drivers/gpio/gpio-menz127.c

   1 /*
   2  * MEN 16Z127 GPIO driver
   3  *
   4  * Copyright (C) 2016 MEN Mikroelektronik GmbH (www.men.de)
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; version 2 of the License.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/io.h>
  14 #include <linux/err.h>
  15 #include <linux/mcb.h>
  16 #include <linux/bitops.h>
  17 #include <linux/gpio/driver.h>
  18
  19 #define MEN_Z127_CTRL   0x00
  20 #define MEN_Z127_PSR    0x04
  21 #define MEN_Z127_IRQR   0x08
  22 #define MEN_Z127_GPIODR 0x0c
  23 #define MEN_Z127_IER1   0x10
  24 #define MEN_Z127_IER2   0x14
  25 #define MEN_Z127_DBER   0x18
  26 #define MEN_Z127_ODER   0x1C
  27 #define GPIO_TO_DBCNT_REG(gpio) ((gpio * 4) + 0x80)
  28
  29 #define MEN_Z127_DB_MIN_US      50
  30 /* 16 bit compare register. Each bit represents 50us */
  31 #define MEN_Z127_DB_MAX_US      (0xffff * MEN_Z127_DB_MIN_US)
  32 #define MEN_Z127_DB_IN_RANGE(db)        ((db >= MEN_Z127_DB_MIN_US) && \
  33                                          (db <= MEN_Z127_DB_MAX_US))
  34
  35 struct men_z127_gpio {
  36         struct gpio_chip gc;
  37         void __iomem *reg_base;
  38         struct resource *mem;
  39 };
  40
  41 static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio,
  42                              unsigned debounce)
  43 {
  44         struct men_z127_gpio *priv = gpiochip_get_data(gc);
  45         struct device *dev = gc->parent;
  46         unsigned int rnd;
  47         u32 db_en, db_cnt;
  48
  49         if (!MEN_Z127_DB_IN_RANGE(debounce)) {
  50                 dev_err(dev, "debounce value %u out of range", debounce);
  51                 return -EINVAL;
  52         }
  53
  54         if (debounce > 0) {
  55                 /* round up or down depending on MSB-1 */
  56                 rnd = fls(debounce) - 1;
  57
  58                 if (rnd && (debounce & BIT(rnd - 1)))
  59                         debounce = round_up(debounce, MEN_Z127_DB_MIN_US);
  60                 else
  61                         debounce = round_down(debounce, MEN_Z127_DB_MIN_US);
  62
  63                 if (debounce > MEN_Z127_DB_MAX_US)
  64                         debounce = MEN_Z127_DB_MAX_US;
  65
  66                 /* 50us per register unit */
  67                 debounce /= 50;
  68         }
  69
  70         spin_lock(&gc->bgpio_lock);
  71
  72         db_en = readl(priv->reg_base + MEN_Z127_DBER);
  73
  74         if (debounce == 0) {
  75                 db_en &= ~BIT(gpio);
  76                 db_cnt = 0;
  77         } else {
  78                 db_en |= BIT(gpio);
  79                 db_cnt = debounce;
  80         }
  81
  82         writel(db_en, priv->reg_base + MEN_Z127_DBER);
  83         writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio));
  84
  85         spin_unlock(&gc->bgpio_lock);
  86
  87         return 0;
  88 }
  89
  90 static int men_z127_set_single_ended(struct gpio_chip *gc,
  91                                      unsigned offset,
  92                                      enum single_ended_mode mode)
  93 {
  94         struct men_z127_gpio *priv = gpiochip_get_data(gc);
  95         u32 od_en;
  96
  97         if (mode != LINE_MODE_OPEN_DRAIN &&
  98             mode != LINE_MODE_PUSH_PULL)
  99                 return -ENOTSUPP;
 100
 101         spin_lock(&gc->bgpio_lock);
 102         od_en = readl(priv->reg_base + MEN_Z127_ODER);
 103
