diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/v850/kernel/rte_cb_leds.c |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/v850/kernel/rte_cb_leds.c')
-rw-r--r-- | arch/v850/kernel/rte_cb_leds.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/arch/v850/kernel/rte_cb_leds.c b/arch/v850/kernel/rte_cb_leds.c new file mode 100644 index 00000000000..b662ad83894 --- /dev/null +++ b/arch/v850/kernel/rte_cb_leds.c @@ -0,0 +1,138 @@ +/* + * include/asm-v850/rte_cb_leds.c -- Midas lab RTE-CB board LED device support + * + * Copyright (C) 2002,03 NEC Electronics Corporation + * Copyright (C) 2002,03 Miles Bader <miles@gnu.org> + * + * This file is subject to the terms and conditions of the GNU General + * Public License. See the file COPYING in the main directory of this + * archive for more details. + * + * Written by Miles Bader <miles@gnu.org> + */ + +#include <linux/config.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> + +#include <asm/uaccess.h> + +#define LEDS_MINOR 169 /* Minor device number, using misc major. */ + +/* The actual LED hardware is write-only, so we hold the contents here too. */ +static unsigned char leds_image[LED_NUM_DIGITS] = { 0 }; + +/* Spinlock protecting the above leds. */ +static DEFINE_SPINLOCK(leds_lock); + +/* Common body of LED read/write functions, checks POS and LEN for + correctness, declares a variable using IMG_DECL, initialized pointing at + the POS position in the LED image buffer, and and iterates COPY_EXPR + until BUF is equal to the last buffer position; finally, sets LEN to be + the amount actually copied. IMG should be a variable declaration + (without an initializer or a terminating semicolon); POS, BUF, and LEN + should all be simple variables. */ +#define DO_LED_COPY(img_decl, pos, buf, len, copy_expr) \ +do { \ + if (pos > LED_NUM_DIGITS) \ + len = 0; \ + else { \ + if (pos + len > LED_NUM_DIGITS) \ + len = LED_NUM_DIGITS - pos; \ + \ + if (len > 0) { \ + int _flags; \ + const char *_end = buf + len; \ + img_decl = &leds_image[pos]; \ + \ + spin_lock_irqsave (leds_lock, _flags); \ + do \ + (copy_expr); \ + while (buf != _end); \ + spin_unlock_irqrestore (leds_lock, _flags); \ + } \ + } \ +} while (0) + +/* Read LEN bytes from LEDs at position POS, into BUF. + Returns actual amount read. */ +unsigned read_leds (unsigned pos, char *buf, unsigned len) +{ + DO_LED_COPY (const char *img, pos, buf, len, *buf++ = *img++); + return len; +} + +/* Write LEN bytes to LEDs at position POS, from BUF. + Returns actual amount written. */ +unsigned write_leds (unsigned pos, const char *buf, unsigned len) +{ + /* We write the actual LED values backwards, because + increasing memory addresses reflect LEDs right-to-left. */ + volatile char *led = &LED (LED_NUM_DIGITS - pos - 1); + /* We invert the value written to the hardware, because 1 = off, + and 0 = on. */ + DO_LED_COPY (char *img, pos, buf, len, + *led-- = 0xFF ^ (*img++ = *buf++)); + return len; +} + + +/* Device functions. */ + +static ssize_t leds_dev_read (struct file *file, char *buf, size_t len, + loff_t *pos) +{ + char temp_buf[LED_NUM_DIGITS]; + len = read_leds (*pos, temp_buf, len); + if (copy_to_user (buf, temp_buf, len)) + return -EFAULT; + *pos += len; + return len; +} + +static ssize_t leds_dev_write (struct file *file, const char *buf, size_t len, + loff_t *pos) +{ + char temp_buf[LED_NUM_DIGITS]; + if (copy_from_user (temp_buf, buf, min_t(size_t, len, LED_NUM_DIGITS))) + return -EFAULT; + len = write_leds (*pos, temp_buf, len); + *pos += len; + return len; +} + +static loff_t leds_dev_lseek (struct file *file, loff_t offs, int whence) +{ + if (whence == 1) + offs += file->f_pos; /* relative */ + else if (whence == 2) + offs += LED_NUM_DIGITS; /* end-relative */ + + if (offs < 0 || offs > LED_NUM_DIGITS) + return -EINVAL; + + file->f_pos = offs; + + return 0; +} + +static struct file_operations leds_fops = { + .read = leds_dev_read, + .write = leds_dev_write, + .llseek = leds_dev_lseek +}; + +static struct miscdevice leds_miscdev = { + .name = "leds", + .minor = LEDS_MINOR, + .fops = &leds_fops +}; + +int __init leds_dev_init (void) +{ + return misc_register (&leds_miscdev); +} + +__initcall (leds_dev_init); |