drivers/nvmem/lan9662-otpc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/iopoll.h>
   4 #include <linux/module.h>
   5 #include <linux/nvmem-provider.h>
   6 #include <linux/of.h>
   7 #include <linux/platform_device.h>
   8
   9 #define OTP_OTP_PWR_DN(t)                       (t + 0x00)
  10 #define OTP_OTP_PWR_DN_OTP_PWRDN_N              BIT(0)
  11 #define OTP_OTP_ADDR_HI(t)                      (t + 0x04)
  12 #define OTP_OTP_ADDR_LO(t)                      (t + 0x08)
  13 #define OTP_OTP_PRGM_DATA(t)                    (t + 0x10)
  14 #define OTP_OTP_PRGM_MODE(t)                    (t + 0x14)
  15 #define OTP_OTP_PRGM_MODE_OTP_PGM_MODE_BYTE     BIT(0)
  16 #define OTP_OTP_RD_DATA(t)                      (t + 0x18)
  17 #define OTP_OTP_FUNC_CMD(t)                     (t + 0x20)
  18 #define OTP_OTP_FUNC_CMD_OTP_PROGRAM            BIT(1)
  19 #define OTP_OTP_FUNC_CMD_OTP_READ               BIT(0)
  20 #define OTP_OTP_CMD_GO(t)                       (t + 0x28)
  21 #define OTP_OTP_CMD_GO_OTP_GO                   BIT(0)
  22 #define OTP_OTP_PASS_FAIL(t)                    (t + 0x2c)
  23 #define OTP_OTP_PASS_FAIL_OTP_READ_PROHIBITED   BIT(3)
  24 #define OTP_OTP_PASS_FAIL_OTP_WRITE_PROHIBITED  BIT(2)
  25 #define OTP_OTP_PASS_FAIL_OTP_FAIL              BIT(0)
  26 #define OTP_OTP_STATUS(t)                       (t + 0x30)
  27 #define OTP_OTP_STATUS_OTP_CPUMPEN              BIT(1)
  28 #define OTP_OTP_STATUS_OTP_BUSY                 BIT(0)
  29
  30 #define OTP_MEM_SIZE 8192
  31 #define OTP_SLEEP_US 10
  32 #define OTP_TIMEOUT_US 500000
  33
  34 struct lan9662_otp {
  35         struct device *dev;
  36         void __iomem *base;
  37 };
  38
  39 static int lan9662_otp_wait_flag_clear(void __iomem *reg, u32 flag)
  40 {
  41         u32 val;
  42
  43         return readl_poll_timeout(reg, val, !(val & flag),
  44                                   OTP_SLEEP_US, OTP_TIMEOUT_US);
  45 }
  46
  47 static int lan9662_otp_power(struct lan9662_otp *otp, bool up)
  48 {
  49         void __iomem *pwrdn = OTP_OTP_PWR_DN(otp->base);
  50
  51         if (up) {
  52                 writel(readl(pwrdn) & ~OTP_OTP_PWR_DN_OTP_PWRDN_N, pwrdn);
  53                 if (lan9662_otp_wait_flag_clear(OTP_OTP_STATUS(otp->base),
  54                                                 OTP_OTP_STATUS_OTP_CPUMPEN))
  55                         return -ETIMEDOUT;
  56         } else {
  57                 writel(readl(pwrdn) | OTP_OTP_PWR_DN_OTP_PWRDN_N, pwrdn);
  58         }
  59
  60         return 0;
  61 }
  62
  63 static int lan9662_otp_execute(struct lan9662_otp *otp)
  64 {
  65         if (lan9662_otp_wait_flag_clear(OTP_OTP_CMD_GO(otp->base),
  66                                         OTP_OTP_CMD_GO_OTP_GO))
  67                 return -ETIMEDOUT;
  68
  69         if (lan9662_otp_wait_flag_clear(OTP_OTP_STATUS(otp->base),
  70                                         OTP_OTP_STATUS_OTP_BUSY))
  71                 return -ETIMEDOUT;
  72
  73         return 0;
  74 }
  75
  76 static void lan9662_otp_set_address(struct lan9662_otp *otp, u32 offset)
  77 {
  78         writel(0xff & (offset >> 8), OTP_OTP_ADDR_HI(otp->base));
  79         writel(0xff & offset, OTP_OTP_ADDR_LO(otp->base));
  80 }
  81
  82 static int lan9662_otp_read_byte(struct lan9662_otp *otp, u32 offset, u8 *dst)
  83 {
  84         u32 pass;
  85         int rc;
  86
  87         lan9662_otp_set_address(otp, offset);
  88         writel(OTP_OTP_FUNC_CMD_OTP_READ, OTP_OTP_FUNC_CMD(otp->base));
  89         writel(OTP_OTP_CMD_GO_OTP_GO, OTP_OTP_CMD_GO(otp->base));
  90         rc = lan9662_otp_execute(otp);
  91         if (!rc) {
  92                 pass = readl(OTP_OTP_PASS_FAIL(otp->base));
  93                 if (pass & OTP_OTP_PASS_FAIL_OTP_READ_PROHIBITED)
  94                         return -EACCES;
  95                 *dst = (u8) readl(OTP_OTP_RD_DATA(otp->base));
  96         }
  97         return rc;
  98 }
  99
 100 static int lan9662_otp_write_byte(struct lan9662_otp *otp, u32 offset, u8 data)
 101 {
 102         u32 pass;
 103         int rc;
 104
