drivers/pinctrl/pinctrl-mcp23s08_spi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* MCP23S08 SPI GPIO driver */
   3
   4 #include <linux/mod_devicetable.h>
   5 #include <linux/module.h>
   6 #include <linux/property.h>
   7 #include <linux/regmap.h>
   8 #include <linux/spi/spi.h>
   9
  10 #include "pinctrl-mcp23s08.h"
  11
  12 #define MCP_MAX_DEV_PER_CS      8
  13
  14 /*
  15  * A given spi_device can represent up to eight mcp23sxx chips
  16  * sharing the same chipselect but using different addresses
  17  * (e.g. chips #0 and #3 might be populated, but not #1 or #2).
  18  * Driver data holds all the per-chip data.
  19  */
  20 struct mcp23s08_driver_data {
  21         unsigned                ngpio;
  22         struct mcp23s08         *mcp[8];
  23         struct mcp23s08         chip[];
  24 };
  25
  26 static int mcp23sxx_spi_write(void *context, const void *data, size_t count)
  27 {
  28         struct mcp23s08 *mcp = context;
  29         struct spi_device *spi = to_spi_device(mcp->dev);
  30         struct spi_message m;
  31         struct spi_transfer t[2] = { { .tx_buf = &mcp->addr, .len = 1, },
  32                                      { .tx_buf = data, .len = count, }, };
  33
  34         spi_message_init(&m);
  35         spi_message_add_tail(&t[0], &m);
  36         spi_message_add_tail(&t[1], &m);
  37
  38         return spi_sync(spi, &m);
  39 }
  40
  41 static int mcp23sxx_spi_gather_write(void *context,
  42                                 const void *reg, size_t reg_size,
  43                                 const void *val, size_t val_size)
  44 {
  45         struct mcp23s08 *mcp = context;
  46         struct spi_device *spi = to_spi_device(mcp->dev);
  47         struct spi_message m;
  48         struct spi_transfer t[3] = { { .tx_buf = &mcp->addr, .len = 1, },
  49                                      { .tx_buf = reg, .len = reg_size, },
  50                                      { .tx_buf = val, .len = val_size, }, };
  51
  52         spi_message_init(&m);
  53         spi_message_add_tail(&t[0], &m);
  54         spi_message_add_tail(&t[1], &m);
  55         spi_message_add_tail(&t[2], &m);
  56
  57         return spi_sync(spi, &m);
  58 }
  59
  60 static int mcp23sxx_spi_read(void *context, const void *reg, size_t reg_size,
  61                                 void *val, size_t val_size)
  62 {
  63         struct mcp23s08 *mcp = context;
  64         struct spi_device *spi = to_spi_device(mcp->dev);
  65         u8 tx[2];
  66
  67         if (reg_size != 1)
  68                 return -EINVAL;
  69
  70         tx[0] = mcp->addr | 0x01;
  71         tx[1] = *((u8 *) reg);
  72
  73         return spi_write_then_read(spi, tx, sizeof(tx), val, val_size);
  74 }
  75
  76 static const struct regmap_bus mcp23sxx_spi_regmap = {
  77         .write = mcp23sxx_spi_write,
  78         .gather_write = mcp23sxx_spi_gather_write,
  79         .read = mcp23sxx_spi_read,
  80 };
  81
  82 static int mcp23s08_spi_regmap_init(struct mcp23s08 *mcp, struct device *dev,
  83                                     unsigned int addr, unsigned int type)
  84 {
  85         const struct regmap_config *config;
  86         struct regmap_config *copy;
  87         const char *name;
  88
  89         switch (type) {
  90         case MCP_TYPE_S08:
  91                 mcp->reg_shift = 0;
  92                 mcp->chip.ngpio = 8;
  93                 mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s08.%d", addr);
  94                 if (!mcp->chip.label)
  95                         return -ENOMEM;
  96
  97                 config = &mcp23x08_regmap;
  98                 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
  99                 if (!name)
 100                         return -ENOMEM;
 101
 102                 break;
 103
 104         case MCP_TYPE_S17:
 105                 mcp->reg_shift = 1;
 106                 mcp->chip.ngpio = 16;
 107                 mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s17.%d", addr);
 108                 if (!mcp->chip.label)
 109                         return -ENOMEM;
 110
 111                 config = &mcp23x17_regmap;
 112                 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
 113                 if (!name)
 114                         return -ENOMEM;
 115
 116                 break;
 117
 118         case MCP_TYPE_S18:
 119                 mcp->reg_shift = 1;
 120                 mcp->chip.ngpio = 16;
 121                 mcp->chip.label = "mcp23s18";
 122
 123                 config = &mcp23x17_regmap;
 124                 name = config->name;
 125                 break;
 126
 127         default:
 128                 dev_err(dev, "invalid device type (%d)\n", type);
 129                 return -EINVAL;
 130         }
 131
 132         copy = devm_kmemdup(dev, config, sizeof(*config), GFP_KERNEL);
