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 =
  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_CHANNEL_OFFSET,
 224                        chip->gpio_state[1]);
 225         xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + XGPIO_CHANNEL_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  * Return: 0 always
 236  */
 237 static int xgpio_remove(struct platform_device *pdev)
 238 {
 239         struct xgpio_instance *chip = platform_get_drvdata(pdev);
 240
 241         of_mm_gpiochip_remove(&chip->mmchip);
 242
 243         return 0;
 244 }
 245
 246 /**
 247  * xgpio_of_probe - Probe method for the GPIO device.
 248  * @pdev: pointer to the platform device
 249  *
 250  * Return:
 251  * It returns 0, if the driver is bound to the GPIO device, or
 252  * a negative value if there is an error.
 253  */
 254 static int xgpio_probe(struct platform_device *pdev)
 255 {
 256         struct xgpio_instance *chip;
 257         int status = 0;
 258         struct device_node *np = pdev->dev.of_node;
 259         u32 is_dual;
 260
 261         chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
 262         if (!chip)
 263                 return -ENOMEM;
 264
 265         platform_set_drvdata(pdev, chip);
 266
 267         /* Update GPIO state shadow register with default value */
 268         of_property_read_u32(np, "xlnx,dout-default", &chip->gpio_state[0]);
 269
 270         /* Update GPIO direction shadow register with default value */
 271         if (of_property_read_u32(np, "xlnx,tri-default", &chip->gpio_dir[0]))
 272                 chip->gpio_dir[0] = 0xFFFFFFFF;
 273
 274         /*
 275          * Check device node and parent device node for device width
 276          * and assume default width of 32
 277          */
 278         if (of_property_read_u32(np, "xlnx,gpio-width", &chip->gpio_width[0]))
 279                 chip->gpio_width[0] = 32;
 280
 281         spin_lock_init(&chip->gpio_lock[0]);
 282
 283         if (of_property_read_u32(np, "xlnx,is-dual", &is_dual))
 284                 is_dual = 0;
 285
 286         if (is_dual) {
 287                 /* Update GPIO state shadow register with default value */
 288                 of_property_read_u32(np, "xlnx,dout-default-2",
 289                                      &chip->gpio_state[1]);
 290
 291                 /* Update GPIO direction shadow register with default value */
 292                 if (of_property_read_u32(np, "xlnx,tri-default-2",
 293                                          &chip->gpio_dir[1]))
 294                         chip->gpio_dir[1] = 0xFFFFFFFF;
 295
 296                 /*
 297                  * Check device node and parent device node for device width
 298                  * and assume default width of 32
 299                  */
 300                 if (of_property_read_u32(np, "xlnx,gpio2-width",
 301                                          &chip->gpio_width[1]))
 302                         chip->gpio_width[1] = 32;
 303
 304                 spin_lock_init(&chip->gpio_lock[1]);
 305         }
 306
 307         chip->mmchip.gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1];
 308         chip->mmchip.gc.dev = &pdev->dev;
 309         chip->mmchip.gc.direction_input = xgpio_dir_in;
 310         chip->mmchip.gc.direction_output = xgpio_dir_out;
 311         chip->mmchip.gc.get = xgpio_get;
 312         chip->mmchip.gc.set = xgpio_set;
 313
 314         chip->mmchip.save_regs = xgpio_save_regs;
 315
 316         /* Call the OF gpio helper to setup and register the GPIO device */
 317         status = of_mm_gpiochip_add(np, &chip->mmchip);
 318         if (status) {
 319                 pr_err("%s: error in probe function with status %d\n",
 320                        np->full_name, status);
 321                 return status;
 322         }
 323
 324         return 0;
 325 }
 326
 327 static const struct of_device_id xgpio_of_match[] = {
 328         { .compatible = "xlnx,xps-gpio-1.00.a", },
 329         { /* end of list */ },
 330 };
 331
 332 MODULE_DEVICE_TABLE(of, xgpio_of_match);
 333
 334 static struct platform_driver xgpio_plat_driver = {
 335         .probe          = xgpio_probe,
 336         .remove         = xgpio_remove,
 337         .driver         = {
 338                         .name = "gpio-xilinx",
 339                         .of_match_table = xgpio_of_match,
 340         },
 341 };
 342
 343 static int __init xgpio_init(void)
 344 {
 345         return platform_driver_register(&xgpio_plat_driver);
 346 }
 347
 348 subsys_initcall(xgpio_init);
 349
 350 static void __exit xgpio_exit(void)
 351 {
 352         platform_driver_unregister(&xgpio_plat_driver);
 353 }
 354 module_exit(xgpio_exit);
 355
 356 MODULE_AUTHOR("Xilinx, Inc.");
 357 MODULE_DESCRIPTION("Xilinx GPIO driver");
 358 MODULE_LICENSE("GPL");