #define CH341_LCR_CS5 … #define CH341_QUIRK_LIMITED_PRESCALER … #define CH341_QUIRK_SIMULATE_BREAK … static const struct usb_device_id id_table[] = …; MODULE_DEVICE_TABLE(usb, id_table); struct ch341_private { … }; static void ch341_set_termios(struct tty_struct *tty, struct usb_serial_port *port, const struct ktermios *old_termios); static int ch341_control_out(struct usb_device *dev, u8 request, u16 value, u16 index) { … } static int ch341_control_in(struct usb_device *dev, u8 request, u16 value, u16 index, char *buf, unsigned bufsize) { … } #define CH341_CLKRATE … #define CH341_CLK_DIV(ps, fact) … #define CH341_MIN_RATE(ps) … static const speed_t ch341_min_rates[] = …; /* Supported range is 46 to 3000000 bps. */ #define CH341_MIN_BPS … #define CH341_MAX_BPS … /* * The device line speed is given by the following equation: * * baudrate = 48000000 / (2^(12 - 3 * ps - fact) * div), where * * 0 <= ps <= 3, * 0 <= fact <= 1, * 2 <= div <= 256 if fact = 0, or * 9 <= div <= 256 if fact = 1 */ static int ch341_get_divisor(struct ch341_private *priv, speed_t speed) { … } static int ch341_set_baudrate_lcr(struct usb_device *dev, struct ch341_private *priv, speed_t baud_rate, u8 lcr) { … } static int ch341_set_handshake(struct usb_device *dev, u8 control) { … } static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) { … } /* -------------------------------------------------------------------------- */ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) { … } static int ch341_detect_quirks(struct usb_serial_port *port) { … } static int ch341_port_probe(struct usb_serial_port *port) { … } static void ch341_port_remove(struct usb_serial_port *port) { … } static int ch341_carrier_raised(struct usb_serial_port *port) { … } static void ch341_dtr_rts(struct usb_serial_port *port, int on) { … } static void ch341_close(struct usb_serial_port *port) { … } /* open this device, set default parameters */ static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) { … } /* Old_termios contains the original termios settings and * tty->termios contains the new setting to be used. */ static void ch341_set_termios(struct tty_struct *tty, struct usb_serial_port *port, const struct ktermios *old_termios) { … } /* * A subset of all CH34x devices don't support a real break condition and * reading CH341_REG_BREAK fails (see also ch341_detect_quirks). This function * simulates a break condition by lowering the baud rate to the minimum * supported by the hardware upon enabling the break condition and sending * a NUL byte. * * Incoming data is corrupted while the break condition is being simulated. * * Normally the duration of the break condition can be controlled individually * by userspace using TIOCSBRK and TIOCCBRK or by passing an argument to * TCSBRKP. Due to how the simulation is implemented the duration can't be * controlled. The duration is always about (1s / 46bd * 9bit) = 196ms. */ static int ch341_simulate_break(struct tty_struct *tty, int break_state) { … } static int ch341_break_ctl(struct tty_struct *tty, int break_state) { … } static int ch341_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear) { … } static void ch341_update_status(struct usb_serial_port *port, unsigned char *data, size_t len) { … } static void ch341_read_int_callback(struct urb *urb) { … } static int ch341_tiocmget(struct tty_struct *tty) { … } static int ch341_reset_resume(struct usb_serial *serial) { … } static struct usb_serial_driver ch341_device = …; static struct usb_serial_driver * const serial_drivers[] = …; module_usb_serial_driver(…); MODULE_LICENSE(…) …;
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