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_state: GPIO state shadow register
  45  * @gpio_dir: GPIO direction shadow register
  46  * @gpio_lock: Lock used for synchronization
  47  * @inited: True if the port has been inited
  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 =
  96             container_of(mm_gc, struct xgpio_instance, mmchip);
  97         u32 val;
  98
  99         val = xgpio_readreg(mm_gc->regs + XGPIO_DATA_OFFSET +
 100                             xgpio_regoffset(chip, gpio));
 101
 102         return !!(val & BIT(xgpio_offset(chip, gpio)));
 103 }
 104
 105 /**
 106  * xgpio_set - Write the specified signal of the GPIO device.
 107  * @gc:     Pointer to gpio_chip device structure.
 108  * @gpio:   GPIO signal number.
 109  * @val:    Value to be written to specified signal.
 110  *
 111  * This function writes the specified value in to the specified signal of the
 112  * GPIO device.
 113  */
 114 static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 115 {
 116         unsigned long flags;
 117         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 118         struct xgpio_instance *chip =
 119             container_of(mm_gc, struct xgpio_instance, mmchip);
 120         int index =  xgpio_index(chip, gpio);
 121         int offset =  xgpio_offset(chip, gpio);
 122
 123         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 124
 125         /* Write to GPIO signal and set its direction to output */
 126         if (val)
 127                 chip->gpio_state[index] |= BIT(offset);
 128         else
 129                 chip->gpio_state[index] &= ~BIT(offset);
 130
 131         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
 132                        xgpio_regoffset(chip, gpio), chip->gpio_state[index]);
 133
 134         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 135 }
 136
 137 /**
 138  * xgpio_dir_in - Set the direction of the specified GPIO signal as input.
 139  * @gc:     Pointer to gpio_chip device structure.
 140  * @gpio:   GPIO signal number.
 141  *
 142  * Return:
 143  * 0 - if direction of GPIO signals is set as input
 144  * otherwise it returns negative error value.
 145  */
 146 static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 147 {
 148         unsigned long flags;
 149         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 150         struct xgpio_instance *chip =
 151             container_of(mm_gc, struct xgpio_instance, mmchip);
 152         int index =  xgpio_index(chip, gpio);
 153         int offset =  xgpio_offset(chip, gpio);
 154
 155         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 156
 157         /* Set the GPIO bit in shadow register and set direction as input */
 158         chip->gpio_dir[index] |= BIT(offset);
 159         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET +
 160                        xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);
 161
 162         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 163
 164         return 0;
 165 }
 166
 167 /**
 168  * xgpio_dir_out - Set the direction of the specified GPIO signal as output.
 169  * @gc:     Pointer to gpio_chip device structure.
 170  * @gpio:   GPIO signal number.
 171  * @val:    Value to be written to specified signal.
 172  *
 173  * This function sets the direction of specified GPIO signal as output.
 174  *
 175  * Return:
 176  * If all GPIO signals of GPIO chip is configured as input then it returns
 177  * error otherwise it returns 0.
 178  */
 179 static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 180 {
 181         unsigned long flags;
 182         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 183         struct xgpio_instance *chip =
 184             container_of(mm_gc, struct xgpio_instance, mmchip);
 185         int index =  xgpio_index(chip, gpio);
 186         int offset =  xgpio_offset(chip, gpio);
 187
 188         spin_lock_irqsave(&chip->gpio_lock[index], flags);
 189
 190         /* Write state of GPIO signal */
 191         if (val)
 192                 chip->gpio_state[index] |= BIT(offset);
 193         else
 194                 chip->gpio_state[index] &= ~BIT(offset);
 195         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
 196                         xgpio_regoffset(chip, gpio), chip->gpio_state[index]);
 197
 198         /* Clear the GPIO bit in shadow register and set direction as output */
 199         chip->gpio_dir[index] &= ~BIT(offset);
 200         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET +
 201                         xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);
 202
 203         spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
 204
 205         return 0;
 206 }
 207
 208 /**
 209  * xgpio_save_regs - Set initial values of GPIO pins
 210  * @mm_gc: Pointer to memory mapped GPIO chip structure
 211  */
 212 static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
 213 {
 214         struct xgpio_instance *chip =
 215             container_of(mm_gc, struct xgpio_instance, mmchip);
 216
 217         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state[0]);
 218         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir[0]);
 219
 220         if (!chip->gpio_width[1])
 221                 return;
 222
 223         xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + XGPIO_TRI_OFFSET,
 224                        chip->gpio_state[1]);
 225         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + XGPIO_TRI_OFFSET,
 226                        chip->gpio_dir[1]);
 227 }
 228
 229 /**
 230  * xgpio_remove - Remove method for the GPIO device.
