aboutsummaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-v3020.c
blob: 1f3117b5a83cf32ddfc9bfc1eceb11684ba0cae3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
/* drivers/rtc/rtc-v3020.c
 *
 * Copyright (C) 2006 8D Technologies inc.
 * Copyright (C) 2004 Compulab Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Driver for the V3020 RTC
 *
 * Changelog:
 *
 *  10-May-2006: Raphael Assenat <raph@8d.com>
 *				- Converted to platform driver
 *				- Use the generic rtc class
 *
 *  ??-???-2004: Someone at Compulab
 *			- Initial driver creation.
 *
 */
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rtc.h>
#include <linux/types.h>
#include <linux/bcd.h>
#include <linux/platform_data/rtc-v3020.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/slab.h>

#include <linux/io.h>

#undef DEBUG

struct v3020;

struct v3020_chip_ops {
	int (*map_io)(struct v3020 *chip, struct platform_device *pdev,
		      struct v3020_platform_data *pdata);
	void (*unmap_io)(struct v3020 *chip);
	unsigned char (*read_bit)(struct v3020 *chip);
	void (*write_bit)(struct v3020 *chip, unsigned char bit);
};

#define V3020_CS	0
#define V3020_WR	1
#define V3020_RD	2
#define V3020_IO	3

struct v3020 {
	/* MMIO access */
	void __iomem *ioaddress;
	int leftshift;

	/* GPIO access */
	struct gpio *gpio;

	const struct v3020_chip_ops *ops;

	struct rtc_device *rtc;
};


static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
			  struct v3020_platform_data *pdata)
{
	if (pdev->num_resources != 1)
		return -EBUSY;

	if (pdev->resource[0].flags != IORESOURCE_MEM)
		return -EBUSY;

	chip->leftshift = pdata->leftshift;
	chip->ioaddress = ioremap(pdev->resource[0].start, 1);
	if (chip->ioaddress == NULL)
		return -EBUSY;

	return 0;
}

static void v3020_mmio_unmap(struct v3020 *chip)
{
	iounmap(chip->ioaddress);
}

static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
{
	writel(bit << chip->leftshift, chip->ioaddress);
}

static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
{
	return !!(readl(chip->ioaddress) & (1 << chip->leftshift));
}

static const struct v3020_chip_ops v3020_mmio_ops = {
	.map_io		= v3020_mmio_map,
	.unmap_io	= v3020_mmio_unmap,
	.read_bit	= v3020_mmio_read_bit,
	.write_bit	= v3020_mmio_write_bit,
};

static struct gpio v3020_gpio[] = {
	{ 0, GPIOF_OUT_INIT_HIGH, "RTC CS"},
	{ 0, GPIOF_OUT_INIT_HIGH, "RTC WR"},
	{ 0, GPIOF_OUT_INIT_HIGH, "RTC RD"},
	{ 0, GPIOF_OUT_INIT_HIGH, "RTC IO"},
};

static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
			  struct v3020_platform_data *pdata)
{
	int err;

	v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
	v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
	v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
	v3020_gpio[V3020_IO].gpio = pdata->gpio_io;

	err = gpio_request_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));

	if (!err)
		chip->gpio = v3020_gpio;

	return err;
}

static void v3020_gpio_unmap(struct v3020 *chip)
{
	gpio_free_array(v3020_gpio, ARRAY_SIZE(v3020_gpio));
}

static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
{
	gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
	gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
	gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
	udelay(1);
	gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
	gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
}

static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
{
	int bit;

	gpio_direction_input(chip->gpio[V3020_IO].gpio);
	gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
	gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
	udelay(1);
	bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
	udelay(1);
	gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
	gpio_set_value(chip->gpio[V3020_CS].gpio, 1);

	return bit;
}

static const struct v3020_chip_ops v3020_gpio_ops = {
	.map_io		= v3020_gpio_map,
	.unmap_io	= v3020_gpio_unmap,
	.read_bit	= v3020_gpio_read_bit,
	.write_bit	= v3020_gpio_write_bit,
};

static void v3020_set_reg(struct v3020 *chip, unsigned char address,
			unsigned char data)
{
	int i;
	unsigned char tmp;

	tmp = address;
	for (i = 0; i < 4; i++) {
		chip->ops->write_bit(chip, (tmp & 1));
		tmp >>= 1;
		udelay(1);
	}

	/* Commands dont have data */
	if (!V3020_IS_COMMAND(address)) {
		for (i = 0; i < 8; i++) {
			chip->ops->write_bit(chip, (data & 1));
			data >>= 1;
			udelay(1);
		}
	}
}

static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
{
	unsigned int data = 0;
	int i;

	for (i = 0; i < 4; i++) {
		chip->ops->write_bit(chip, (address & 1));
		address >>= 1;
		udelay(1);
	}

	for (i = 0; i < 8; i++) {
		data >>= 1;
		if (chip->ops->read_bit(chip))
			data |= 0x80;
		udelay(1);
	}

	return data;
}

static int v3020_read_time(struct device *dev, struct rtc_time *dt)
{
	struct v3020 *chip = dev_get_drvdata(dev);
	int tmp;

	/* Copy the current time to ram... */
	v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);

