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