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 <dm/of.h>
  12 #include <dt-bindings/gpio/gpio.h>
  13
  14 DECLARE_GLOBAL_DATA_PTR;
  15
  16 /* Flags for each GPIO */
  17 #define GPIOF_OUTPUT    (1 << 0)        /* Currently set as an output */
  18 #define GPIOF_HIGH      (1 << 1)        /* Currently set high */
  19 #define GPIOF_ODR       (1 << 2)        /* Currently set to open drain mode */
  20
  21 struct gpio_state {
  22         const char *label;      /* label given by requester */
  23         u8 flags;               /* flags (GPIOF_...) */
  24 };
  25
  26 /* Access routines for GPIO state */
  27 static u8 *get_gpio_flags(struct udevice *dev, unsigned offset)
  28 {
  29         struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  30         struct gpio_state *state = dev_get_priv(dev);
  31
  32         if (offset >= uc_priv->gpio_count) {
  33                 static u8 invalid_flags;
  34                 printf("sandbox_gpio: error: invalid gpio %u\n", offset);
  35                 return &invalid_flags;
  36         }
  37
  38         return &state[offset].flags;
  39 }
  40
  41 static int get_gpio_flag(struct udevice *dev, unsigned offset, int flag)
  42 {
  43         return (*get_gpio_flags(dev, offset) & flag) != 0;
  44 }
  45
  46 static int set_gpio_flag(struct udevice *dev, unsigned offset, int flag,
  47                          int value)
  48 {
  49         u8 *gpio = get_gpio_flags(dev, offset);
  50
  51         if (value)
  52                 *gpio |= flag;
  53         else
  54                 *gpio &= ~flag;
  55
  56         return 0;
  57 }
  58
  59 /*
  60  * Back-channel sandbox-internal-only access to GPIO state
  61  */
  62
  63 int sandbox_gpio_get_value(struct udevice *dev, unsigned offset)
  64 {
  65         if (get_gpio_flag(dev, offset, GPIOF_OUTPUT))
  66                 debug("sandbox_gpio: get_value on output gpio %u\n", offset);
  67         return get_gpio_flag(dev, offset, GPIOF_HIGH);
  68 }
  69
  70 int sandbox_gpio_set_value(struct udevice *dev, unsigned offset, int value)
  71 {
  72         return set_gpio_flag(dev, offset, GPIOF_HIGH, value);
  73 }
  74
  75 int sandbox_gpio_get_open_drain(struct udevice *dev, unsigned offset)
  76 {
  77         return get_gpio_flag(dev, offset, GPIOF_ODR);
  78 }
  79
  80 int sandbox_gpio_set_open_drain(struct udevice *dev, unsigned offset, int value)
  81 {
  82         return set_gpio_flag(dev, offset, GPIOF_ODR, value);
  83 }
  84
  85 int sandbox_gpio_get_direction(struct udevice *dev, unsigned offset)
  86 {
  87         return get_gpio_flag(dev, offset, GPIOF_OUTPUT);
  88 }
  89
  90 int sandbox_gpio_set_direction(struct udevice *dev, unsigned offset, int output)
  91 {
  92         return set_gpio_flag(dev, offset, GPIOF_OUTPUT, output);
  93 }
  94
  95 /*
  96  * These functions implement the public interface within U-Boot
  97  */
  98
  99 /* set GPIO port 'offset' as an input */
 100 static int sb_gpio_direction_input(struct udevice *dev, unsigned offset)
 101 {
 102         debug("%s: offset:%u\n", __func__, offset);
 103
 104         return sandbox_gpio_set_direction(dev, offset, 0);
 105 }
 106
 107 /* set GPIO port 'offset' as an output, with polarity 'value' */
 108 static int sb_gpio_direction_output(struct udevice *dev, unsigned offset,
 109                                     int value)
 110 {
 111         debug("%s: offset:%u, value = %d\n", __func__, offset, value);
 112
 113         return sandbox_gpio_set_direction(dev, offset, 1) |
 114                 sandbox_gpio_set_value(dev, offset, value);
 115 }
 116
 117 /* read GPIO IN value of port 'offset' */
 118 static int sb_gpio_get_value(struct udevice *dev, unsigned offset)
 119 {
 120         debug("%s: offset:%u\n", __func__, offset);
 121
 122         return sandbox_gpio_get_value(dev, offset);
 123 }
 124
 125 /* write GPIO OUT value to port 'offset' */
 126 static int sb_gpio_set_value(struct udevice *dev, unsigned offset, int value)
 127 {
