drivers/gpio/sandbox.c

   1 /*
   2  * Copyright (c) 2011 The Chromium OS Authors.
   3  * SPDX-License-Identifier:     GPL-2.0+
   4  */
   5
   6 #include <common.h>
   7 #include <dm.h>
   8 #include <fdtdec.h>
   9 #include <malloc.h>
  10 #include <asm/gpio.h>
  11 #include <dt-bindings/gpio/gpio.h>
  12
  13 DECLARE_GLOBAL_DATA_PTR;
  14
  15 /* Flags for each GPIO */
  16 #define GPIOF_OUTPUT    (1 << 0)        /* Currently set as an output */
  17 #define GPIOF_HIGH      (1 << 1)        /* Currently set high */
  18
  19 struct gpio_state {
  20         const char *label;      /* label given by requester */
  21         u8 flags;               /* flags (GPIOF_...) */
  22 };
  23
  24 /* Access routines for GPIO state */
  25 static u8 *get_gpio_flags(struct udevice *dev, unsigned offset)
  26 {
  27         struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  28         struct gpio_state *state = dev_get_priv(dev);
  29
  30         if (offset >= uc_priv->gpio_count) {
  31                 static u8 invalid_flags;
  32                 printf("sandbox_gpio: error: invalid gpio %u\n", offset);
  33                 return &invalid_flags;
  34         }
  35
  36         return &state[offset].flags;
  37 }
  38
  39 static int get_gpio_flag(struct udevice *dev, unsigned offset, int flag)
  40 {
  41         return (*get_gpio_flags(dev, offset) & flag) != 0;
  42 }
  43
  44 static int set_gpio_flag(struct udevice *dev, unsigned offset, int flag,
  45                          int value)
  46 {
  47         u8 *gpio = get_gpio_flags(dev, offset);
  48
  49         if (value)
  50                 *gpio |= flag;
  51         else
  52                 *gpio &= ~flag;
  53
  54         return 0;
  55 }
  56
  57 /*
  58  * Back-channel sandbox-internal-only access to GPIO state
  59  */
  60
  61 int sandbox_gpio_get_value(struct udevice *dev, unsigned offset)
  62 {
  63         if (get_gpio_flag(dev, offset, GPIOF_OUTPUT))
  64                 debug("sandbox_gpio: get_value on output gpio %u\n", offset);
  65         return get_gpio_flag(dev, offset, GPIOF_HIGH);
  66 }
  67
  68 int sandbox_gpio_set_value(struct udevice *dev, unsigned offset, int value)
  69 {
  70         return set_gpio_flag(dev, offset, GPIOF_HIGH, value);
  71 }
  72
  73 int sandbox_gpio_get_direction(struct udevice *dev, unsigned offset)
  74 {
  75         return get_gpio_flag(dev, offset, GPIOF_OUTPUT);
  76 }
  77
  78 int sandbox_gpio_set_direction(struct udevice *dev, unsigned offset, int output)
  79 {
  80         return set_gpio_flag(dev, offset, GPIOF_OUTPUT, output);
  81 }
  82
  83 /*
  84  * These functions implement the public interface within U-Boot
  85  */
  86
  87 /* set GPIO port 'offset' as an input */
  88 static int sb_gpio_direction_input(struct udevice *dev, unsigned offset)
  89 {
  90         debug("%s: offset:%u\n", __func__, offset);
  91
  92         return sandbox_gpio_set_direction(dev, offset, 0);
  93 }
  94
  95 /* set GPIO port 'offset' as an output, with polarity 'value' */
  96 static int sb_gpio_direction_output(struct udevice *dev, unsigned offset,
  97                                     int value)
  98 {
  99         debug("%s: offset:%u, value = %d\n", __func__, offset, value);
 100
 101         return sandbox_gpio_set_direction(dev, offset, 1) |
 102                 sandbox_gpio_set_value(dev, offset, value);
 103 }
 104
 105 /* read GPIO IN value of port 'offset' */
 106 static int sb_gpio_get_value(struct udevice *dev, unsigned offset)
 107 {
