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14556f04 AB |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | // Copyright (C) 2012 Sven Schnelle <svens@stackframe.org> | |
7418a119 SS |
3 | |
4 | #include <linux/platform_device.h> | |
5 | #include <linux/module.h> | |
6 | #include <linux/init.h> | |
7 | #include <linux/rtc.h> | |
8 | #include <linux/types.h> | |
9 | #include <linux/bcd.h> | |
10c2a2e7 | 10 | #include <linux/platform_data/rtc-ds2404.h> |
7418a119 SS |
11 | #include <linux/delay.h> |
12 | #include <linux/gpio.h> | |
13 | #include <linux/slab.h> | |
14 | ||
15 | #include <linux/io.h> | |
16 | ||
17 | #define DS2404_STATUS_REG 0x200 | |
18 | #define DS2404_CONTROL_REG 0x201 | |
19 | #define DS2404_RTC_REG 0x202 | |
20 | ||
21 | #define DS2404_WRITE_SCRATCHPAD_CMD 0x0f | |
22 | #define DS2404_READ_SCRATCHPAD_CMD 0xaa | |
23 | #define DS2404_COPY_SCRATCHPAD_CMD 0x55 | |
24 | #define DS2404_READ_MEMORY_CMD 0xf0 | |
25 | ||
7418a119 SS |
26 | #define DS2404_RST 0 |
27 | #define DS2404_CLK 1 | |
28 | #define DS2404_DQ 2 | |
29 | ||
30 | struct ds2404_gpio { | |
31 | const char *name; | |
32 | unsigned int gpio; | |
33 | }; | |
34 | ||
35 | struct ds2404 { | |
36 | struct ds2404_gpio *gpio; | |
7418a119 SS |
37 | struct rtc_device *rtc; |
38 | }; | |
39 | ||
40 | static struct ds2404_gpio ds2404_gpio[] = { | |
41 | { "RTC RST", 0 }, | |
42 | { "RTC CLK", 0 }, | |
43 | { "RTC DQ", 0 }, | |
44 | }; | |
45 | ||
46 | static int ds2404_gpio_map(struct ds2404 *chip, struct platform_device *pdev, | |
47 | struct ds2404_platform_data *pdata) | |
48 | { | |
49 | int i, err; | |
50 | ||
51 | ds2404_gpio[DS2404_RST].gpio = pdata->gpio_rst; | |
52 | ds2404_gpio[DS2404_CLK].gpio = pdata->gpio_clk; | |
53 | ds2404_gpio[DS2404_DQ].gpio = pdata->gpio_dq; | |
54 | ||
55 | for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) { | |
56 | err = gpio_request(ds2404_gpio[i].gpio, ds2404_gpio[i].name); | |
57 | if (err) { | |
0fae8237 | 58 | dev_err(&pdev->dev, "error mapping gpio %s: %d\n", |
7418a119 SS |
59 | ds2404_gpio[i].name, err); |
60 | goto err_request; | |
61 | } | |
62 | if (i != DS2404_DQ) | |
63 | gpio_direction_output(ds2404_gpio[i].gpio, 1); | |
64 | } | |
65 | ||
66 | chip->gpio = ds2404_gpio; | |
67 | return 0; | |
68 | ||
69 | err_request: | |
70 | while (--i >= 0) | |
71 | gpio_free(ds2404_gpio[i].gpio); | |
72 | return err; | |
73 | } | |
74 | ||
d9aa5ca4 | 75 | static void ds2404_gpio_unmap(void *data) |
7418a119 SS |
76 | { |
77 | int i; | |
78 | ||
79 | for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) | |
80 | gpio_free(ds2404_gpio[i].gpio); | |
81 | } | |
82 | ||
7418a119 SS |
83 | static void ds2404_reset(struct device *dev) |
84 | { | |
85 | gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 0); | |
86 | udelay(1000); | |
87 | gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 1); | |
88 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0); | |
