USB: Added driver for a Delcom USB 7-segment LED Display

Added basic support for a Delcom USB 7-segment LED Display

Signed-off by: Harrison Metzger <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/ABI/testing/sysfs-bus-usb-devices-usbsevseg

···
+Where:		/sys/bus/usb/.../powered
+Date:		August 2008
+Kernel Version:	2.6.26
+Contact:	Harrison Metzger <[e-mail]>
+Description:	Controls whether the device's display will powered.
+		A value of 0 is off and a non-zero value is on.
+
+Where:		/sys/bus/usb/.../mode_msb
+Where:		/sys/bus/usb/.../mode_lsb
+Date:		August 2008
+Kernel Version:	2.6.26
+Contact:	Harrison Metzger <[e-mail]>
+Description:	Controls the devices display mode.
+		For a 6 character display the values are
+			MSB 0x06; LSB 0x3F, and
+		for an 8 character display the values are
+			MSB 0x08; LSB 0xFF.
+
+Where:		/sys/bus/usb/.../textmode
+Date:		August 2008
+Kernel Version:	2.6.26
+Contact:	Harrison Metzger <[e-mail]>
+Description:	Controls the way the device interprets its text buffer.
+		raw:	each character controls its segment manually
+		hex:	each character is between 0-15
+		ascii:	each character is between '0'-'9' and 'A'-'F'.
+
+Where:		/sys/bus/usb/.../text
+Date:		August 2008
+Kernel Version:	2.6.26
+Contact:	Harrison Metzger <[e-mail]>
+Description:	The text (or data) for the device to display
+
+Where:		/sys/bus/usb/.../decimals
+Date:		August 2008
+Kernel Version:	2.6.26
+Contact:	Harrison Metzger <[e-mail]>
+Description:	Controls the decimal places on the device.
+		To set the nth decimal place, give this field
+		the value of 10 ** n. Assume this field has
+		the value k and has 1 or more decimal places set,
+		to set the mth place (where m is not already set),
+		change this fields value to k + 10 ** m.

Documentation/usb/misc_usbsevseg.txt

···
+USB 7-Segment Numeric Display
+Manufactured by Delcom Engineering
+
+Device Information
+------------------
+USB VENDOR_ID	0x0fc5
+USB PRODUCT_ID	0x1227
+Both the 6 character and 8 character displays have PRODUCT_ID,
+and according to Delcom Engineering no queryable information
+can be obtained from the device to tell them apart.
+
+Device Modes
+------------
+By default, the driver assumes the display is only 6 characters
+The mode for 6 characters is:
+	MSB 0x06; LSB 0x3f
+For the 8 character display:
+	MSB 0x08; LSB 0xff
+The device can accept "text" either in raw, hex, or ascii textmode.
+raw controls each segment manually,
+hex expects a value between 0-15 per character,
+ascii expects a value between '0'-'9' and 'A'-'F'.
+The default is ascii.
+
+Device Operation
+----------------
+1.	Turn on the device:
+	echo 1 > /sys/bus/usb/.../powered
+2.	Set the device's mode:
+	echo $mode_msb > /sys/bus/usb/.../mode_msb
+	echo $mode_lsb > /sys/bus/usb/.../mode_lsb
+3.	Set the textmode:
+	echo $textmode > /sys/bus/usb/.../textmode
+4.	set the text (for example):
+	echo "123ABC" > /sys/bus/usb/.../text (ascii)
+	echo "A1B2" > /sys/bus/usb/.../text (ascii)
+	echo -ne "\x01\x02\x03" > /sys/bus/usb/.../text (hex)
+5.	Set the decimal places.
+	The device has either 6 or 8 decimal points.
+	to set the nth decimal place calculate 10 ** n
+	and echo it in to /sys/bus/usb/.../decimals
+	To set multiple decimals points sum up each power.
+	For example, to set the 0th and 3rd decimal place
+	echo 1001 > /sys/bus/usb/.../decimals
+
+

drivers/usb/misc/Kconfig

···
 	  To compile this driver as a module, choose M here.  The module
 	  will be called adutux.
 
