drivers/gpio/gpio-xilinx.c

   1 /*
   2  * Xilinx gpio driver for xps/axi_gpio IP.
   3  *
   4  * Copyright 2008 - 2013 Xilinx, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2
   8  * as published by the Free Software Foundation.
   9  *
  10  * You should have received a copy of the GNU General Public License
  11  * along with this program; if not, write to the Free Software
  12  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  13  */
  14
  15 #include <linux/bitops.h>
  16 #include <linux/init.h>
  17 #include <linux/errno.h>
  18 #include <linux/module.h>
  19 #include <linux/of_device.h>
  20 #include <linux/of_platform.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/io.h>
  23 #include <linux/gpio.h>
  24 #include <linux/slab.h>
  25
  26 /* Register Offset Definitions */
  27 #define XGPIO_DATA_OFFSET   (0x0)       /* Data register  */
  28 #define XGPIO_TRI_OFFSET    (0x4)       /* I/O direction register  */
  29
  30 #define XGPIO_CHANNEL_OFFSET    0x8
  31
  32 /* Read/Write access to the GPIO registers */
  33 #if defined(CONFIG_ARCH_ZYNQ) || defined(CONFIG_X86)
  34 # define xgpio_readreg(offset)          readl(offset)
  35 # define xgpio_writereg(offset, val)    writel(val, offset)
  36 #else
  37 # define xgpio_readreg(offset)          __raw_readl(offset)
  38 # define xgpio_writereg(offset, val)    __raw_writel(val, offset)
  39 #endif
  40
  41 /**
  42  * struct xgpio_instance - Stores information about GPIO device
  43  * @mmchip: OF GPIO chip for memory mapped banks
  44  * @gpio_width: GPIO width for every channel
  45  * @gpio_state: GPIO state shadow register
  46  * @gpio_dir: GPIO direction shadow register
  47  * @gpio_lock: Lock used for synchronization
  48  */
  49 struct xgpio_instance {
  50         struct of_mm_gpio_chip mmchip;
  51         unsigned int gpio_width[2];
  52         u32 gpio_state[2];
  53         u32 gpio_dir[2];
  54         spinlock_t gpio_lock[2];
  55 };
  56
  57 static inline int xgpio_index(struct xgpio_instance *chip, int gpio)
  58 {
  59         if (gpio >= chip->gpio_width[0])
  60                 return 1;
  61
  62         return 0;
  63 }
  64
  65 static inline int xgpio_regoffset(struct xgpio_instance *chip, int gpio)
  66 {
  67         if (xgpio_index(chip, gpio))
  68                 return XGPIO_CHANNEL_OFFSET;
  69
  70         return 0;
  71 }
  72
  73 static inline int xgpio_offset(struct xgpio_instance *chip, int gpio)
  74 {
  75         if (xgpio_index(chip, gpio))
  76                 return gpio - chip->gpio_width[0];
  77
  78         return gpio;
  79 }
  80
  81 /**
  82  * xgpio_get - Read the specified signal of the GPIO device.
  83  * @gc:     Pointer to gpio_chip device structure.
  84  * @gpio:   GPIO signal number.
  85  *
  86  * This function reads the specified signal of the GPIO device.
  87  *
  88  * Return:
  89  * 0 if direction of GPIO signals is set as input otherwise it
  90  * returns negative error value.
  91  */
  92 static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
  93 {
  94         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
  95         struct xgpio_instance *chip = gpiochip_get_data(gc);
  96         u32 val;
  97
  98         val = xgpio_readreg(mm_gc->regs + XGPIO_DATA_OFFSET +
  99                             xgpio_regoffset(chip, gpio));
 100
 101         return !!(val & BIT(xgpio_offset(chip, gpio)));
 102 }
 103
 104 /**
 105  * xgpio_set - Write the specified signal of the GPIO device.
 106  * @gc:     Pointer to gpio_chip device structure.
 107  * @gpio:   GPIO signal number.
 108  * @val:    Value to be written to specified signal.
 109  *
 110  * This function writes the specified value in to the specified signal of the
 111  * GPIO device.
 112  */
 113 static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 114 {
 115         unsigned long flags;
 116         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 117         struct xgpio_instance *chip = gpiochip_get_data(gc);
 118         int index =  xgpio_index(chip, gpio);
 119         int offset =  xgpio_offset(chip, gpio);
 120
 121         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 122
 123         /* Write to GPIO signal and set its direction to output */
 124         if (val)
 125                 chip->gpio_state[index] |= BIT(offset);
 126         else
 127                 chip->gpio_state[index] &= ~BIT(offset);
 128
 129         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
 130                        xgpio_regoffset(chip, gpio), chip->gpio_state[index]);
 131
 132         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 133 }
 134
 135 /**
 136  * xgpio_set_multiple - Write the specified signals of the GPIO device.