89 | gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 0); | |
90 | udelay(10); | |
91 | } | |
92 | ||
93 | static void ds2404_write_byte(struct device *dev, u8 byte) | |
94 | { | |
95 | int i; | |
96 | ||
97 | gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 1); | |
98 | for (i = 0; i < 8; i++) { | |
99 | gpio_set_value(ds2404_gpio[DS2404_DQ].gpio, byte & (1 << i)); | |
100 | udelay(10); | |
101 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1); | |
102 | udelay(10); | |
103 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0); | |
104 | udelay(10); | |
105 | } | |
106 | } | |
107 | ||
108 | static u8 ds2404_read_byte(struct device *dev) | |
109 | { | |
110 | int i; | |
111 | u8 ret = 0; | |
112 | ||
113 | gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio); | |
114 | ||
115 | for (i = 0; i < 8; i++) { | |
116 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0); | |
117 | udelay(10); | |
118 | if (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio)) | |
119 | ret |= 1 << i; | |
120 | gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1); | |
121 | udelay(10); | |
122 | } | |
123 | return ret; | |
124 | } | |
125 | ||
126 | static void ds2404_read_memory(struct device *dev, u16 offset, | |
127 | int length, u8 *out) | |
128 | { | |
129 | ds2404_reset(dev); | |
130 | ds2404_write_byte(dev, DS2404_READ_MEMORY_CMD); | |
131 | ds2404_write_byte(dev, offset & 0xff); | |
132 | ds2404_write_byte(dev, (offset >> 8) & 0xff); | |
133 | while (length--) | |
134 | *out++ = ds2404_read_byte(dev); | |
135 | } | |
136 | ||
137 | static void ds2404_write_memory(struct device *dev, u16 offset, | |
138 | int length, u8 *out) | |
139 | { | |
140 | int i; | |
141 | u8 ta01, ta02, es; | |
142 | ||
143 | ds2404_reset(dev); | |
144 | ds2404_write_byte(dev, DS2404_WRITE_SCRATCHPAD_CMD); | |
145 | ds2404_write_byte(dev, offset & 0xff); | |
146 | ds2404_write_byte(dev, (offset >> 8) & 0xff); | |
147 | ||
148 | for (i = 0; i < length; i++) | |
149 | ds2404_write_byte(dev, out[i]); | |
150 | ||
151 | ds2404_reset(dev); | |
152 | ds2404_write_byte(dev, DS2404_READ_SCRATCHPAD_CMD); | |
153 | ||
154 | ta01 = ds2404_read_byte(dev); | |
155 | ta02 = ds2404_read_byte(dev); | |
156 | es = ds2404_read_byte(dev); | |
157 | ||
158 | for (i = 0; i < length; i++) { | |
159 | if (out[i] != ds2404_read_byte(dev)) { | |
0fae8237 | 160 | dev_err(dev, "read invalid data\n"); |
7418a119 SS |
161 | return; |
162 | } | |
163 | } | |
164 | ||
165 | ds2404_reset(dev); | |
166 | ds2404_write_byte(dev, DS2404_COPY_SCRATCHPAD_CMD); | |
167 | ds2404_write_byte(dev, ta01); | |
168 | ds2404_write_byte(dev, ta02); | |
169 | ds2404_write_byte(dev, es); | |
170 | ||
171 | gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio); | |
172 | while (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio)) | |
173 | ; | |
174 | } | |
175 | ||
176 | static void ds2404_enable_osc(struct device *dev) | |
