USB: add Printer Gadget Driver (25a010c8) · Commits · e / devices / android_kernel_teracube_2e

Documentation/usb/gadget_printer.txt

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			Linux USB Printer Gadget Driver
			06/04/2007

			Copyright (C) 2007 Craig W. Nadler <craig@nadler.us>



			GENERAL
			=======

			This driver may be used if you are writing printer firmware using Linux as
			the embedded OS. This driver has nothing to do with using a printer with
			your Linux host system.

			You will need a USB device controller and a Linux driver for it that accepts
			a gadget / "device class" driver using the Linux USB Gadget API. After the
			USB device controller driver is loaded then load the printer gadget driver.
			This will present a printer interface to the USB Host that your USB Device
			port is connected to.

			This driver is structured for printer firmware that runs in user mode. The
			user mode printer firmware will read and write data from the kernel mode
			printer gadget driver using a device file. The printer returns a printer status
			byte when the USB HOST sends a device request to get the printer status. The
			user space firmware can read or write this status byte using a device file
			/dev/g_printer . Both blocking and non-blocking read/write calls are supported.




			HOWTO USE THIS DRIVER
			=====================

			To load the USB device controller driver and the printer gadget driver. The
			following example uses the Netchip 2280 USB device controller driver:

			modprobe net2280
			modprobe g_printer


			The follow command line parameter can be used when loading the printer gadget
			(ex: modprobe g_printer idVendor=0x0525 idProduct=0xa4a8 ):

			idVendor - This is the Vendor ID used in the device descriptor. The default is
			the Netchip vendor id 0x0525. YOU MUST CHANGE TO YOUR OWN VENDOR ID
			BEFORE RELEASING A PRODUCT. If you plan to release a product and don't
			already have a Vendor ID please see www.usb.org for details on how to
			get one.

			idProduct - This is the Product ID used in the device descriptor. The default
			is 0xa4a8, you should change this to an ID that's not used by any of
			your other USB products if you have any. It would be a good idea to
			start numbering your products starting with say 0x0001.

			bcdDevice - This is the version number of your product. It would be a good idea
			to put your firmware version here.

			iManufacturer - A string containing the name of the Vendor.

			iProduct - A string containing the Product Name.

			iSerialNum - A string containing the Serial Number. This should be changed for
			each unit of your product.

			iPNPstring - The PNP ID string used for this printer. You will want to set
			either on the command line or hard code the PNP ID string used for
			your printer product.

			qlen - The number of 8k buffers to use per endpoint. The default is 10, you
			should tune this for your product. You may also want to tune the
			size of each buffer for your product.




			USING THE EXAMPLE CODE
			======================

			This example code talks to stdout, instead of a print engine.

			To compile the test code below:

			1) save it to a file called prn_example.c
			2) compile the code with the follow command:
			gcc prn_example.c -o prn_example



			To read printer data from the host to stdout:

			# prn_example -read_data


			To write printer data from a file (data_file) to the host:

			# cat data_file \| prn_example -write_data


			To get the current printer status for the gadget driver:

			# prn_example -get_status

			Printer status is:
			Printer is NOT Selected
			Paper is Out
			Printer OK


			To set printer to Selected/On-line:

			# prn_example -selected


			To set printer to Not Selected/Off-line:

			# prn_example -not_selected


			To set paper status to paper out:

			# prn_example -paper_out


			To set paper status to paper loaded:

			# prn_example -paper_loaded


			To set error status to printer OK:

			# prn_example -no_error


			To set error status to ERROR:

			# prn_example -error




			EXAMPLE CODE
			============


			#include <stdio.h>
			#include <stdlib.h>
			#include <fcntl.h>
			#include <linux/poll.h>
			#include <sys/ioctl.h>
			#include <linux/usb/g_printer.h>

