1/* drivers/rtc/rtc-v3020.c
2 *
3 * Copyright (C) 2006 8D Technologies inc.
4 * Copyright (C) 2004 Compulab Ltd.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Driver for the V3020 RTC
11 *
12 * Changelog:
13 *
14 *  10-May-2006: Raphael Assenat <raph@8d.com>
15 *				- Converted to platform driver
16 *				- Use the generic rtc class
17 *
18 *  ??-???-2004: Someone at Compulab
19 *  			- Initial driver creation.
20 *
21 */
22#include <linux/platform_device.h>
23#include <linux/module.h>
24#include <linux/init.h>
25#include <linux/rtc.h>
26#include <linux/types.h>
27#include <linux/bcd.h>
28#include <linux/rtc-v3020.h>
29
30#include <asm/io.h>
31
32#undef DEBUG
33
34struct v3020 {
35	void __iomem *ioaddress;
36	int leftshift;
37	struct rtc_device *rtc;
38};
39
40static void v3020_set_reg(struct v3020 *chip, unsigned char address,
41			unsigned char data)
42{
43	int i;
44	unsigned char tmp;
45
46	tmp = address;
47	for (i = 0; i < 4; i++) {
48		writel((tmp & 1) << chip->leftshift, chip->ioaddress);
49		tmp >>= 1;
50	}
51
52	/* Commands dont have data */
53	if (!V3020_IS_COMMAND(address)) {
54		for (i = 0; i < 8; i++) {
55			writel((data & 1) << chip->leftshift, chip->ioaddress);
56			data >>= 1;
57		}
58	}
59}
60
61static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
62{
63	unsigned int data=0;
64	int i;
65
66	for (i = 0; i < 4; i++) {
67		writel((address & 1) << chip->leftshift, chip->ioaddress);
68		address >>= 1;
69	}
70
71	for (i = 0; i < 8; i++) {
72		data >>= 1;
73		if (readl(chip->ioaddress) & (1 << chip->leftshift))
74			data |= 0x80;
75	}
76
77	return data;
78}
79
80static int v3020_read_time(struct device *dev, struct rtc_time *dt)
81{
82	struct v3020 *chip = dev_get_drvdata(dev);
83	int tmp;
84
85	/* Copy the current time to ram... */
86	v3020_set_reg(chip, V3020_CMD_CLOCK2RAM, 0);
87
88	/* ...and then read constant values. */
89	tmp = v3020_get_reg(chip, V3020_SECONDS);
90	dt->tm_sec	= BCD2BIN(tmp);
91	tmp = v3020_get_reg(chip, V3020_MINUTES);
92	dt->tm_min	= BCD2BIN(tmp);
93	tmp = v3020_get_reg(chip, V3020_HOURS);
94	dt->tm_hour	= BCD2BIN(tmp);
95	tmp = v3020_get_reg(chip, V3020_MONTH_DAY);
96	dt->tm_mday	= BCD2BIN(tmp);
97	tmp = v3020_get_reg(chip, V3020_MONTH);
98	dt->tm_mon	= BCD2BIN(tmp);
99	tmp = v3020_get_reg(chip, V3020_WEEK_DAY);
100	dt->tm_wday	= BCD2BIN(tmp);
101	tmp = v3020_get_reg(chip, V3020_YEAR);
102	dt->tm_year = BCD2BIN(tmp)+100;
103
104#ifdef DEBUG
105	printk("\n%s : Read RTC values\n",__FUNCTION__);
106	printk("tm_hour: %i\n",dt->tm_hour);
107	printk("tm_min : %i\n",dt->tm_min);
108	printk("tm_sec : %i\n",dt->tm_sec);
109	printk("tm_year: %i\n",dt->tm_year);
110	printk("tm_mon : %i\n",dt->tm_mon);
111	printk("tm_mday: %i\n",dt->tm_mday);
112	printk("tm_wday: %i\n",dt->tm_wday);
113#endif
114
115	return 0;
116}
117
118
119static int v3020_set_time(struct device *dev, struct rtc_time *dt)
120{
121	struct v3020 *chip = dev_get_drvdata(dev);
122
123#ifdef DEBUG
