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_dir_in - Set the direction of the specified GPIO signal as input.
 137  * @gc:     Pointer to gpio_chip device structure.
 138  * @gpio:   GPIO signal number.
 139  *
 140  * Return:
 141  * 0 - if direction of GPIO signals is set as input
 142  * otherwise it returns negative error value.
 143  */
 144 static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 145 {
 146         unsigned long flags;
 147         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 148         struct xgpio_instance *chip = gpiochip_get_data(gc);
 149         int index =  xgpio_index(chip, gpio);
 150         int offset =  xgpio_offset(chip, gpio);
 151
 152         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 153
 154         /* Set the GPIO bit in shadow register and set direction as input */
 155         chip->gpio_dir[index] |= BIT(offset);
 156         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET +
 157                        xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);
 158
 159         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 160
 161         return 0;
 162 }
 163
 164 /**
 165  * xgpio_dir_out - Set the direction of the specified GPIO signal as output.
 166  * @gc:     Pointer to gpio_chip device structure.
 167  * @gpio:   GPIO signal number.
 168  * @val:    Value to be written to specified signal.
 169  *
 170  * This function sets the direction of specified GPIO signal as output.
 171  *
 172  * Return:
 173  * If all GPIO signals of GPIO chip is configured as input then it returns
 174  * error otherwise it returns 0.
 175  */
 176 static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 177 {
 178         unsigned long flags;
 179         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 180         struct xgpio_instance *chip = gpiochip_get_data(gc);
 181         int index =  xgpio_index(chip, gpio);
 182         int offset =  xgpio_offset(chip, gpio);
 183
 184         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 185
 186         /* Write state of GPIO signal */
 187         if (val)
 188                 chip->gpio_state[index] |= BIT(offset);
 189         else
 190                 chip->gpio_state[index] &= ~BIT(offset);
 191         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
 192                         xgpio_regoffset(chip, gpio), chip->gpio_state[index]);
 193
 194         /* Clear the GPIO bit in shadow register and set direction as output */
 195         chip->gpio_dir[index] &= ~BIT(offset);
 196         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET +
 197                         xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);
 198
 199         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 200
 201         return 0;
 202 }
 203
 204 /**
 205  * xgpio_save_regs - Set initial values of GPIO pins
 206  * @mm_gc: Pointer to memory mapped GPIO chip structure
 207  */
 208 static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
 209 {
 210         struct xgpio_instance *chip =
 211                 container_of(mm_gc, struct xgpio_instance, mmchip);
 212
 213         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state[0]);
 214         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir[0]);
 215
 216         if (!chip->gpio_width[1])
 217                 return;
 218
 219         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + XGPIO_CHANNEL_OFFSET,
 220                        chip->gpio_state[1]);
 221         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + XGPIO_CHANNEL_OFFSET,
 222                        chip->gpio_dir[1]);
 223 }
 224
 225 /**
 226  * xgpio_remove - Remove method for the GPIO device.
 227  * @pdev: pointer to the platform device
 228  *
 229  * This function remove gpiochips and frees all the allocated resources.
 230  *
 231  * Return: 0 always
 232  */
 233 static int xgpio_remove(struct platform_device *pdev)
 234 {
 235         struct xgpio_instance *chip = platform_get_drvdata(pdev);
 236
 237         of_mm_gpiochip_remove(&chip->mmchip);
 238
 239         return 0;
 240 }
 241
 242 /**
 243  * xgpio_of_probe - Probe method for the GPIO device.
 244  * @pdev: pointer to the platform device
 245  *
 246  * Return:
 247  * It returns 0, if the driver is bound to the GPIO device, or
 248  * a negative value if there is an error.
