drivers/video/via/via-gpio.c

   1 /*
   2  * Support for viafb GPIO ports.
   3  *
   4  * Copyright 2009 Jonathan Corbet <corbet@lwn.net>
   5  * Distributable under version 2 of the GNU General Public License.
   6  */
   7
   8 #include <linux/spinlock.h>
   9 #include <linux/gpio.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/via-core.h>
  12 #include <linux/via-gpio.h>
  13 #include <linux/export.h>
  14
  15 /*
  16  * The ports we know about.  Note that the port-25 gpios are not
  17  * mentioned in the datasheet.
  18  */
  19
  20 struct viafb_gpio {
  21         char *vg_name;  /* Data sheet name */
  22         u16 vg_io_port;
  23         u8  vg_port_index;
  24         int  vg_mask_shift;
  25 };
  26
  27 static struct viafb_gpio viafb_all_gpios[] = {
  28         {
  29                 .vg_name = "VGPIO0",  /* Guess - not in datasheet */
  30                 .vg_io_port = VIASR,
  31                 .vg_port_index = 0x25,
  32                 .vg_mask_shift = 1
  33         },
  34         {
  35                 .vg_name = "VGPIO1",
  36                 .vg_io_port = VIASR,
  37                 .vg_port_index = 0x25,
  38                 .vg_mask_shift = 0
  39         },
  40         {
  41                 .vg_name = "VGPIO2",  /* aka DISPCLKI0 */
  42                 .vg_io_port = VIASR,
  43                 .vg_port_index = 0x2c,
  44                 .vg_mask_shift = 1
  45         },
  46         {
  47                 .vg_name = "VGPIO3",  /* aka DISPCLKO0 */
  48                 .vg_io_port = VIASR,
  49                 .vg_port_index = 0x2c,
  50                 .vg_mask_shift = 0
  51         },
  52         {
  53                 .vg_name = "VGPIO4",  /* DISPCLKI1 */
  54                 .vg_io_port = VIASR,
  55                 .vg_port_index = 0x3d,
  56                 .vg_mask_shift = 1
  57         },
  58         {
  59                 .vg_name = "VGPIO5",  /* DISPCLKO1 */
  60                 .vg_io_port = VIASR,
  61                 .vg_port_index = 0x3d,
  62                 .vg_mask_shift = 0
  63         },
  64 };
  65
  66 #define VIAFB_NUM_GPIOS ARRAY_SIZE(viafb_all_gpios)
  67
  68 /*
  69  * This structure controls the active GPIOs, which may be a subset
  70  * of those which are known.
  71  */
  72
  73 struct viafb_gpio_cfg {
  74         struct gpio_chip gpio_chip;
  75         struct viafb_dev *vdev;
  76         struct viafb_gpio *active_gpios[VIAFB_NUM_GPIOS];
  77         const char *gpio_names[VIAFB_NUM_GPIOS];
  78 };
  79
  80 /*
  81  * GPIO access functions
  82  */
  83 static void via_gpio_set(struct gpio_chip *chip, unsigned int nr,
  84                          int value)
  85 {
  86         struct viafb_gpio_cfg *cfg = container_of(chip,
  87                                                   struct viafb_gpio_cfg,
  88                                                   gpio_chip);
  89         u8 reg;
  90         struct viafb_gpio *gpio;
  91         unsigned long flags;
  92
  93         spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
  94         gpio = cfg->active_gpios[nr];
  95         reg = via_read_reg(VIASR, gpio->vg_port_index);
  96         reg |= 0x40 << gpio->vg_mask_shift;  /* output enable */
  97         if (value)
  98                 reg |= 0x10 << gpio->vg_mask_shift;
  99         else
 100                 reg &= ~(0x10 << gpio->vg_mask_shift);
 101         via_write_reg(VIASR, gpio->vg_port_index, reg);
 102         spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
 103 }
 104
 105 static int via_gpio_dir_out(struct gpio_chip *chip, unsigned int nr,
 106                             int value)
 107 {
 108         via_gpio_set(chip, nr, value);
 109         return 0;
 110 }
 111
 112 /*
 113  * Set the input direction.  I'm not sure this is right; we should
 114  * be able to do input without disabling output.
