1 // SPDX-License-Identifier: GPL-2.0-only 2 /* linux/drivers/char/pc8736x_gpio.c 3 4 National Semiconductor PC8736x GPIO driver. Allows a user space 5 process to play with the GPIO pins. 6 7 Copyright (c) 2005,2006 Jim Cromie <jim.cromie@gmail.com> 8 9 adapted from linux/drivers/char/scx200_gpio.c 10 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>, 11 */ 12 13 #include <linux/fs.h> 14 #include <linux/module.h> 15 #include <linux/errno.h> 16 #include <linux/kernel.h> 17 #include <linux/init.h> 18 #include <linux/cdev.h> 19 #include <linux/io.h> 20 #include <linux/ioport.h> 21 #include <linux/mutex.h> 22 #include <linux/nsc_gpio.h> 23 #include <linux/platform_device.h> 24 #include <linux/uaccess.h> 25 26 #define DEVNAME "pc8736x_gpio" 27 28 MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>"); 29 MODULE_DESCRIPTION("NatSemi/Winbond PC-8736x GPIO Pin Driver"); 30 MODULE_LICENSE("GPL"); 31 32 static int major; /* default to dynamic major */ 33 module_param(major, int, 0); 34 MODULE_PARM_DESC(major, "Major device number"); 35 36 static DEFINE_MUTEX(pc8736x_gpio_config_lock); 37 static unsigned pc8736x_gpio_base; 38 static u8 pc8736x_gpio_shadow[4]; 39 40 #define SIO_BASE1 0x2E /* 1st command-reg to check */ 41 #define SIO_BASE2 0x4E /* alt command-reg to check */ 42 43 #define SIO_SID 0x20 /* SuperI/O ID Register */ 44 #define SIO_SID_PC87365 0xe5 /* Expected value in ID Register for PC87365 */ 45 #define SIO_SID_PC87366 0xe9 /* Expected value in ID Register for PC87366 */ 46 47 #define SIO_CF1 0x21 /* chip config, bit0 is chip enable */ 48 49 #define PC8736X_GPIO_RANGE 16 /* ioaddr range */ 50 #define PC8736X_GPIO_CT 32 /* minors matching 4 8 bit ports */ 51 52 #define SIO_UNIT_SEL 0x7 /* unit select reg */ 53 #define SIO_UNIT_ACT 0x30 /* unit enable */ 54 #define SIO_GPIO_UNIT 0x7 /* unit number of GPIO */ 55 #define SIO_VLM_UNIT 0x0D 56 #define SIO_TMS_UNIT 0x0E 57 58 /* config-space addrs to read/write each unit's runtime addr */ 59 #define SIO_BASE_HADDR 0x60 60 #define SIO_BASE_LADDR 0x61 61 62 /* GPIO config-space pin-control addresses */ 63 #define SIO_GPIO_PIN_SELECT 0xF0 64 #define SIO_GPIO_PIN_CONFIG 0xF1 65 #define SIO_GPIO_PIN_EVENT 0xF2 66 67 static unsigned char superio_cmd = 0; 68 static unsigned char selected_device = 0xFF; /* bogus start val */ 69 70 /* GPIO port runtime access, functionality */ 71 static int port_offset[] = { 0, 4, 8, 10 }; /* non-uniform offsets ! */ 72 /* static int event_capable[] = { 1, 1, 0, 0 }; ports 2,3 are hobbled */ 73 74 #define PORT_OUT 0 75 #define PORT_IN 1 76 #define PORT_EVT_EN 2 77 #define PORT_EVT_STST 3 78 79 static struct platform_device *pdev; /* use in dev_*() */ 80 81 static inline void superio_outb(int addr, int val) 82 { 83 outb_p(addr, superio_cmd); 84 outb_p(val, superio_cmd + 1); 85 } 86 87 static inline int superio_inb(int addr) 88 { 89 outb_p(addr, superio_cmd); 90 return inb_p(superio_cmd + 1); 91 } 92 93 static int pc8736x_superio_present(void) 94 { 95 int id; 96 97 /* try the 2 possible values, read a hardware reg to verify */ 98 superio_cmd = SIO_BASE1; 99 id = superio_inb(SIO_SID); 100 if (id == SIO_SID_PC87365 || id == SIO_SID_PC87366) 101 return superio_cmd; 102 103 superio_cmd = SIO_BASE2; 104 id = superio_inb(SIO_SID); 105 if (id == SIO_SID_PC87365 || id == SIO_SID_PC87366) 