diff options
Diffstat (limited to 'drivers/char/cs5535_gpio.c')
| -rw-r--r-- | drivers/char/cs5535_gpio.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/char/cs5535_gpio.c b/drivers/char/cs5535_gpio.c new file mode 100644 index 000000000000..5d72f50de1ac --- /dev/null +++ b/drivers/char/cs5535_gpio.c @@ -0,0 +1,250 @@ +/* + * 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 */ +}; + +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_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_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 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); + unregister_chrdev_region(dev_id, CS5535_GPIO_COUNT); + if (gpio_base != 0) + release_region(gpio_base, CS5535_GPIO_SIZE); +} + +module_init(cs5535_gpio_init); +module_exit(cs5535_gpio_cleanup); |