 108         debug("%s: offset:%u\n", __func__, offset);
 109
 110         return sandbox_gpio_get_value(dev, offset);
 111 }
 112
 113 /* write GPIO OUT value to port 'offset' */
 114 static int sb_gpio_set_value(struct udevice *dev, unsigned offset, int value)
 115 {
 116         debug("%s: offset:%u, value = %d\n", __func__, offset, value);
 117
 118         if (!sandbox_gpio_get_direction(dev, offset)) {
 119                 printf("sandbox_gpio: error: set_value on input gpio %u\n",
 120                        offset);
 121                 return -1;
 122         }
 123
 124         return sandbox_gpio_set_value(dev, offset, value);
 125 }
 126
 127 static int sb_gpio_get_function(struct udevice *dev, unsigned offset)
 128 {
 129         if (get_gpio_flag(dev, offset, GPIOF_OUTPUT))
 130                 return GPIOF_OUTPUT;
 131         return GPIOF_INPUT;
 132 }
 133
 134 static int sb_gpio_xlate(struct udevice *dev, struct gpio_desc *desc,
 135                          struct fdtdec_phandle_args *args)
 136 {
 137         desc->offset = args->args[0];
 138         if (args->args_count < 2)
 139                 return 0;
 140         if (args->args[1] & GPIO_ACTIVE_LOW)
 141                 desc->flags |= GPIOD_ACTIVE_LOW;
 142         if (args->args[1] & 2)
 143                 desc->flags |= GPIOD_IS_IN;
 144         if (args->args[1] & 4)
 145                 desc->flags |= GPIOD_IS_OUT;
 146         if (args->args[1] & 8)
 147                 desc->flags |= GPIOD_IS_OUT_ACTIVE;
 148
 149         return 0;
 150 }
 151
 152 static const struct dm_gpio_ops gpio_sandbox_ops = {
 153         .direction_input        = sb_gpio_direction_input,
 154         .direction_output       = sb_gpio_direction_output,
 155         .get_value              = sb_gpio_get_value,
 156         .set_value              = sb_gpio_set_value,
 157         .get_function           = sb_gpio_get_function,
 158         .xlate                  = sb_gpio_xlate,
 159 };
 160
 161 static int sandbox_gpio_ofdata_to_platdata(struct udevice *dev)
 162 {
 163         struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
 164
 165         uc_priv->gpio_count = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
 166                                              "num-gpios", 0);
 167         uc_priv->bank_name = fdt_getprop(gd->fdt_blob, dev->of_offset,
 168                                          "gpio-bank-name", NULL);
 169
 170         return 0;
 171 }
 172
 173 static int gpio_sandbox_probe(struct udevice *dev)
 174 {
 175         struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
 176
 177         if (dev->of_offset == -1) {
 178                 /* Tell the uclass how many GPIOs we have */
 179                 uc_priv->gpio_count = CONFIG_SANDBOX_GPIO_COUNT;
 180         }
 181
 182         dev->priv = calloc(sizeof(struct gpio_state), uc_priv->gpio_count);
 183
 184         return 0;
 185 }
 186
 187 static int gpio_sandbox_remove(struct udevice *dev)
 188 {
 189         free(dev->priv);
 190
 191         return 0;
 192 }
 193
 194 static const struct udevice_id sandbox_gpio_ids[] = {
 195         { .compatible = "sandbox,gpio" },
 196         { }
 197 };
 198
 199 U_BOOT_DRIVER(gpio_sandbox) = {
 200         .name   = "gpio_sandbox",
 201         .id     = UCLASS_GPIO,
 202         .of_match = sandbox_gpio_ids,
 203         .ofdata_to_platdata = sandbox_gpio_ofdata_to_platdata,
 204         .probe  = gpio_sandbox_probe,
 205         .remove = gpio_sandbox_remove,
 206         .ops    = &gpio_sandbox_ops,
 207 };