	/* ...and then read constant values. */
	tmp = v3020_get_reg(chip, V3020_SECONDS);
	dt->tm_sec	= bcd2bin(tmp);
	tmp = v3020_get_reg(chip, V3020_MINUTES);
	dt->tm_min	= bcd2bin(tmp);
	tmp = v3020_get_reg(chip, V3020_HOURS);
	dt->tm_hour	= bcd2bin(tmp);
	tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
	dt->tm_mday	= bcd2bin(tmp);
	tmp = v3020_get_reg(chip, V3020_MONTH);
	dt->tm_mon    = bcd2bin(tmp) - 1;
	tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
	dt->tm_wday	= bcd2bin(tmp);
	tmp = v3020_get_reg(chip, V3020_YEAR);
	dt->tm_year = bcd2bin(tmp)+100;

	dev_dbg(dev, "\n%s : Read RTC values\n", __func__);
	dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
	dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
	dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
	dev_dbg(dev, "tm_year: %i\n", dt->tm_year);
	dev_dbg(dev, "tm_mon : %i\n", dt->tm_mon);
	dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
	dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);

	return 0;
}


static int v3020_set_time(struct device *dev, struct rtc_time *dt)
{
	struct v3020 *chip = dev_get_drvdata(dev);

	dev_dbg(dev, "\n%s : Setting RTC values\n", __func__);
	dev_dbg(dev, "tm_sec : %i\n", dt->tm_sec);
	dev_dbg(dev, "tm_min : %i\n", dt->tm_min);
	dev_dbg(dev, "tm_hour: %i\n", dt->tm_hour);
	dev_dbg(dev, "tm_mday: %i\n", dt->tm_mday);
	dev_dbg(dev, "tm_wday: %i\n", dt->tm_wday);
	dev_dbg(dev, "tm_year: %i\n", dt->tm_year);

	/* Write all the values to ram... */
	v3020_set_reg(chip, V3020_SECONDS,	bin2bcd(dt->tm_sec));
	v3020_set_reg(chip, V3020_MINUTES,	bin2bcd(dt->tm_min));
	v3020_set_reg(chip, V3020_HOURS,	bin2bcd(dt->tm_hour));
	v3020_set_reg(chip, V3020_MONTH_DAY,	bin2bcd(dt->tm_mday));
	v3020_set_reg(chip, V3020_MONTH,	bin2bcd(dt->tm_mon + 1));
	v3020_set_reg(chip, V3020_WEEK_DAY,	bin2bcd(dt->tm_wday));
	v3020_set_reg(chip, V3020_YEAR,		bin2bcd(dt->tm_year % 100));

	/* ...and set the clock. */
	v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);

	/* Compulab used this delay here. I dont know why,
	 * the datasheet does not specify a delay. */
	/*mdelay(5);*/

	return 0;
}

static const struct rtc_class_ops v3020_rtc_ops = {
	.read_time	= v3020_read_time,
	.set_time	= v3020_set_time,
};

static int rtc_probe(struct platform_device *pdev)
{
	struct v3020_platform_data *pdata = dev_get_platdata(&pdev->dev);
	struct v3020 *chip;
	int retval = -EBUSY;
	int i;
	int temp;

	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
	if (!chip)
		return -ENOMEM;

	if (pdata->use_gpio)
		chip->ops = &v3020_gpio_ops;
	else
		chip->ops = &v3020_mmio_ops;

	retval = chip->ops->map_io(chip, pdev, pdata);
	if (retval)
		return retval;

	/* Make sure the v3020 expects a communication cycle
	 * by reading 8 times */
	for (i = 0; i < 8; i++)
		temp = chip->ops->read_bit(chip);

	/* Test chip by doing a write/read sequence
	 * to the chip ram */
	v3020_set_reg(chip, V3020_SECONDS, 0x33);
	if (v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
		retval = -ENODEV;
		goto err_io;
	}

	/* Make sure frequency measurement mode, test modes, and lock
	 * are all disabled */
	v3020_set_reg(chip, V3020_STATUS_0, 0x0);

	if (pdata->use_gpio)
		dev_info(&pdev->dev, "Chip available at GPIOs "
			 "%d, %d, %d, %d\n",
			 chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
			 chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
	else
		dev_info(&pdev->dev, "Chip available at "
			 "physical address 0x%llx,"
			 "data connected to D%d\n",
			 (unsigned long long)pdev->resource[0].start,
			 chip->leftshift);

	platform_set_drvdata(pdev, chip);

	chip->rtc = devm_rtc_device_register(&pdev->dev, "v3020",
					&v3020_rtc_ops, THIS_MODULE);
	if (IS_ERR(chip->rtc)) {
		retval = PTR_ERR(chip->rtc);
		goto err_io;
	}

	return 0;

err_io:
	chip->ops->unmap_io(chip);

	return retval;
}

static int rtc_remove(struct platform_device *dev)
{
	struct v3020 *chip = platform_get_drvdata(dev);

	chip->ops->unmap_io(chip);

	return 0;
}

static struct platform_driver rtc_device_driver = {
	.probe	= rtc_probe,
	.remove = rtc_remove,
	.driver = {
		.name	= "v3020",
	},
};

module_platform_driver(rtc_device_driver);

MODULE_DESCRIPTION("V3020 RTC");
MODULE_AUTHOR("Raphael Assenat");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:v3020");