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,
  84                                     const struct mcp23s08_info *info)
  85 {
  86         struct regmap_config *copy;
  87         const char *name;
  88
  89         switch (info->type) {
  90         case MCP_TYPE_S08:
  91                 mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s08.%d", addr);
  92                 if (!mcp->chip.label)
  93                         return -ENOMEM;
  94
  95                 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
  96                 if (!name)
  97                         return -ENOMEM;
  98
  99                 break;
 100
 101         case MCP_TYPE_S17:
 102                 mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s17.%d", addr);
 103                 if (!mcp->chip.label)
 104                         return -ENOMEM;
 105
 106                 name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
 107                 if (!name)
 108                         return -ENOMEM;
 109
 110                 break;
 111
 112         case MCP_TYPE_S18:
 113                 mcp->chip.label = info->label;
 114                 name = info->regmap->name;
 115                 break;
 116
 117         default:
 118                 dev_err(dev, "invalid device type (%d)\n", info->type);
 119                 return -EINVAL;
 120         }
 121
 122         mcp->reg_shift = info->reg_shift;
 123         mcp->chip.ngpio = info->ngpio;
 124         copy = devm_kmemdup(dev, info->regmap, sizeof(*info->regmap), GFP_KERNEL);
 125         if (!copy)
 126                 return -ENOMEM;
 127
 128         copy->name = name;
 129
 130         mcp->regmap = devm_regmap_init(dev, &mcp23sxx_spi_regmap, mcp, copy);
 131         if (IS_ERR(mcp->regmap))
 132                 dev_err(dev, "regmap init failed for %s\n", mcp->chip.label);
 133         return PTR_ERR_OR_ZERO(mcp->regmap);
 134 }
 135
 136 static int mcp23s08_probe(struct spi_device *spi)
 137 {
 138         struct mcp23s08_driver_data *data;
 139         const struct mcp23s08_info *info;
 140         struct device *dev = &spi->dev;
 141         unsigned long spi_present_mask;
 142         unsigned int ngpio = 0;
 143         unsigned int addr;
 144         int chips;
 145         int ret;
 146         u32 v;
 147
 148         info = spi_get_device_match_data(spi);
 149
 150         ret = device_property_read_u32(dev, "microchip,spi-present-mask", &v);
 151         if (ret) {
 152                 ret = device_property_read_u32(dev, "mcp,spi-present-mask", &v);
 153                 if (ret) {
 154                         dev_err(dev, "missing spi-present-mask");
 155                         return ret;
 156                 }
 157         }
 158         spi_present_mask = v;
 159
 160         if (!spi_present_mask || spi_present_mask >= BIT(MCP_MAX_DEV_PER_CS)) {
 161                 dev_err(dev, "invalid spi-present-mask");
 162                 return -ENODEV;
 163         }
 164
 165         chips = hweight_long(spi_present_mask);
 166
 167         data = devm_kzalloc(dev, struct_size(data, chip, chips), GFP_KERNEL);
 168         if (!data)
 169                 return -ENOMEM;
 170
 171         spi_set_drvdata(spi, data);
 172
 173         for_each_set_bit(addr, &spi_present_mask, MCP_MAX_DEV_PER_CS) {
 174                 data->mcp[addr] = &data->chip[--chips];
 175                 data->mcp[addr]->irq = spi->irq;
 176
 177                 ret = mcp23s08_spi_regmap_init(data->mcp[addr], dev, addr, info);
 178                 if (ret)
 179                         return ret;
 180
 181                 data->mcp[addr]->pinctrl_desc.name = devm_kasprintf(dev, GFP_KERNEL,
 182                                                                     "mcp23xxx-pinctrl.%d",
 183                                                                     addr);
 184                 if (!data->mcp[addr]->pinctrl_desc.name)
 185                         return -ENOMEM;
 186
 187                 ret = mcp23s08_probe_one(data->mcp[addr], dev, 0x40 | (addr << 1),
 188                                          info->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 mcp23s08_info mcp23s08_spi = {
 200         .regmap = &mcp23x08_regmap,
 201         .type = MCP_TYPE_S08,
 202         .ngpio = 8,
 203         .reg_shift = 0,
 204 };
 205
 206 static const struct mcp23s08_info mcp23s17_spi = {
 207         .regmap = &mcp23x17_regmap,
 208         .type = MCP_TYPE_S17,
 209         .ngpio = 16,
 210         .reg_shift = 1,
 211 };
 212
 213 static const struct mcp23s08_info mcp23s18_spi = {
 214         .regmap = &mcp23x17_regmap,
 215         .label = "mcp23s18",
 216         .type = MCP_TYPE_S18,
 217         .ngpio = 16,
 218         .reg_shift = 1,
 219 };
 220
 221 static const struct spi_device_id mcp23s08_ids[] = {
 222         { "mcp23s08", (kernel_ulong_t)&mcp23s08_spi },
 223         { "mcp23s17", (kernel_ulong_t)&mcp23s17_spi },
 224         { "mcp23s18", (kernel_ulong_t)&mcp23s18_spi },
 225         { }
 226 };
 227 MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
 228
 229 static const struct of_device_id mcp23s08_spi_of_match[] = {
 230         { .compatible = "microchip,mcp23s08", .data = &mcp23s08_spi },
 231         { .compatible = "microchip,mcp23s17", .data = &mcp23s17_spi },
 232         { .compatible = "microchip,mcp23s18", .data = &mcp23s18_spi },
 233 /* NOTE: The use of the mcp prefix is deprecated and will be removed. */
 234         { .compatible = "mcp,mcp23s08", .data = &mcp23s08_spi },
 235         { .compatible = "mcp,mcp23s17", .data = &mcp23s17_spi },
 236         { }
 237 };
 238 MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
 239
 240 static struct spi_driver mcp23s08_driver = {
 241         .probe          = mcp23s08_probe,
 242         .id_table       = mcp23s08_ids,
 243         .driver = {
 244                 .name   = "mcp23s08",
 245                 .of_match_table = mcp23s08_spi_of_match,
 246         },
 247 };
 248
 249 static int __init mcp23s08_spi_init(void)
 250 {
 251         return spi_register_driver(&mcp23s08_driver);
 252 }
 253
 254 /*
 255  * Register after SPI postcore initcall and before
 256  * subsys initcalls that may rely on these GPIOs.
 257  */
 258 subsys_initcall(mcp23s08_spi_init);
 259
 260 static void mcp23s08_spi_exit(void)
 261 {
 262         spi_unregister_driver(&mcp23s08_driver);
 263 }
 264 module_exit(mcp23s08_spi_exit);
 265
 266 MODULE_LICENSE("GPL");