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f02f8aee AA |
1 | /* |
2 | * NXP LPC18xx/LPC43xx EEPROM memory NVMEM driver | |
3 | * | |
4 | * Copyright (c) 2015 Ariel D'Alessandro <ariel@vanguardiasur.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License version 2 as published by | |
8 | * the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | #include <linux/clk.h> | |
12 | #include <linux/device.h> | |
13 | #include <linux/delay.h> | |
14 | #include <linux/err.h> | |
15 | #include <linux/io.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/nvmem-provider.h> | |
18 | #include <linux/platform_device.h> | |
f02f8aee AA |
19 | #include <linux/reset.h> |
20 | ||
21 | /* Registers */ | |
22 | #define LPC18XX_EEPROM_AUTOPROG 0x00c | |
23 | #define LPC18XX_EEPROM_AUTOPROG_WORD 0x1 | |
24 | ||
25 | #define LPC18XX_EEPROM_CLKDIV 0x014 | |
26 | ||
27 | #define LPC18XX_EEPROM_PWRDWN 0x018 | |
28 | #define LPC18XX_EEPROM_PWRDWN_NO 0x0 | |
29 | #define LPC18XX_EEPROM_PWRDWN_YES 0x1 | |
30 | ||
31 | #define LPC18XX_EEPROM_INTSTAT 0xfe0 | |
32 | #define LPC18XX_EEPROM_INTSTAT_END_OF_PROG BIT(2) | |
33 | ||
34 | #define LPC18XX_EEPROM_INTSTATCLR 0xfe8 | |
35 | #define LPC18XX_EEPROM_INTSTATCLR_PROG_CLR_ST BIT(2) | |
36 | ||
37 | /* Fixed page size (bytes) */ | |
38 | #define LPC18XX_EEPROM_PAGE_SIZE 0x80 | |
39 | ||
40 | /* EEPROM device requires a ~1500 kHz clock (min 800 kHz, max 1600 kHz) */ | |
41 | #define LPC18XX_EEPROM_CLOCK_HZ 1500000 | |
42 | ||
43 | /* EEPROM requires 3 ms of erase/program time between each writing */ | |
44 | #define LPC18XX_EEPROM_PROGRAM_TIME 3 | |
45 | ||
46 | struct lpc18xx_eeprom_dev { | |
47 | struct clk *clk; | |
48 | void __iomem *reg_base; | |
49 | void __iomem *mem_base; | |
50 | struct nvmem_device *nvmem; | |
51 | unsigned reg_bytes; | |
52 | unsigned val_bytes; | |
2e8d0733 | 53 | int size; |
f02f8aee AA |
54 | }; |
55 | ||
56 | static inline void lpc18xx_eeprom_writel(struct lpc18xx_eeprom_dev *eeprom, | |
57 | u32 reg, u32 val) | |
58 | { | |
59 | writel(val, eeprom->reg_base + reg); | |
60 | } | |
61 | ||
62 | static inline u32 lpc18xx_eeprom_readl(struct lpc18xx_eeprom_dev *eeprom, | |
63 | u32 reg) | |
64 | { | |
65 | return readl(eeprom->reg_base + reg); | |
66 | } | |
67 | ||
68 | static int lpc18xx_eeprom_busywait_until_prog(struct lpc18xx_eeprom_dev *eeprom) | |
69 | { | |
70 | unsigned long end; | |
71 | u32 val; | |
72 | ||
73 | /* Wait until EEPROM program operation has finished */ | |
74 | end = jiffies + msecs_to_jiffies(LPC18XX_EEPROM_PROGRAM_TIME * 10); | |
75 | ||
76 | while (time_is_after_jiffies(end)) { | |
77 | val = lpc18xx_eeprom_readl(eeprom, LPC18XX_EEPROM_INTSTAT); | |
78 | ||
79 | if (val & LPC18XX_EEPROM_INTSTAT_END_OF_PROG) { | |
80 | lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_INTSTATCLR, | |
81 | LPC18XX_EEPROM_INTSTATCLR_PROG_CLR_ST); | |
82 | return 0; | |
83 | } | |
84 | ||
85 | usleep_range(LPC18XX_EEPROM_PROGRAM_TIME * USEC_PER_MSEC, | |
86 | (LPC18XX_EEPROM_PROGRAM_TIME + 1) * USEC_PER_MSEC); | |
87 | } | |
88 | ||
89 | return -ETIMEDOUT; | |
90 | } | |
91 | ||
2e8d0733 SK |
92 | static int lpc18xx_eeprom_gather_write(void *context, unsigned int reg, |
93 | void *val, size_t bytes) | |
f02f8aee AA |
94 | { |
95 | struct lpc18xx_eeprom_dev *eeprom = context; | |
2e8d0733 | 96 | unsigned int offset = reg; |
