drivers/gpio/gpio-cs5535.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AMD CS5535/CS5536 GPIO driver
   4  * Copyright (C) 2006  Advanced Micro Devices, Inc.
   5  * Copyright (C) 2007-2009  Andres Salomon <dilinger@collabora.co.uk>
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/module.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/gpio/driver.h>
  13 #include <linux/io.h>
  14 #include <linux/cs5535.h>
  15 #include <asm/msr.h>
  16
  17 #define DRV_NAME "cs5535-gpio"
  18
  19 /*
  20  * Some GPIO pins
  21  *  31-29,23 : reserved (always mask out)
  22  *  28       : Power Button
  23  *  26       : PME#
  24  *  22-16    : LPC
  25  *  14,15    : SMBus
  26  *  9,8      : UART1
  27  *  7        : PCI INTB
  28  *  3,4      : UART2/DDC
  29  *  2        : IDE_IRQ0
  30  *  1        : AC_BEEP
  31  *  0        : PCI INTA
  32  *
  33  * If a mask was not specified, allow all except
  34  * reserved and Power Button
  35  */
  36 #define GPIO_DEFAULT_MASK 0x0F7FFFFF
  37
  38 static ulong mask = GPIO_DEFAULT_MASK;
  39 module_param_named(mask, mask, ulong, 0444);
  40 MODULE_PARM_DESC(mask, "GPIO channel mask.");
  41
  42 /*
  43  * FIXME: convert this singleton driver to use the state container
  44  * design pattern, see Documentation/driver-api/driver-model/design-patterns.rst
  45  */
  46 static struct cs5535_gpio_chip {
  47         struct gpio_chip chip;
  48         resource_size_t base;
  49
  50         struct platform_device *pdev;
  51         spinlock_t lock;
  52 } cs5535_gpio_chip;
  53
  54 /*
  55  * The CS5535/CS5536 GPIOs support a number of extra features not defined
  56  * by the gpio_chip API, so these are exported.  For a full list of the
  57  * registers, see include/linux/cs5535.h.
  58  */
  59
  60 static void errata_outl(struct cs5535_gpio_chip *chip, u32 val,
  61                 unsigned int reg)
  62 {
  63         unsigned long addr = chip->base + 0x80 + reg;
  64
  65         /*
  66          * According to the CS5536 errata (#36), after suspend
  67          * a write to the high bank GPIO register will clear all
  68          * non-selected bits; the recommended workaround is a
  69          * read-modify-write operation.
  70          *
  71          * Don't apply this errata to the edge status GPIOs, as writing
  72          * to their lower bits will clear them.
  73          */
  74         if (reg != GPIO_POSITIVE_EDGE_STS && reg != GPIO_NEGATIVE_EDGE_STS) {
  75                 if (val & 0xffff)
  76                         val |= (inl(addr) & 0xffff); /* ignore the high bits */
  77                 else
  78                         val |= (inl(addr) ^ (val >> 16));
  79         }
  80         outl(val, addr);
  81 }
  82
  83 static void __cs5535_gpio_set(struct cs5535_gpio_chip *chip, unsigned offset,
  84                 unsigned int reg)
  85 {
  86         if (offset < 16)
  87                 /* low bank register */
  88                 outl(1 << offset, chip->base + reg);
  89         else
  90                 /* high bank register */
  91                 errata_outl(chip, 1 << (offset - 16), reg);
  92 }
  93
  94 void cs5535_gpio_set(unsigned offset, unsigned int reg)
  95 {
  96         struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
  97         unsigned long flags;
  98
  99         spin_lock_irqsave(&chip->lock, flags);
 100         __cs5535_gpio_set(chip, offset, reg);
 101         spin_unlock_irqrestore(&chip->lock, flags);
 102 }
 103 EXPORT_SYMBOL_GPL(cs5535_gpio_set);
 104
 105 static void __cs5535_gpio_clear(struct cs5535_gpio_chip *chip, unsigned offset,
 106                 unsigned int reg)
 107 {
 108         if (offset < 16)
 109                 /* low bank register */
 110                 outl(1 << (offset + 16), chip->base + reg);
 111         else
 112                 /* high bank register */
 113                 errata_outl(chip, 1 << offset, reg);
 114 }
 115
 116 void cs5535_gpio_clear(unsigned offset, unsigned int reg)
 117 {
 118         struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
 119         unsigned long flags;
 120
 121         spin_lock_irqsave(&chip->lock, flags);
 122         __cs5535_gpio_clear(chip, offset, reg);
 123         spin_unlock_irqrestore(&chip->lock, flags);
