initial commit

Makefile

+obj-m = cp210x.o
+KVERSION = $(shell uname -r)
+all:
+	make -C /lib/modules/$(KVERSION)/build M=$(PWD) modules
+clean:
+	make -C /lib/modules/$(KVERSION)/build M=$(PWD) clean
+

README.md

+# CP210x GPIO control
+A patch to the CP210x USB to UART Bridges driver that adds GPIO pins control by implementing ioctl function and a python script to program devices.
+
+## Supported OS
+* Kubuntu Linux 13.04 (kernel 3.8.0-32)
+
+## Tested devices
+* CP2103
+* CP2104
+
+## Install
+1. Build:
+
+        ./build_driver
+
+2. Reload driver (from the built directory):
+
+        sudo rmmod 210x
+        sudo insmod 210x.ko
+
+## Program GPIO_MAS
+1. Examples:
+    * Set all 1's:
+
+            ./cp210x_gpio.py -d /dev/ttyUSB0 -m 0xff 0xff
+
+    * Set GPIO[3]=1, others - 0:
+    
+            ./cp210x_gpio.py -d /dev/ttyUSB1 -m 0xff 0x08
+    
+## Changes in the driver
+* Changes in the driver cp210x.c are based on the patch found [here](https://lkml.org/lkml/2012/5/1/2)
+* GPIO_VALUE=arg[23:16], GPIO_MASK=arg[7:0]
+
+## Unresolved questions
+* Silabs drivers in 2.6.x and 3.x.x for GPIOs differ: 
+    * 2.6.x: GPIO_VALUE=arg[23:16], GPIO_MASK=arg[7:0] - this matches the patch
+    * 3.x.x: GPIO_VALUE=arg[15: 8], GPIO_MASK=arg[7:0]
+
+## Links
+* [Silabs CP210x USB to UART Bridge VCP Drivers](http://www.silabs.com/products/mcu/pages/usbtouartbridgevcpdrivers.aspx) - supported kernels 2.6.x, 3.x.x (but 3.x.x are not up-to-date - cannot be built in 3.8.0)
+* [cp210x: Add ioctl for GPIO support](https://lkml.org/lkml/2012/5/1/2) - patch
\ No newline at end of file

build_driver.sh

+#!/bin/bash
+
+CP210X_NAME="cp210x.c"
+CP210X_ADDRESS="https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/plain/drivers/usb/serial/cp210x.c?id=refs/tags/v"
+
+PATCH_NAME="cp210x.patch"
+
+LINUX_KERNEL_VERSION=$(uname -r | cut -f1 -d"-")
+LKV_P1=$(echo $LINUX_KERNEL_VERSION | cut -f1 -d".")
+LKV_P2=$(echo $LINUX_KERNEL_VERSION | cut -f2 -d".")
+LKV_P3=$(echo $LINUX_KERNEL_VERSION | cut -f3 -d".")
+
+if [ $LKV_P3 = 0 ]; then
+  CP210X_VERSION=$(echo "$LKV_P1.$LKV_P2")
+else
+  CP210X_VERSION=$(echo "$LKV_P1.$LKV_P2.$LKV_P3")
+fi
+
+#uncomment if patch doesn't work 
+#CP210X_VERSION="3.8.0"
+
+#get the file to patch
+if [ ! -f $CP210X_NAME ]; then
+  wget -O $CP210X_NAME "${CP210X_ADDRESS}${CP210X_VERSION}"
+fi
+
+#patch
+patch -r - -Np1 < $PATCH_NAME
+
+#run make
+make clean
+make