 231  * @pdev: pointer to the platform device
 232  *
 233  * This function remove gpiochips and frees all the allocated resources.
 234  */
 235 static int xgpio_remove(struct platform_device *pdev)
 236 {
 237         struct xgpio_instance *chip = platform_get_drvdata(pdev);
 238
 239         of_mm_gpiochip_remove(&chip->mmchip);
 240
 241         return 0;
 242 }
 243
 244 /**
 245  * xgpio_of_probe - Probe method for the GPIO device.
 246  * @pdev: pointer to the platform device
 247  *
 248  * Return:
 249  * It returns 0, if the driver is bound to the GPIO device, or
 250  * a negative value if there is an error.
 251  */
 252 static int xgpio_probe(struct platform_device *pdev)
 253 {
 254         struct xgpio_instance *chip;
 255         int status = 0;
 256         struct device_node *np = pdev->dev.of_node;
 257         u32 is_dual;
 258
 259         chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
 260         if (!chip)
 261                 return -ENOMEM;
 262
 263         platform_set_drvdata(pdev, chip);
 264
 265         /* Update GPIO state shadow register with default value */
 266         of_property_read_u32(np, "xlnx,dout-default", &chip->gpio_state[0]);
 267
 268         /* Update GPIO direction shadow register with default value */
 269         if (of_property_read_u32(np, "xlnx,tri-default", &chip->gpio_dir[0]))
 270                 chip->gpio_dir[0] = 0xFFFFFFFF;
 271
 272         /*
 273          * Check device node and parent device node for device width
 274          * and assume default width of 32
 275          */
 276         if (of_property_read_u32(np, "xlnx,gpio-width", &chip->gpio_width[0]))
 277                 chip->gpio_width[0] = 32;
 278
 279         spin_lock_init(&chip->gpio_lock[0]);
 280
 281         if (of_property_read_u32(np, "xlnx,is-dual", &is_dual))
 282                 is_dual = 0;
 283
 284         if (is_dual) {
 285                 /* Update GPIO state shadow register with default value */
 286                 of_property_read_u32(np, "xlnx,dout-default-2",
 287                                      &chip->gpio_state[1]);
 288
 289                 /* Update GPIO direction shadow register with default value */
 290                 if (of_property_read_u32(np, "xlnx,tri-default-2",
 291                                          &chip->gpio_dir[1]))
 292                         chip->gpio_dir[1] = 0xFFFFFFFF;
 293
 294                 /*
 295                  * Check device node and parent device node for device width
 296                  * and assume default width of 32
 297                  */
 298                 if (of_property_read_u32(np, "xlnx,gpio2-width",
 299                                          &chip->gpio_width[1]))
 300                         chip->gpio_width[1] = 32;
 301
 302                 spin_lock_init(&chip->gpio_lock[1]);
 303         }
 304
 305         chip->mmchip.gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1];
 306         chip->mmchip.gc.dev = &pdev->dev;
 307         chip->mmchip.gc.direction_input = xgpio_dir_in;
 308         chip->mmchip.gc.direction_output = xgpio_dir_out;
 309         chip->mmchip.gc.get = xgpio_get;
 310         chip->mmchip.gc.set = xgpio_set;
 311
 312         chip->mmchip.save_regs = xgpio_save_regs;
 313
 314         /* Call the OF gpio helper to setup and register the GPIO device */
 315         status = of_mm_gpiochip_add(np, &chip->mmchip);
 316         if (status) {
 317                 pr_err("%s: error in probe function with status %d\n",
 318                        np->full_name, status);
 319                 return status;
 320         }
 321
 322         return 0;
 323 }
 324
 325 static const struct of_device_id xgpio_of_match[] = {
 326         { .compatible = "xlnx,xps-gpio-1.00.a", },
 327         { /* end of list */ },
 328 };
 329
 330 MODULE_DEVICE_TABLE(of, xgpio_of_match);
 331
 332 static struct platform_driver xgpio_plat_driver = {
 333         .probe          = xgpio_probe,
 334         .remove         = xgpio_remove,
 335         .driver         = {
 336                         .name = "gpio-xilinx",
 337                         .of_match_table = xgpio_of_match,
 338         },
 339 };
 340
 341 static int __init xgpio_init(void)
 342 {
 343         return platform_driver_register(&xgpio_plat_driver);
 344 }
 345
 346 subsys_initcall(xgpio_init);
 347
 348 static void __exit xgpio_exit(void)
 349 {
 350         platform_driver_unregister(&xgpio_plat_driver);
 351 }
 352 module_exit(xgpio_exit);
 353
 354 MODULE_AUTHOR("Xilinx, Inc.");
 355 MODULE_DESCRIPTION("Xilinx GPIO driver");
 356 MODULE_LICENSE("GPL");