 124 }
 125 EXPORT_SYMBOL_GPL(cs5535_gpio_clear);
 126
 127 int cs5535_gpio_isset(unsigned offset, unsigned int reg)
 128 {
 129         struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
 130         unsigned long flags;
 131         long val;
 132
 133         spin_lock_irqsave(&chip->lock, flags);
 134         if (offset < 16)
 135                 /* low bank register */
 136                 val = inl(chip->base + reg);
 137         else {
 138                 /* high bank register */
 139                 val = inl(chip->base + 0x80 + reg);
 140                 offset -= 16;
 141         }
 142         spin_unlock_irqrestore(&chip->lock, flags);
 143
 144         return (val & (1 << offset)) ? 1 : 0;
 145 }
 146 EXPORT_SYMBOL_GPL(cs5535_gpio_isset);
 147
 148 int cs5535_gpio_set_irq(unsigned group, unsigned irq)
 149 {
 150         uint32_t lo, hi;
 151
 152         if (group > 7 || irq > 15)
 153                 return -EINVAL;
 154
 155         rdmsr(MSR_PIC_ZSEL_HIGH, lo, hi);
 156
 157         lo &= ~(0xF << (group * 4));
 158         lo |= (irq & 0xF) << (group * 4);
 159
 160         wrmsr(MSR_PIC_ZSEL_HIGH, lo, hi);
 161         return 0;
 162 }
 163 EXPORT_SYMBOL_GPL(cs5535_gpio_set_irq);
 164
 165 void cs5535_gpio_setup_event(unsigned offset, int pair, int pme)
 166 {
 167         struct cs5535_gpio_chip *chip = &cs5535_gpio_chip;
 168         uint32_t shift = (offset % 8) * 4;
 169         unsigned long flags;
 170         uint32_t val;
 171
 172         if (offset >= 24)
 173                 offset = GPIO_MAP_W;
 174         else if (offset >= 16)
 175                 offset = GPIO_MAP_Z;
 176         else if (offset >= 8)
 177                 offset = GPIO_MAP_Y;
 178         else
 179                 offset = GPIO_MAP_X;
 180
 181         spin_lock_irqsave(&chip->lock, flags);
 182         val = inl(chip->base + offset);
 183
 184         /* Clear whatever was there before */
 185         val &= ~(0xF << shift);
 186
 187         /* Set the new value */
 188         val |= ((pair & 7) << shift);
 189
 190         /* Set the PME bit if this is a PME event */
 191         if (pme)
 192                 val |= (1 << (shift + 3));
 193
 194         outl(val, chip->base + offset);
 195         spin_unlock_irqrestore(&chip->lock, flags);
 196 }
 197 EXPORT_SYMBOL_GPL(cs5535_gpio_setup_event);
 198
 199 /*
 200  * Generic gpio_chip API support.
 201  */
 202
 203 static int chip_gpio_request(struct gpio_chip *c, unsigned offset)
 204 {
 205         struct cs5535_gpio_chip *chip = gpiochip_get_data(c);
 206         unsigned long flags;
 207
 208         spin_lock_irqsave(&chip->lock, flags);
 209
 210         /* check if this pin is available */
 211         if ((mask & (1 << offset)) == 0) {
 212                 dev_info(&chip->pdev->dev,
 213                         "pin %u is not available (check mask)\n", offset);
 214                 spin_unlock_irqrestore(&chip->lock, flags);
 215                 return -EINVAL;
 216         }
 217
 218         /* disable output aux 1 & 2 on this pin */
 219         __cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_AUX1);
 220         __cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_AUX2);
 221
 222         /* disable input aux 1 on this pin */
 223         __cs5535_gpio_clear(chip, offset, GPIO_INPUT_AUX1);
 224
 225         spin_unlock_irqrestore(&chip->lock, flags);
 226
 227         return 0;
 228 }
 229
 230 static int chip_gpio_get(struct gpio_chip *chip, unsigned offset)
 231 {
 232         return cs5535_gpio_isset(offset, GPIO_READ_BACK);
 233 }
 234
 235 static void chip_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
 236 {
 237         if (val)
 238                 cs5535_gpio_set(offset, GPIO_OUTPUT_VAL);
 239         else
 240                 cs5535_gpio_clear(offset, GPIO_OUTPUT_VAL);
 241 }
 242
 243 static int chip_direction_input(struct gpio_chip *c, unsigned offset)
 244 {
 245         struct cs5535_gpio_chip *chip = gpiochip_get_data(c);
 246         unsigned long flags;
 247
 248         spin_lock_irqsave(&chip->lock, flags);
 249         __cs5535_gpio_set(chip, offset, GPIO_INPUT_ENABLE);
 250         __cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_ENABLE);
