drivers/mfd/rsmu_spi.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * SPI driver for Renesas Synchronization Management Unit (SMU) devices.
   4  *
   5  * Copyright (C) 2021 Integrated Device Technology, Inc., a Renesas Company.
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/kernel.h>
  10 #include <linux/mfd/core.h>
  11 #include <linux/mfd/rsmu.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/regmap.h>
  15 #include <linux/slab.h>
  16 #include <linux/spi/spi.h>
  17
  18 #include "rsmu.h"
  19
  20 #define RSMU_CM_PAGE_ADDR               0x7C
  21 #define RSMU_SABRE_PAGE_ADDR            0x7F
  22 #define RSMU_PAGE_MASK                  0xFFFFFF80
  23 #define RSMU_ADDR_MASK                  0x7F
  24
  25 static int rsmu_read_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes)
  26 {
  27         struct spi_device *client = to_spi_device(rsmu->dev);
  28         struct spi_transfer xfer = {0};
  29         struct spi_message msg;
  30         u8 cmd[RSMU_MAX_READ_COUNT + 1] = {0};
  31         u8 rsp[RSMU_MAX_READ_COUNT + 1] = {0};
  32         int ret;
  33
  34         if (bytes > RSMU_MAX_READ_COUNT)
  35                 return -EINVAL;
  36
  37         cmd[0] = reg | 0x80;
  38         xfer.rx_buf = rsp;
  39         xfer.len = bytes + 1;
  40         xfer.tx_buf = cmd;
  41         xfer.bits_per_word = client->bits_per_word;
  42         xfer.speed_hz = client->max_speed_hz;
  43
  44         spi_message_init(&msg);
  45         spi_message_add_tail(&xfer, &msg);
  46
  47         /*
  48          * 4-wire SPI is a shift register, so for every byte you send,
  49          * you get one back at the same time. Example read from 0xC024,
  50          * which has value of 0x2D
  51          *
  52          * MOSI:
  53          *       7C 00 C0 #Set page register
  54          *       A4 00    #MSB is set, so this is read command
  55          * MISO:
  56          *       XX 2D    #XX is a dummy byte from sending A4 and we
  57          *                 need to throw it away
  58          */
  59         ret = spi_sync(client, &msg);
  60         if (ret >= 0)
  61                 memcpy(buf, &rsp[1], xfer.len-1);
  62
  63         return ret;
  64 }
  65
  66 static int rsmu_write_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes)
  67 {
  68         struct spi_device *client = to_spi_device(rsmu->dev);
  69         struct spi_transfer xfer = {0};
  70         struct spi_message msg;
  71         u8 cmd[RSMU_MAX_WRITE_COUNT + 1] = {0};
  72
  73         if (bytes > RSMU_MAX_WRITE_COUNT)
  74                 return -EINVAL;
  75
  76         cmd[0] = reg;
  77         memcpy(&cmd[1], buf, bytes);
  78
  79         xfer.len = bytes + 1;
  80         xfer.tx_buf = cmd;
  81         xfer.bits_per_word = client->bits_per_word;
  82         xfer.speed_hz = client->max_speed_hz;
  83         spi_message_init(&msg);
  84         spi_message_add_tail(&xfer, &msg);
  85
  86         return  spi_sync(client, &msg);
  87 }
  88
  89 /*
  90  * 1-byte (1B) offset addressing:
  91  * 16-bit register address: the lower 7 bits of the register address come
  92  * from the offset addr byte and the upper 9 bits come from the page register.
  93  */
  94 static int rsmu_write_page_register(struct rsmu_ddata *rsmu, u32 reg)
  95 {
  96         u8 page_reg;
  97         u8 buf[4];
  98         u16 bytes;
  99         u32 page;
 100         int err;
 101
 102         switch (rsmu->type) {
 103         case RSMU_CM:
 104                 /* Do not modify page register for none-scsr registers */
 105                 if (reg < RSMU_CM_SCSR_BASE)
 106                         return 0;
 107                 page_reg = RSMU_CM_PAGE_ADDR;
 108                 page = reg & RSMU_PAGE_MASK;
 109                 buf[0] = (u8)(page & 0xFF);
 110                 buf[1] = (u8)((page >> 8) & 0xFF);
 111                 buf[2] = (u8)((page >> 16) & 0xFF);
 112                 buf[3] = (u8)((page >> 24) & 0xFF);
 113                 bytes = 4;
 114                 break;
 115         case RSMU_SABRE:
 116                 /* Do not modify page register if reg is page register itself */
 117                 if ((reg & RSMU_ADDR_MASK) == RSMU_ADDR_MASK)
 118                         return 0;
 119                 page_reg = RSMU_SABRE_PAGE_ADDR;
 120                 page = reg & RSMU_PAGE_MASK;
 121                 /* The three page bits are located in the single Page Register */
 122                 buf[0] = (u8)((page >> 7) & 0x7);
 123                 bytes = 1;
 124                 break;
 125         default:
 126                 dev_err(rsmu->dev, "Unsupported RSMU device type: %d\n", rsmu->type);
 127                 return -ENODEV;
 128         }
 129
 130         /* Simply return if we are on the same page */
 131         if (rsmu->page == page)
 132                 return 0;
 133
 134         err = rsmu_write_device(rsmu, page_reg, buf, bytes);
 135         if (err)
