drivers/gpio/gpio-syscon.c

   1 /*
   2  *  SYSCON GPIO driver
   3  *
   4  *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  */
  11
  12 #include <linux/err.h>
  13 #include <linux/gpio.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/of_device.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/regmap.h>
  19 #include <linux/mfd/syscon.h>
  20
  21 #define GPIO_SYSCON_FEAT_IN     BIT(0)
  22 #define GPIO_SYSCON_FEAT_OUT    BIT(1)
  23 #define GPIO_SYSCON_FEAT_DIR    BIT(2)
  24
  25 /* SYSCON driver is designed to use 32-bit wide registers */
  26 #define SYSCON_REG_SIZE         (4)
  27 #define SYSCON_REG_BITS         (SYSCON_REG_SIZE * 8)
  28
  29 /**
  30  * struct syscon_gpio_data - Configuration for the device.
  31  * compatible:          SYSCON driver compatible string.
  32  * flags:               Set of GPIO_SYSCON_FEAT_ flags:
  33  *                      GPIO_SYSCON_FEAT_IN:    GPIOs supports input,
  34  *                      GPIO_SYSCON_FEAT_OUT:   GPIOs supports output,
  35  *                      GPIO_SYSCON_FEAT_DIR:   GPIOs supports switch direction.
  36  * bit_count:           Number of bits used as GPIOs.
  37  * dat_bit_offset:      Offset (in bits) to the first GPIO bit.
  38  * dir_bit_offset:      Optional offset (in bits) to the first bit to switch
  39  *                      GPIO direction (Used with GPIO_SYSCON_FEAT_DIR flag).
  40  * set:         HW specific callback to assigns output value
  41  *                      for signal "offset"
  42  */
  43
  44 struct syscon_gpio_data {
  45         const char      *compatible;
  46         unsigned int    flags;
  47         unsigned int    bit_count;
  48         unsigned int    dat_bit_offset;
  49         unsigned int    dir_bit_offset;
  50         void            (*set)(struct gpio_chip *chip,
  51                                unsigned offset, int value);
  52 };
  53
  54 struct syscon_gpio_priv {
  55         struct gpio_chip                chip;
  56         struct regmap                   *syscon;
  57         const struct syscon_gpio_data   *data;
  58         u32                             dreg_offset;
  59         u32                             dir_reg_offset;
  60 };
  61
  62 static int syscon_gpio_get(struct gpio_chip *chip, unsigned offset)
  63 {
  64         struct syscon_gpio_priv *priv = gpiochip_get_data(chip);
  65         unsigned int val, offs;
  66         int ret;
  67
  68         offs = priv->dreg_offset + priv->data->dat_bit_offset + offset;
  69
  70         ret = regmap_read(priv->syscon,
  71                           (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, &val);
  72         if (ret)
  73                 return ret;
  74
  75         return !!(val & BIT(offs % SYSCON_REG_BITS));
  76 }
  77
  78 static void syscon_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
  79 {
  80         struct syscon_gpio_priv *priv = gpiochip_get_data(chip);
  81         unsigned int offs;
  82
  83         offs = priv->dreg_offset + priv->data->dat_bit_offset + offset;
  84
  85         regmap_update_bits(priv->syscon,
  86                            (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
  87                            BIT(offs % SYSCON_REG_BITS),
  88                            val ? BIT(offs % SYSCON_REG_BITS) : 0);
  89 }
  90
  91 static int syscon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
  92 {
  93         struct syscon_gpio_priv *priv = gpiochip_get_data(chip);
  94
  95         if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) {
  96                 unsigned int offs;
  97
  98                 offs = priv->dir_reg_offset +
  99                        priv->data->dir_bit_offset + offset;
 100
 101                 regmap_update_bits(priv->syscon,
 102                                    (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
 103                                    BIT(offs % SYSCON_REG_BITS), 0);
 104         }
 105
 106         return 0;
 107 }
 108
 109 static int syscon_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int val)
 110 {
 111         struct syscon_gpio_priv *priv = gpiochip_get_data(chip);
 112
 113         if (priv->data->flags & GPIO_SYSCON_FEAT_DIR) {
 114                 unsigned int offs;
 115
 116                 offs = priv->dir_reg_offset +
 117                        priv->data->dir_bit_offset + offset;
 118
 119                 regmap_update_bits(priv->syscon,
 120                                    (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
 121                                    BIT(offs % SYSCON_REG_BITS),
 122                                    BIT(offs % SYSCON_REG_BITS));
 123         }
 124
 125         priv->data->set(chip, offset, val);
 126
 127         return 0;
 128 }
 129
 130 static const struct syscon_gpio_data clps711x_mctrl_gpio = {
