/* linux/drivers/char/pc8736x_gpio.c National Semiconductor PC8736x GPIO driver. Allows a user space process to play with the GPIO pins. Copyright (c) 2005,2006 Jim Cromie <jim.cromie@gmail.com> adapted from linux/drivers/char/scx200_gpio.c Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>, */ #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/io.h> #include <linux/ioport.h> #include <linux/mutex.h> #include <linux/nsc_gpio.h> #include <linux/platform_device.h> #include <asm/uaccess.h> #define DEVNAME "pc8736x_gpio" MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>"); MODULE_DESCRIPTION("NatSemi/Winbond PC-8736x GPIO Pin Driver"); MODULE_LICENSE("GPL"); static int major; /* default to dynamic major */ module_param(major, int, 0); MODULE_PARM_DESC(major, "Major device number"); static DEFINE_MUTEX(pc8736x_gpio_config_lock); static unsigned pc8736x_gpio_base; static u8 pc8736x_gpio_shadow[4]; #define SIO_BASE1 0x2E /* 1st command-reg to check */ #define SIO_BASE2 0x4E /* alt command-reg to check */ #define SIO_SID 0x20 /* SuperI/O ID Register */ #define SIO_SID_VALUE 0xe9 /* Expected value in SuperI/O ID Register */ #define SIO_CF1 0x21 /* chip config, bit0 is chip enable */ #define PC8736X_GPIO_RANGE 16 /* ioaddr range */ #define PC8736X_GPIO_CT 32 /* minors matching 4 8 bit ports */ #define SIO_UNIT_SEL 0x7 /* unit select reg */ #define SIO_UNIT_ACT 0x30 /* unit enable */ #define SIO_GPIO_UNIT 0x7 /* unit number of GPIO */ #define SIO_VLM_UNIT 0x0D #define SIO_TMS_UNIT 0x0E /* config-space addrs to read/write each unit's runtime addr */ #define SIO_BASE_HADDR 0x60 #define SIO_BASE_LADDR 0x61 /* GPIO config-space pin-control addresses */ #define SIO_GPIO_PIN_SELECT 0xF0 #define SIO_GPIO_PIN_CONFIG 0xF1 #define SIO_GPIO_PIN_EVENT 0xF2 static unsigned char superio_cmd = 0; static unsigned char selected_device = 0xFF; /* bogus start val */ /* GPIO port runtime access, functionality */ static int port_offset[] = { 0, 4, 8, 10 }; /* non-uniform offsets ! */ /* static int event_capable[] = { 1, 1, 0, 0 }; ports 2,3 are hobbled */ #define PORT_OUT 0 #define PORT_IN 1 #define PORT_EVT_EN 2 #define PORT_EVT_STST 3 static struct platform_device *pdev; /* use in dev_*() */ static inline void superio_outb(int addr, int val) { outb_p(addr, superio_cmd); outb_p(val, superio_cmd + 1); } static inline int superio_inb(int addr) { outb_p(addr, superio_cmd); return inb_p(superio_cmd + 1); } static int pc8736x_superio_present(void) { /* try the 2 possible values, read a hardware reg to verify */ superio_cmd = SIO_BASE1; if (superio_inb(SIO_SID) == SIO_SID_VALUE) return superio_cmd; superio_cmd = SIO_BASE2; if (superio_inb(SIO_SID) == SIO_SID_VALUE) return superio_cmd; return 0; } static void device_select(unsigned devldn) { superio_outb(SIO_UNIT_SEL, devldn); selected_device = devldn; } static void select_pin(unsigned iminor) { /* select GPIO port/pin from device minor number */ device_select(SIO_GPIO_UNIT); superio_outb(SIO_GPIO_PIN_SELECT, ((iminor << 1) & 0xF0) | (iminor & 0x7)); } static inline u32 pc8736x_gpio_configure_fn(unsigned index, u32 mask, u32 bits, u32 func_slct) { u32 config, new_config; mutex_lock(&pc8736x_gpio_config_lock); device_select(SIO_GPIO_UNIT); select_pin(index); /* read current config value */ config = superio_inb(func_slct); /* set new config */ new_config = (config & mask) | bits; superio_outb(func_slct, new_config); mutex_unlock(&pc8736x_gpio_config_lock); return config; } static u32 pc8736x_gpio_configure(unsigned index, u32 mask, u32 bits) { return pc8736x_gpio_configure_fn(index, mask, bits, SIO_GPIO_PIN_CONFIG); } static int pc8736x_gpio_get(unsigned minor) { int port, bit, val; port = minor >> 3; bit = minor & 7; val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN); val >>= bit; val &= 1; dev_dbg(&pdev->dev, "_gpio_get(%d from %x bit %d) == val %d\n", minor, pc8736x_gpio_base + port_offset[port] + PORT_IN, bit, val); return val; } static void pc8736x_gpio_set(unsigned minor, int val) { int port, bit, curval; minor &= 0x1f; port = minor >> 3; bit = minor & 7; curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT); dev_dbg(&pdev->dev, "addr:%x cur:%x bit-pos:%d