 136                 dev_err(rsmu->dev, "Failed to set page offset 0x%x\n", page);
 137         else
 138                 /* Remember the last page */
 139                 rsmu->page = page;
 140
 141         return err;
 142 }
 143
 144 static int rsmu_reg_read(void *context, unsigned int reg, unsigned int *val)
 145 {
 146         struct rsmu_ddata *rsmu = spi_get_drvdata((struct spi_device *)context);
 147         u8 addr = (u8)(reg & RSMU_ADDR_MASK);
 148         int err;
 149
 150         err = rsmu_write_page_register(rsmu, reg);
 151         if (err)
 152                 return err;
 153
 154         err = rsmu_read_device(rsmu, addr, (u8 *)val, 1);
 155         if (err)
 156                 dev_err(rsmu->dev, "Failed to read offset address 0x%x\n", addr);
 157
 158         return err;
 159 }
 160
 161 static int rsmu_reg_write(void *context, unsigned int reg, unsigned int val)
 162 {
 163         struct rsmu_ddata *rsmu = spi_get_drvdata((struct spi_device *)context);
 164         u8 addr = (u8)(reg & RSMU_ADDR_MASK);
 165         u8 data = (u8)val;
 166         int err;
 167
 168         err = rsmu_write_page_register(rsmu, reg);
 169         if (err)
 170                 return err;
 171
 172         err = rsmu_write_device(rsmu, addr, &data, 1);
 173         if (err)
 174                 dev_err(rsmu->dev,
 175                         "Failed to write offset address 0x%x\n", addr);
 176
 177         return err;
 178 }
 179
 180 static const struct regmap_config rsmu_cm_regmap_config = {
 181         .reg_bits = 32,
 182         .val_bits = 8,
 183         .max_register = 0x20120000,
 184         .reg_read = rsmu_reg_read,
 185         .reg_write = rsmu_reg_write,
 186         .cache_type = REGCACHE_NONE,
 187 };
 188
 189 static const struct regmap_config rsmu_sabre_regmap_config = {
 190         .reg_bits = 16,
 191         .val_bits = 8,
 192         .max_register = 0x400,
 193         .reg_read = rsmu_reg_read,
 194         .reg_write = rsmu_reg_write,
 195         .cache_type = REGCACHE_NONE,
 196 };
 197
 198 static int rsmu_spi_probe(struct spi_device *client)
 199 {
 200         const struct spi_device_id *id = spi_get_device_id(client);
 201         const struct regmap_config *cfg;
 202         struct rsmu_ddata *rsmu;
 203         int ret;
 204
 205         rsmu = devm_kzalloc(&client->dev, sizeof(*rsmu), GFP_KERNEL);
 206         if (!rsmu)
 207                 return -ENOMEM;
 208
 209         spi_set_drvdata(client, rsmu);
 210
 211         rsmu->dev = &client->dev;
 212         rsmu->type = (enum rsmu_type)id->driver_data;
 213
 214         /* Initialize regmap */
 215         switch (rsmu->type) {
 216         case RSMU_CM:
 217                 cfg = &rsmu_cm_regmap_config;
 218                 break;
 219         case RSMU_SABRE:
 220                 cfg = &rsmu_sabre_regmap_config;
 221                 break;
 222         default:
 223                 dev_err(rsmu->dev, "Unsupported RSMU device type: %d\n", rsmu->type);
 224                 return -ENODEV;
 225         }
 226
 227         rsmu->regmap = devm_regmap_init(&client->dev, NULL, client, cfg);
 228         if (IS_ERR(rsmu->regmap)) {
 229                 ret = PTR_ERR(rsmu->regmap);
 230                 dev_err(rsmu->dev, "Failed to allocate register map: %d\n", ret);
 231                 return ret;
 232         }
 233
 234         return rsmu_core_init(rsmu);
 235 }
 236
 237 static void rsmu_spi_remove(struct spi_device *client)
 238 {
 239         struct rsmu_ddata *rsmu = spi_get_drvdata(client);
 240
 241         rsmu_core_exit(rsmu);
 242 }
 243
 244 static const struct spi_device_id rsmu_spi_id[] = {
 245         { "8a34000",  RSMU_CM },
 246         { "8a34001",  RSMU_CM },
 247         { "82p33810", RSMU_SABRE },
 248         { "82p33811", RSMU_SABRE },
 249         {}
 250 };
 251 MODULE_DEVICE_TABLE(spi, rsmu_spi_id);
 252
 253 static const struct of_device_id rsmu_spi_of_match[] = {
 254         { .compatible = "idt,8a34000",  .data = (void *)RSMU_CM },
 255         { .compatible = "idt,8a34001",  .data = (void *)RSMU_CM },
 256         { .compatible = "idt,82p33810", .data = (void *)RSMU_SABRE },
 257         { .compatible = "idt,82p33811", .data = (void *)RSMU_SABRE },
 258         {}
 259 };
 260 MODULE_DEVICE_TABLE(of, rsmu_spi_of_match);
 261
 262 static struct spi_driver rsmu_spi_driver = {
 263         .driver = {
 264                 .name = "rsmu-spi",
 265                 .of_match_table = rsmu_spi_of_match,
 266         },
 267         .probe = rsmu_spi_probe,
 268         .remove = rsmu_spi_remove,
 269         .id_table = rsmu_spi_id,
 270 };
 271
 272 static int __init rsmu_spi_init(void)
 273 {
 274         return spi_register_driver(&rsmu_spi_driver);
 275 }
 276 subsys_initcall(rsmu_spi_init);
 277
 278 static void __exit rsmu_spi_exit(void)
 279 {
 280         spi_unregister_driver(&rsmu_spi_driver);
 281 }
 282 module_exit(rsmu_spi_exit);
 283
 284 MODULE_DESCRIPTION("Renesas SMU SPI driver");
 285 MODULE_LICENSE("GPL");