The Winchiphead CH341 IC is more than a UART interface. Amongst other things, it can talk to an I2C bus. Several people have contributed to an out of tree driver: Tse Lun Bien, Marco Gittler and Till Harbaum. https://github.com/allanbian1017/i2c-ch341-usb.git This commit integrates the I2C portions into the CH341 serial driver and exposes the I2C device. Tested with a CH341A, CH341B and CH341T. Signed-off-by: Frank Zago <frank@xxxxxxxx> --- I didn't find a way to say a USB device has several functions. I followed what the CP210x driver did with gpio, but I think it's a hack. The private data for the I2C part should be linked to the USB device, not the serial port. It works here and in the cp210x driver because there is only 1 serial port in the device. If it had 2 or more ports, I believe bad things would happen. So is there a better way to handle USB devices like that? For info, the CH341A/B supports 3 different modes, each with a different USB PID, usually selected by jumpers. All of them support I2C, but only 2 support UART, one supports SPI and 2 support GPIOs. drivers/usb/serial/Kconfig | 4 +- drivers/usb/serial/ch341.c | 284 ++++++++++++++++++++++++++++++++++++- 2 files changed, 283 insertions(+), 5 deletions(-) diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig index de5c01257060..3771dc5dd055 100644 --- a/drivers/usb/serial/Kconfig +++ b/drivers/usb/serial/Kconfig @@ -106,7 +106,7 @@ config USB_SERIAL_CH341 tristate "USB Winchiphead CH341 Single Port Serial Driver" help Say Y here if you want to use a Winchiphead CH341 single port - USB to serial adapter. + USB to serial adapter. This driver also provide access to I2C. To compile this driver as a module, choose M here: the module will be called ch341. diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index 2db917eab799..fc695b745fa5 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -4,12 +4,19 @@ * Copyright 2007, Werner Cornelius <werner@xxxxxxxxxxxxxxxxxxxx> * Copyright 2009, Boris Hajduk <boris@xxxxxxxxxx> * - * ch341.c implements a serial port driver for the Winchiphead CH341. + * I2C code: + * Copyright (c) 2016 Tse Lun Bien + * Copyright (c) 2014 Marco Gittler + * Copyright (C) 2006-2007 Till Harbaum (Till@xxxxxxxxxxx) + * + * ch341.c implements a serial port driver for the Winchiphead CH341, + * with I2C support * * 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. + * This driver only supports the asynchronous serial and I2C + * interfaces. */ #include <linux/kernel.h> @@ -19,6 +26,7 @@ #include <linux/usb.h> #include <linux/usb/serial.h> #include <linux/serial.h> +#include <linux/i2c.h> #include <asm/unaligned.h> #define DEFAULT_BAUD_RATE 9600 @@ -80,6 +88,20 @@ #define CH341_QUIRK_LIMITED_PRESCALER BIT(0) #define CH341_QUIRK_SIMULATE_BREAK BIT(1) +#define CH341_I2C_LOW_SPEED 0 /* low speed - 20kHz */ +#define CH341_I2C_STANDARD_SPEED 1 /* standard speed - 100kHz */ +#define CH341_I2C_FAST_SPEED 2 /* fast speed - 400kHz */ +#define CH341_I2C_HIGH_SPEED 3 /* high speed - 750kHz */ + +#define CH341_REQ_I2C_STREAM 0xAA + +#define CH341_I2C_STM_STA 0x74 +#define CH341_I2C_STM_STO 0x75 +#define CH341_I2C_STM_OUT 0x80 +#define CH341_I2C_STM_IN 0xC0 +#define CH341_I2C_STM_SET 0x60 +#define CH341_I2C_STM_END 0x00 + static const struct usb_device_id id_table[] = { { USB_DEVICE(0x1a86, 0x5512) }, { USB_DEVICE(0x1a86, 0x5523) }, @@ -99,8 +121,260 @@ struct ch341_private { u8 lcr; unsigned long quirks; unsigned long break_end; + +#ifdef CONFIG_I2C + /* I2C */ + struct i2c_adapter adapter; + bool i2c_registered; + u8 ep_in; + u8 ep_out; + u8 in_buf[32]; + u8 out_buf[32]; +#endif +}; + +#ifdef CONFIG_I2C +static int ch341_i2c_bulk(struct usb_serial_port *port, int out_len, int in_len) +{ + struct usb_device *dev = port->serial->dev; + struct ch341_private *priv = usb_get_serial_port_data(port); + int retval; + int actual; + + dev_dbg(&dev->dev, "bulk_out %d bytes, bulk_in %d bytes\n", + out_len, (in_len == 0) ? 