 104         if (mode == LINE_MODE_OPEN_DRAIN)
 105                 od_en |= BIT(offset);
 106         else
 107                 /* Implicitly LINE_MODE_PUSH_PULL */
 108                 od_en &= ~BIT(offset);
 109
 110         writel(od_en, priv->reg_base + MEN_Z127_ODER);
 111         spin_unlock(&gc->bgpio_lock);
 112
 113         return 0;
 114 }
 115
 116 static int men_z127_probe(struct mcb_device *mdev,
 117                           const struct mcb_device_id *id)
 118 {
 119         struct men_z127_gpio *men_z127_gpio;
 120         struct device *dev = &mdev->dev;
 121         int ret;
 122
 123         men_z127_gpio = devm_kzalloc(dev, sizeof(struct men_z127_gpio),
 124                                      GFP_KERNEL);
 125         if (!men_z127_gpio)
 126                 return -ENOMEM;
 127
 128         men_z127_gpio->mem = mcb_request_mem(mdev, dev_name(dev));
 129         if (IS_ERR(men_z127_gpio->mem)) {
 130                 dev_err(dev, "failed to request device memory");
 131                 return PTR_ERR(men_z127_gpio->mem);
 132         }
 133
 134         men_z127_gpio->reg_base = ioremap(men_z127_gpio->mem->start,
 135                                           resource_size(men_z127_gpio->mem));
 136         if (men_z127_gpio->reg_base == NULL) {
 137                 ret = -ENXIO;
 138                 goto err_release;
 139         }
 140
 141         mcb_set_drvdata(mdev, men_z127_gpio);
 142
 143         ret = bgpio_init(&men_z127_gpio->gc, &mdev->dev, 4,
 144                          men_z127_gpio->reg_base + MEN_Z127_PSR,
 145                          men_z127_gpio->reg_base + MEN_Z127_CTRL,
 146                          NULL,
 147                          men_z127_gpio->reg_base + MEN_Z127_GPIODR,
 148                          NULL, 0);
 149         if (ret)
 150                 goto err_unmap;
 151
 152         men_z127_gpio->gc.set_debounce = men_z127_debounce;
 153         men_z127_gpio->gc.set_single_ended = men_z127_set_single_ended;
 154
 155         ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio);
 156         if (ret) {
 157                 dev_err(dev, "failed to register MEN 16Z127 GPIO controller");
 158                 goto err_unmap;
 159         }
 160
 161         dev_info(dev, "MEN 16Z127 GPIO driver registered");
 162
 163         return 0;
 164
 165 err_unmap:
 166         iounmap(men_z127_gpio->reg_base);
 167 err_release:
 168         mcb_release_mem(men_z127_gpio->mem);
 169         return ret;
 170 }
 171
 172 static void men_z127_remove(struct mcb_device *mdev)
 173 {
 174         struct men_z127_gpio *men_z127_gpio = mcb_get_drvdata(mdev);
 175
 176         gpiochip_remove(&men_z127_gpio->gc);
 177         iounmap(men_z127_gpio->reg_base);
 178         mcb_release_mem(men_z127_gpio->mem);
 179 }
 180
 181 static const struct mcb_device_id men_z127_ids[] = {
 182         { .device = 0x7f },
 183         { }
 184 };
 185 MODULE_DEVICE_TABLE(mcb, men_z127_ids);
 186
 187 static struct mcb_driver men_z127_driver = {
 188         .driver = {
 189                 .name = "z127-gpio",
 190         },
 191         .probe = men_z127_probe,
 192         .remove = men_z127_remove,
 193         .id_table = men_z127_ids,
 194 };
 195 module_mcb_driver(men_z127_driver);
 196
 197 MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
 198 MODULE_DESCRIPTION("MEN 16z127 GPIO Controller");
 199 MODULE_LICENSE("GPL v2");
 200 MODULE_ALIAS("mcb:16z127");