drivers/video/fbdev/via/via-gpio.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Support for viafb GPIO ports.
   4  *
   5  * Copyright 2009 Jonathan Corbet <corbet@lwn.net>
   6  */
   7
   8 #include <linux/spinlock.h>
   9 #include <linux/gpio/driver.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 = gpiochip_get_data(chip);
  87         u8 reg;
  88         struct viafb_gpio *gpio;
  89         unsigned long flags;
  90
  91         spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
  92         gpio = cfg->active_gpios[nr];
  93         reg = via_read_reg(VIASR, gpio->vg_port_index);
  94         reg |= 0x40 << gpio->vg_mask_shift;  /* output enable */
  95         if (value)
  96                 reg |= 0x10 << gpio->vg_mask_shift;
  97         else
  98                 reg &= ~(0x10 << gpio->vg_mask_shift);
  99         via_write_reg(VIASR, gpio->vg_port_index, reg);
 100         spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
 101 }
 102
 103 static int via_gpio_dir_out(struct gpio_chip *chip, unsigned int nr,
 104                             int value)
 105 {
 106         via_gpio_set(chip, nr, value);
 107         return 0;
 108 }
 109
 110 /*
 111  * Set the input direction.  I'm not sure this is right; we should
 112  * be able to do input without disabling output.
 113  */
 114 static int via_gpio_dir_input(struct gpio_chip *chip, unsigned int nr)
 115 {
 116         struct viafb_gpio_cfg *cfg = gpiochip_get_data(chip);
 117         struct viafb_gpio *gpio;
 118         unsigned long flags;
 119
 120         spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
 121         gpio = cfg->active_gpios[nr];
 122         via_write_reg_mask(VIASR, gpio->vg_port_index, 0,
 123                         0x40 << gpio->vg_mask_shift);
 124         spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
 125         return 0;
 126 }
 127
 128 static int via_gpio_get(struct gpio_chip *chip, unsigned int nr)
 129 {
 130         struct viafb_gpio_cfg *cfg = gpiochip_get_data(chip);
 131         u8 reg;
 132         struct viafb_gpio *gpio;
 133         unsigned long flags;
 134
 135         spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
 136         gpio = cfg->active_gpios[nr];
 137         reg = via_read_reg(VIASR, gpio->vg_port_index);
 138         spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
 139         return !!(reg & (0x04 << gpio->vg_mask_shift));
 140 }
 141
 142
 143 static struct viafb_gpio_cfg viafb_gpio_config = {
 144         .gpio_chip = {
 145                 .label = "VIAFB onboard GPIO",
 146                 .owner = THIS_MODULE,
 147                 .direction_output = via_gpio_dir_out,
 148                 .set = via_gpio_set,
 149                 .direction_input = via_gpio_dir_input,
 150                 .get = via_gpio_get,
 151                 .base = -1,
 152                 .ngpio = 0,
 153                 .can_sleep = 0
 154         }
 155 };
 156
 157 /*
 158  * Manage the software enable bit.
 159  */
 160 static void viafb_gpio_enable(struct viafb_gpio *gpio)
 161 {
 162         via_write_reg_mask(VIASR, gpio->vg_port_index, 0x02, 0x02);
 163 }
 164
 165 static void viafb_gpio_disable(struct viafb_gpio *gpio)
 166 {
 167         via_write_reg_mask(VIASR, gpio->vg_port_index, 0, 0x02);
 168 }
 169
 170 #ifdef CONFIG_PM
 171
 172 static int viafb_gpio_suspend(void *private)
 173 {
 174         return 0;
 175 }
 176
 177 static int viafb_gpio_resume(void *private)
 178 {
 179         int i;
 180
 181         for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i += 2)
 182                 viafb_gpio_enable(viafb_gpio_config.active_gpios[i]);
 183         return 0;
 184 }
 185
 186 static struct viafb_pm_hooks viafb_gpio_pm_hooks = {
 187         .suspend = viafb_gpio_suspend,
 188         .resume = viafb_gpio_resume
 189 };
 190 #endif /* CONFIG_PM */
 191
 192 /*
 193  * Look up a specific gpio and return the number it was assigned.
 194  */
 195 int viafb_gpio_lookup(const char *name)
 196 {
 197         int i;
 198
 199         for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i++)
 200                 if (!strcmp(name, viafb_gpio_config.active_gpios[i]->vg_name))
 201                         return viafb_gpio_config.gpio_chip.base + i;
 202         return -1;
 203 }
 204 EXPORT_SYMBOL_GPL(viafb_gpio_lookup);
 205
 206 /*
 207  * Platform device stuff.