+config USB_SEVSEG
+	tristate "USB 7-Segment LED Display"
+	depends on USB
+	help
+	  Say Y here if you have a USB 7-Segment Display by Delcom
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called usbsevseg.
+
 config USB_RIO500
 	tristate "USB Diamond Rio500 support"
 	depends on USB

drivers/usb/misc/Makefile

···
 obj-$(CONFIG_USB_TEST)		+= usbtest.o
 obj-$(CONFIG_USB_TRANCEVIBRATOR)	+= trancevibrator.o
 obj-$(CONFIG_USB_USS720)	+= uss720.o
+obj-$(CONFIG_USB_SEVSEG)	+= usbsevseg.o
 
 obj-$(CONFIG_USB_SISUSBVGA)	+= sisusbvga/
 

drivers/usb/misc/usbsevseg.c

···
+/*
+ * USB 7 Segment Driver
+ *
+ * Copyright (C) 2008 Harrison Metzger <[e-mail]>
+ * Based on usbled.c by Greg Kroah-Hartman ([e-mail])
+ *
+ *	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, version 2.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/usb.h>
+
+
+#define DRIVER_AUTHOR "Harrison Metzger <[e-mail]>"
+#define DRIVER_DESC "USB 7 Segment Driver"
+
+#define VENDOR_ID	0x0fc5
+#define PRODUCT_ID	0x1227
+#define MAXLEN		6
+
+/* table of devices that work with this driver */
+static struct usb_device_id id_table[] = {
+	{ USB_DEVICE(VENDOR_ID, PRODUCT_ID) },
+	{ },
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+/* the different text display modes the device is capable of */
+static char *display_textmodes[] = {"raw", "hex", "ascii", NULL};
+
+struct usb_sevsegdev {
+	struct usb_device *udev;
+
+	u8 powered;
+	u8 mode_msb;
+	u8 mode_lsb;
+	u8 decimals[MAXLEN];
+	u8 textmode;
+	u8 text[MAXLEN];
+	u16 textlength;
+};
+
+/* sysfs_streq can't replace this completely
+ * If the device was in hex mode, and the user wanted a 0,
+ * if str commands are used, we would assume the end of string
+ * so mem commands are used.
+ */
+inline size_t my_memlen(const char *buf, size_t count)
+{
+	if (count > 0 && buf[count-1] == '\n')
+		return count - 1;
+	else
+		return count;
+}
+
+static void update_display_powered(struct usb_sevsegdev *mydev)
+{
+	int rc;
+
+	rc = usb_control_msg(mydev->udev,
+			usb_sndctrlpipe(mydev->udev, 0),
+			0x12,
+			0x48,
+			(80 * 0x100) + 10, /*  (power mode) */
+			(0x00 * 0x100) + (mydev->powered ? 1 : 0),
+			NULL,
+			0,
+			2000);
+	if (rc < 0)
+		dev_dbg(&mydev->udev->dev, "power retval = %d\n", rc);
+}
+
+static void update_display_mode(struct usb_sevsegdev *mydev)
+{
+	int rc;
+
+	rc = usb_control_msg(mydev->udev,
+			usb_sndctrlpipe(mydev->udev, 0),
+			0x12,
+			0x48,
+			(82 * 0x100) + 10, /* (set mode) */
+			(mydev->mode_msb * 0x100) + mydev->mode_lsb,
+			NULL,
+			0,
+			2000);
+
+	if (rc < 0)
+		dev_dbg(&mydev->udev->dev, "mode retval = %d\n", rc);
+}
+
+static void update_display_visual(struct usb_sevsegdev *mydev)
+{
+	int rc;
+	int i;
+	unsigned char *buffer;
+	u8 decimals = 0;
+
+	buffer = kzalloc(MAXLEN, GFP_KERNEL);
+	if (!buffer) {
+		dev_err(&mydev->udev->dev, "out of memory\n");
+		return;
+	}
+
+	/* The device is right to left, where as you write left to right */
+	for (i = 0; i < mydev->textlength; i++)
+		buffer[i] = mydev->text[mydev->textlength-1-i];
+
+	rc = usb_control_msg(mydev->udev,
+			usb_sndctrlpipe(mydev->udev, 0),
+			0x12,
