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7418a119 SS |
1 | /* |
2 | * Copyright (C) 2012 Sven Schnelle <svens@stackframe.org> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | */ | |
9 | ||
10 | #include <linux/platform_device.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/rtc.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/bcd.h> | |
16 | #include <linux/rtc-ds2404.h> | |
17 | #include <linux/delay.h> | |
18 | #include <linux/gpio.h> | |
19 | #include <linux/slab.h> | |
20 | ||
21 | #include <linux/io.h> | |
22 | ||
23 | #define DS2404_STATUS_REG 0x200 | |
24 | #define DS2404_CONTROL_REG 0x201 | |
25 | #define DS2404_RTC_REG 0x202 | |
26 | ||
27 | #define DS2404_WRITE_SCRATCHPAD_CMD 0x0f | |
28 | #define DS2404_READ_SCRATCHPAD_CMD 0xaa | |
29 | #define DS2404_COPY_SCRATCHPAD_CMD 0x55 | |
30 | #define DS2404_READ_MEMORY_CMD 0xf0 | |
31 | ||
32 | struct ds2404; | |
33 | ||
34 | struct ds2404_chip_ops { | |
35 | int (*map_io)(struct ds2404 *chip, struct platform_device *pdev, | |
36 | struct ds2404_platform_data *pdata); | |
37 | void (*unmap_io)(struct ds2404 *chip); | |
38 | }; | |
39 | ||
40 | #define DS2404_RST 0 | |
41 | #define DS2404_CLK 1 | |
42 | #define DS2404_DQ 2 | |
43 | ||
44 | struct ds2404_gpio { | |
45 | const char *name; | |
46 | unsigned int gpio; | |
47 | }; | |
48 | ||
49 | struct ds2404 { | |
50 | struct ds2404_gpio *gpio; | |
c4c23f58 | 51 | const struct ds2404_chip_ops *ops; |
7418a119 SS |
52 | struct rtc_device *rtc; |
53 | }; | |
54 | ||
55 | static struct ds2404_gpio ds2404_gpio[] = { | |
56 | { "RTC RST", 0 }, | |
57 | { "RTC CLK", 0 }, | |
58 | { "RTC DQ", 0 }, | |
59 | }; | |
60 | ||
61 | static int ds2404_gpio_map(struct ds2404 *chip, struct platform_device *pdev, | |
62 | struct ds2404_platform_data *pdata) | |
63 | { | |
64 | int i, err; | |
65 | ||
66 | ds2404_gpio[DS2404_RST].gpio = pdata->gpio_rst; | |
67 | ds2404_gpio[DS2404_CLK].gpio = pdata->gpio_clk; | |
68 | ds2404_gpio[DS2404_DQ].gpio = pdata->gpio_dq; | |
69 | ||
70 | for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) { | |
71 | err = gpio_request(ds2404_gpio[i].gpio, ds2404_gpio[i].name); | |
72 | if (err) { | |
0fae8237 | 73 | dev_err(&pdev->dev, "error mapping gpio %s: %d\n", |
7418a119 SS |
74 | ds2404_gpio[i].name, err); |
75 | goto err_request; | |
76 | } | |
77 | if (i != DS2404_DQ) | |
78 | gpio_direction_output(ds2404_gpio[i].gpio, 1); | |
79 | } | |
80 | ||
81 | chip->gpio = ds2404_gpio; | |
82 | return 0; | |
83 | ||
84 | err_request: | |
85 | while (--i >= 0) | |
86 | gpio_free(ds2404_gpio[i].gpio); | |
87 | return err; | |
88 | } | |
89 | ||
90 | static void ds2404_gpio_unmap(struct ds2404 *chip) | |
91 | { | |
92 | int i; | |
93 | ||
94 | for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) | |
95 | gpio_free(ds2404_gpio[i].gpio); | |
96 | } | |
97 | ||
c4c23f58 | 98 | static const struct ds2404_chip_ops ds2404_gpio_ops = { |
7418a119 SS |
99 | .map_io = ds2404_gpio_map, |
100 | .unmap_io = ds2404_gpio_unmap, | |
101 | }; | |