 115  */
 116 static int via_gpio_dir_input(struct gpio_chip *chip, unsigned int nr)
 117 {
 118         struct viafb_gpio_cfg *cfg = container_of(chip,
 119                                                   struct viafb_gpio_cfg,
 120                                                   gpio_chip);
 121         struct viafb_gpio *gpio;
 122         unsigned long flags;
 123
 124         spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
 125         gpio = cfg->active_gpios[nr];
 126         via_write_reg_mask(VIASR, gpio->vg_port_index, 0,
 127                         0x40 << gpio->vg_mask_shift);
 128         spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
 129         return 0;
 130 }
 131
 132 static int via_gpio_get(struct gpio_chip *chip, unsigned int nr)
 133 {
 134         struct viafb_gpio_cfg *cfg = container_of(chip,
 135                                                   struct viafb_gpio_cfg,
 136                                                   gpio_chip);
 137         u8 reg;
 138         struct viafb_gpio *gpio;
 139         unsigned long flags;
 140
 141         spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
 142         gpio = cfg->active_gpios[nr];
 143         reg = via_read_reg(VIASR, gpio->vg_port_index);
 144         spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
 145         return reg & (0x04 << gpio->vg_mask_shift);
 146 }
 147
 148
 149 static struct viafb_gpio_cfg viafb_gpio_config = {
 150         .gpio_chip = {
 151                 .label = "VIAFB onboard GPIO",
 152                 .owner = THIS_MODULE,
 153                 .direction_output = via_gpio_dir_out,
 154                 .set = via_gpio_set,
 155                 .direction_input = via_gpio_dir_input,
 156                 .get = via_gpio_get,
 157                 .base = -1,
 158                 .ngpio = 0,
 159                 .can_sleep = 0
 160         }
 161 };
 162
 163 /*
 164  * Manage the software enable bit.
 165  */
 166 static void viafb_gpio_enable(struct viafb_gpio *gpio)
 167 {
 168         via_write_reg_mask(VIASR, gpio->vg_port_index, 0x02, 0x02);
 169 }
 170
 171 static void viafb_gpio_disable(struct viafb_gpio *gpio)
 172 {
 173         via_write_reg_mask(VIASR, gpio->vg_port_index, 0, 0x02);
 174 }
 175
 176 #ifdef CONFIG_PM
 177
 178 static int viafb_gpio_suspend(void *private)
 179 {
 180         return 0;
 181 }
 182
 183 static int viafb_gpio_resume(void *private)
 184 {
 185         int i;
 186
 187         for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i += 2)
 188                 viafb_gpio_enable(viafb_gpio_config.active_gpios[i]);
 189         return 0;
 190 }
 191
 192 static struct viafb_pm_hooks viafb_gpio_pm_hooks = {
 193         .suspend = viafb_gpio_suspend,
 194         .resume = viafb_gpio_resume
 195 };
 196 #endif /* CONFIG_PM */
 197
 198 /*
 199  * Look up a specific gpio and return the number it was assigned.
 200  */
 201 int viafb_gpio_lookup(const char *name)
 202 {
 203         int i;
 204
 205         for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i++)
 206                 if (!strcmp(name, viafb_gpio_config.active_gpios[i]->vg_name))
 207                         return viafb_gpio_config.gpio_chip.base + i;
 208         return -1;
 209 }
 210 EXPORT_SYMBOL_GPL(viafb_gpio_lookup);
 211
 212 /*
 213  * Platform device stuff.
 214  */
 215 static int viafb_gpio_probe(struct platform_device *platdev)
 216 {
 217         struct viafb_dev *vdev = platdev->dev.platform_data;
 218         struct via_port_cfg *port_cfg = vdev->port_cfg;
 219         int i, ngpio = 0, ret;
 220         struct viafb_gpio *gpio;
 221         unsigned long flags;
 222
 223         /*
 224          * Set up entries for all GPIOs which have been configured to
 225          * operate as such (as opposed to as i2c ports).
