ia64/linux-2.6.18-xen.hg

view arch/v850/kernel/rte_cb_leds.c @ 854:950b9eb27661

usbback: fix urb interval value for interrupt urbs.

Signed-off-by: Noboru Iwamatsu <n_iwamatsu@jp.fujitsu.com>
author Keir Fraser <keir.fraser@citrix.com>
date Mon Apr 06 13:51:20 2009 +0100 (2009-04-06)
parents 831230e53067
children
line source
1 /*
2 * include/asm-v850/rte_cb_leds.c -- Midas lab RTE-CB board LED device support
3 *
4 * Copyright (C) 2002,03 NEC Electronics Corporation
5 * Copyright (C) 2002,03 Miles Bader <miles@gnu.org>
6 *
7 * This file is subject to the terms and conditions of the GNU General
8 * Public License. See the file COPYING in the main directory of this
9 * archive for more details.
10 *
11 * Written by Miles Bader <miles@gnu.org>
12 */
14 #include <linux/init.h>
15 #include <linux/spinlock.h>
16 #include <linux/fs.h>
17 #include <linux/miscdevice.h>
19 #include <asm/uaccess.h>
21 #define LEDS_MINOR 169 /* Minor device number, using misc major. */
23 /* The actual LED hardware is write-only, so we hold the contents here too. */
24 static unsigned char leds_image[LED_NUM_DIGITS] = { 0 };
26 /* Spinlock protecting the above leds. */
27 static DEFINE_SPINLOCK(leds_lock);
29 /* Common body of LED read/write functions, checks POS and LEN for
30 correctness, declares a variable using IMG_DECL, initialized pointing at
31 the POS position in the LED image buffer, and and iterates COPY_EXPR
32 until BUF is equal to the last buffer position; finally, sets LEN to be
33 the amount actually copied. IMG should be a variable declaration
34 (without an initializer or a terminating semicolon); POS, BUF, and LEN
35 should all be simple variables. */
36 #define DO_LED_COPY(img_decl, pos, buf, len, copy_expr) \
37 do { \
38 if (pos > LED_NUM_DIGITS) \
39 len = 0; \
40 else { \
41 if (pos + len > LED_NUM_DIGITS) \
42 len = LED_NUM_DIGITS - pos; \
43 \
44 if (len > 0) { \
45 int _flags; \
46 const char *_end = buf + len; \
47 img_decl = &leds_image[pos]; \
48 \
49 spin_lock_irqsave (leds_lock, _flags); \
50 do \
51 (copy_expr); \
52 while (buf != _end); \
53 spin_unlock_irqrestore (leds_lock, _flags); \
54 } \
55 } \
56 } while (0)
58 /* Read LEN bytes from LEDs at position POS, into BUF.
59 Returns actual amount read. */
60 unsigned read_leds (unsigned pos, char *buf, unsigned len)
61 {
62 DO_LED_COPY (const char *img, pos, buf, len, *buf++ = *img++);
63 return len;
64 }
66 /* Write LEN bytes to LEDs at position POS, from BUF.
67 Returns actual amount written. */
68 unsigned write_leds (unsigned pos, const char *buf, unsigned len)
69 {
70 /* We write the actual LED values backwards, because
71 increasing memory addresses reflect LEDs right-to-left. */
72 volatile char *led = &LED (LED_NUM_DIGITS - pos - 1);
73 /* We invert the value written to the hardware, because 1 = off,
74 and 0 = on. */
75 DO_LED_COPY (char *img, pos, buf, len,
76 *led-- = 0xFF ^ (*img++ = *buf++));
77 return len;
78 }
81 /* Device functions. */
83 static ssize_t leds_dev_read (struct file *file, char *buf, size_t len,
84 loff_t *pos)
85 {
86 char temp_buf[LED_NUM_DIGITS];
87 len = read_leds (*pos, temp_buf, len);
88 if (copy_to_user (buf, temp_buf, len))
89 return -EFAULT;
90 *pos += len;
91 return len;
92 }
94 static ssize_t leds_dev_write (struct file *file, const char *buf, size_t len,
95 loff_t *pos)
96 {
97 char temp_buf[LED_NUM_DIGITS];
98 if (copy_from_user (temp_buf, buf, min_t(size_t, len, LED_NUM_DIGITS)))
99 return -EFAULT;
100 len = write_leds (*pos, temp_buf, len);
101 *pos += len;
102 return len;
103 }
105 static loff_t leds_dev_lseek (struct file *file, loff_t offs, int whence)
106 {
107 if (whence == 1)
108 offs += file->f_pos; /* relative */
109 else if (whence == 2)
110 offs += LED_NUM_DIGITS; /* end-relative */
112 if (offs < 0 || offs > LED_NUM_DIGITS)
113 return -EINVAL;
115 file->f_pos = offs;
117 return 0;
118 }
120 static struct file_operations leds_fops = {
121 .read = leds_dev_read,
122 .write = leds_dev_write,
123 .llseek = leds_dev_lseek
124 };
126 static struct miscdevice leds_miscdev = {
127 .name = "leds",
128 .minor = LEDS_MINOR,
129 .fops = &leds_fops
130 };
132 int __init leds_dev_init (void)
133 {
134 return misc_register (&leds_miscdev);
135 }
137 __initcall (leds_dev_init);