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1// SPDX-License-Identifier: GPL-2.0-only
2/* drivers/rtc/rtc-v3020.c
3 *
4 * Copyright (C) 2006 8D Technologies inc.
5 * Copyright (C) 2004 Compulab Ltd.
6 *
7 * Driver for the V3020 RTC
8 *
9 * Changelog:
10 *
11 * 10-May-2006: Raphael Assenat <raph@8d.com>
12 * - Converted to platform driver
13 * - Use the generic rtc class
14 *
15 * ??-???-2004: Someone at Compulab
16 * - Initial driver creation.
17 */
18#include <linux/platform_device.h>
19#include <linux/module.h>
20#include <linux/init.h>
21#include <linux/rtc.h>
22#include <linux/types.h>
23#include <linux/bcd.h>
24#include <linux/platform_data/rtc-v3020.h>
25#include <linux/delay.h>
26#include <linux/gpio.h>
27#include <linux/slab.h>
28
29#include <linux/io.h>
30
31#undef DEBUG
32
33struct v3020;
34
35struct v3020_chip_ops {
36 int (*map_io)(struct v3020 *chip, struct platform_device *pdev,
37 struct v3020_platform_data *pdata);
38 void (*unmap_io)(struct v3020 *chip);
39 unsigned char (*read_bit)(struct v3020 *chip);
40 void (*write_bit)(struct v3020 *chip, unsigned char bit);
41};
42
43#define V3020_CS 0
44#define V3020_WR 1
45#define V3020_RD 2
46#define V3020_IO 3
47
48struct v3020 {
49 /* MMIO access */
50 void __iomem *ioaddress;
51 int leftshift;
52
53 /* GPIO access */
54 struct gpio *gpio;
55
56 const struct v3020_chip_ops *ops;
57
58 struct rtc_device *rtc;
59};
60
61
62static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
63 struct v3020_platform_data *pdata)
64{
65 if (pdev->num_resources != 1)
66 return -EBUSY;
67
68 if (pdev->resource[0].flags != IORESOURCE_MEM)
69 return -EBUSY;
70
71 chip->leftshift = pdata->leftshift;
72 chip->ioaddress = ioremap(pdev->resource[0].start, 1);
73 if (chip->ioaddress == NULL)
74 return -EBUSY;
75
76 return 0;
77}
78
79static void v3020_mmio_unmap(struct v3020 *chip)
80{
81 iounmap(chip->ioaddress);
82}
83
84static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
85{
86 writel(bit << chip->leftshift, chip->ioaddress);
87}
88
89static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
90{
91 return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
92}
93
94static const struct v3020_chip_ops v3020_mmio_ops = {
95 .map_io = v3020_mmio_map,
96 .unmap_io = v3020_mmio_unmap,
97 .read_bit = v3020_mmio_read_bit,
98 .write_bit = v3020_mmio_write_bit,
99};
100
101static struct gpio v3020_gpio[] = {
102 { 0, GPIOF_OUT_INIT_HIGH, "RTC CS"},
103 { 0, GPIOF_OUT_INIT_HIGH, "RTC WR"},
104 { 0, GPIOF_OUT_INIT_HIGH, "RTC RD"},
105 { 0, GPIOF_OUT_INIT_HIGH, "RTC IO"},
106};
107
108static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
109 struct v3020_platform_data *pdata)
110{
111 int err;
112
113 v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
114 v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
115 v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
116 v3020_gpio[V3020_IO].gpio = pdata->gpio_io;
117
118 err = gpio_request_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
119
120 if (!err)
121 chip->gpio = v3020_gpio;
122
123 return err;
124}
125
126static void v3020_gpio_unmap(struct v3020 *chip)
127{
128 gpio_free_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
129}
130
131static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
132{
133 gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
134 gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
135 gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
136 udelay(1);
137 gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
138 gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
139}
140
141static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
142{
143 int bit;
144
145 gpio_direction_input(chip->gpio[V3020_IO].gpio);
146 gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
147 gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
148 udelay(1);
149 bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
150 udelay(1);
151 gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
152 gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
153
154 return bit;
155}
156
157static const struct v3020_chip_ops v3020_gpio_ops = {
158 .map_io = v3020_gpio_map,
159 .unmap_io = v3020_gpio_unmap,
160 .read_bit = v3020_gpio_read_bit,
161 .write_bit = v3020_gpio_write_bit,
162};
163
164static void v3020_set_reg(struct v3020 *chip, unsigned char address,
165 unsigned char data)
166{
167 int i;
168 unsigned char tmp;
169
170 tmp = address;
171 for (i = 0; i < 4; i++) {
172 chip->ops->write_bit(chip, (tmp & 1));
173 tmp >>= 1;
174 udelay(1);
175 }
176
177 /* Commands dont have data */
178 if (!V3020_IS_COMMAND(address)) {
179 for (i = 0; i < 8; i++) {
180 chip->ops->write_bit(chip, (data & 1));
181 data >>= 1;
182 udelay(1);
183 }
184 }
185}
186
187static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
188{
189 unsigned int data = 0;
190 int i;
191
192 for (i = 0; i < 4; i++) {
193 chip->ops->write_bit(chip, (address & 1));
194 address >>= 1;
195 udelay(1);
196 }
197
198 for (i = 0; i < 8; i++) {
199 data >>= 1;
200 if (chip->ops->read_bit(chip))