f02f8aee AA |
97 | int ret; |
98 | ||
2e8d0733 SK |
99 | /* |
100 | * The last page contains the EEPROM initialization data and is not | |
101 | * writable. | |
102 | */ | |
103 | if ((reg > eeprom->size - LPC18XX_EEPROM_PAGE_SIZE) || | |
104 | (reg + bytes > eeprom->size - LPC18XX_EEPROM_PAGE_SIZE)) | |
f02f8aee AA |
105 | return -EINVAL; |
106 | ||
2e8d0733 | 107 | |
f02f8aee AA |
108 | lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN, |
109 | LPC18XX_EEPROM_PWRDWN_NO); | |
110 | ||
111 | /* Wait 100 us while the EEPROM wakes up */ | |
112 | usleep_range(100, 200); | |
113 | ||
2e8d0733 | 114 | while (bytes) { |
f02f8aee AA |
115 | writel(*(u32 *)val, eeprom->mem_base + offset); |
116 | ret = lpc18xx_eeprom_busywait_until_prog(eeprom); | |
117 | if (ret < 0) | |
118 | return ret; | |
119 | ||
2e8d0733 | 120 | bytes -= eeprom->val_bytes; |
f02f8aee AA |
121 | val += eeprom->val_bytes; |
122 | offset += eeprom->val_bytes; | |
123 | } | |
124 | ||
125 | lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN, | |
126 | LPC18XX_EEPROM_PWRDWN_YES); | |
127 | ||
128 | return 0; | |
129 | } | |
130 | ||
2e8d0733 SK |
131 | static int lpc18xx_eeprom_read(void *context, unsigned int offset, |
132 | void *val, size_t bytes) | |
f02f8aee AA |
133 | { |
134 | struct lpc18xx_eeprom_dev *eeprom = context; | |
f02f8aee AA |
135 | |
136 | lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN, | |
137 | LPC18XX_EEPROM_PWRDWN_NO); | |
138 | ||
139 | /* Wait 100 us while the EEPROM wakes up */ | |
140 | usleep_range(100, 200); | |
141 | ||
2e8d0733 | 142 | while (bytes) { |
f02f8aee | 143 | *(u32 *)val = readl(eeprom->mem_base + offset); |
2e8d0733 | 144 | bytes -= eeprom->val_bytes; |
f02f8aee AA |
145 | val += eeprom->val_bytes; |
146 | offset += eeprom->val_bytes; | |
147 | } | |
148 | ||
149 | lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN, | |
150 | LPC18XX_EEPROM_PWRDWN_YES); | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
f02f8aee AA |
155 | |
156 | static struct nvmem_config lpc18xx_nvmem_config = { | |
157 | .name = "lpc18xx-eeprom", | |
2e8d0733 SK |
158 | .stride = 4, |
159 | .word_size = 4, | |
160 | .reg_read = lpc18xx_eeprom_read, | |
161 | .reg_write = lpc18xx_eeprom_gather_write, | |
f02f8aee AA |
162 | }; |
163 | ||
164 | static int lpc18xx_eeprom_probe(struct platform_device *pdev) | |
165 | { | |
166 | struct lpc18xx_eeprom_dev *eeprom; | |
167 | struct device *dev = &pdev->dev; | |
168 | struct reset_control *rst; | |
169 | unsigned long clk_rate; | |
f02f8aee AA |
170 | struct resource *res; |
171 | int ret; | |
172 | ||
173 | eeprom = devm_kzalloc(dev, sizeof(*eeprom), GFP_KERNEL); | |
174 | if (!eeprom) | |
175 | return -ENOMEM; | |
176 | ||
177 | res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "reg"); | |
178 | eeprom->reg_base = devm_ioremap_resource(dev, res); | |
179 | if (IS_ERR(eeprom->reg_base)) | |
180 | return PTR_ERR(eeprom->reg_base); | |
181 | ||
182 | res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mem"); | |
183 | eeprom->mem_base = devm_ioremap_resource(dev, res); | |
184 | if (IS_ERR(eeprom->mem_base)) | |
185 | return PTR_ERR(eeprom->mem_base); | |
186 | ||
187 | eeprom->clk = devm_clk_get(&pdev->dev, "eeprom"); | |
188 | if (IS_ERR(eeprom->clk)) { | |
189 | dev_err(&pdev->dev, "failed to get eeprom clock\n"); | |