cur-bit:%x + new:%d -> bit-new:%d\n", pc8736x_gpio_base + port_offset[port] + PORT_OUT, curval, bit, (curval & ~(1 << bit)), val, (val << bit)); val = (curval & ~(1 << bit)) | (val << bit); dev_dbg(&pdev->dev, "gpio_set(minor:%d port:%d bit:%d)" " %2x -> %2x\n", minor, port, bit, curval, val); outb_p(val, pc8736x_gpio_base + port_offset[port] + PORT_OUT); curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT); val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN); dev_dbg(&pdev->dev, "wrote %x, read: %x\n", curval, val); pc8736x_gpio_shadow[port] = val; } static int pc8736x_gpio_current(unsigned minor) { int port, bit; minor &= 0x1f; port = minor >> 3; bit = minor & 7; return ((pc8736x_gpio_shadow[port] >> bit) & 0x01); } static void pc8736x_gpio_change(unsigned index) { pc8736x_gpio_set(index, !pc8736x_gpio_current(index)); } static struct nsc_gpio_ops pc8736x_gpio_ops = { .owner = THIS_MODULE, .gpio_config = pc8736x_gpio_configure, .gpio_dump = nsc_gpio_dump, .gpio_get = pc8736x_gpio_get, .gpio_set = pc8736x_gpio_set, .gpio_change = pc8736x_gpio_change, .gpio_current = pc8736x_gpio_current }; static int pc8736x_gpio_open(struct inode *inode, struct file *file) { unsigned m = iminor(inode); file->private_data = &pc8736x_gpio_ops; dev_dbg(&pdev->dev, "open %d\n", m); if (m >= PC8736X_GPIO_CT) return -EINVAL; return nonseekable_open(inode, file); } static const struct file_operations pc8736x_gpio_fileops = { .owner = THIS_MODULE, .open = pc8736x_gpio_open, .write = nsc_gpio_write, .read = nsc_gpio_read, }; static void __init pc8736x_init_shadow(void) { int port; /* read the current values driven on the GPIO signals */ for (port = 0; port < 4; ++port) pc8736x_gpio_shadow[port] = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT); } static struct cdev pc8736x_gpio_cdev; static int __init pc8736x_gpio_init(void) { int rc; dev_t devid; pdev = platform_device_alloc(DEVNAME, 0); if (!pdev) return -ENOMEM; rc = platform_device_add(pdev); if (rc) { rc = -ENODEV; goto undo_platform_dev_alloc; } dev_info(&pdev->dev, "NatSemi pc8736x GPIO Driver Initializing\n"); if (!pc8736x_superio_present()) { rc = -ENODEV; dev_err(&pdev->dev, "no device found\n"); goto undo_platform_dev_add; } pc8736x_gpio_ops.dev = &pdev->dev; /* Verify that chip and it's GPIO unit are both enabled. My BIOS does this, so I take minimum action here */ rc = superio_inb(SIO_CF1); if (!(rc & 0x01)) { rc = -ENODEV; dev_err(&pdev->dev, "device not enabled\n"); goto undo_platform_dev_add; } device_select(SIO_GPIO_UNIT); if (!superio_inb(SIO_UNIT_ACT)) { rc = -ENODEV; dev_err(&pdev->dev, "GPIO unit not enabled\n"); goto undo_platform_dev_add; } /* read the GPIO unit base addr that chip responds to */ pc8736x_gpio_base = (superio_inb(SIO_BASE_HADDR) << 8 | superio_inb(SIO_BASE_LADDR)); if (!request_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE, DEVNAME)) { rc = -ENODEV; dev_err(&pdev->dev, "GPIO ioport %x busy\n", pc8736x_gpio_base); goto undo_platform_dev_add; } dev_info(&pdev->dev, "GPIO ioport %x reserved\n", pc8736x_gpio_base); if (major) { devid = MKDEV(major, 0); rc = register_chrdev_region(devid, PC8736X_GPIO_CT, DEVNAME); } else { rc = alloc_chrdev_region(&devid, 0, PC8736X_GPIO_CT, DEVNAME); major = MAJOR(devid); } if (rc < 0) { dev_err(&pdev->dev, "register-chrdev failed: %d\n", rc); goto undo_request_region; } if (!major) { major = rc; dev_dbg(&pdev->dev, "got dynamic major %d\n", major); } pc8736x_init_shadow(); /* ignore minor errs, and succeed */ cdev_init(&pc8736x_gpio_cdev, &pc8736x_gpio_fileops); cdev_add(&pc8736x_gpio_cdev, devid, PC8736X_GPIO_CT); return 0; undo_request_region: release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE); undo_platform_dev_add: platform_device_del(pdev); undo_platform_dev_alloc: platform_device_put(pdev); return rc; } static void __exit pc8736x_gpio_cleanup(void) { dev_dbg(&pdev->dev, "cleanup\n"); cdev_del(&pc8736x_gpio_cdev); unregister_chrdev_region(MKDEV(major,0), PC8736X_GPIO_CT); release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE); platform_device_del(pdev); platform_device_put(pdev); } module_init(pc8736x_gpio_init); module_exit(pc8736x_gpio_cleanup);