 249  */
 250 static int xgpio_probe(struct platform_device *pdev)
 251 {
 252         struct xgpio_instance *chip;
 253         int status = 0;
 254         struct device_node *np = pdev->dev.of_node;
 255         u32 is_dual;
 256
 257         chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
 258         if (!chip)
 259                 return -ENOMEM;
 260
 261         platform_set_drvdata(pdev, chip);
 262
 263         /* Update GPIO state shadow register with default value */
 264         of_property_read_u32(np, "xlnx,dout-default", &chip->gpio_state[0]);
 265
 266         /* Update GPIO direction shadow register with default value */
 267         if (of_property_read_u32(np, "xlnx,tri-default", &chip->gpio_dir[0]))
 268                 chip->gpio_dir[0] = 0xFFFFFFFF;
 269
 270         /*
 271          * Check device node and parent device node for device width
 272          * and assume default width of 32
 273          */
 274         if (of_property_read_u32(np, "xlnx,gpio-width", &chip->gpio_width[0]))
 275                 chip->gpio_width[0] = 32;
 276
 277         spin_lock_init(&chip->gpio_lock[0]);
 278
 279         if (of_property_read_u32(np, "xlnx,is-dual", &is_dual))
 280                 is_dual = 0;
 281
 282         if (is_dual) {
 283                 /* Update GPIO state shadow register with default value */
 284                 of_property_read_u32(np, "xlnx,dout-default-2",
 285                                      &chip->gpio_state[1]);
 286
 287                 /* Update GPIO direction shadow register with default value */
 288                 if (of_property_read_u32(np, "xlnx,tri-default-2",
 289                                          &chip->gpio_dir[1]))
 290                         chip->gpio_dir[1] = 0xFFFFFFFF;
 291
 292                 /*
 293                  * Check device node and parent device node for device width
 294                  * and assume default width of 32
 295                  */
 296                 if (of_property_read_u32(np, "xlnx,gpio2-width",
 297                                          &chip->gpio_width[1]))
 298                         chip->gpio_width[1] = 32;
 299
 300                 spin_lock_init(&chip->gpio_lock[1]);
 301         }
 302
 303         chip->mmchip.gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1];
 304         chip->mmchip.gc.parent = &pdev->dev;
 305         chip->mmchip.gc.direction_input = xgpio_dir_in;
 306         chip->mmchip.gc.direction_output = xgpio_dir_out;
 307         chip->mmchip.gc.get = xgpio_get;
 308         chip->mmchip.gc.set = xgpio_set;
 309
 310         chip->mmchip.save_regs = xgpio_save_regs;
 311
 312         /* Call the OF gpio helper to setup and register the GPIO device */
 313         status = of_mm_gpiochip_add_data(np, &chip->mmchip, chip);
 314         if (status) {
 315                 pr_err("%s: error in probe function with status %d\n",
 316                        np->full_name, status);
 317                 return status;
 318         }
 319
 320         return 0;
 321 }
 322
 323 static const struct of_device_id xgpio_of_match[] = {
 324         { .compatible = "xlnx,xps-gpio-1.00.a", },
 325         { /* end of list */ },
 326 };
 327
 328 MODULE_DEVICE_TABLE(of, xgpio_of_match);
 329
 330 static struct platform_driver xgpio_plat_driver = {
 331         .probe          = xgpio_probe,
 332         .remove         = xgpio_remove,
 333         .driver         = {
 334                         .name = "gpio-xilinx",
 335                         .of_match_table = xgpio_of_match,
 336         },
 337 };
 338
 339 static int __init xgpio_init(void)
 340 {
 341         return platform_driver_register(&xgpio_plat_driver);
 342 }
 343
 344 subsys_initcall(xgpio_init);
 345
 346 static void __exit xgpio_exit(void)
 347 {
 348         platform_driver_unregister(&xgpio_plat_driver);
 349 }
 350 module_exit(xgpio_exit);
 351
 352 MODULE_AUTHOR("Xilinx, Inc.");
 353 MODULE_DESCRIPTION("Xilinx GPIO driver");
 354 MODULE_LICENSE("GPL");