 226          */
 227         for (i = 0; i < VIAFB_NUM_PORTS; i++) {
 228                 if (port_cfg[i].mode != VIA_MODE_GPIO)
 229                         continue;
 230                 for (gpio = viafb_all_gpios;
 231                      gpio < viafb_all_gpios + VIAFB_NUM_GPIOS; gpio++)
 232                         if (gpio->vg_port_index == port_cfg[i].ioport_index) {
 233                                 viafb_gpio_config.active_gpios[ngpio] = gpio;
 234                                 viafb_gpio_config.gpio_names[ngpio] =
 235                                         gpio->vg_name;
 236                                 ngpio++;
 237                         }
 238         }
 239         viafb_gpio_config.gpio_chip.ngpio = ngpio;
 240         viafb_gpio_config.gpio_chip.names = viafb_gpio_config.gpio_names;
 241         viafb_gpio_config.vdev = vdev;
 242         if (ngpio == 0) {
 243                 printk(KERN_INFO "viafb: no GPIOs configured\n");
 244                 return 0;
 245         }
 246         /*
 247          * Enable the ports.  They come in pairs, with a single
 248          * enable bit for both.
 249          */
 250         spin_lock_irqsave(&viafb_gpio_config.vdev->reg_lock, flags);
 251         for (i = 0; i < ngpio; i += 2)
 252                 viafb_gpio_enable(viafb_gpio_config.active_gpios[i]);
 253         spin_unlock_irqrestore(&viafb_gpio_config.vdev->reg_lock, flags);
 254         /*
 255          * Get registered.
 256          */
 257         viafb_gpio_config.gpio_chip.base = -1;  /* Dynamic */
 258         ret = gpiochip_add(&viafb_gpio_config.gpio_chip);
 259         if (ret) {
 260                 printk(KERN_ERR "viafb: failed to add gpios (%d)\n", ret);
 261                 viafb_gpio_config.gpio_chip.ngpio = 0;
 262         }
 263 #ifdef CONFIG_PM
 264         viafb_pm_register(&viafb_gpio_pm_hooks);
 265 #endif
 266         return ret;
 267 }
 268
 269
 270 static int viafb_gpio_remove(struct platform_device *platdev)
 271 {
 272         unsigned long flags;
 273         int ret = 0, i;
 274
 275 #ifdef CONFIG_PM
 276         viafb_pm_unregister(&viafb_gpio_pm_hooks);
 277 #endif
 278
 279         /*
 280          * Get unregistered.
 281          */
 282         if (viafb_gpio_config.gpio_chip.ngpio > 0) {
 283                 ret = gpiochip_remove(&viafb_gpio_config.gpio_chip);
 284                 if (ret) { /* Somebody still using it? */
 285                         printk(KERN_ERR "Viafb: GPIO remove failed\n");
 286                         return ret;
 287                 }
 288         }
 289         /*
 290          * Disable the ports.
 291          */
 292         spin_lock_irqsave(&viafb_gpio_config.vdev->reg_lock, flags);
 293         for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i += 2)
 294                 viafb_gpio_disable(viafb_gpio_config.active_gpios[i]);
 295         viafb_gpio_config.gpio_chip.ngpio = 0;
 296         spin_unlock_irqrestore(&viafb_gpio_config.vdev->reg_lock, flags);
 297         return ret;
 298 }
 299
 300 static struct platform_driver via_gpio_driver = {
 301         .driver = {
 302                 .name = "viafb-gpio",
 303         },
 304         .probe = viafb_gpio_probe,
 305         .remove = viafb_gpio_remove,
 306 };
 307
 308 int viafb_gpio_init(void)
 309 {
 310         return platform_driver_register(&via_gpio_driver);
 311 }
 312
 313 void viafb_gpio_exit(void)
 314 {
 315         platform_driver_unregister(&via_gpio_driver);
 316 }