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
  95                 config = &mcp23x08_regmap;
  96                 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
  97                 break;
  98
  99         case MCP_TYPE_S17:
 100                 mcp->reg_shift = 1;
 101                 mcp->chip.ngpio = 16;
 102                 mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s17.%d", addr);
 103
 104                 config = &mcp23x17_regmap;
 105                 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
 106                 break;
 107
 108         case MCP_TYPE_S18:
 109                 mcp->reg_shift = 1;
 110                 mcp->chip.ngpio = 16;
 111                 mcp->chip.label = "mcp23s18";
 112
 113                 config = &mcp23x17_regmap;
 114                 name = config->name;
 115                 break;
 116
 117         default:
 118                 dev_err(dev, "invalid device type (%d)\n", type);
 119                 return -EINVAL;
 120         }
 121
 122         copy = devm_kmemdup(dev, &config, sizeof(config), GFP_KERNEL);
 123         if (!copy)
 124                 return -ENOMEM;
 125
 126         copy->name = name;
 127
 128         mcp->regmap = devm_regmap_init(dev, &mcp23sxx_spi_regmap, mcp, copy);
 129         return PTR_ERR_OR_ZERO(mcp->regmap);
 130 }
 131
 132 static int mcp23s08_probe(struct spi_device *spi)
 133 {
 134         struct device *dev = &spi->dev;
 135         struct mcp23s08_driver_data *data;
 136         unsigned long spi_present_mask;
 137         const void *match;
 138         unsigned int addr;
 139         unsigned int ngpio = 0;
 140         int chips;
 141         int type;
 142         int ret;
 143         u32 v;
 144
 145         match = device_get_match_data(dev);
 146         if (match)
 147                 type = (int)(uintptr_t)match;
 148         else
 149                 type = spi_get_device_id(spi)->driver_data;
 150
 151         ret = device_property_read_u32(dev, "microchip,spi-present-mask", &v);
 152         if (ret) {
 153                 ret = device_property_read_u32(dev, "mcp,spi-present-mask", &v);
 154                 if (ret) {
 155                         dev_err(dev, "missing spi-present-mask");
 156                         return ret;
 157                 }
 158         }
 159         spi_present_mask = v;
 160
 161         if (!spi_present_mask || spi_present_mask >= BIT(MCP_MAX_DEV_PER_CS)) {
 162                 dev_err(dev, "invalid spi-present-mask");
 163                 return -ENODEV;
 164         }
 165
 166         chips = hweight_long(spi_present_mask);
 167
 168         data = devm_kzalloc(dev, struct_size(data, chip, chips), GFP_KERNEL);
 169         if (!data)
 170                 return -ENOMEM;
 171
 172         spi_set_drvdata(spi, data);
 173
 174         for_each_set_bit(addr, &spi_present_mask, MCP_MAX_DEV_PER_CS) {
 175                 data->mcp[addr] = &data->chip[--chips];
 176                 data->mcp[addr]->irq = spi->irq;
 177
 178                 ret = mcp23s08_spi_regmap_init(data->mcp[addr], dev, addr, type);
 179                 if (ret)
 180                         return ret;
 181
 182                 data->mcp[addr]->pinctrl_desc.name = devm_kasprintf(dev, GFP_KERNEL,
 183                                                                     "mcp23xxx-pinctrl.%d",
 184                                                                     addr);
 185                 if (!data->mcp[addr]->pinctrl_desc.name)
 186                         return -ENOMEM;
 187
 188                 ret = mcp23s08_probe_one(data->mcp[addr], dev, 0x40 | (addr << 1), type, -1);
 189                 if (ret < 0)
 190                         return ret;
 191
 192                 ngpio += data->mcp[addr]->chip.ngpio;
 193         }
 194         data->ngpio = ngpio;
 195
 196         return 0;
 197 }
 198
 199 static const struct spi_device_id mcp23s08_ids[] = {
 200         { "mcp23s08", MCP_TYPE_S08 },
 201         { "mcp23s17", MCP_TYPE_S17 },
 202         { "mcp23s18", MCP_TYPE_S18 },
 203         { }
 204 };
 205 MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
 206
 207 static const struct of_device_id mcp23s08_spi_of_match[] = {
 208         {
 209                 .compatible = "microchip,mcp23s08",
 210                 .data = (void *) MCP_TYPE_S08,
 211         },
 212         {
 213                 .compatible = "microchip,mcp23s17",
 214                 .data = (void *) MCP_TYPE_S17,
 215         },
 216         {
 217                 .compatible = "microchip,mcp23s18",
 218                 .data = (void *) MCP_TYPE_S18,
 219         },
 220 /* NOTE: The use of the mcp prefix is deprecated and will be removed. */
 221         {
 222                 .compatible = "mcp,mcp23s08",
 223                 .data = (void *) MCP_TYPE_S08,
 224         },
 225         {
 226                 .compatible = "mcp,mcp23s17",
 227                 .data = (void *) MCP_TYPE_S17,
 228         },
 229         { }
 230 };
 231 MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
 232
 233 static struct spi_driver mcp23s08_driver = {
 234         .probe          = mcp23s08_probe,
 235         .id_table       = mcp23s08_ids,
 236         .driver = {
 237                 .name   = "mcp23s08",
 238                 .of_match_table = mcp23s08_spi_of_match,
 239         },
 240 };
 241
 242 static int __init mcp23s08_spi_init(void)
 243 {
 244         return spi_register_driver(&mcp23s08_driver);
 245 }
 246
 247 /*
 248  * Register after SPI postcore initcall and before
 249  * subsys initcalls that may rely on these GPIOs.
 250  */
 251 subsys_initcall(mcp23s08_spi_init);
 252
 253 static void mcp23s08_spi_exit(void)
 254 {
 255         spi_unregister_driver(&mcp23s08_driver);
 256 }
 257 module_exit(mcp23s08_spi_exit);
 258
 259 MODULE_LICENSE("GPL");