+			0x48,
+			(85 * 0x100) + 10, /* (write text) */
+			(0 * 0x100) + mydev->textmode, /* mode  */
+			buffer,
+			mydev->textlength,
+			2000);
+
+	if (rc < 0)
+		dev_dbg(&mydev->udev->dev, "write retval = %d\n", rc);
+
+	kfree(buffer);
+
+	/* The device is right to left, where as you write left to right */
+	for (i = 0; i < sizeof(mydev->decimals); i++)
+		decimals |= mydev->decimals[i] << i;
+
+	rc = usb_control_msg(mydev->udev,
+			usb_sndctrlpipe(mydev->udev, 0),
+			0x12,
+			0x48,
+			(86 * 0x100) + 10, /* (set decimal) */
+			(0 * 0x100) + decimals, /* decimals */
+			NULL,
+			0,
+			2000);
+
+	if (rc < 0)
+		dev_dbg(&mydev->udev->dev, "decimal retval = %d\n", rc);
+}
+
+#define MYDEV_ATTR_SIMPLE_UNSIGNED(name, update_fcn)		\
+static ssize_t show_attr_##name(struct device *dev, 		\
+	struct device_attribute *attr, char *buf) 		\
+{								\
+	struct usb_interface *intf = to_usb_interface(dev);	\
+	struct usb_sevsegdev *mydev = usb_get_intfdata(intf);	\
+								\
+	return sprintf(buf, "%u\n", mydev->name);		\
+}								\
+								\
+static ssize_t set_attr_##name(struct device *dev, 		\
+	struct device_attribute *attr, const char *buf, size_t count) \
+{								\
+	struct usb_interface *intf = to_usb_interface(dev);	\
+	struct usb_sevsegdev *mydev = usb_get_intfdata(intf);	\
+								\
+	mydev->name = simple_strtoul(buf, NULL, 10);		\
+	update_fcn(mydev); \
+								\
+	return count;						\
+}								\
+static DEVICE_ATTR(name, S_IWUGO | S_IRUGO, show_attr_##name, set_attr_##name);
+
+static ssize_t show_attr_text(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
+
+	return snprintf(buf, mydev->textlength, "%s\n", mydev->text);
+}
+
+static ssize_t set_attr_text(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
+	size_t end = my_memlen(buf, count);
+
+	if (end > sizeof(mydev->text))
+		return -EINVAL;
+
+	memset(mydev->text, 0, sizeof(mydev->text));
+	mydev->textlength = end;
+
+	if (end > 0)
+		memcpy(mydev->text, buf, end);
+
+	update_display_visual(mydev);
+	return count;
+}
+
+static DEVICE_ATTR(text, S_IWUGO | S_IRUGO, show_attr_text, set_attr_text);
+
+static ssize_t show_attr_decimals(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
+	int i;
+	int pos;
+
+	for (i = 0; i < sizeof(mydev->decimals); i++) {
+		pos = sizeof(mydev->decimals) - 1 - i;
+		if (mydev->decimals[i] == 0)
+			buf[pos] = '0';
+		else if (mydev->decimals[i] == 1)
+			buf[pos] = '1';
+		else
+			buf[pos] = 'x';
+	}
+
+	buf[sizeof(mydev->decimals)] = '\n';
+	return sizeof(mydev->decimals) + 1;
+}
+
+static ssize_t set_attr_decimals(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
+	size_t end = my_memlen(buf, count);
+	int i;
+
+	if (end > sizeof(mydev->decimals))
+		return -EINVAL;
+
+	for (i = 0; i < end; i++)
+		if (buf[i] != '0' && buf[i] != '1')
+			return -EINVAL;
+
+	memset(mydev->decimals, 0, sizeof(mydev->decimals));
+	for (i = 0; i < end; i++)
+		if (buf[i] == '1')
+			mydev->decimals[end-1-i] = 1;
+
+	update_display_visual(mydev);
+
+	return count;
+}
+
+static DEVICE_ATTR(decimals, S_IWUGO | S_IRUGO,
+	show_attr_decimals, set_attr_decimals);
+