190 | return PTR_ERR(eeprom->clk); | |
191 | } | |
192 | ||
193 | ret = clk_prepare_enable(eeprom->clk); | |
194 | if (ret < 0) { | |
195 | dev_err(dev, "failed to prepare/enable eeprom clk: %d\n", ret); | |
196 | return ret; | |
197 | } | |
198 | ||
aed0c46e | 199 | rst = devm_reset_control_get_exclusive(dev, NULL); |
f02f8aee AA |
200 | if (IS_ERR(rst)) { |
201 | dev_err(dev, "failed to get reset: %ld\n", PTR_ERR(rst)); | |
202 | ret = PTR_ERR(rst); | |
203 | goto err_clk; | |
204 | } | |
205 | ||
206 | ret = reset_control_assert(rst); | |
207 | if (ret < 0) { | |
208 | dev_err(dev, "failed to assert reset: %d\n", ret); | |
209 | goto err_clk; | |
210 | } | |
211 | ||
2e8d0733 SK |
212 | eeprom->val_bytes = 4; |
213 | eeprom->reg_bytes = 4; | |
f02f8aee AA |
214 | |
215 | /* | |
216 | * Clock rate is generated by dividing the system bus clock by the | |
217 | * division factor, contained in the divider register (minus 1 encoded). | |
218 | */ | |
219 | clk_rate = clk_get_rate(eeprom->clk); | |
220 | clk_rate = DIV_ROUND_UP(clk_rate, LPC18XX_EEPROM_CLOCK_HZ) - 1; | |
221 | lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_CLKDIV, clk_rate); | |
222 | ||
223 | /* | |
224 | * Writing a single word to the page will start the erase/program cycle | |
225 | * automatically | |
226 | */ | |
227 | lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_AUTOPROG, | |
228 | LPC18XX_EEPROM_AUTOPROG_WORD); | |
229 | ||
230 | lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN, | |
231 | LPC18XX_EEPROM_PWRDWN_YES); | |
232 | ||
2e8d0733 SK |
233 | eeprom->size = resource_size(res); |
234 | lpc18xx_nvmem_config.size = resource_size(res); | |
f02f8aee | 235 | lpc18xx_nvmem_config.dev = dev; |
2e8d0733 | 236 | lpc18xx_nvmem_config.priv = eeprom; |
f02f8aee AA |
237 | |
238 | eeprom->nvmem = nvmem_register(&lpc18xx_nvmem_config); | |
239 | if (IS_ERR(eeprom->nvmem)) { | |
240 | ret = PTR_ERR(eeprom->nvmem); | |
241 | goto err_clk; | |
242 | } | |
243 | ||
244 | platform_set_drvdata(pdev, eeprom); | |
245 | ||
246 | return 0; | |
247 | ||
248 | err_clk: | |
249 | clk_disable_unprepare(eeprom->clk); | |
250 | ||
251 | return ret; | |
252 | } | |
253 | ||
254 | static int lpc18xx_eeprom_remove(struct platform_device *pdev) | |
255 | { | |
256 | struct lpc18xx_eeprom_dev *eeprom = platform_get_drvdata(pdev); | |
257 | int ret; | |
258 | ||
259 | ret = nvmem_unregister(eeprom->nvmem); | |
260 | if (ret < 0) | |
261 | return ret; | |
262 | ||
263 | clk_disable_unprepare(eeprom->clk); | |
264 | ||
265 | return 0; | |
266 | } | |
267 | ||
268 | static const struct of_device_id lpc18xx_eeprom_of_match[] = { | |
269 | { .compatible = "nxp,lpc1857-eeprom" }, | |
270 | { }, | |
271 | }; | |
272 | MODULE_DEVICE_TABLE(of, lpc18xx_eeprom_of_match); | |
273 | ||
274 | static struct platform_driver lpc18xx_eeprom_driver = { | |
275 | .probe = lpc18xx_eeprom_probe, | |
276 | .remove = lpc18xx_eeprom_remove, | |
277 | .driver = { | |
278 | .name = "lpc18xx-eeprom", | |
279 | .of_match_table = lpc18xx_eeprom_of_match, | |
280 | }, | |
281 | }; | |
282 | ||
283 | module_platform_driver(lpc18xx_eeprom_driver); | |
284 | ||
285 | MODULE_AUTHOR("Ariel D'Alessandro <ariel@vanguardiasur.com.ar>"); | |
286 | MODULE_DESCRIPTION("NXP LPC18xx EEPROM memory Driver"); | |
287 | MODULE_LICENSE("GPL v2"); |