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
lan9662_otp_wait_flag_clear(void __iomem * reg,u32 flag)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
lan9662_otp_power(struct lan9662_otp * otp,bool up)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
lan9662_otp_execute(struct lan9662_otp * otp)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
lan9662_otp_set_address(struct lan9662_otp * otp,u32 offset)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
lan9662_otp_read_byte(struct lan9662_otp * otp,u32 offset,u8 * dst)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
lan9662_otp_write_byte(struct lan9662_otp * otp,u32 offset,u8 data)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
lan9662_otp_read(void * context,unsigned int offset,void * _val,size_t bytes)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
lan9662_otp_write(void * context,unsigned int offset,void * _val,size_t bytes)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
lan9662_otp_probe(struct platform_device * pdev)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");
223