102 | ||
103 | static void ds2404_reset(struct device *dev) | |
104 | { | |
105 | gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 0); | |
106 | udelay(1000); | |
107 | gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 1); | |
108 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0); | |
109 | gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 0); | |
110 | udelay(10); | |
111 | } | |
112 | ||
113 | static void ds2404_write_byte(struct device *dev, u8 byte) | |
114 | { | |
115 | int i; | |
116 | ||
117 | gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 1); | |
118 | for (i = 0; i < 8; i++) { | |
119 | gpio_set_value(ds2404_gpio[DS2404_DQ].gpio, byte & (1 << i)); | |
120 | udelay(10); | |
121 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1); | |
122 | udelay(10); | |
123 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0); | |
124 | udelay(10); | |
125 | } | |
126 | } | |
127 | ||
128 | static u8 ds2404_read_byte(struct device *dev) | |
129 | { | |
130 | int i; | |
131 | u8 ret = 0; | |
132 | ||
133 | gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio); | |
134 | ||
135 | for (i = 0; i < 8; i++) { | |
136 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0); | |
137 | udelay(10); | |
138 | if (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio)) | |
139 | ret |= 1 << i; | |
140 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1); | |
141 | udelay(10); | |
142 | } | |
143 | return ret; | |
144 | } | |
145 | ||
146 | static void ds2404_read_memory(struct device *dev, u16 offset, | |
147 | int length, u8 *out) | |
148 | { | |
149 | ds2404_reset(dev); | |
150 | ds2404_write_byte(dev, DS2404_READ_MEMORY_CMD); | |
151 | ds2404_write_byte(dev, offset & 0xff); | |
152 | ds2404_write_byte(dev, (offset >> 8) & 0xff); | |
153 | while (length--) | |
154 | *out++ = ds2404_read_byte(dev); | |
155 | } | |
156 | ||
157 | static void ds2404_write_memory(struct device *dev, u16 offset, | |
158 | int length, u8 *out) | |
159 | { | |
160 | int i; | |
161 | u8 ta01, ta02, es; | |
162 | ||
163 | ds2404_reset(dev); | |
164 | ds2404_write_byte(dev, DS2404_WRITE_SCRATCHPAD_CMD); | |
165 | ds2404_write_byte(dev, offset & 0xff); | |
166 | ds2404_write_byte(dev, (offset >> 8) & 0xff); | |
167 | ||
168 | for (i = 0; i < length; i++) | |
169 | ds2404_write_byte(dev, out[i]); | |
170 | ||
171 | ds2404_reset(dev); | |
172 | ds2404_write_byte(dev, DS2404_READ_SCRATCHPAD_CMD); | |
173 | ||
174 | ta01 = ds2404_read_byte(dev); | |
175 | ta02 = ds2404_read_byte(dev); | |
176 | es = ds2404_read_byte(dev); | |
177 | ||
178 | for (i = 0; i < length; i++) { | |
179 | if (out[i] != ds2404_read_byte(dev)) { | |
0fae8237 | 180 | dev_err(dev, "read invalid data\n"); |
7418a119 SS |
181 | return; |
182 | } | |
183 | } | |
184 | ||
185 | ds2404_reset(dev); | |
186 | ds2404_write_byte(dev, DS2404_COPY_SCRATCHPAD_CMD); | |
187 | ds2404_write_byte(dev, ta01); | |
188 | ds2404_write_byte(dev, ta02); | |
189 | ds2404_write_byte(dev, es); | |
190 | ||
