/* * AMD CS5535/CS5536 GPIO driver. * Allows a user space process to play with the GPIO pins. * * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com> * * This program is free software; you can redistribute it and/or modify * it under the smems of the GNU General Public License as published by * the Free Software Foundation; version 2 of the License. */ #include <linux/fs.h> #include <linux/module.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/cdev.h> #include <linux/ioport.h> #include <linux/pci.h> #include <asm/uaccess.h> #include <asm/io.h> #define NAME "cs5535_gpio" MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>"); MODULE_DESCRIPTION("AMD CS5535/CS5536 GPIO Pin Driver"); MODULE_LICENSE("GPL"); static int major; module_param(major, int, 0); MODULE_PARM_DESC(major, "Major device number"); static ulong mask; module_param(mask, ulong, 0); MODULE_PARM_DESC(mask, "GPIO channel mask"); #define MSR_LBAR_GPIO 0x5140000C static u32 gpio_base; static struct pci_device_id divil_pci[] = { { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA) }, { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA) }, { } /* NULL entry */ }; MODULE_DEVICE_TABLE(pci, divil_pci); static struct cdev cs5535_gpio_cdev; /* reserve 32 entries even though some aren't usable */ #define CS5535_GPIO_COUNT 32 /* IO block size */ #define CS5535_GPIO_SIZE 256 struct gpio_regmap { u32 rd_offset; u32 wr_offset; char on; char off; }; static struct gpio_regmap rm[] = { { 0x30, 0x00, '1', '0' }, /* GPIOx_READ_BACK / GPIOx_OUT_VAL */ { 0x20, 0x20, 'I', 'i' }, /* GPIOx_IN_EN */ { 0x04, 0x04, 'O', 'o' }, /* GPIOx_OUT_EN */ { 0x08, 0x08, 't', 'T' }, /* GPIOx_OUT_OD_EN */ { 0x18, 0x18, 'P', 'p' }, /* GPIOx_OUT_PU_EN */ { 0x1c, 0x1c, 'D', 'd' }, /* GPIOx_OUT_PD_EN */ }; /** * Gets the register offset for the GPIO bank. * Low (0-15) starts at 0x00, high (16-31) starts at 0x80 */ static inline u32 cs5535_lowhigh_base(int reg) { return (reg & 0x10) << 3; } static ssize_t cs5535_gpio_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { u32 m = iminor(file->f_path.dentry->d_inode); int i, j; u32 base = gpio_base + cs5535_lowhigh_base(m); u32 m0, m1; char c; /** * Creates the mask for atomic bit programming. * The high 16 bits and the low 16 bits are used to set the mask. * For example, GPIO 15 maps to 31,15: 0,1 => On; 1,0=> Off */ m1 = 1 << (m & 0x0F); m0 = m1 << 16; for (i = 0; i < len; ++i) { if (get_user(c, data+i)) return -EFAULT; for (j = 0; j < ARRAY_SIZE(rm); j++) { if (c == rm[j].on) { outl(m1, base + rm[j].wr_offset); break; } else if (c == rm[j].off) { outl(m0, base + rm[j].wr_offset); break; } } } *ppos = 0; return len; } static ssize_t cs5535_gpio_read(struct file *file, char __user *buf, size_t len, loff_t *ppos) { u32 m = iminor(file->f_path.dentry->d_inode); u32 base = gpio_base + cs5535_lowhigh_base(m); int rd_bit = 1 << (m & 0x0f); int i; char ch; ssize_t count = 0; if (*ppos >= ARRAY_SIZE(rm)) return 0; for (i = *ppos; (i < (*ppos + len)) && (i < ARRAY_SIZE(rm)); i++) { ch = (inl(base + rm[i].rd_offset) & rd_bit) ? rm[i].on : rm[i].off; if (put_user(ch, buf+count)) return -EFAULT; count++; } /* add a line-feed if there is room */ if ((i == ARRAY_SIZE(rm)) && (count < len)) { put_user('\n', buf + count); count++; } *ppos += count; return count; } static int cs5535_gpio_open(struct inode *inode, struct file *file) { u32 m = iminor(inode); /* the mask says which pins are usable by this driver */ if ((mask & (1 << m)) == 0) return -EINVAL; return nonseekable_open(inode, file); } static const struct file_operations cs5535_gpio_fops = { .owner = THIS_MODULE, .write = cs5535_gpio_write, .read = cs5535_gpio_read, .open = cs5535_gpio_open }; static int __init cs5535_gpio_init(void) { dev_t dev_id; u32 low, hi; int retval; if (pci_dev_present(divil_pci) == 0) { printk(KERN_WARNING NAME ": DIVIL not found\n"); return -ENODEV; } /* Grab the GPIO I/O range */ rdmsr(MSR_LBAR_GPIO, low, hi); /* Check the mask and whether GPIO is enabled (sanity check) */ if (hi != 0x0000f001) { printk(KERN_WARNING NAME ": GPIO not enabled\n"); return -ENODEV; } /* Mask off the IO base address */ gpio_base = low & 0x0000ff00; /** * Some GPIO pins * 31-29,23 : reserved (always mask out) * 28 : Power Button * 26 : PME# * 22-16 : LPC * 14,15 : SMBus * 9,8 : UART1 * 7 : PCI INTB * 3,4 : UART2/DDC * 2 : IDE_IRQ0 * 0 : PCI INTA * * If a mask was not specified, be conservative and only allow: * 1,2,5,6,10-13,24,25,27 */ if (mask != 0) mask &= 0x1f7fffff; else mask = 0x0b003c66; if (request_region(gpio_base, CS5535_GPIO_SIZE, NAME) == 0) { printk(KERN_ERR NAME ": can't allocate I/O for GPIO\n"); return -ENODEV; } if (major) { dev_id = MKDEV(major, 0); retval = register_chrdev_region(dev_id, CS5535_GPIO_COUNT, NAME); } else { retval = alloc_chrdev_region(&dev_id, 0, CS5535_GPIO_COUNT, NAME); major = MAJOR(dev_id); } if (retval) { release_region(gpio_base, CS5535_GPIO_SIZE); return -1; } printk(KERN_DEBUG NAME ": base=%#x mask=%#lx major=%d\n", gpio_base, mask, major); cdev_init(&cs5535_gpio_cdev, &cs5535_gpio_fops); cdev_add(&cs5535_gpio_cdev, dev_id, CS5535_GPIO_COUNT); return 0; } static void __exit cs5535_gpio_cleanup(void) { dev_t dev_id = MKDEV(major, 0); cdev_del(&cs5535_gpio_cdev); unregister_chrdev_region(dev_id, CS5535_GPIO_COUNT); release_region(gpio_base, CS5535_GPIO_SIZE); } module_init(cs5535_gpio_init); module_exit(cs5535_gpio_cleanup);