			#define PRINTER_FILE "/dev/g_printer"
			#define BUF_SIZE 512


			/*
			* 'usage()' - Show program usage.
			*/

			static void
			usage(const char option) / I - Option string or NULL */
			{
			if (option) {
			fprintf(stderr,"prn_example: Unknown option \"%s\"!\n",
			option);
			}

			fputs("\n", stderr);
			fputs("Usage: prn_example -[options]\n", stderr);
			fputs("Options:\n", stderr);
			fputs("\n", stderr);
			fputs("-get_status Get the current printer status.\n", stderr);
			fputs("-selected Set the selected status to selected.\n", stderr);
			fputs("-not_selected Set the selected status to NOT selected.\n",
			stderr);
			fputs("-error Set the error status to error.\n", stderr);
			fputs("-no_error Set the error status to NO error.\n", stderr);
			fputs("-paper_out Set the paper status to paper out.\n", stderr);
			fputs("-paper_loaded Set the paper status to paper loaded.\n",
			stderr);
			fputs("-read_data Read printer data from driver.\n", stderr);
			fputs("-write_data Write printer sata to driver.\n", stderr);
			fputs("-NB_read_data (Non-Blocking) Read printer data from driver.\n",
			stderr);
			fputs("\n\n", stderr);

			exit(1);
			}


			static int
			read_printer_data()
			{
			struct pollfd fd[1];

			/* Open device file for printer gadget. */
			fd[0].fd = open(PRINTER_FILE, O_RDWR);
			if (fd[0].fd < 0) {
			printf("Error %d opening %s\n", fd[0].fd, PRINTER_FILE);
			close(fd[0].fd);
			return(-1);
			}

			fd[0].events = POLLIN \| POLLRDNORM;

			while (1) {
			static char buf[BUF_SIZE];
			int bytes_read;
			int retval;

			/* Wait for up to 1 second for data. */
			retval = poll(fd, 1, 1000);

			if (retval && (fd[0].revents & POLLRDNORM)) {

			/* Read data from printer gadget driver. */
			bytes_read = read(fd[0].fd, buf, BUF_SIZE);

			if (bytes_read < 0) {
			printf("Error %d reading from %s\n",
			fd[0].fd, PRINTER_FILE);
			close(fd[0].fd);
			return(-1);
			} else if (bytes_read > 0) {
			/* Write data to standard OUTPUT (stdout). */
			fwrite(buf, 1, bytes_read, stdout);
			fflush(stdout);
			}

			}

			}

			/* Close the device file. */
			close(fd[0].fd);

			return 0;
			}


			static int
			write_printer_data()
			{
			struct pollfd fd[1];

			/* Open device file for printer gadget. */
			fd[0].fd = open (PRINTER_FILE, O_RDWR);
			if (fd[0].fd < 0) {
			printf("Error %d opening %s\n", fd[0].fd, PRINTER_FILE);
			close(fd[0].fd);
			return(-1);
			}

			fd[0].events = POLLOUT \| POLLWRNORM;

			while (1) {
			int retval;
			static char buf[BUF_SIZE];
			/* Read data from standard INPUT (stdin). */
			int bytes_read = fread(buf, 1, BUF_SIZE, stdin);

			if (!bytes_read) {
			break;
			}

			while (bytes_read) {

			/* Wait for up to 1 second to sent data. */
			retval = poll(fd, 1, 1000);

			/* Write data to printer gadget driver. */
			if (retval && (fd[0].revents & POLLWRNORM)) {
			retval = write(fd[0].fd, buf, bytes_read);
			if (retval < 0) {
			printf("Error %d writing to %s\n",
			fd[0].fd,
			PRINTER_FILE);
			close(fd[0].fd);
			return(-1);
			} else {
			bytes_read -= retval;
			}

			}

			}

			}

			/* Wait until the data has been sent. */
			fsync(fd[0].fd);

			/* Close the device file. */
			close(fd[0].fd);

			return 0;
			}


			static int
			read_NB_printer_data()
			{
			int fd;
			static char buf[BUF_SIZE];
			int bytes_read;