cp210x.patch

+--- a/cp210x.c	2013-10-30 18:43:43.000000000 -0600
++++ b/cp210x.c	2013-10-30 19:23:02.410147064 -0600
+@@ -31,6 +31,8 @@
+  */
+ static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *);
+ static void cp210x_close(struct usb_serial_port *);
++static int cp210x_ioctl(struct tty_struct *tty,
++	unsigned int cmd, unsigned long arg);
+ static void cp210x_get_termios(struct tty_struct *, struct usb_serial_port *);
+ static void cp210x_get_termios_port(struct usb_serial_port *port,
+ 	unsigned int *cflagp, unsigned int *baudp);
+@@ -174,6 +176,7 @@
+ 	.bulk_out_size		= 256,
+ 	.open			= cp210x_open,
+ 	.close			= cp210x_close,
++	.ioctl			= cp210x_ioctl,
+ 	.break_ctl		= cp210x_break_ctl,
+ 	.set_termios		= cp210x_set_termios,
+ 	.tiocmget		= cp210x_tiocmget,
+@@ -187,6 +190,10 @@
+ 	&cp210x_device, NULL
+ };
+ 
++/* IOCTLs */
++#define IOCTL_GPIOGET	 0x8000
++#define IOCTL_GPIOSET	 0x8001
++
+ /* Config request types */
+ #define REQTYPE_HOST_TO_INTERFACE	0x41
+ #define REQTYPE_INTERFACE_TO_HOST	0xc1
+@@ -220,11 +227,16 @@
+ #define CP210X_SET_CHARS	0x19
+ #define CP210X_GET_BAUDRATE	0x1D
+ #define CP210X_SET_BAUDRATE	0x1E
++#define CP210X_VENDOR_SPECIFIC	0xFF
+ 
+ /* CP210X_IFC_ENABLE */
+ #define UART_ENABLE		0x0001
+ #define UART_DISABLE		0x0000
+ 
++/* CP210X_VENDOR_SPECIFIC */
++#define CP210X_WRITE_LATCH	0x37E1
++#define CP210X_READ_LATCH	0x00C2
++
+ /* CP210X_(SET|GET)_BAUDDIV */
+ #define BAUD_RATE_GEN_FREQ	0x384000
+ 
+@@ -449,6 +461,54 @@
+ 	mutex_unlock(&port->serial->disc_mutex);
+ }
+ 
++static int cp210x_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
++{
++	struct usb_serial_port *port = tty->driver_data;
++	struct usb_serial *serial = port->serial;
++	int result = 0;
++	struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
++	unsigned int latch_setting = 0;
++
++	switch (cmd) {
++	    case IOCTL_GPIOGET:
++		result = usb_control_msg(
++			      serial->dev,
++			      usb_rcvctrlpipe(serial->dev, 0),
++			      CP210X_VENDOR_SPECIFIC,
++			      REQTYPE_DEVICE_TO_HOST,
++			      CP210X_READ_LATCH,
++			      spriv->bInterfaceNumber,
++			      &latch_setting, 1,
++			      USB_CTRL_GET_TIMEOUT);
++		if (result != 1)
++		    return -EPROTO;
++		*(unsigned long *)arg = (unsigned long)latch_setting;
++		return 0;
++	    break;
++	    case IOCTL_GPIOSET:
++		latch_setting = *(unsigned int *)arg & 0x000000FF;
++		//why [23:16] bits are taken for value is unknown
++		latch_setting |= (*(unsigned int *)arg & 0x00FF0000) >> 8;
++		
++		result = usb_control_msg(
++			      serial->dev,
++			      usb_sndctrlpipe(serial->dev, 0),
++			      CP210X_VENDOR_SPECIFIC,
++			      REQTYPE_HOST_TO_DEVICE,
++			      CP210X_WRITE_LATCH,
++			      latch_setting,
++			      NULL, 0,
++			      USB_CTRL_SET_TIMEOUT);
++		if (result != 0)
++		    return -EPROTO;
++		return 0;
++	    break;
++	    default:
++	    break;
++	}
++	return -ENOIOCTLCMD;
++}
++
+ /*
+  * cp210x_get_termios
+  * Reads the baud rate, data bits, parity, stop bits and flow control mode

cp210x_gpio.py

+#!/usr/bin/python
+#-----------------------------------------------------------------------------
+# FILE NAME  : cp210x_gpio.py
+# DESCRIPTION: control GPIO pins for CP210X USB to UART Bridges
+# Copyright (C) 2013 Elphel, Inc
+#-----------------------------------------------------------------------------
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# The four essential freedoms with GNU GPL software are:
+# * to run the program for any purpose
+# * to study how the program works and change it to make it do what you wish
+# * to redistribute copies so you can help your neighbor
+# * to distribute copies of your modified versions to others
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#-----------------------------------------------------------------------------
+__author__ = "Oleg Dzhimiev"
+__copyright__ = "Copyright 2013, Elphel, Inc."
+__license__ = "GPL"
+__version__ = "3.0+"
+__maintainer__ = "Oleg Dzhimiev"
+__email__ = "oleg@elphel.com"
+__status__ = "Released"
+
+import array, fcntl
+import argparse # http://docs.python.org/2/howto/argparse.html
+
+IOCTL_GPIOGET = 0x8000
+IOCTL_GPIOSET = 0x8001
+
+parser = argparse.ArgumentParser()
+parser.add_argument('-d', '--device', default="/dev/ttyUSB0", help='USB device. Default: /dev/ttyUSB0')
+parser.add_argument("gpio_value", help="hex value for GPIO. Example (GPIO[3:0]): 0xf - all 1's, 0x0 - all 0's")
+parser.add_argument('-m', '--mask', default="0xff",help='hex value for masking out GPIO bits: 1 - enable rewrite, 0 - disable. Example (GPIO[3:0]): -m 0xf')
+args = parser.parse_args()
+    
+device=args.device
+mask = int(args.mask,0)
+gpio = (int(args.gpio_value,0)<<16)|mask
+
+print ('Target GPIO value:'),gpio
+
+try:
+    fd = open(device, 'r+')
+except:
+    raise Exception(str(device)+' is not present')
+
+buf = array.array('l', [0])
+fcntl.ioctl(fd, IOCTL_GPIOGET, buf, 1)
+print ('Old GPIO value:'),hex(buf[0])
+
+buf[0] = gpio
+
+fcntl.ioctl(fd, IOCTL_GPIOSET, buf, 1)
+fcntl.ioctl(fd, IOCTL_GPIOGET, buf, 1)
+print ('New GPIO value:'),hex(buf[0])
+