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 #ifdef CONFIG_ARCH_ZYNQ
  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  * struct of_mm_gpio_chip mmchip: OF GPIO chip for memory mapped banks
  44  * gpio_state: GPIO state shadow register
  45  * gpio_dir: GPIO direction shadow register
  46  * offset: GPIO channel offset
  47  * gpio_lock: Lock used for synchronization
  48  */
  49 struct xgpio_instance {
  50         struct of_mm_gpio_chip mmchip;
  51         u32 gpio_state;
  52         u32 gpio_dir;
  53         u32 offset;
  54         spinlock_t gpio_lock;
  55 };
  56
  57 /**
  58  * xgpio_get - Read the specified signal of the GPIO device.
  59  * @gc:     Pointer to gpio_chip device structure.
  60  * @gpio:   GPIO signal number.
  61  *
  62  * This function reads the specified signal of the GPIO device. It returns 0 if
  63  * the signal clear, 1 if signal is set or negative value on error.
  64  */
  65 static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
  66 {
  67         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
  68         struct xgpio_instance *chip =
  69             container_of(mm_gc, struct xgpio_instance, mmchip);
  70
  71         void __iomem *regs = mm_gc->regs + chip->offset;
  72
  73         return !!(xgpio_readreg(regs + XGPIO_DATA_OFFSET) & BIT(gpio));
  74 }
  75
  76 /**
  77  * xgpio_set - Write the specified signal of the GPIO device.
  78  * @gc:     Pointer to gpio_chip device structure.
  79  * @gpio:   GPIO signal number.
  80  * @val:    Value to be written to specified signal.
  81  *
  82  * This function writes the specified value in to the specified signal of the
  83  * GPIO device.
  84  */
  85 static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
  86 {
  87         unsigned long flags;
  88         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
  89         struct xgpio_instance *chip =
  90             container_of(mm_gc, struct xgpio_instance, mmchip);
  91         void __iomem *regs = mm_gc->regs;
  92
  93         spin_lock_irqsave(&chip->gpio_lock, flags);
  94
  95         /* Write to GPIO signal and set its direction to output */
  96         if (val)
  97                 chip->gpio_state |= BIT(gpio);
  98         else
  99                 chip->gpio_state &= ~BIT(gpio);
 100
 101         xgpio_writereg(regs + chip->offset + XGPIO_DATA_OFFSET,
 102                                                          chip->gpio_state);
 103
 104         spin_unlock_irqrestore(&chip->gpio_lock, flags);
 105 }
 106
 107 /**
 108  * xgpio_dir_in - Set the direction of the specified GPIO signal as input.
 109  * @gc:     Pointer to gpio_chip device structure.
 110  * @gpio:   GPIO signal number.
 111  *
 112  * This function sets the direction of specified GPIO signal as input.
 113  * It returns 0 if direction of GPIO signals is set as input otherwise it
 114  * returns negative error value.
 115  */
 116 static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 117 {
 118         unsigned long flags;
 119         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 120         struct xgpio_instance *chip =
 121             container_of(mm_gc, struct xgpio_instance, mmchip);
 122         void __iomem *regs = mm_gc->regs;
 123
 124         spin_lock_irqsave(&chip->gpio_lock, flags);
 125
 126         /* Set the GPIO bit in shadow register and set direction as input */
 127         chip->gpio_dir |= BIT(gpio);
 128         xgpio_writereg(regs + chip->offset + XGPIO_TRI_OFFSET, chip->gpio_dir);
 129
 130         spin_unlock_irqrestore(&chip->gpio_lock, flags);
 131
 132         return 0;
 133 }
 134
 135 /**
 136  * xgpio_dir_out - Set the direction of the specified GPIO signal as output.
 137  * @gc:     Pointer to gpio_chip device structure.
 138  * @gpio:   GPIO signal number.
 139  * @val:    Value to be written to specified signal.
 140  *
 141  * This function sets the direction of specified GPIO signal as output. If all
 142  * GPIO signals of GPIO chip is configured as input then it returns
 143  * error otherwise it returns 0.
 144  */
 145 static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 146 {
 147         unsigned long flags;
 148         struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 149         struct xgpio_instance *chip =
 150             container_of(mm_gc, struct xgpio_instance, mmchip);
 151         void __iomem *regs = mm_gc->regs;
 152
 153         spin_lock_irqsave(&chip->gpio_lock, flags);
 154
 155         /* Write state of GPIO signal */
 156         if (val)
 157                 chip->gpio_state |= BIT(gpio);
 158         else
 159                 chip->gpio_state &= ~BIT(gpio);
 160         xgpio_writereg(regs + chip->offset + XGPIO_DATA_OFFSET,
 161                        chip->gpio_state);
 162
 163         /* Clear the GPIO bit in shadow register and set direction as output */
 164         chip->gpio_dir &= ~BIT(gpio);
 165         xgpio_writereg(regs + chip->offset + XGPIO_TRI_OFFSET, chip->gpio_dir);
 166
 167         spin_unlock_irqrestore(&chip->gpio_lock, flags);
 168
 169         return 0;
 170 }
 171
 172 /**
 173  * xgpio_save_regs - Set initial values of GPIO pins
 174  * @mm_gc: pointer to memory mapped GPIO chip structure
 175  */
 176 static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
 177 {
 178         struct xgpio_instance *chip =
 179             container_of(mm_gc, struct xgpio_instance, mmchip);
 180
 181         xgpio_writereg(mm_gc->regs + chip->offset + XGPIO_DATA_OFFSET,
 182                                                         chip->gpio_state);
 183         xgpio_writereg(mm_gc->regs + chip->offset + XGPIO_TRI_OFFSET,
 184                                                          chip->gpio_dir);
 185 }
 186
 187 /**
 188  * xgpio_of_probe - Probe method for the GPIO device.
