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140 lines
3.5 KiB
140 lines
3.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* 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 <[email protected]> |
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Copyright (c) 2005 Jim Cromie <[email protected]> |
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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 <linux/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_inode(file)); |
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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_inode(file)); |
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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 <[email protected]>"); |
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MODULE_DESCRIPTION("NatSemi GPIO Common Methods"); |
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MODULE_LICENSE("GPL");
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