drivers/gpio/gpio-menz127.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * MEN 16Z127 GPIO driver
   4  *
   5  * Copyright (C) 2016 MEN Mikroelektronik GmbH (www.men.de)
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/io.h>
  11 #include <linux/err.h>
  12 #include <linux/mcb.h>
  13 #include <linux/bitops.h>
  14 #include <linux/gpio/driver.h>
  15
  16 #define MEN_Z127_CTRL   0x00
  17 #define MEN_Z127_PSR    0x04
  18 #define MEN_Z127_IRQR   0x08
  19 #define MEN_Z127_GPIODR 0x0c
  20 #define MEN_Z127_IER1   0x10
  21 #define MEN_Z127_IER2   0x14
  22 #define MEN_Z127_DBER   0x18
  23 #define MEN_Z127_ODER   0x1C
  24 #define GPIO_TO_DBCNT_REG(gpio) ((gpio * 4) + 0x80)
  25
  26 #define MEN_Z127_DB_MIN_US      50
  27 /* 16 bit compare register. Each bit represents 50us */
  28 #define MEN_Z127_DB_MAX_US      (0xffff * MEN_Z127_DB_MIN_US)
  29 #define MEN_Z127_DB_IN_RANGE(db)        ((db >= MEN_Z127_DB_MIN_US) && \
  30                                          (db <= MEN_Z127_DB_MAX_US))
  31
  32 struct men_z127_gpio {
  33         struct gpio_chip gc;
  34         void __iomem *reg_base;
  35         struct resource *mem;
  36 };
  37
  38 static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio,
  39                              unsigned debounce)
  40 {
  41         struct men_z127_gpio *priv = gpiochip_get_data(gc);
  42         struct device *dev = gc->parent;
  43         unsigned int rnd;
  44         u32 db_en, db_cnt;
  45
  46         if (!MEN_Z127_DB_IN_RANGE(debounce)) {
  47                 dev_err(dev, "debounce value %u out of range", debounce);
  48                 return -EINVAL;
  49         }
  50
  51         if (debounce > 0) {
  52                 /* round up or down depending on MSB-1 */
  53                 rnd = fls(debounce) - 1;
  54
  55                 if (rnd && (debounce & BIT(rnd - 1)))
  56                         debounce = roundup(debounce, MEN_Z127_DB_MIN_US);
  57                 else
  58                         debounce = rounddown(debounce, MEN_Z127_DB_MIN_US);
  59
  60                 if (debounce > MEN_Z127_DB_MAX_US)
  61                         debounce = MEN_Z127_DB_MAX_US;
  62
  63                 /* 50us per register unit */
  64                 debounce /= 50;
  65         }
  66
  67         raw_spin_lock(&gc->bgpio_lock);
  68
  69         db_en = readl(priv->reg_base + MEN_Z127_DBER);
  70
  71         if (debounce == 0) {
  72                 db_en &= ~BIT(gpio);
  73                 db_cnt = 0;
  74         } else {
  75                 db_en |= BIT(gpio);
  76                 db_cnt = debounce;
  77         }
  78
  79         writel(db_en, priv->reg_base + MEN_Z127_DBER);
  80         writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio));
  81
  82         raw_spin_unlock(&gc->bgpio_lock);
  83
  84         return 0;
  85 }
  86
  87 static int men_z127_set_single_ended(struct gpio_chip *gc,
  88                                      unsigned offset,
  89                                      enum pin_config_param param)
  90 {
  91         struct men_z127_gpio *priv = gpiochip_get_data(gc);
  92         u32 od_en;
  93
  94         raw_spin_lock(&gc->bgpio_lock);
  95         od_en = readl(priv->reg_base + MEN_Z127_ODER);
  96
  97         if (param == PIN_CONFIG_DRIVE_OPEN_DRAIN)
  98                 od_en |= BIT(offset);
  99         else
 100                 /* Implicitly PIN_CONFIG_DRIVE_PUSH_PULL */
 101                 od_en &= ~BIT(offset);
 102
 103         writel(od_en, priv->reg_base + MEN_Z127_ODER);
