140 lines
3.5 KiB
C
140 lines
3.5 KiB
C
/* linux/drivers/char/nsc_gpio.c
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National Semiconductor common GPIO device-file/VFS methods.
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Allows a user space process to control the GPIO pins.
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Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
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Copyright (c) 2005 Jim Cromie <jim.cromie@gmail.com>
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*/
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/nsc_gpio.h>
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#include <linux/platform_device.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#define NAME "nsc_gpio"
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void nsc_gpio_dump(struct nsc_gpio_ops *amp, unsigned index)
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{
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/* retrieve current config w/o changing it */
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u32 config = amp->gpio_config(index, ~0, 0);
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/* user requested via 'v' command, so its INFO */
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dev_info(amp->dev, "io%02u: 0x%04x %s %s %s %s %s %s %s\tio:%d/%d\n",
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index, config,
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(config & 1) ? "OE" : "TS", /* output-enabled/tristate */
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(config & 2) ? "PP" : "OD", /* push pull / open drain */
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(config & 4) ? "PUE" : "PUD", /* pull up enabled/disabled */
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(config & 8) ? "LOCKED" : "", /* locked / unlocked */
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(config & 16) ? "LEVEL" : "EDGE",/* level/edge input */
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(config & 32) ? "HI" : "LO", /* trigger on rise/fall edge */
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(config & 64) ? "DEBOUNCE" : "", /* debounce */
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amp->gpio_get(index), amp->gpio_current(index));
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}
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ssize_t nsc_gpio_write(struct file *file, const char __user *data,
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size_t len, loff_t *ppos)
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{
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unsigned m = iminor(file->f_path.dentry->d_inode);
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struct nsc_gpio_ops *amp = file->private_data;
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struct device *dev = amp->dev;
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size_t i;
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int err = 0;
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for (i = 0; i < len; ++i) {
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char c;
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if (get_user(c, data + i))
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return -EFAULT;
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switch (c) {
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case '0':
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amp->gpio_set(m, 0);
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break;
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case '1':
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amp->gpio_set(m, 1);
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break;
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case 'O':
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dev_dbg(dev, "GPIO%d output enabled\n", m);
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amp->gpio_config(m, ~1, 1);
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break;
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case 'o':
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dev_dbg(dev, "GPIO%d output disabled\n", m);
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amp->gpio_config(m, ~1, 0);
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break;
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case 'T':
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dev_dbg(dev, "GPIO%d output is push pull\n", m);
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amp->gpio_config(m, ~2, 2);
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break;
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case 't':
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dev_dbg(dev, "GPIO%d output is open drain\n", m);
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amp->gpio_config(m, ~2, 0);
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break;
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case 'P':
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dev_dbg(dev, "GPIO%d pull up enabled\n", m);
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amp->gpio_config(m, ~4, 4);
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break;
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case 'p':
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dev_dbg(dev, "GPIO%d pull up disabled\n", m);
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amp->gpio_config(m, ~4, 0);
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break;
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case 'v':
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/* View Current pin settings */
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amp->gpio_dump(amp, m);
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break;
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case '\n':
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/* end of settings string, do nothing */
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break;
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default:
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dev_err(dev, "io%2d bad setting: chr<0x%2x>\n",
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m, (int)c);
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err++;
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}
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}
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if (err)
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return -EINVAL; /* full string handled, report error */
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return len;
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}
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ssize_t nsc_gpio_read(struct file *file, char __user * buf,
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size_t len, loff_t * ppos)
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{
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unsigned m = iminor(file->f_path.dentry->d_inode);
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int value;
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struct nsc_gpio_ops *amp = file->private_data;
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value = amp->gpio_get(m);
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if (put_user(value ? '1' : '0', buf))
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return -EFAULT;
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return 1;
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}
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/* common file-ops routines for both scx200_gpio and pc87360_gpio */
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EXPORT_SYMBOL(nsc_gpio_write);
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EXPORT_SYMBOL(nsc_gpio_read);
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EXPORT_SYMBOL(nsc_gpio_dump);
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static int __init nsc_gpio_init(void)
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{
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printk(KERN_DEBUG NAME " initializing\n");
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return 0;
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}
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static void __exit nsc_gpio_cleanup(void)
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{
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printk(KERN_DEBUG NAME " cleanup\n");
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}
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module_init(nsc_gpio_init);
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module_exit(nsc_gpio_cleanup);
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MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
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MODULE_DESCRIPTION("NatSemi GPIO Common Methods");
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MODULE_LICENSE("GPL");
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