 137  * @gc:     Pointer to gpio_chip device structure.
 138  * @mask:   Mask of the GPIOS to modify.
 139  * @bits:   Value to be wrote on each GPIO
 140  *
 141  * This function writes the specified values into the specified signals of the
 142  * GPIO devices.
 143  */
 144 static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
 145                                unsigned long *bits)
 146 {
 147         unsigned long flags;
 148         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 149         struct xgpio_instance *chip = gpiochip_get_data(gc);
 150         int index = xgpio_index(chip, 0);
 151         int offset, i;
 152
 153         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 154
 155         /* Write to GPIO signals */
 156         for (i = 0; i < gc->ngpio; i++) {
 157                 if (*mask == 0)
 158                         break;
 159                 if (index !=  xgpio_index(chip, i)) {
 160                         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
 161                                        xgpio_regoffset(chip, i),
 162                                        chip->gpio_state[index]);
 163                         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 164                         index =  xgpio_index(chip, i);
 165                         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 166                 }
 167                 if (__test_and_clear_bit(i, mask)) {
 168                         offset =  xgpio_offset(chip, i);
 169                         if (test_bit(i, bits))
 170                                 chip->gpio_state[index] |= BIT(offset);
 171                         else
 172                                 chip->gpio_state[index] &= ~BIT(offset);
 173                 }
 174         }
 175
 176         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
 177                        xgpio_regoffset(chip, i), chip->gpio_state[index]);
 178
 179         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 180 }
 181
 182 /**
 183  * xgpio_dir_in - Set the direction of the specified GPIO signal as input.
 184  * @gc:     Pointer to gpio_chip device structure.
 185  * @gpio:   GPIO signal number.
 186  *
 187  * Return:
 188  * 0 - if direction of GPIO signals is set as input
 189  * otherwise it returns negative error value.
 190  */
 191 static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 192 {
 193         unsigned long flags;
 194         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 195         struct xgpio_instance *chip = gpiochip_get_data(gc);
 196         int index =  xgpio_index(chip, gpio);
 197         int offset =  xgpio_offset(chip, gpio);
 198
 199         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 200
 201         /* Set the GPIO bit in shadow register and set direction as input */
 202         chip->gpio_dir[index] |= BIT(offset);
 203         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET +
 204                        xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);
 205
 206         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 207
 208         return 0;
 209 }
 210
 211 /**
 212  * xgpio_dir_out - Set the direction of the specified GPIO signal as output.
 213  * @gc:     Pointer to gpio_chip device structure.
 214  * @gpio:   GPIO signal number.
 215  * @val:    Value to be written to specified signal.
 216  *
 217  * This function sets the direction of specified GPIO signal as output.
 218  *
 219  * Return:
 220  * If all GPIO signals of GPIO chip is configured as input then it returns
 221  * error otherwise it returns 0.
 222  */
 223 static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 224 {
 225         unsigned long flags;
 226         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 227         struct xgpio_instance *chip = gpiochip_get_data(gc);
 228         int index =  xgpio_index(chip, gpio);
 229         int offset =  xgpio_offset(chip, gpio);
 230
 231         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 232
 233         /* Write state of GPIO signal */
 234         if (val)
 235                 chip->gpio_state[index] |= BIT(offset);
 236         else
 237                 chip->gpio_state[index] &= ~BIT(offset);
 238         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
 239                         xgpio_regoffset(chip, gpio), chip->gpio_state[index]);
 240
 241         /* Clear the GPIO bit in shadow register and set direction as output */
 242         chip->gpio_dir[index] &= ~BIT(offset);
 243         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET +
 244                         xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);
 245
 246         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 247
 248         return 0;
 249 }
 250
 251 /**
 252  * xgpio_save_regs - Set initial values of GPIO pins
 253  * @mm_gc: Pointer to memory mapped GPIO chip structure
 254  */
 255 static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
 256 {
 257         struct xgpio_instance *chip =
 258                 container_of(mm_gc, struct xgpio_instance, mmchip);
 259
 260         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state[0]);
 261         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir[0]);
 262
 263         if (!chip->gpio_width[1])
 264                 return;
 265
 266         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + XGPIO_CHANNEL_OFFSET,
 267                        chip->gpio_state[1]);
 268         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + XGPIO_CHANNEL_OFFSET,
 269                        chip->gpio_dir[1]);
 270 }
 271
 272 /**
 273  * xgpio_remove - Remove method for the GPIO device.
 274  * @pdev: pointer to the platform device
 275  *
 276  * This function remove gpiochips and frees all the allocated resources.