 128         debug("%s: offset:%u, value = %d\n", __func__, offset, value);
 129
 130         if (!sandbox_gpio_get_direction(dev, offset)) {
 131                 printf("sandbox_gpio: error: set_value on input gpio %u\n",
 132                        offset);
 133                 return -1;
 134         }
 135
 136         return sandbox_gpio_set_value(dev, offset, value);
 137 }
 138
 139 /* read GPIO ODR value of port 'offset' */
 140 static int sb_gpio_get_open_drain(struct udevice *dev, unsigned offset)
 141 {
 142         debug("%s: offset:%u\n", __func__, offset);
 143
 144         return sandbox_gpio_get_open_drain(dev, offset);
 145 }
 146
 147 /* write GPIO ODR value to port 'offset' */
 148 static int sb_gpio_set_open_drain(struct udevice *dev, unsigned offset, int value)
 149 {
 150         debug("%s: offset:%u, value = %d\n", __func__, offset, value);
 151
 152         if (!sandbox_gpio_get_direction(dev, offset)) {
 153                 printf("sandbox_gpio: error: set_open_drain on input gpio %u\n",
 154                        offset);
 155                 return -1;
 156         }
 157
 158         return sandbox_gpio_set_open_drain(dev, offset, value);
 159 }
 160
 161 static int sb_gpio_get_function(struct udevice *dev, unsigned offset)
 162 {
 163         if (get_gpio_flag(dev, offset, GPIOF_OUTPUT))
 164                 return GPIOF_OUTPUT;
 165         return GPIOF_INPUT;
 166 }
 167
 168 static int sb_gpio_xlate(struct udevice *dev, struct gpio_desc *desc,
 169                          struct ofnode_phandle_args *args)
 170 {
 171         desc->offset = args->args[0];
 172         if (args->args_count < 2)
 173                 return 0;
 174         if (args->args[1] & GPIO_ACTIVE_LOW)
 175                 desc->flags |= GPIOD_ACTIVE_LOW;
 176         if (args->args[1] & 2)
 177                 desc->flags |= GPIOD_IS_IN;
 178         if (args->args[1] & 4)
 179                 desc->flags |= GPIOD_IS_OUT;
 180         if (args->args[1] & 8)
 181                 desc->flags |= GPIOD_IS_OUT_ACTIVE;
 182
 183         return 0;
 184 }
 185
 186 static const struct dm_gpio_ops gpio_sandbox_ops = {
 187         .direction_input        = sb_gpio_direction_input,
 188         .direction_output       = sb_gpio_direction_output,
 189         .get_value              = sb_gpio_get_value,
 190         .set_value              = sb_gpio_set_value,
 191         .get_open_drain         = sb_gpio_get_open_drain,
 192         .set_open_drain         = sb_gpio_set_open_drain,
 193         .get_function           = sb_gpio_get_function,
 194         .xlate                  = sb_gpio_xlate,
 195 };
 196
 197 static int sandbox_gpio_ofdata_to_platdata(struct udevice *dev)
 198 {
 199         struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
 200
 201         uc_priv->gpio_count = dev_read_u32_default(dev, "num-gpios", 0);
 202         uc_priv->bank_name = dev_read_string(dev, "gpio-bank-name");
 203
 204         return 0;
 205 }
 206
 207 static int gpio_sandbox_probe(struct udevice *dev)
 208 {
 209         struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
 210
 211         if (!dev_of_valid(dev))
 212                 /* Tell the uclass how many GPIOs we have */
 213                 uc_priv->gpio_count = CONFIG_SANDBOX_GPIO_COUNT;
 214
 215         dev->priv = calloc(sizeof(struct gpio_state), uc_priv->gpio_count);
 216
 217         return 0;
 218 }
 219
 220 static int gpio_sandbox_remove(struct udevice *dev)
 221 {
 222         free(dev->priv);
 223
 224         return 0;
 225 }
 226
 227 static const struct udevice_id sandbox_gpio_ids[] = {
 228         { .compatible = "sandbox,gpio" },
 229         { }
 230 };
 231
 232 U_BOOT_DRIVER(gpio_sandbox) = {
 233         .name   = "gpio_sandbox",
 234         .id     = UCLASS_GPIO,
 235         .of_match = sandbox_gpio_ids,
 236         .ofdata_to_platdata = sandbox_gpio_ofdata_to_platdata,
 237         .probe  = gpio_sandbox_probe,
 238         .remove = gpio_sandbox_remove,
 239         .ops    = &gpio_sandbox_ops,
 240 };