191 | gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio); | |
192 | while (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio)) | |
193 | ; | |
194 | } | |
195 | ||
196 | static void ds2404_enable_osc(struct device *dev) | |
197 | { | |
198 | u8 in[1] = { 0x10 }; /* enable oscillator */ | |
199 | ds2404_write_memory(dev, 0x201, 1, in); | |
200 | } | |
201 | ||
202 | static int ds2404_read_time(struct device *dev, struct rtc_time *dt) | |
203 | { | |
204 | unsigned long time = 0; | |
205 | ||
206 | ds2404_read_memory(dev, 0x203, 4, (u8 *)&time); | |
207 | time = le32_to_cpu(time); | |
208 | ||
209 | rtc_time_to_tm(time, dt); | |
210 | return rtc_valid_tm(dt); | |
211 | } | |
212 | ||
213 | static int ds2404_set_mmss(struct device *dev, unsigned long secs) | |
214 | { | |
215 | u32 time = cpu_to_le32(secs); | |
216 | ds2404_write_memory(dev, 0x203, 4, (u8 *)&time); | |
217 | return 0; | |
218 | } | |
219 | ||
220 | static const struct rtc_class_ops ds2404_rtc_ops = { | |
221 | .read_time = ds2404_read_time, | |
222 | .set_mmss = ds2404_set_mmss, | |
223 | }; | |
224 | ||
225 | static int rtc_probe(struct platform_device *pdev) | |
226 | { | |
77bf3822 | 227 | struct ds2404_platform_data *pdata = dev_get_platdata(&pdev->dev); |
7418a119 SS |
228 | struct ds2404 *chip; |
229 | int retval = -EBUSY; | |
230 | ||
2a444cf7 | 231 | chip = devm_kzalloc(&pdev->dev, sizeof(struct ds2404), GFP_KERNEL); |
7418a119 SS |
232 | if (!chip) |
233 | return -ENOMEM; | |
234 | ||
235 | chip->ops = &ds2404_gpio_ops; | |
236 | ||
237 | retval = chip->ops->map_io(chip, pdev, pdata); | |
238 | if (retval) | |
239 | goto err_chip; | |
240 | ||
241 | dev_info(&pdev->dev, "using GPIOs RST:%d, CLK:%d, DQ:%d\n", | |
242 | chip->gpio[DS2404_RST].gpio, chip->gpio[DS2404_CLK].gpio, | |
243 | chip->gpio[DS2404_DQ].gpio); | |
244 | ||
245 | platform_set_drvdata(pdev, chip); | |
246 | ||
2a444cf7 JH |
247 | chip->rtc = devm_rtc_device_register(&pdev->dev, "ds2404", |
248 | &ds2404_rtc_ops, THIS_MODULE); | |
7418a119 SS |
249 | if (IS_ERR(chip->rtc)) { |
250 | retval = PTR_ERR(chip->rtc); | |
251 | goto err_io; | |
252 | } | |
253 | ||
254 | ds2404_enable_osc(&pdev->dev); | |
255 | return 0; | |
256 | ||
257 | err_io: | |
258 | chip->ops->unmap_io(chip); | |
259 | err_chip: | |
7418a119 SS |
260 | return retval; |
261 | } | |
262 | ||
263 | static int rtc_remove(struct platform_device *dev) | |
264 | { | |
265 | struct ds2404 *chip = platform_get_drvdata(dev); | |
7418a119 SS |
266 | |
267 | chip->ops->unmap_io(chip); | |
7418a119 SS |
268 | |
269 | return 0; | |
270 | } | |
271 | ||
272 | static struct platform_driver rtc_device_driver = { | |
273 | .probe = rtc_probe, | |
274 | .remove = rtc_remove, | |
275 | .driver = { | |
276 | .name = "ds2404", | |
7418a119 SS |
277 | }, |
278 | }; | |
56ae1b8e | 279 | module_platform_driver(rtc_device_driver); |
7418a119 SS |
280 | |
281 | MODULE_DESCRIPTION("DS2404 RTC"); | |
282 | MODULE_AUTHOR("Sven Schnelle"); | |
283 | MODULE_LICENSE("GPL"); | |
284 | MODULE_ALIAS("platform:ds2404"); |