 277  *
 278  * Return: 0 always
 279  */
 280 static int xgpio_remove(struct platform_device *pdev)
 281 {
 282         struct xgpio_instance *chip = platform_get_drvdata(pdev);
 283
 284         of_mm_gpiochip_remove(&chip->mmchip);
 285
 286         return 0;
 287 }
 288
 289 /**
 290  * xgpio_of_probe - Probe method for the GPIO device.
 291  * @pdev: pointer to the platform device
 292  *
 293  * Return:
 294  * It returns 0, if the driver is bound to the GPIO device, or
 295  * a negative value if there is an error.
 296  */
 297 static int xgpio_probe(struct platform_device *pdev)
 298 {
 299         struct xgpio_instance *chip;
 300         int status = 0;
 301         struct device_node *np = pdev->dev.of_node;
 302         u32 is_dual;
 303
 304         chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
 305         if (!chip)
 306                 return -ENOMEM;
 307
 308         platform_set_drvdata(pdev, chip);
 309
 310         /* Update GPIO state shadow register with default value */
 311         of_property_read_u32(np, "xlnx,dout-default", &chip->gpio_state[0]);
 312
 313         /* Update GPIO direction shadow register with default value */
 314         if (of_property_read_u32(np, "xlnx,tri-default", &chip->gpio_dir[0]))
 315                 chip->gpio_dir[0] = 0xFFFFFFFF;
 316
 317         /*
 318          * Check device node and parent device node for device width
 319          * and assume default width of 32
 320          */
 321         if (of_property_read_u32(np, "xlnx,gpio-width", &chip->gpio_width[0]))
 322                 chip->gpio_width[0] = 32;
 323
 324         spin_lock_init(&chip->gpio_lock[0]);
 325
 326         if (of_property_read_u32(np, "xlnx,is-dual", &is_dual))
 327                 is_dual = 0;
 328
 329         if (is_dual) {
 330                 /* Update GPIO state shadow register with default value */
 331                 of_property_read_u32(np, "xlnx,dout-default-2",
 332                                      &chip->gpio_state[1]);
 333
 334                 /* Update GPIO direction shadow register with default value */
 335                 if (of_property_read_u32(np, "xlnx,tri-default-2",
 336                                          &chip->gpio_dir[1]))
 337                         chip->gpio_dir[1] = 0xFFFFFFFF;
 338
 339                 /*
 340                  * Check device node and parent device node for device width
 341                  * and assume default width of 32
 342                  */
 343                 if (of_property_read_u32(np, "xlnx,gpio2-width",
 344                                          &chip->gpio_width[1]))
 345                         chip->gpio_width[1] = 32;
 346
 347                 spin_lock_init(&chip->gpio_lock[1]);
 348         }
 349
 350         chip->mmchip.gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1];
 351         chip->mmchip.gc.parent = &pdev->dev;
 352         chip->mmchip.gc.direction_input = xgpio_dir_in;
 353         chip->mmchip.gc.direction_output = xgpio_dir_out;
 354         chip->mmchip.gc.get = xgpio_get;
 355         chip->mmchip.gc.set = xgpio_set;
 356         chip->mmchip.gc.set_multiple = xgpio_set_multiple;
 357
 358         chip->mmchip.save_regs = xgpio_save_regs;
 359
 360         /* Call the OF gpio helper to setup and register the GPIO device */
 361         status = of_mm_gpiochip_add_data(np, &chip->mmchip, chip);
 362         if (status) {
 363                 pr_err("%s: error in probe function with status %d\n",
 364                        np->full_name, status);
 365                 return status;
 366         }
 367
 368         return 0;
 369 }
 370
 371 static const struct of_device_id xgpio_of_match[] = {
 372         { .compatible = "xlnx,xps-gpio-1.00.a", },
 373         { /* end of list */ },
 374 };
 375
 376 MODULE_DEVICE_TABLE(of, xgpio_of_match);
 377
 378 static struct platform_driver xgpio_plat_driver = {
 379         .probe          = xgpio_probe,
 380         .remove         = xgpio_remove,
 381         .driver         = {
 382                         .name = "gpio-xilinx",
 383                         .of_match_table = xgpio_of_match,
 384         },
 385 };
 386
 387 static int __init xgpio_init(void)
 388 {
 389         return platform_driver_register(&xgpio_plat_driver);
 390 }
 391
 392 subsys_initcall(xgpio_init);
 393
 394 static void __exit xgpio_exit(void)
 395 {
 396         platform_driver_unregister(&xgpio_plat_driver);
 397 }
 398 module_exit(xgpio_exit);
 399
 400 MODULE_AUTHOR("Xilinx, Inc.");
 401 MODULE_DESCRIPTION("Xilinx GPIO driver");
 402 MODULE_LICENSE("GPL");