 208  */
 209 static int viafb_gpio_probe(struct platform_device *platdev)
 210 {
 211         struct viafb_dev *vdev = platdev->dev.platform_data;
 212         struct via_port_cfg *port_cfg = vdev->port_cfg;
 213         int i, ngpio = 0, ret;
 214         struct viafb_gpio *gpio;
 215         unsigned long flags;
 216
 217         /*
 218          * Set up entries for all GPIOs which have been configured to
 219          * operate as such (as opposed to as i2c ports).
 220          */
 221         for (i = 0; i < VIAFB_NUM_PORTS; i++) {
 222                 if (port_cfg[i].mode != VIA_MODE_GPIO)
 223                         continue;
 224                 for (gpio = viafb_all_gpios;
 225                      gpio < viafb_all_gpios + VIAFB_NUM_GPIOS; gpio++)
 226                         if (gpio->vg_port_index == port_cfg[i].ioport_index) {
 227                                 viafb_gpio_config.active_gpios[ngpio] = gpio;
 228                                 viafb_gpio_config.gpio_names[ngpio] =
 229                                         gpio->vg_name;
 230                                 ngpio++;
 231                         }
 232         }
 233         viafb_gpio_config.gpio_chip.ngpio = ngpio;
 234         viafb_gpio_config.gpio_chip.names = viafb_gpio_config.gpio_names;
 235         viafb_gpio_config.vdev = vdev;
 236         if (ngpio == 0) {
 237                 printk(KERN_INFO "viafb: no GPIOs configured\n");
 238                 return 0;
 239         }
 240         /*
 241          * Enable the ports.  They come in pairs, with a single
 242          * enable bit for both.
 243          */
 244         spin_lock_irqsave(&viafb_gpio_config.vdev->reg_lock, flags);
 245         for (i = 0; i < ngpio; i += 2)
 246                 viafb_gpio_enable(viafb_gpio_config.active_gpios[i]);
 247         spin_unlock_irqrestore(&viafb_gpio_config.vdev->reg_lock, flags);
 248         /*
 249          * Get registered.
 250          */
 251         viafb_gpio_config.gpio_chip.base = -1;  /* Dynamic */
 252         ret = gpiochip_add_data(&viafb_gpio_config.gpio_chip,
 253                                 &viafb_gpio_config);
 254         if (ret) {
 255                 printk(KERN_ERR "viafb: failed to add gpios (%d)\n", ret);
 256                 viafb_gpio_config.gpio_chip.ngpio = 0;
 257         }
 258 #ifdef CONFIG_PM
 259         viafb_pm_register(&viafb_gpio_pm_hooks);
 260 #endif
 261         return ret;
 262 }
 263
 264
 265 static int viafb_gpio_remove(struct platform_device *platdev)
 266 {
 267         unsigned long flags;
 268         int i;
 269
 270 #ifdef CONFIG_PM
 271         viafb_pm_unregister(&viafb_gpio_pm_hooks);
 272 #endif
 273
 274         /*
 275          * Get unregistered.
 276          */
 277         if (viafb_gpio_config.gpio_chip.ngpio > 0) {
 278                 gpiochip_remove(&viafb_gpio_config.gpio_chip);
 279         }
 280         /*
 281          * Disable the ports.
 282          */
 283         spin_lock_irqsave(&viafb_gpio_config.vdev->reg_lock, flags);
 284         for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i += 2)
 285                 viafb_gpio_disable(viafb_gpio_config.active_gpios[i]);
 286         viafb_gpio_config.gpio_chip.ngpio = 0;
 287         spin_unlock_irqrestore(&viafb_gpio_config.vdev->reg_lock, flags);
 288         return 0;
 289 }
 290
 291 static struct platform_driver via_gpio_driver = {
 292         .driver = {
 293                 .name = "viafb-gpio",
 294         },
 295         .probe = viafb_gpio_probe,
 296         .remove = viafb_gpio_remove,
 297 };
 298
 299 int viafb_gpio_init(void)
 300 {
 301         return platform_driver_register(&via_gpio_driver);
 302 }
 303
 304 void viafb_gpio_exit(void)
 305 {
 306         platform_driver_unregister(&via_gpio_driver);
 307 }