			/* Open device file for printer gadget. */
			fd = open(PRINTER_FILE, O_RDWR\|O_NONBLOCK);
			if (fd < 0) {
			printf("Error %d opening %s\n", fd, PRINTER_FILE);
			close(fd);
			return(-1);
			}

			while (1) {
			/* Read data from printer gadget driver. */
			bytes_read = read(fd, buf, BUF_SIZE);
			if (bytes_read <= 0) {
			break;
			}

			/* Write data to standard OUTPUT (stdout). */
			fwrite(buf, 1, bytes_read, stdout);
			fflush(stdout);
			}

			/* Close the device file. */
			close(fd);

			return 0;
			}


			static int
			get_printer_status()
			{
			int retval;
			int fd;

			/* Open device file for printer gadget. */
			fd = open(PRINTER_FILE, O_RDWR);
			if (fd < 0) {
			printf("Error %d opening %s\n", fd, PRINTER_FILE);
			close(fd);
			return(-1);
			}

			/* Make the IOCTL call. */
			retval = ioctl(fd, GADGET_GET_PRINTER_STATUS);
			if (retval < 0) {
			fprintf(stderr, "ERROR: Failed to set printer status\n");
			return(-1);
			}

			/* Close the device file. */
			close(fd);

			return(retval);
			}


			static int
			set_printer_status(unsigned char buf, int clear_printer_status_bit)
			{
			int retval;
			int fd;

			retval = get_printer_status();
			if (retval < 0) {
			fprintf(stderr, "ERROR: Failed to get printer status\n");
			return(-1);
			}

			/* Open device file for printer gadget. */
			fd = open(PRINTER_FILE, O_RDWR);

			if (fd < 0) {
			printf("Error %d opening %s\n", fd, PRINTER_FILE);
			close(fd);
			return(-1);
			}

			if (clear_printer_status_bit) {
			retval &= ~buf;
			} else {
			retval \|= buf;
			}

			/* Make the IOCTL call. */
			if (ioctl(fd, GADGET_SET_PRINTER_STATUS, (unsigned char)retval)) {
			fprintf(stderr, "ERROR: Failed to set printer status\n");
			return(-1);
			}

			/* Close the device file. */
			close(fd);

			return 0;
			}


			static int
			display_printer_status()
			{
			char printer_status;

			printer_status = get_printer_status();
			if (printer_status < 0) {
			fprintf(stderr, "ERROR: Failed to get printer status\n");
			return(-1);
			}

			printf("Printer status is:\n");
			if (printer_status & PRINTER_SELECTED) {
			printf(" Printer is Selected\n");
			} else {
			printf(" Printer is NOT Selected\n");
			}
			if (printer_status & PRINTER_PAPER_EMPTY) {
			printf(" Paper is Out\n");
			} else {
			printf(" Paper is Loaded\n");
			}
			if (printer_status & PRINTER_NOT_ERROR) {
			printf(" Printer OK\n");
			} else {
			printf(" Printer ERROR\n");
			}

			return(0);
			}


			int
			main(int argc, char *argv[])
			{
			int i; /* Looping var */
			int retval = 0;

			/* No Args */
			if (argc == 1) {
			usage(0);
			exit(0);
			}

			for (i = 1; i < argc && !retval; i ++) {

			if (argv[i][0] != '-') {
			continue;
			}

			if (!strcmp(argv[i], "-get_status")) {
			if (display_printer_status()) {
			retval = 1;
			}

			} else if (!strcmp(argv[i], "-paper_loaded")) {
			if (set_printer_status(PRINTER_PAPER_EMPTY, 1)) {
			retval = 1;
			}

			} else if (!strcmp(argv[i], "-paper_out")) {
			if (set_printer_status(PRINTER_PAPER_EMPTY, 0)) {
			retval = 1;
			}

			} else if (!strcmp(argv[i], "-selected")) {
			if (set_printer_status(PRINTER_SELECTED, 0)) {
			retval = 1;
			}

