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         if (IS_ERR(mcp->regmap))
 130                 dev_err(dev, "regmap init failed for %s\n", mcp->chip.label);
 131         return PTR_ERR_OR_ZERO(mcp->regmap);
 132 }
 133
 134 static int mcp23s08_probe(struct spi_device *spi)
 135 {
 136         struct device *dev = &spi->dev;
 137         struct mcp23s08_driver_data *data;
 138         unsigned long spi_present_mask;
 139         const void *match;
 140         unsigned int addr;
 141         unsigned int ngpio = 0;
 142         int chips;
 143         int type;
 144         int ret;
 145         u32 v;
 146
 147         match = device_get_match_data(dev);
 148         if (match)
 149                 type = (int)(uintptr_t)match;
 150         else
 151                 type = spi_get_device_id(spi)->driver_data;
 152
 153         ret = device_property_read_u32(dev, "microchip,spi-present-mask", &v);
 154         if (ret) {
 155                 ret = device_property_read_u32(dev, "mcp,spi-present-mask", &v);
 156                 if (ret) {
 157                         dev_err(dev, "missing spi-present-mask");
 158                         return ret;
 159                 }
 160         }
 161         spi_present_mask = v;
 162
 163         if (!spi_present_mask || spi_present_mask >= BIT(MCP_MAX_DEV_PER_CS)) {
 164                 dev_err(dev, "invalid spi-present-mask");
 165                 return -ENODEV;
 166         }
 167
 168         chips = hweight_long(spi_present_mask);
 169
 170         data = devm_kzalloc(dev, struct_size(data, chip, chips), GFP_KERNEL);
 171         if (!data)
 172                 return -ENOMEM;
 173
 174         spi_set_drvdata(spi, data);
 175
 176         for_each_set_bit(addr, &spi_present_mask, MCP_MAX_DEV_PER_CS) {
 177                 data->mcp[addr] = &data->chip[--chips];
 178                 data->mcp[addr]->irq = spi->irq;
 179
 180                 ret = mcp23s08_spi_regmap_init(data->mcp[addr], dev, addr, type);
 181                 if (ret)
 182                         return ret;
 183
 184                 data->mcp[addr]->pinctrl_desc.name = devm_kasprintf(dev, GFP_KERNEL,
 185                                                                     "mcp23xxx-pinctrl.%d",
 186                                                                     addr);
 187                 if (!data->mcp[addr]->pinctrl_desc.name)
 188                         return -ENOMEM;
 189
 190                 ret = mcp23s08_probe_one(data->mcp[addr], dev, 0x40 | (addr << 1), type, -1);
 191                 if (ret < 0)
 192                         return ret;
 193
 194                 ngpio += data->mcp[addr]->chip.ngpio;
 195         }
 196         data->ngpio = ngpio;
 197
 198         return 0;
 199 }
 200
 201 static const struct spi_device_id mcp23s08_ids[] = {
 202         { "mcp23s08", MCP_TYPE_S08 },
 203         { "mcp23s17", MCP_TYPE_S17 },
 204         { "mcp23s18", MCP_TYPE_S18 },
 205         { }
 206 };
 207 MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
 208
 209 static const struct of_device_id mcp23s08_spi_of_match[] = {
 210         {
 211                 .compatible = "microchip,mcp23s08",
 212                 .data = (void *) MCP_TYPE_S08,
 213         },
 214         {
 215                 .compatible = "microchip,mcp23s17",
 216                 .data = (void *) MCP_TYPE_S17,
 217         },
 218         {
 219                 .compatible = "microchip,mcp23s18",
 220                 .data = (void *) MCP_TYPE_S18,
 221         },
 222 /* NOTE: The use of the mcp prefix is deprecated and will be removed. */
 223         {
 224                 .compatible = "mcp,mcp23s08",
 225                 .data = (void *) MCP_TYPE_S08,
 226         },
 227         {
 228                 .compatible = "mcp,mcp23s17",
 229                 .data = (void *) MCP_TYPE_S17,
 230         },
 231         { }
 232 };
 233 MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
 234
 235 static struct spi_driver mcp23s08_driver = {
 236         .probe          = mcp23s08_probe,
 237         .id_table       = mcp23s08_ids,
 238         .driver = {
 239                 .name   = "mcp23s08",
 240                 .of_match_table = mcp23s08_spi_of_match,
 241         },
 242 };
 243
 244 static int __init mcp23s08_spi_init(void)
 245 {
 246         return spi_register_driver(&mcp23s08_driver);
 247 }
 248
 249 /*
 250  * Register after SPI postcore initcall and before
 251  * subsys initcalls that may rely on these GPIOs.
 252  */
 253 subsys_initcall(mcp23s08_spi_init);
 254
 255 static void mcp23s08_spi_exit(void)
 256 {
 257         spi_unregister_driver(&mcp23s08_driver);
 258 }
 259 module_exit(mcp23s08_spi_exit);
 260
 261 MODULE_LICENSE("GPL");