 104         raw_spin_unlock(&gc->bgpio_lock);
 105
 106         return 0;
 107 }
 108
 109 static int men_z127_set_config(struct gpio_chip *gc, unsigned offset,
 110                                unsigned long config)
 111 {
 112         enum pin_config_param param = pinconf_to_config_param(config);
 113
 114         switch (param) {
 115         case PIN_CONFIG_DRIVE_OPEN_DRAIN:
 116         case PIN_CONFIG_DRIVE_PUSH_PULL:
 117                 return men_z127_set_single_ended(gc, offset, param);
 118
 119         case PIN_CONFIG_INPUT_DEBOUNCE:
 120                 return men_z127_debounce(gc, offset,
 121                         pinconf_to_config_argument(config));
 122
 123         default:
 124                 break;
 125         }
 126
 127         return -ENOTSUPP;
 128 }
 129
 130 static void men_z127_release_mem(void *data)
 131 {
 132         struct resource *res = data;
 133
 134         mcb_release_mem(res);
 135 }
 136
 137 static int men_z127_probe(struct mcb_device *mdev,
 138                           const struct mcb_device_id *id)
 139 {
 140         struct men_z127_gpio *men_z127_gpio;
 141         struct device *dev = &mdev->dev;
 142         int ret;
 143
 144         men_z127_gpio = devm_kzalloc(dev, sizeof(struct men_z127_gpio),
 145                                      GFP_KERNEL);
 146         if (!men_z127_gpio)
 147                 return -ENOMEM;
 148
 149         men_z127_gpio->mem = mcb_request_mem(mdev, dev_name(dev));
 150         if (IS_ERR(men_z127_gpio->mem))
 151                 return dev_err_probe(dev, PTR_ERR(men_z127_gpio->mem),
 152                                      "failed to request device memory");
 153
 154         ret = devm_add_action_or_reset(dev, men_z127_release_mem,
 155                                        men_z127_gpio->mem);
 156         if (ret)
 157                 return ret;
 158
 159         men_z127_gpio->reg_base = devm_ioremap(dev, men_z127_gpio->mem->start,
 160                                         resource_size(men_z127_gpio->mem));
 161         if (men_z127_gpio->reg_base == NULL)
 162                 return -ENXIO;
 163
 164         mcb_set_drvdata(mdev, men_z127_gpio);
 165
 166         ret = bgpio_init(&men_z127_gpio->gc, &mdev->dev, 4,
 167                          men_z127_gpio->reg_base + MEN_Z127_PSR,
 168                          men_z127_gpio->reg_base + MEN_Z127_CTRL,
 169                          NULL,
 170                          men_z127_gpio->reg_base + MEN_Z127_GPIODR,
 171                          NULL, 0);
 172         if (ret)
 173                 return ret;
 174
 175         men_z127_gpio->gc.set_config = men_z127_set_config;
 176
 177         ret = devm_gpiochip_add_data(dev, &men_z127_gpio->gc, men_z127_gpio);
 178         if (ret)
 179                 return dev_err_probe(dev, ret,
 180                         "failed to register MEN 16Z127 GPIO controller");
 181
 182         return 0;
 183 }
 184
 185 static const struct mcb_device_id men_z127_ids[] = {
 186         { .device = 0x7f },
 187         { }
 188 };
 189 MODULE_DEVICE_TABLE(mcb, men_z127_ids);
 190
 191 static struct mcb_driver men_z127_driver = {
 192         .driver = {
 193                 .name = "z127-gpio",
 194         },
 195         .probe = men_z127_probe,
 196         .id_table = men_z127_ids,
 197 };
 198 module_mcb_driver(men_z127_driver);
 199
 200 MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
 201 MODULE_DESCRIPTION("MEN 16z127 GPIO Controller");
 202 MODULE_LICENSE("GPL v2");
 203 MODULE_ALIAS("mcb:16z127");
 204 MODULE_IMPORT_NS("MCB");