0 : 32); + + retval = usb_bulk_msg(dev, usb_sndbulkpipe(dev, priv->ep_out), + priv->out_buf, out_len, &actual, 2000); + if (retval < 0) + return retval; + + if (in_len == 0) + return actual; + + memset(priv->in_buf, 0, sizeof(priv->in_buf)); + retval = usb_bulk_msg(dev, usb_rcvbulkpipe(dev, priv->ep_in), + priv->in_buf, 32, &actual, 2000); + if (retval < 0) + return retval; + + return actual; +} + +static int ch341_i2c_check_dev(struct usb_serial_port *port, u8 addr) +{ + struct ch341_private *priv = usb_get_serial_port_data(port); + int retval; + + priv->out_buf[0] = CH341_REQ_I2C_STREAM; + priv->out_buf[1] = CH341_I2C_STM_STA; + priv->out_buf[2] = CH341_I2C_STM_OUT; /* must be zero length */ + priv->out_buf[3] = (addr << 1) | 0x1; + priv->out_buf[4] = CH341_I2C_STM_IN; /* zero length here as well */ + priv->out_buf[5] = CH341_I2C_STM_STO; + priv->out_buf[6] = CH341_I2C_STM_END; + + retval = ch341_i2c_bulk(port, 7, 1); + if (retval < 0) + return retval; + + if (priv->in_buf[0] & 0x80) + return -ETIMEDOUT; + + return 0; +} + +static int ch341_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, + int num) +{ + struct usb_serial_port *port = adapter->algo_data; + struct ch341_private *priv = usb_get_serial_port_data(port); + int retval; + int i; + int l; + + dev_dbg(&port->serial->dev->dev, "master xfer %d messages\n", num); + + retval = ch341_i2c_check_dev(port, msgs[0].addr); + if (retval < 0) + return retval; + + if (num == 1) { + /* size larger than endpoint max transfer size */ + if ((msgs[0].len + 6) > 32) + return -EIO; + + if (msgs[0].flags & I2C_M_RD) { + priv->out_buf[0] = CH341_REQ_I2C_STREAM; + priv->out_buf[1] = CH341_I2C_STM_STA; + priv->out_buf[2] = CH341_I2C_STM_OUT | 0x1; + priv->out_buf[3] = (msgs[0].addr << 1) | 0x1; + + if (msgs[0].len) { + for (i = 0, l = msgs[0].len; l > 1; l--, i++) + priv->out_buf[i + 4] = + CH341_I2C_STM_IN | 1; + priv->out_buf[msgs[0].len + 3] = + CH341_I2C_STM_IN; + } + + priv->out_buf[msgs[0].len + 4] = CH341_I2C_STM_STO; + priv->out_buf[msgs[0].len + 5] = CH341_I2C_STM_END; + + retval = ch341_i2c_bulk(port, msgs[0].len + 6, msgs[0].len); + if (retval < 0) + return retval; + + memcpy(msgs[0].buf, priv->in_buf, msgs[0].len); + } else { + priv->out_buf[0] = CH341_REQ_I2C_STREAM; + priv->out_buf[1] = CH341_I2C_STM_STA; + priv->out_buf[2] = + CH341_I2C_STM_OUT | (msgs[0].len + 1); + priv->out_buf[3] = msgs[0].addr << 1; + + memcpy(&priv->out_buf[4], msgs[0].buf, msgs[0].len); + + priv->out_buf[msgs[0].len + 4] = CH341_I2C_STM_STO; + priv->out_buf[msgs[0].len + 5] = CH341_I2C_STM_END; + + retval = ch341_i2c_bulk(port, msgs[0].len + 6, 0); + if (retval < 0) + return retval; + } + } else if (num == 2) { + if (!