 251         spin_unlock_irqrestore(&chip->lock, flags);
 252
 253         return 0;
 254 }
 255
 256 static int chip_direction_output(struct gpio_chip *c, unsigned offset, int val)
 257 {
 258         struct cs5535_gpio_chip *chip = gpiochip_get_data(c);
 259         unsigned long flags;
 260
 261         spin_lock_irqsave(&chip->lock, flags);
 262
 263         __cs5535_gpio_set(chip, offset, GPIO_INPUT_ENABLE);
 264         __cs5535_gpio_set(chip, offset, GPIO_OUTPUT_ENABLE);
 265         if (val)
 266                 __cs5535_gpio_set(chip, offset, GPIO_OUTPUT_VAL);
 267         else
 268                 __cs5535_gpio_clear(chip, offset, GPIO_OUTPUT_VAL);
 269
 270         spin_unlock_irqrestore(&chip->lock, flags);
 271
 272         return 0;
 273 }
 274
 275 static const char * const cs5535_gpio_names[] = {
 276         "GPIO0", "GPIO1", "GPIO2", "GPIO3",
 277         "GPIO4", "GPIO5", "GPIO6", "GPIO7",
 278         "GPIO8", "GPIO9", "GPIO10", "GPIO11",
 279         "GPIO12", "GPIO13", "GPIO14", "GPIO15",
 280         "GPIO16", "GPIO17", "GPIO18", "GPIO19",
 281         "GPIO20", "GPIO21", "GPIO22", NULL,
 282         "GPIO24", "GPIO25", "GPIO26", "GPIO27",
 283         "GPIO28", NULL, NULL, NULL,
 284 };
 285
 286 static struct cs5535_gpio_chip cs5535_gpio_chip = {
 287         .chip = {
 288                 .owner = THIS_MODULE,
 289                 .label = DRV_NAME,
 290
 291                 .base = 0,
 292                 .ngpio = 32,
 293                 .names = cs5535_gpio_names,
 294                 .request = chip_gpio_request,
 295
 296                 .get = chip_gpio_get,
 297                 .set = chip_gpio_set,
 298
 299                 .direction_input = chip_direction_input,
 300                 .direction_output = chip_direction_output,
 301         },
 302 };
 303
 304 static int cs5535_gpio_probe(struct platform_device *pdev)
 305 {
 306         struct resource *res;
 307         int err = -EIO;
 308         ulong mask_orig = mask;
 309
 310         /* There are two ways to get the GPIO base address; one is by
 311          * fetching it from MSR_LBAR_GPIO, the other is by reading the
 312          * PCI BAR info.  The latter method is easier (especially across
 313          * different architectures), so we'll stick with that for now.  If
 314          * it turns out to be unreliable in the face of crappy BIOSes, we
 315          * can always go back to using MSRs.. */
 316
 317         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 318         if (!res) {
 319                 dev_err(&pdev->dev, "can't fetch device resource info\n");
 320                 return err;
 321         }
 322
 323         if (!devm_request_region(&pdev->dev, res->start, resource_size(res),
 324                                  pdev->name)) {
 325                 dev_err(&pdev->dev, "can't request region\n");
 326                 return err;
 327         }
 328
 329         /* set up the driver-specific struct */
 330         cs5535_gpio_chip.base = res->start;
 331         cs5535_gpio_chip.pdev = pdev;
 332         spin_lock_init(&cs5535_gpio_chip.lock);
 333
 334         dev_info(&pdev->dev, "reserved resource region %pR\n", res);
 335
 336         /* mask out reserved pins */
 337         mask &= 0x1F7FFFFF;
 338
 339         /* do not allow pin 28, Power Button, as there's special handling
 340          * in the PMC needed. (note 12, p. 48) */
 341         mask &= ~(1 << 28);
 342
 343         if (mask_orig != mask)
 344                 dev_info(&pdev->dev, "mask changed from 0x%08lX to 0x%08lX\n",
 345                                 mask_orig, mask);
 346
 347         /* finally, register with the generic GPIO API */
 348         return devm_gpiochip_add_data(&pdev->dev, &cs5535_gpio_chip.chip,
 349                                       &cs5535_gpio_chip);
 350 }
 351
 352 static struct platform_driver cs5535_gpio_driver = {
 353         .driver = {
 354                 .name = DRV_NAME,
 355         },
 356         .probe = cs5535_gpio_probe,
 357 };
 358
 359 module_platform_driver(cs5535_gpio_driver);
 360
 361 MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
 362 MODULE_DESCRIPTION("AMD CS5535/CS5536 GPIO driver");
 363 MODULE_LICENSE("GPL");
 364 MODULE_ALIAS("platform:" DRV_NAME);