drivers/nvmem/qcom-spmi-sdam.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2017, 2020 The Linux Foundation. All rights reserved.
   4  */
   5
   6 #include <linux/device.h>
   7 #include <linux/module.h>
   8 #include <linux/of.h>
   9 #include <linux/of_platform.h>
  10 #include <linux/nvmem-provider.h>
  11 #include <linux/regmap.h>
  12
  13 #define SDAM_MEM_START                  0x40
  14 #define REGISTER_MAP_ID                 0x40
  15 #define REGISTER_MAP_VERSION            0x41
  16 #define SDAM_SIZE                       0x44
  17 #define SDAM_PBS_TRIG_SET               0xE5
  18 #define SDAM_PBS_TRIG_CLR               0xE6
  19
  20 struct sdam_chip {
  21         struct platform_device          *pdev;
  22         struct regmap                   *regmap;
  23         struct nvmem_config             sdam_config;
  24         unsigned int                    base;
  25         unsigned int                    size;
  26 };
  27
  28 /* read only register offsets */
  29 static const u8 sdam_ro_map[] = {
  30         REGISTER_MAP_ID,
  31         REGISTER_MAP_VERSION,
  32         SDAM_SIZE
  33 };
  34
  35 static bool sdam_is_valid(struct sdam_chip *sdam, unsigned int offset,
  36                                 size_t len)
  37 {
  38         unsigned int sdam_mem_end = SDAM_MEM_START + sdam->size - 1;
  39
  40         if (!len)
  41                 return false;
  42
  43         if (offset >= SDAM_MEM_START && offset <= sdam_mem_end
  44                                 && (offset + len - 1) <= sdam_mem_end)
  45                 return true;
  46         else if ((offset == SDAM_PBS_TRIG_SET || offset == SDAM_PBS_TRIG_CLR)
  47                                 && (len == 1))
  48                 return true;
  49
  50         return false;
  51 }
  52
  53 static bool sdam_is_ro(unsigned int offset, size_t len)
  54 {
  55         int i;
  56
  57         for (i = 0; i < ARRAY_SIZE(sdam_ro_map); i++)
  58                 if (offset <= sdam_ro_map[i] && (offset + len) > sdam_ro_map[i])
  59                         return true;
  60
  61         return false;
  62 }
  63
  64 static int sdam_read(void *priv, unsigned int offset, void *val,
  65                                 size_t bytes)
  66 {
  67         struct sdam_chip *sdam = priv;
  68         struct device *dev = &sdam->pdev->dev;
  69         int rc;
  70
  71         if (!sdam_is_valid(sdam, offset, bytes)) {
  72                 dev_err(dev, "Invalid SDAM offset %#x len=%zd\n",
  73                         offset, bytes);
  74                 return -EINVAL;
  75         }
  76
  77         rc = regmap_bulk_read(sdam->regmap, sdam->base + offset, val, bytes);
  78         if (rc < 0)
  79                 dev_err(dev, "Failed to read SDAM offset %#x len=%zd, rc=%d\n",
  80                                                 offset, bytes, rc);
  81
  82         return rc;
  83 }
  84
  85 static int sdam_write(void *priv, unsigned int offset, void *val,
  86                                 size_t bytes)
  87 {
  88         struct sdam_chip *sdam = priv;
  89         struct device *dev = &sdam->pdev->dev;
  90         int rc;
  91
  92         if (!sdam_is_valid(sdam, offset, bytes)) {
  93                 dev_err(dev, "Invalid SDAM offset %#x len=%zd\n",
  94                         offset, bytes);
  95                 return -EINVAL;
  96         }
  97
  98         if (sdam_is_ro(offset, bytes)) {
  99                 dev_err(dev, "Invalid write offset %#x len=%zd\n",
 100                         offset, bytes);
 101                 return -EINVAL;
 102         }
 103
 104         rc = regmap_bulk_write(sdam->regmap, sdam->base + offset, val, bytes);
 105         if (rc < 0)
 106                 dev_err(dev, "Failed to write SDAM offset %#x len=%zd, rc=%d\n",
 107                                                 offset, bytes, rc);
 108
 109         return rc;
 110 }
 111
 112 static int sdam_probe(struct platform_device *pdev)
 113 {
 114         struct sdam_chip *sdam;
 115         struct nvmem_device *nvmem;
 116         unsigned int val;
 117         int rc;
 118
 119         sdam = devm_kzalloc(&pdev->dev, sizeof(*sdam), GFP_KERNEL);
 120         if (!sdam)
 121                 return -ENOMEM;
 122
 123         sdam->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 124         if (!sdam->regmap) {
 125                 dev_err(&pdev->dev, "Failed to get regmap handle\n");
 126                 return -ENXIO;
 127         }
 128
 129         rc = of_property_read_u32(pdev->dev.of_node, "reg", &sdam->base);
 130         if (rc < 0) {
 131                 dev_err(&pdev->dev, "Failed to get SDAM base, rc=%d\n", rc);
 132                 return -EINVAL;
 133         }
 134
 135         rc = regmap_read(sdam->regmap, sdam->base + SDAM_SIZE, &val);
 136         if (rc < 0) {
 137                 dev_err(&pdev->dev, "Failed to read SDAM_SIZE rc=%d\n", rc);
 138                 return -EINVAL;
 139         }
 140         sdam->size = val * 32;
 141
 142         sdam->sdam_config.dev = &pdev->dev;
 143         sdam->sdam_config.name = "spmi_sdam";
 144         sdam->sdam_config.id = NVMEM_DEVID_AUTO;
 145         sdam->sdam_config.owner = THIS_MODULE,
 146         sdam->sdam_config.stride = 1;
 147         sdam->sdam_config.word_size = 1;
 148         sdam->sdam_config.reg_read = sdam_read;
 149         sdam->sdam_config.reg_write = sdam_write;
 150         sdam->sdam_config.priv = sdam;
 151
 152         nvmem = devm_nvmem_register(&pdev->dev, &sdam->sdam_config);
 153         if (IS_ERR(nvmem)) {
 154                 dev_err(&pdev->dev,
 155                         "Failed to register SDAM nvmem device rc=%ld\n",
 156                         PTR_ERR(nvmem));
 157                 return -ENXIO;
 158         }
 159         dev_dbg(&pdev->dev,
 160                 "SDAM base=%#x size=%u registered successfully\n",
 161                 sdam->base, sdam->size);
 162
 163         return 0;
 164 }
 165
 166 static const struct of_device_id sdam_match_table[] = {
 167         { .compatible = "qcom,spmi-sdam" },
 168         {},
 169 };
 170
 171 static struct platform_driver sdam_driver = {
 172         .driver = {
 173                 .name = "qcom,spmi-sdam",
 174                 .of_match_table = sdam_match_table,
 175         },
 176         .probe          = sdam_probe,
 177 };
 178
 179 static int __init sdam_init(void)
 180 {
 181         return platform_driver_register(&sdam_driver);
 182 }
 183 subsys_initcall(sdam_init);
 184
 185 static void __exit sdam_exit(void)
 186 {
 187         return platform_driver_unregister(&sdam_driver);
 188 }
 189 module_exit(sdam_exit);
 190
 191 MODULE_DESCRIPTION("QCOM SPMI SDAM driver");
 192 MODULE_LICENSE("GPL v2");