201 data |= 0x80;
202 udelay(1);
203 }
204
205 return data;
206}
207
208static int v3020_read_time(struct device *dev, struct rtc_time *dt)
209{
210 struct v3020 *chip = dev_get_drvdata(dev);
211 int tmp;
212
213 /* Copy the current time to ram... */
214 v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
215
216 /* ...and then read constant values. */
217 tmp = v3020_get_reg(chip, V3020_SECONDS);
218 dt->tm_sec = bcd2bin(tmp);
219 tmp = v3020_get_reg(chip, V3020_MINUTES);
220 dt->tm_min = bcd2bin(tmp);
221 tmp = v3020_get_reg(chip, V3020_HOURS);
222 dt->tm_hour = bcd2bin(tmp);
223 tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
224 dt->tm_mday = bcd2bin(tmp);
225 tmp = v3020_get_reg(chip, V3020_MONTH);
226 dt->tm_mon = bcd2bin(tmp) - 1;
227 tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
228 dt->tm_wday = bcd2bin(tmp);
229 tmp = v3020_get_reg(chip, V3020_YEAR);
230 dt->tm_year = bcd2bin(tmp)+100;
231
232 dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
233 dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
234 dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
235 dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
236 dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
237 dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
238 dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
239 dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
240
241 return 0;
242}
243
244
245static int v3020_set_time(struct device *dev, struct rtc_time *dt)
246{
247 struct v3020 *chip = dev_get_drvdata(dev);
248
249 dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
250 dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
251 dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
252 dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
253 dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
254 dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
255 dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
256
257 /* Write all the values to ram... */
258 v3020_set_reg(chip, V3020_SECONDS, bin2bcd(dt->tm_sec));
259 v3020_set_reg(chip, V3020_MINUTES, bin2bcd(dt->tm_min));
260 v3020_set_reg(chip, V3020_HOURS, bin2bcd(dt->tm_hour));
261 v3020_set_reg(chip, V3020_MONTH_DAY, bin2bcd(dt->tm_mday));
262 v3020_set_reg(chip, V3020_MONTH, bin2bcd(dt->tm_mon + 1));
263 v3020_set_reg(chip, V3020_WEEK_DAY, bin2bcd(dt->tm_wday));
264 v3020_set_reg(chip, V3020_YEAR, bin2bcd(dt->tm_year % 100));
265
266 /* ...and set the clock. */
267 v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
268
269 /* Compulab used this delay here. I dont know why,
270 * the datasheet does not specify a delay. */
271 /*mdelay(5);*/
272
273 return 0;
274}
275
276static const struct rtc_class_ops v3020_rtc_ops = {
277 .read_time = v3020_read_time,
278 .set_time = v3020_set_time,
279};
280
281static int rtc_probe(struct platform_device *pdev)
282{
283 struct v3020_platform_data *pdata = dev_get_platdata(&pdev->dev);
284 struct v3020 *chip;
285 int retval;
286 int i;
287
288 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
289 if (!chip)
290 return -ENOMEM;
291
292 if (pdata->use_gpio)
293 chip->ops = &v3020_gpio_ops;
294 else
295 chip->ops = &v3020_mmio_ops;
296
297 retval = chip->ops->map_io(chip, pdev, pdata);
298 if (retval)
299 return retval;
300
301 /* Make sure the v3020 expects a communication cycle
302 * by reading 8 times */
303 for (i = 0; i < 8; i++)
304 chip->ops->read_bit(chip);
305
306 /* Test chip by doing a write/read sequence
307 * to the chip ram */
308 v3020_set_reg(chip, V3020_SECONDS, 0x33);
309 if (v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
310 retval = -ENODEV;
311 goto err_io;
312 }
313
314 /* Make sure frequency measurement mode, test modes, and lock
315 * are all disabled */
316 v3020_set_reg(chip, V3020_STATUS_0, 0x0);
317
318 if (pdata->use_gpio)
319 dev_info(&pdev->dev, "Chip available at GPIOs "
320 "%d, %d, %d, %d\n",
321 chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
322 chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
323 else
324 dev_info(&pdev->dev, "Chip available at "
325 "physical address 0x%llx,"
326 "data connected to D%d\n",
327 (unsigned long long)pdev->resource[0].start,
328 chip->leftshift);
329
330 platform_set_drvdata(pdev, chip);
331
332 chip->rtc = devm_rtc_device_register(&pdev->dev, "v3020",
333 &v3020_rtc_ops, THIS_MODULE);
334 if (IS_ERR(chip->rtc)) {
335 retval = PTR_ERR(chip->rtc);
336 goto err_io;
337 }
338
339 return 0;
340
341err_io:
342 chip->ops->unmap_io(chip);
343
344 return retval;
345}
346
347static int rtc_remove(struct platform_device *dev)
348{
349 struct v3020 *chip = platform_get_drvdata(dev);
350
351 chip->ops->unmap_io(chip);
352
353 return 0;
354}
355
356static struct platform_driver rtc_device_driver = {
357 .probe = rtc_probe,
358 .remove = rtc_remove,
359 .driver = {
360 .name = "v3020",
361 },
362};
363
364module_platform_driver(rtc_device_driver);
365
366MODULE_DESCRIPTION("V3020 RTC");
367MODULE_AUTHOR("Raphael Assenat");
368MODULE_LICENSE("GPL");
369MODULE_ALIAS("platform:v3020");