177 | { | |
178 | u8 in[1] = { 0x10 }; /* enable oscillator */ | |
179 | ds2404_write_memory(dev, 0x201, 1, in); | |
180 | } | |
181 | ||
182 | static int ds2404_read_time(struct device *dev, struct rtc_time *dt) | |
183 | { | |
184 | unsigned long time = 0; | |
8aec4b87 | 185 | __le32 hw_time = 0; |
7418a119 | 186 | |
8aec4b87 NMG |
187 | ds2404_read_memory(dev, 0x203, 4, (u8 *)&hw_time); |
188 | time = le32_to_cpu(hw_time); | |
7418a119 | 189 | |
53523216 | 190 | rtc_time64_to_tm(time, dt); |
22652ba7 | 191 | return 0; |
7418a119 SS |
192 | } |
193 | ||
be2b0437 | 194 | static int ds2404_set_time(struct device *dev, struct rtc_time *dt) |
7418a119 | 195 | { |
be2b0437 | 196 | u32 time = cpu_to_le32(rtc_tm_to_time64(dt)); |
7418a119 SS |
197 | ds2404_write_memory(dev, 0x203, 4, (u8 *)&time); |
198 | return 0; | |
199 | } | |
200 | ||
201 | static const struct rtc_class_ops ds2404_rtc_ops = { | |
202 | .read_time = ds2404_read_time, | |
be2b0437 | 203 | .set_time = ds2404_set_time, |
7418a119 SS |
204 | }; |
205 | ||
206 | static int rtc_probe(struct platform_device *pdev) | |
207 | { | |
77bf3822 | 208 | struct ds2404_platform_data *pdata = dev_get_platdata(&pdev->dev); |
7418a119 SS |
209 | struct ds2404 *chip; |
210 | int retval = -EBUSY; | |
211 | ||
2a444cf7 | 212 | chip = devm_kzalloc(&pdev->dev, sizeof(struct ds2404), GFP_KERNEL); |
7418a119 SS |
213 | if (!chip) |
214 | return -ENOMEM; | |
215 | ||
13bfa942 AB |
216 | chip->rtc = devm_rtc_allocate_device(&pdev->dev); |
217 | if (IS_ERR(chip->rtc)) | |
218 | return PTR_ERR(chip->rtc); | |
219 | ||
c7ac260f | 220 | retval = ds2404_gpio_map(chip, pdev, pdata); |
7418a119 | 221 | if (retval) |
d9aa5ca4 AB |
222 | return retval; |
223 | ||
224 | retval = devm_add_action_or_reset(&pdev->dev, ds2404_gpio_unmap, chip); | |
225 | if (retval) | |
226 | return retval; | |
7418a119 SS |
227 | |
228 | dev_info(&pdev->dev, "using GPIOs RST:%d, CLK:%d, DQ:%d\n", | |
229 | chip->gpio[DS2404_RST].gpio, chip->gpio[DS2404_CLK].gpio, | |
230 | chip->gpio[DS2404_DQ].gpio); | |
231 | ||
232 | platform_set_drvdata(pdev, chip); | |
233 | ||
13bfa942 AB |
234 | chip->rtc->ops = &ds2404_rtc_ops; |
235 | chip->rtc->range_max = U32_MAX; | |
236 | ||
fdcfd854 | 237 | retval = devm_rtc_register_device(chip->rtc); |
13bfa942 | 238 | if (retval) |
d9aa5ca4 | 239 | return retval; |
7418a119 SS |
240 | |
241 | ds2404_enable_osc(&pdev->dev); | |
242 | return 0; | |
7418a119 SS |
243 | } |
244 | ||
245 | static struct platform_driver rtc_device_driver = { | |
246 | .probe = rtc_probe, | |
7418a119 SS |
247 | .driver = { |
248 | .name = "ds2404", | |
7418a119 SS |
249 | }, |
250 | }; | |
56ae1b8e | 251 | module_platform_driver(rtc_device_driver); |
7418a119 SS |
252 | |
253 | MODULE_DESCRIPTION("DS2404 RTC"); | |
254 | MODULE_AUTHOR("Sven Schnelle"); | |
255 | MODULE_LICENSE("GPL"); | |
256 | MODULE_ALIAS("platform:ds2404"); |