			} else if (!strcmp(argv[i], "-not_selected")) {
			if (set_printer_status(PRINTER_SELECTED, 1)) {
			retval = 1;
			}

			} else if (!strcmp(argv[i], "-error")) {
			if (set_printer_status(PRINTER_NOT_ERROR, 1)) {
			retval = 1;
			}

			} else if (!strcmp(argv[i], "-no_error")) {
			if (set_printer_status(PRINTER_NOT_ERROR, 0)) {
			retval = 1;
			}

			} else if (!strcmp(argv[i], "-read_data")) {
			if (read_printer_data()) {
			retval = 1;
			}

			} else if (!strcmp(argv[i], "-write_data")) {
			if (write_printer_data()) {
			retval = 1;
			}

			} else if (!strcmp(argv[i], "-NB_read_data")) {
			if (read_NB_printer_data()) {
			retval = 1;
			}

			} else {
			usage(argv[i]);
			retval = 1;
			}
			}

			exit(retval);
			}

drivers/usb/gadget/Kconfig

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	@@ -548,6 +548,20 @@ config USB_MIDI_GADGET
	Say "y" to link the driver statically, or "m" to build a		Say "y" to link the driver statically, or "m" to build a
	dynamically linked module called "g_midi".		dynamically linked module called "g_midi".

			config USB_G_PRINTER
			tristate "Printer Gadget"
			help
			The Printer Gadget channels data between the USB host and a
			userspace program driving the print engine. The user space
			program reads and writes the device file /dev/g_printer to
			receive or send printer data. It can use ioctl calls to
			the device file to get or set printer status.

			Say "y" to link the driver statically, or "m" to build a
			dynamically linked module called "g_printer".

			For more information, see Documentation/usb/gadget_printer.txt
			which includes sample code for accessing the device file.

	# put drivers that need isochronous transfer support (for audio		# put drivers that need isochronous transfer support (for audio
	# or video class gadget drivers), or specific hardware, here.		# or video class gadget drivers), or specific hardware, here.

drivers/usb/gadget/Makefile

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	@@ -28,6 +28,8 @@ g_midi-objs := gmidi.o usbstring.o config.o epautoconf.o
	gadgetfs-objs := inode.o		gadgetfs-objs := inode.o
	g_file_storage-objs := file_storage.o usbstring.o config.o \		g_file_storage-objs := file_storage.o usbstring.o config.o \
	epautoconf.o		epautoconf.o
			g_printer-objs := printer.o usbstring.o config.o \
			epautoconf.o

	ifeq ($(CONFIG_USB_ETH_RNDIS),y)		ifeq ($(CONFIG_USB_ETH_RNDIS),y)
	g_ether-objs += rndis.o		g_ether-objs += rndis.o
	@@ -38,5 +40,6 @@ obj-$(CONFIG_USB_ETH) += g_ether.o
	obj-$(CONFIG_USB_GADGETFS) += gadgetfs.o		obj-$(CONFIG_USB_GADGETFS) += gadgetfs.o
	obj-$(CONFIG_USB_FILE_STORAGE) += g_file_storage.o		obj-$(CONFIG_USB_FILE_STORAGE) += g_file_storage.o
	obj-$(CONFIG_USB_G_SERIAL) += g_serial.o		obj-$(CONFIG_USB_G_SERIAL) += g_serial.o
			obj-$(CONFIG_USB_G_PRINTER) += g_printer.o
	obj-$(CONFIG_USB_MIDI_GADGET) += g_midi.o		obj-$(CONFIG_USB_MIDI_GADGET) += g_midi.o

drivers/usb/gadget/printer.c

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Preview size limit exceeded, changes collapsed.

include/linux/usb/Kbuild

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	@@ -3,4 +3,5 @@ unifdef-y += cdc.h
	unifdef-y += ch9.h		unifdef-y += ch9.h
	unifdef-y += gadgetfs.h		unifdef-y += gadgetfs.h
	unifdef-y += midi.h		unifdef-y += midi.h
			unifdef-y += g_printer.h