 189  * @np: pointer to device tree node
 190  *
 191  * This function probes the GPIO device in the device tree. It initializes the
 192  * driver data structure. It returns 0, if the driver is bound to the GPIO
 193  * device, or a negative value if there is an error.
 194  */
 195 static int xgpio_of_probe(struct device_node *np)
 196 {
 197         struct xgpio_instance *chip;
 198         int status = 0;
 199         const u32 *tree_info;
 200
 201         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 202         if (!chip)
 203                 return -ENOMEM;
 204
 205         /* Update GPIO state shadow register with default value */
 206         of_property_read_u32(np, "xlnx,dout-default", &chip->gpio_state);
 207
 208         /* By default, all pins are inputs */
 209         chip->gpio_dir = 0xFFFFFFFF;
 210
 211         /* Update GPIO direction shadow register with default value */
 212         of_property_read_u32(np, "xlnx,tri-default", &chip->gpio_dir);
 213
 214         /* By default assume full GPIO controller */
 215         chip->mmchip.gc.ngpio = 32;
 216
 217         /* Check device node and parent device node for device width */
 218         of_property_read_u32(np, "xlnx,gpio-width",
 219                               (u32 *)&chip->mmchip.gc.ngpio);
 220
 221         spin_lock_init(&chip->gpio_lock);
 222
 223         chip->mmchip.gc.direction_input = xgpio_dir_in;
 224         chip->mmchip.gc.direction_output = xgpio_dir_out;
 225         chip->mmchip.gc.get = xgpio_get;
 226         chip->mmchip.gc.set = xgpio_set;
 227
 228         chip->mmchip.save_regs = xgpio_save_regs;
 229
 230         /* Call the OF gpio helper to setup and register the GPIO device */
 231         status = of_mm_gpiochip_add(np, &chip->mmchip);
 232         if (status) {
 233                 kfree(chip);
 234                 pr_err("%s: error in probe function with status %d\n",
 235                        np->full_name, status);
 236                 return status;
 237         }
 238
 239         pr_info("XGpio: %s: registered, base is %d\n", np->full_name,
 240                                                         chip->mmchip.gc.base);
 241
 242         tree_info = of_get_property(np, "xlnx,is-dual", NULL);
 243         if (tree_info && be32_to_cpup(tree_info)) {
 244                 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 245                 if (!chip)
 246                         return -ENOMEM;
 247
 248                 /* Add dual channel offset */
 249                 chip->offset = XGPIO_CHANNEL_OFFSET;
 250
 251                 /* Update GPIO state shadow register with default value */
 252                 of_property_read_u32(np, "xlnx,dout-default-2",
 253                                      &chip->gpio_state);
 254
 255                 /* By default, all pins are inputs */
 256                 chip->gpio_dir = 0xFFFFFFFF;
 257
 258                 /* Update GPIO direction shadow register with default value */
 259                 of_property_read_u32(np, "xlnx,tri-default-2", &chip->gpio_dir);
 260
 261                 /* By default assume full GPIO controller */
 262                 chip->mmchip.gc.ngpio = 32;
 263
 264                 /* Check device node and parent device node for device width */
 265                 of_property_read_u32(np, "xlnx,gpio2-width",
 266                                      (u32 *)&chip->mmchip.gc.ngpio);
 267
 268                 spin_lock_init(&chip->gpio_lock);
 269
 270                 chip->mmchip.gc.direction_input = xgpio_dir_in;
 271                 chip->mmchip.gc.direction_output = xgpio_dir_out;
 272                 chip->mmchip.gc.get = xgpio_get;
 273                 chip->mmchip.gc.set = xgpio_set;
 274
 275                 chip->mmchip.save_regs = xgpio_save_regs;
 276
 277                 /* Call the OF gpio helper to setup and register the GPIO dev */
 278                 status = of_mm_gpiochip_add(np, &chip->mmchip);
 279                 if (status) {
 280                         kfree(chip);
 281                         pr_err("%s: error in probe function with status %d\n",
 282                         np->full_name, status);
 283                         return status;
 284                 }
 285                 pr_info("XGpio: %s: dual channel registered, base is %d\n",
 286                                         np->full_name, chip->mmchip.gc.base);
 287         }
 288
 289         return 0;
 290 }
 291
 292 static const struct of_device_id xgpio_of_match[] = {
 293         { .compatible = "xlnx,xps-gpio-1.00.a", },
 294         { /* end of list */ },
 295 };
 296
 297 static int __init xgpio_init(void)
 298 {
 299         struct device_node *np;
 300
 301         for_each_matching_node(np, xgpio_of_match)
 302                 xgpio_of_probe(np);
 303
 304         return 0;
 305 }
 306
 307 /* Make sure we get initialized before anyone else tries to use us */
 308 subsys_initcall(xgpio_init);
 309 /* No exit call at the moment as we cannot unregister of GPIO chips */
 310
 311 MODULE_AUTHOR("Xilinx, Inc.");
 312 MODULE_DESCRIPTION("Xilinx GPIO driver");
 313 MODULE_LICENSE("GPL");