+static ssize_t show_attr_textmode(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
+	int i;
+
+	buf[0] = 0;
+
+	for (i = 0; display_textmodes[i]; i++) {
+		if (mydev->textmode == i) {
+			strcat(buf, " [");
+			strcat(buf, display_textmodes[i]);
+			strcat(buf, "] ");
+		} else {
+			strcat(buf, " ");
+			strcat(buf, display_textmodes[i]);
+			strcat(buf, " ");
+		}
+	}
+	strcat(buf, "\n");
+
+
+	return strlen(buf);
+}
+
+static ssize_t set_attr_textmode(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_sevsegdev *mydev = usb_get_intfdata(intf);
+	int i;
+
+	for (i = 0; display_textmodes[i]; i++) {
+		if (sysfs_streq(display_textmodes[i], buf)) {
+			mydev->textmode = i;
+			update_display_visual(mydev);
+			return count;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static DEVICE_ATTR(textmode, S_IWUGO | S_IRUGO,
+	show_attr_textmode, set_attr_textmode);
+
+
+MYDEV_ATTR_SIMPLE_UNSIGNED(powered, update_display_powered);
+MYDEV_ATTR_SIMPLE_UNSIGNED(mode_msb, update_display_mode);
+MYDEV_ATTR_SIMPLE_UNSIGNED(mode_lsb, update_display_mode);
+
+static struct attribute *dev_attrs[] = {
+	&dev_attr_powered.attr,
+	&dev_attr_text.attr,
+	&dev_attr_textmode.attr,
+	&dev_attr_decimals.attr,
+	&dev_attr_mode_msb.attr,
+	&dev_attr_mode_lsb.attr,
+	NULL
+};
+
+static struct attribute_group dev_attr_grp = {
+	.attrs = dev_attrs,
+};
+
+static int sevseg_probe(struct usb_interface *interface,
+	const struct usb_device_id *id)
+{
+	struct usb_device *udev = interface_to_usbdev(interface);
+	struct usb_sevsegdev *mydev = NULL;
+	int rc = -ENOMEM;
+
+	mydev = kzalloc(sizeof(struct usb_sevsegdev), GFP_KERNEL);
+	if (mydev == NULL) {
+		dev_err(&interface->dev, "Out of memory\n");
+		goto error_mem;
+	}
+
+	mydev->udev = usb_get_dev(udev);
+	usb_set_intfdata(interface, mydev);
+
+	/*set defaults */
+	mydev->textmode = 0x02; /* ascii mode */
+	mydev->mode_msb = 0x06; /* 6 characters */
+	mydev->mode_lsb = 0x3f; /* scanmode for 6 chars */
+
+	rc = sysfs_create_group(&interface->dev.kobj, &dev_attr_grp);
+	if (rc)
+		goto error;
+
+	dev_info(&interface->dev, "USB 7 Segment device now attached\n");
+	return 0;
+
+error:
+	usb_set_intfdata(interface, NULL);
+	usb_put_dev(mydev->udev);
+	kfree(mydev);
+error_mem:
+	return rc;
+}
+
+static void sevseg_disconnect(struct usb_interface *interface)
+{
+	struct usb_sevsegdev *mydev;
+
+	mydev = usb_get_intfdata(interface);
+	sysfs_remove_group(&interface->dev.kobj, &dev_attr_grp);
+	usb_set_intfdata(interface, NULL);
+	usb_put_dev(mydev->udev);
+	kfree(mydev);
+	dev_info(&interface->dev, "USB 7 Segment now disconnected\n");
+}
+
+static struct usb_driver sevseg_driver = {
+	.name =		"usbsevseg",
+	.probe =	sevseg_probe,
+	.disconnect =	sevseg_disconnect,
+	.id_table =	id_table,
+};
+
+static int __init usb_sevseg_init(void)
+{
+	int rc = 0;
+
+	rc = usb_register(&sevseg_driver);
+	if (rc)
+		err("usb_register failed. Error number %d", rc);
+	return rc;
+}
+
+static void __exit usb_sevseg_exit(void)
+{
+	usb_deregister(&sevseg_driver);
+}
+
+module_init(usb_sevseg_init);
+module_exit(usb_sevseg_exit);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");