 131         /* ARM CLPS711X SYSFLG1 Bits 8-10 */
 132         .compatible     = "cirrus,ep7209-syscon1",
 133         .flags          = GPIO_SYSCON_FEAT_IN,
 134         .bit_count      = 3,
 135         .dat_bit_offset = 0x40 * 8 + 8,
 136 };
 137
 138 #define KEYSTONE_LOCK_BIT BIT(0)
 139
 140 static void keystone_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
 141 {
 142         struct syscon_gpio_priv *priv = gpiochip_get_data(chip);
 143         unsigned int offs;
 144         int ret;
 145
 146         offs = priv->dreg_offset + priv->data->dat_bit_offset + offset;
 147
 148         if (!val)
 149                 return;
 150
 151         ret = regmap_update_bits(
 152                         priv->syscon,
 153                         (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
 154                         BIT(offs % SYSCON_REG_BITS) | KEYSTONE_LOCK_BIT,
 155                         BIT(offs % SYSCON_REG_BITS) | KEYSTONE_LOCK_BIT);
 156         if (ret < 0)
 157                 dev_err(chip->parent, "gpio write failed ret(%d)\n", ret);
 158 }
 159
 160 static const struct syscon_gpio_data keystone_dsp_gpio = {
 161         /* ARM Keystone 2 */
 162         .compatible     = NULL,
 163         .flags          = GPIO_SYSCON_FEAT_OUT,
 164         .bit_count      = 28,
 165         .dat_bit_offset = 4,
 166         .set            = keystone_gpio_set,
 167 };
 168
 169 static const struct of_device_id syscon_gpio_ids[] = {
 170         {
 171                 .compatible     = "cirrus,ep7209-mctrl-gpio",
 172                 .data           = &clps711x_mctrl_gpio,
 173         },
 174         {
 175                 .compatible     = "ti,keystone-dsp-gpio",
 176                 .data           = &keystone_dsp_gpio,
 177         },
 178         { }
 179 };
 180 MODULE_DEVICE_TABLE(of, syscon_gpio_ids);
 181
 182 static int syscon_gpio_probe(struct platform_device *pdev)
 183 {
 184         struct device *dev = &pdev->dev;
 185         struct syscon_gpio_priv *priv;
 186         struct device_node *np = dev->of_node;
 187         int ret;
 188
 189         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 190         if (!priv)
 191                 return -ENOMEM;
 192
 193         priv->data = of_device_get_match_data(dev);
 194
 195         if (priv->data->compatible) {
 196                 priv->syscon = syscon_regmap_lookup_by_compatible(
 197                                         priv->data->compatible);
 198                 if (IS_ERR(priv->syscon))
 199                         return PTR_ERR(priv->syscon);
 200         } else {
 201                 priv->syscon =
 202                         syscon_regmap_lookup_by_phandle(np, "gpio,syscon-dev");
 203                 if (IS_ERR(priv->syscon) && np->parent)
 204                         priv->syscon = syscon_node_to_regmap(np->parent);
 205                 if (IS_ERR(priv->syscon))
 206                         return PTR_ERR(priv->syscon);
 207
 208                 ret = of_property_read_u32_index(np, "gpio,syscon-dev", 1,
 209                                                  &priv->dreg_offset);
 210                 if (ret)
 211                         dev_err(dev, "can't read the data register offset!\n");
 212
 213                 priv->dreg_offset <<= 3;
 214
 215                 ret = of_property_read_u32_index(np, "gpio,syscon-dev", 2,
 216                                                  &priv->dir_reg_offset);
 217                 if (ret)
 218                         dev_dbg(dev, "can't read the dir register offset!\n");
 219
 220                 priv->dir_reg_offset <<= 3;
 221         }
 222
 223         priv->chip.parent = dev;
 224         priv->chip.owner = THIS_MODULE;
 225         priv->chip.label = dev_name(dev);
 226         priv->chip.base = -1;
 227         priv->chip.ngpio = priv->data->bit_count;
 228         priv->chip.get = syscon_gpio_get;
 229         if (priv->data->flags & GPIO_SYSCON_FEAT_IN)
 230                 priv->chip.direction_input = syscon_gpio_dir_in;
 231         if (priv->data->flags & GPIO_SYSCON_FEAT_OUT) {
 232                 priv->chip.set = priv->data->set ? : syscon_gpio_set;
 233                 priv->chip.direction_output = syscon_gpio_dir_out;
 234         }
 235
 236         platform_set_drvdata(pdev, priv);
 237
 238         return devm_gpiochip_add_data(&pdev->dev, &priv->chip, priv);
 239 }
 240
 241 static struct platform_driver syscon_gpio_driver = {
 242         .driver = {
 243                 .name           = "gpio-syscon",
 244                 .of_match_table = syscon_gpio_ids,
 245         },
 246         .probe  = syscon_gpio_probe,
 247 };
 248 module_platform_driver(syscon_gpio_driver);
 249
 250 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 251 MODULE_DESCRIPTION("SYSCON GPIO driver");
 252 MODULE_LICENSE("GPL");