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
 34struct lan9662_otp {
 35	struct device *dev;
 36	void __iomem *base;
 37};
 38
 39static 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
 47static 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
 63static 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
 76static 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
 82static 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
100static 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
122static 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
142static 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
173static 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
182static 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
205static const struct of_device_id lan9662_otp_match[] = {
206	{ .compatible = "microchip,lan9662-otpc", },
207	{ },
208};
209MODULE_DEVICE_TABLE(of, lan9662_otp_match);
210
211static 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};
218module_platform_driver(lan9662_otp_driver);
219
220MODULE_AUTHOR("Horatiu Vultur <horatiu.vultur@microchip.com>");
221MODULE_DESCRIPTION("lan9662 OTP driver");
222MODULE_LICENSE("GPL");