xref: /linux/drivers/nvmem/lan9662-otpc.c (revision 7ae9fb1b7ecbb5d85d07857943f677fd1a559b18)
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