 133         if (!copy)
 134                 return -ENOMEM;
 135
 136         copy->name = name;
 137
 138         mcp->regmap = devm_regmap_init(dev, &mcp23sxx_spi_regmap, mcp, copy);
 139         if (IS_ERR(mcp->regmap))
 140                 dev_err(dev, "regmap init failed for %s\n", mcp->chip.label);
 141         return PTR_ERR_OR_ZERO(mcp->regmap);
 142 }
 143
 144 static int mcp23s08_probe(struct spi_device *spi)
 145 {
 146         struct device *dev = &spi->dev;
 147         struct mcp23s08_driver_data *data;
 148         unsigned long spi_present_mask;
 149         const void *match;
 150         unsigned int addr;
 151         unsigned int ngpio = 0;
 152         int chips;
 153         int type;
 154         int ret;
 155         u32 v;
 156
 157         match = device_get_match_data(dev);
 158         if (match)
 159                 type = (int)(uintptr_t)match;
 160         else
 161                 type = spi_get_device_id(spi)->driver_data;
 162
 163         ret = device_property_read_u32(dev, "microchip,spi-present-mask", &v);
 164         if (ret) {
 165                 ret = device_property_read_u32(dev, "mcp,spi-present-mask", &v);
 166                 if (ret) {
 167                         dev_err(dev, "missing spi-present-mask");
 168                         return ret;
 169                 }
 170         }
 171         spi_present_mask = v;
 172
 173         if (!spi_present_mask || spi_present_mask >= BIT(MCP_MAX_DEV_PER_CS)) {
 174                 dev_err(dev, "invalid spi-present-mask");
 175                 return -ENODEV;
 176         }
 177
 178         chips = hweight_long(spi_present_mask);
 179
 180         data = devm_kzalloc(dev, struct_size(data, chip, chips), GFP_KERNEL);
 181         if (!data)
 182                 return -ENOMEM;
 183
 184         spi_set_drvdata(spi, data);
 185
 186         for_each_set_bit(addr, &spi_present_mask, MCP_MAX_DEV_PER_CS) {
 187                 data->mcp[addr] = &data->chip[--chips];
 188                 data->mcp[addr]->irq = spi->irq;
 189
 190                 ret = mcp23s08_spi_regmap_init(data->mcp[addr], dev, addr, type);
 191                 if (ret)
 192                         return ret;
 193
 194                 data->mcp[addr]->pinctrl_desc.name = devm_kasprintf(dev, GFP_KERNEL,
 195                                                                     "mcp23xxx-pinctrl.%d",
 196                                                                     addr);
 197                 if (!data->mcp[addr]->pinctrl_desc.name)
 198                         return -ENOMEM;
 199
 200                 ret = mcp23s08_probe_one(data->mcp[addr], dev, 0x40 | (addr << 1), type, -1);
 201                 if (ret < 0)
 202                         return ret;
 203
 204                 ngpio += data->mcp[addr]->chip.ngpio;
 205         }
 206         data->ngpio = ngpio;
 207
 208         return 0;
 209 }
 210
 211 static const struct spi_device_id mcp23s08_ids[] = {
 212         { "mcp23s08", MCP_TYPE_S08 },
 213         { "mcp23s17", MCP_TYPE_S17 },
 214         { "mcp23s18", MCP_TYPE_S18 },
 215         { }
 216 };
 217 MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
 218
 219 static const struct of_device_id mcp23s08_spi_of_match[] = {
 220         {
 221                 .compatible = "microchip,mcp23s08",
 222                 .data = (void *) MCP_TYPE_S08,
 223         },
 224         {
 225                 .compatible = "microchip,mcp23s17",
 226                 .data = (void *) MCP_TYPE_S17,
 227         },
 228         {
 229                 .compatible = "microchip,mcp23s18",
 230                 .data = (void *) MCP_TYPE_S18,
 231         },
 232 /* NOTE: The use of the mcp prefix is deprecated and will be removed. */
 233         {
 234                 .compatible = "mcp,mcp23s08",
 235                 .data = (void *) MCP_TYPE_S08,
 236         },
 237         {
 238                 .compatible = "mcp,mcp23s17",
 239                 .data = (void *) MCP_TYPE_S17,
 240         },
 241         { }
 242 };
 243 MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
 244
 245 static struct spi_driver mcp23s08_driver = {
 246         .probe          = mcp23s08_probe,
 247         .id_table       = mcp23s08_ids,
 248         .driver = {
 249                 .name   = "mcp23s08",
 250                 .of_match_table = mcp23s08_spi_of_match,
 251         },
 252 };
 253
 254 static int __init mcp23s08_spi_init(void)
 255 {
 256         return spi_register_driver(&mcp23s08_driver);
 257 }
 258
 259 /*
 260  * Register after SPI postcore initcall and before
 261  * subsys initcalls that may rely on these GPIOs.
 262  */
 263 subsys_initcall(mcp23s08_spi_init);
 264
 265 static void mcp23s08_spi_exit(void)
 266 {
 267         spi_unregister_driver(&mcp23s08_driver);
 268 }
 269 module_exit(mcp23s08_spi_exit);
 270
 271 MODULE_LICENSE("GPL");