106 return superio_cmd; 107 108 return 0; 109 } 110 111 static void device_select(unsigned devldn) 112 { 113 superio_outb(SIO_UNIT_SEL, devldn); 114 selected_device = devldn; 115 } 116 117 static void select_pin(unsigned iminor) 118 { 119 /* select GPIO port/pin from device minor number */ 120 device_select(SIO_GPIO_UNIT); 121 superio_outb(SIO_GPIO_PIN_SELECT, 122 ((iminor << 1) & 0xF0) | (iminor & 0x7)); 123 } 124 125 static inline u32 pc8736x_gpio_configure_fn(unsigned index, u32 mask, u32 bits, 126 u32 func_slct) 127 { 128 u32 config, new_config; 129 130 mutex_lock(&pc8736x_gpio_config_lock); 131 132 device_select(SIO_GPIO_UNIT); 133 select_pin(index); 134 135 /* read current config value */ 136 config = superio_inb(func_slct); 137 138 /* set new config */ 139 new_config = (config & mask) | bits; 140 superio_outb(func_slct, new_config); 141 142 mutex_unlock(&pc8736x_gpio_config_lock); 143 144 return config; 145 } 146 147 static u32 pc8736x_gpio_configure(unsigned index, u32 mask, u32 bits) 148 { 149 return pc8736x_gpio_configure_fn(index, mask, bits, 150 SIO_GPIO_PIN_CONFIG); 151 } 152 153 static int pc8736x_gpio_get(unsigned minor) 154 { 155 int port, bit, val; 156 157 port = minor >> 3; 158 bit = minor & 7; 159 val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN); 160 val >>= bit; 161 val &= 1; 162 163 dev_dbg(&pdev->dev, "_gpio_get(%d from %x bit %d) == val %d\n", 164 minor, pc8736x_gpio_base + port_offset[port] + PORT_IN, bit, 165 val); 166 167 return val; 168 } 169 170 static void pc8736x_gpio_set(unsigned minor, int val) 171 { 172 int port, bit, curval; 173 174 minor &= 0x1f; 175 port = minor >> 3; 176 bit = minor & 7; 177 curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT); 178 179 dev_dbg(&pdev->dev, "addr:%x cur:%x bit-pos:%d cur-bit:%x + new:%d -> bit-new:%d\n", 180 pc8736x_gpio_base + port_offset[port] + PORT_OUT, 181 curval, bit, (curval & ~(1 << bit)), val, (val << bit)); 182 183 val = (curval & ~(1 << bit)) | (val << bit); 184 185 dev_dbg(&pdev->dev, "gpio_set(minor:%d port:%d bit:%d)" 186 " %2x -> %2x\n", minor, port, bit, curval, val); 187 188 outb_p(val, pc8736x_gpio_base + port_offset[port] + PORT_OUT); 189 190 curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT); 191 val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN); 192 193 dev_dbg(&pdev->dev, "wrote %x, read: %x\n", curval, val); 194 pc8736x_gpio_shadow[port] = val; 195 } 196 197 static int pc8736x_gpio_current(unsigned minor) 198 { 199 int port, bit; 200 minor &= 0x1f; 201 port = minor >> 3; 202 bit = minor & 7; 203 return ((pc8736x_gpio_shadow[port] >> bit) & 0x01); 204 } 205 206 static void pc8736x_gpio_change(unsigned index) 207 { 208 pc8736x_gpio_set(index, !pc8736x_gpio_current(index)); 209 } 210 211 static struct nsc_gpio_ops pc8736x_gpio_ops = { 212 .owner = THIS_MODULE, 213 .gpio_config = pc8736x_gpio_configure, 214 .gpio_dump = nsc_gpio_dump, 215 .gpio_get = pc8736x_gpio_get, 216 .gpio_set = pc8736x_gpio_set, 217 .gpio_change = pc8736x_gpio_change, 218 .gpio_current = pc8736x_gpio_current 219 }; 220 221 static int pc8736x_gpio_open(struct inode *inode, struct file *file) 222 { 223 unsigned m = iminor(inode); 224 file->private_data = &pc8736x_gpio_ops; 225 226 dev_dbg(&pdev->dev, "open %d\n", m); 227 228 if (m >= PC8736X_GPIO_CT) 229 return -EINVAL; 230 return nonseekable_open(inode, file); 231 } 232 233 static const struct file_operations pc8736x_gpio_fileops = { 234 .owner = THIS_MODULE, 235 .open = pc8736x_gpio_open, 236 .write = nsc_gpio_write, 237 .read = nsc_gpio_read, 238 }; 239 240 static void __init pc8736x_init_shadow(void) 241 { 242 int port; 243 244 /* read the current values driven on the GPIO signals */ 245 for (port = 0; port < 4; ++port) 246 pc8736x_gpio_shadow[port] 247 = inb_p(pc8736x_gpio_base + port_offset[port] 248 + PORT_OUT); 249 250 } 251 252 static struct cdev pc8736x_gpio_cdev; 253 254 static int __init pc8736x_gpio_init(void) 255 { 256 int rc; 257 dev_t devid; 258 259 pdev = platform_device_alloc(DEVNAME, 0); 260 if (!pdev) 261 return -ENOMEM; 262 263 rc = platform_device_add(pdev); 264 if (rc) { 265 rc = -ENODEV; 266 goto undo_platform_dev_alloc; 267 } 268 dev_info(&pdev->dev, "NatSemi pc8736x GPIO Driver Initializing\n"); 269 270 if (!pc8736x_superio_present()) { 271 rc = -ENODEV; 272 dev_err(&pdev->dev, "no device found\n"); 273 goto undo_platform_dev_add; 274 } 275 pc8736x_gpio_ops.dev = &pdev->dev; 276 277 /* Verify that chip and it's GPIO unit are both enabled. 278 My BIOS does this, so I take minimum action here 279 */ 280 rc = superio_inb(SIO_CF1); 281 if (!(rc & 0x01)) { 282 rc = -ENODEV; 283 dev_err(&pdev->dev, "device not enabled\n"); 284 goto undo_platform_dev_add; 285 } 286 device_select(SIO_GPIO_UNIT); 287 if (!superio_inb(SIO_UNIT_ACT)) { 288 rc = -ENODEV; 289 dev_err(&pdev->dev, "GPIO unit not enabled\n"); 290 goto undo_platform_dev_add; 291 } 292 293 /* read the GPIO unit base addr that chip responds to */ 294 pc8736x_gpio_base = (superio_inb(SIO_BASE_HADDR) << 8 295 | superio_inb(SIO_BASE_LADDR)); 296 297 if (!request_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE, DEVNAME)) { 298 rc = -ENODEV; 299 dev_err(&pdev->dev, "GPIO ioport %x busy\n", 300 pc8736x_gpio_base); 301 goto undo_platform_dev_add; 302 } 303 dev_info(&pdev->dev, "GPIO ioport %x reserved\n", pc8736x_gpio_base); 304 305 if (major) { 306 devid = MKDEV(major, 0); 307 rc = register_chrdev_region(devid, PC8736X_GPIO_CT, DEVNAME); 308 } else { 309 rc = alloc_chrdev_region(&devid, 0, PC8736X_GPIO_CT, DEVNAME); 310 major = MAJOR(devid); 311 } 312 313 if (rc < 0) { 314 dev_err(&pdev->dev, "register-chrdev failed: %d\n", rc); 315 goto undo_request_region; 316 } 317 if (!major) { 318 major = rc; 319 dev_dbg(&pdev->dev, "got dynamic major %d\n", major); 320 } 321 322 pc8736x_init_shadow(); 323 324 /* ignore minor errs, and succeed */ 325 cdev_init(&pc8736x_gpio_cdev, &pc8736x_gpio_fileops); 326 cdev_add(&pc8736x_gpio_cdev, devid, PC8736X_GPIO_CT); 327 328 return 0; 329 330 undo_request_region: 331 release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE); 332 undo_platform_dev_add: 333 platform_device_del(pdev); 334 undo_platform_dev_alloc: 335 platform_device_put(pdev); 336 337 return rc; 338 } 339 340 static void __exit pc8736x_gpio_cleanup(void) 341 { 342 dev_dbg(&pdev->dev, "cleanup\n"); 343 344 cdev_del(&pc8736x_gpio_cdev); 345 unregister_chrdev_region(MKDEV(major,0), PC8736X_GPIO_CT); 346 release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE); 347 348 platform_device_unregister(pdev); 349 } 350 351 module_init(pc8736x_gpio_init); 352 module_exit(pc8736x_gpio_cleanup); 353