 105         lan9662_otp_set_address(otp, offset);
 106         writel(OTP_OTP_PRGM_MODE_OTP_PGM_MODE_BYTE, OTP_OTP_PRGM_MODE(otp->base));
 107         writel(data, OTP_OTP_PRGM_DATA(otp->base));
 108         writel(OTP_OTP_FUNC_CMD_OTP_PROGRAM, OTP_OTP_FUNC_CMD(otp->base));
 109         writel(OTP_OTP_CMD_GO_OTP_GO, OTP_OTP_CMD_GO(otp->base));
 110
 111         rc = lan9662_otp_execute(otp);
 112         if (!rc) {
 113                 pass = readl(OTP_OTP_PASS_FAIL(otp->base));
 114                 if (pass & OTP_OTP_PASS_FAIL_OTP_WRITE_PROHIBITED)
 115                         return -EACCES;
 116                 if (pass & OTP_OTP_PASS_FAIL_OTP_FAIL)
 117                         return -EIO;
 118         }
 119         return rc;
 120 }
 121
 122 static int lan9662_otp_read(void *context, unsigned int offset,
 123                             void *_val, size_t bytes)
 124 {
 125         struct lan9662_otp *otp = context;
 126         u8 *val = _val;
 127         uint8_t data;
 128         int i, rc = 0;
 129
 130         lan9662_otp_power(otp, true);
 131         for (i = 0; i < bytes; i++) {
 132                 rc = lan9662_otp_read_byte(otp, offset + i, &data);
 133                 if (rc < 0)
 134                         break;
 135                 *val++ = data;
 136         }
 137         lan9662_otp_power(otp, false);
 138
 139         return rc;
 140 }
 141
 142 static int lan9662_otp_write(void *context, unsigned int offset,
 143                              void *_val, size_t bytes)
 144 {
 145         struct lan9662_otp *otp = context;
 146         u8 *val = _val;
 147         u8 data, newdata;
 148         int i, rc = 0;
 149
 150         lan9662_otp_power(otp, true);
 151         for (i = 0; i < bytes; i++) {
 152                 /* Skip zero bytes */
 153                 if (val[i]) {
 154                         rc = lan9662_otp_read_byte(otp, offset + i, &data);
 155                         if (rc < 0)
 156                                 break;
 157
 158                         newdata = data | val[i];
 159                         if (newdata == data)
 160                                 continue;
 161
 162                         rc = lan9662_otp_write_byte(otp, offset + i,
 163                                                       newdata);
 164                         if (rc < 0)
 165                                 break;
 166                 }
 167         }
 168         lan9662_otp_power(otp, false);
 169
 170         return rc;
 171 }
 172
 173 static struct nvmem_config otp_config = {
 174         .name = "lan9662-otp",
 175         .stride = 1,
 176         .word_size = 1,
 177         .reg_read = lan9662_otp_read,
 178         .reg_write = lan9662_otp_write,
 179         .size = OTP_MEM_SIZE,
 180 };
 181
 182 static int lan9662_otp_probe(struct platform_device *pdev)
 183 {
 184         struct device *dev = &pdev->dev;
 185         struct nvmem_device *nvmem;
 186         struct lan9662_otp *otp;
 187
 188         otp = devm_kzalloc(&pdev->dev, sizeof(*otp), GFP_KERNEL);
 189         if (!otp)
 190                 return -ENOMEM;
 191
 192         otp->dev = dev;
 193         otp->base = devm_platform_ioremap_resource(pdev, 0);
 194         if (IS_ERR(otp->base))
 195                 return PTR_ERR(otp->base);
 196
 197         otp_config.priv = otp;
 198         otp_config.dev = dev;
 199
 200         nvmem = devm_nvmem_register(dev, &otp_config);
 201
 202         return PTR_ERR_OR_ZERO(nvmem);
 203 }
 204
 205 static const struct of_device_id lan9662_otp_match[] = {
 206         { .compatible = "microchip,lan9662-otpc", },
 207         { },
 208 };
 209 MODULE_DEVICE_TABLE(of, lan9662_otp_match);
 210
 211 static struct platform_driver lan9662_otp_driver = {
 212         .probe = lan9662_otp_probe,
 213         .driver = {
 214                 .name = "lan9662-otp",
 215                 .of_match_table = lan9662_otp_match,
 216         },
 217 };
 218 module_platform_driver(lan9662_otp_driver);
 219
 220 MODULE_AUTHOR("Horatiu Vultur <horatiu.vultur@microchip.com>");
 221 MODULE_DESCRIPTION("lan9662 OTP driver");
 222 MODULE_LICENSE("GPL");