(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) { + /* size larger than endpoint max transfer size */ + if (((msgs[0].len + 4) > 32) || + ((msgs[1].len + 6) > 32)) + return -EIO; + + /* write data phase */ + priv->out_buf[0] = CH341_REQ_I2C_STREAM; + priv->out_buf[1] = CH341_I2C_STM_STA; + priv->out_buf[2] = + CH341_I2C_STM_OUT | (msgs[0].len + 1); + priv->out_buf[3] = msgs[0].addr << 1; + + memcpy(&priv->out_buf[4], msgs[0].buf, msgs[0].len); + + retval = ch341_i2c_bulk(port, msgs[0].len + 4, 0); + if (retval < 0) + return retval; + + /* read data phase */ + priv->out_buf[0] = CH341_REQ_I2C_STREAM; + priv->out_buf[1] = CH341_I2C_STM_STA; + priv->out_buf[2] = CH341_I2C_STM_OUT | 0x1; + priv->out_buf[3] = (msgs[1].addr << 1) | 0x1; + + if (msgs[1].len) { + for (i = 0, l = msgs[1].len; l > 1; l--, i++) + priv->out_buf[i + 4] = + CH341_I2C_STM_IN | 1; + priv->out_buf[msgs[1].len + 3] = + CH341_I2C_STM_IN; + } + + priv->out_buf[msgs[1].len + 4] = CH341_I2C_STM_STO; + priv->out_buf[msgs[1].len + 5] = CH341_I2C_STM_END; + + retval = ch341_i2c_bulk(port, msgs[1].len + 6, msgs[1].len); + if (retval < 0) + return retval; + + memcpy(msgs[1].buf, priv->in_buf, msgs[1].len); + } else { + return -EIO; + } + } else { + dev_err(&port->serial->dev->dev, + "This case(num > 2) is not supported for now\n"); + return -EIO; + } + + return num; +} + + +static u32 ch341_i2c_func(struct i2c_adapter *adapter) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm ch341_i2c_algorithm = { + .master_xfer = ch341_i2c_xfer, + .functionality = ch341_i2c_func, }; +static void ch341_i2c_setup(struct usb_serial_port *port) +{ + struct ch341_private *priv = usb_get_serial_port_data(port); + const struct usb_host_interface *setting = + port->serial->interface->cur_altsetting; + int retval = -ENOMEM; + + priv->ep_out = setting->endpoint[1].desc.bEndpointAddress; + priv->ep_in = setting->endpoint[0].desc.bEndpointAddress; + + /* setup i2c adapter description */ + priv->adapter.owner = THIS_MODULE; + priv->adapter.class = I2C_CLASS_HWMON; + priv->adapter.algo = &ch341_i2c_algorithm; + priv->adapter.algo_data = port; + snprintf(priv->adapter.name, sizeof(priv->adapter.name), + "i2c-ch341-usb at bus %03d device %03d", + port->serial->dev->bus->busnum, port->serial->dev->devnum); + + priv->adapter.dev.parent = &port->serial->dev->dev; + + /* and finally attach to i2c layer */ + i2c_add_adapter(&priv->adapter); + + /* set ch341 i2c speed */ + priv->out_buf[0] = CH341_REQ_I2C_STREAM; + priv->out_buf[1] = CH341_I2C_STM_SET | CH341_I2C_STANDARD_SPEED; + priv->out_buf[2] = CH341_I2C_STM_END; + retval = ch341_i2c_bulk(port, 3, 0); + if (retval < 0) { + dev_err(&priv->adapter.dev, "failure setting I2C speed\n"); + goto error; + } + + priv->i2c_registered = true; + + dev_info(&priv->adapter.dev, "registered i2c device\n"); + + return; + +error: + i2c_del_adapter(&priv->adapter); +} + +static void ch341_i2c_remove(struct usb_serial_port *port) +{ + struct ch341_private *priv = usb_get_serial_port_data(port); + + if (priv->i2c_registered) { + priv->i2c_registered = false; + i2c_del_adapter(&priv->adapter); + } +} + +#else + +static int ch341_i2c_setup(struct usb_serial *serial) +{ + return 0; +} + +static void ch341_i2c_remove(struct usb_serial *serial) +{ + return 0; +} + +#endif + static void ch341_set_termios(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios); @@ -414,9 +688,12 @@ static int ch341_port_probe(struct usb_serial_port *port) if (r < 0) goto error; + ch341_i2c_setup(port); + return 0; -error: kfree(priv); +error: + kfree(priv); return r; } @@ -424,6 +701,7 @@ static void ch341_port_remove(struct usb_serial_port *port) { struct ch341_private *priv; + ch341_i2c_remove(port); priv = usb_get_serial_port_data(port); kfree(priv); } -- 2.27.0