124	printk("\n%s : Setting RTC values\n",__FUNCTION__);
125	printk("tm_sec : %i\n",dt->tm_sec);
126	printk("tm_min : %i\n",dt->tm_min);
127	printk("tm_hour: %i\n",dt->tm_hour);
128	printk("tm_mday: %i\n",dt->tm_mday);
129	printk("tm_wday: %i\n",dt->tm_wday);
130	printk("tm_year: %i\n",dt->tm_year);
131#endif
132
133	/* Write all the values to ram... */
134	v3020_set_reg(chip, V3020_SECONDS, 	BIN2BCD(dt->tm_sec));
135	v3020_set_reg(chip, V3020_MINUTES, 	BIN2BCD(dt->tm_min));
136	v3020_set_reg(chip, V3020_HOURS, 	BIN2BCD(dt->tm_hour));
137	v3020_set_reg(chip, V3020_MONTH_DAY,	BIN2BCD(dt->tm_mday));
138	v3020_set_reg(chip, V3020_MONTH, 	BIN2BCD(dt->tm_mon));
139	v3020_set_reg(chip, V3020_WEEK_DAY, 	BIN2BCD(dt->tm_wday));
140	v3020_set_reg(chip, V3020_YEAR, 	BIN2BCD(dt->tm_year % 100));
141
142	/* ...and set the clock. */
143	v3020_set_reg(chip, V3020_CMD_RAM2CLOCK, 0);
144
145	/* Compulab used this delay here. I dont know why,
146	 * the datasheet does not specify a delay. */
147	/*mdelay(5);*/
148
149	return 0;
150}
151
152static const struct rtc_class_ops v3020_rtc_ops = {
153	.read_time	= v3020_read_time,
154	.set_time	= v3020_set_time,
155};
156
157static int rtc_probe(struct platform_device *pdev)
158{
159	struct v3020_platform_data *pdata = pdev->dev.platform_data;
160	struct v3020 *chip;
161	struct rtc_device *rtc;
162	int retval = -EBUSY;
163	int i;
164	int temp;
165
166	if (pdev->num_resources != 1)
167		return -EBUSY;
168
169	if (pdev->resource[0].flags != IORESOURCE_MEM)
170		return -EBUSY;
171
172	chip = kzalloc(sizeof *chip, GFP_KERNEL);
173	if (!chip)
174		return -ENOMEM;
175
176	chip->leftshift = pdata->leftshift;
177	chip->ioaddress = ioremap(pdev->resource[0].start, 1);
178	if (chip->ioaddress == NULL)
179		goto err_chip;
180
181	/* Make sure the v3020 expects a communication cycle
182	 * by reading 8 times */
183	for (i = 0; i < 8; i++)
184		temp = readl(chip->ioaddress);
185
186	/* Test chip by doing a write/read sequence
187	 * to the chip ram */
188	v3020_set_reg(chip, V3020_SECONDS, 0x33);
189	if(v3020_get_reg(chip, V3020_SECONDS) != 0x33) {
190		retval = -ENODEV;
191		goto err_io;
192	}
193
194	/* Make sure frequency measurment mode, test modes, and lock
195	 * are all disabled */
196	v3020_set_reg(chip, V3020_STATUS_0, 0x0);
197
198	dev_info(&pdev->dev, "Chip available at physical address 0x%llx,"
199		"data connected to D%d\n",
200		(unsigned long long)pdev->resource[0].start,
201		chip->leftshift);
202
203	platform_set_drvdata(pdev, chip);
204
205	rtc = rtc_device_register("v3020",
206				&pdev->dev, &v3020_rtc_ops, THIS_MODULE);
207	if (IS_ERR(rtc)) {
208		retval = PTR_ERR(rtc);
209		goto err_io;
210	}
211	chip->rtc = rtc;
212
213	return 0;
214
215err_io:
216	iounmap(chip->ioaddress);
217err_chip:
218	kfree(chip);
219
220	return retval;
221}
222
223static int rtc_remove(struct platform_device *dev)
224{
225	struct v3020 *chip = platform_get_drvdata(dev);
226	struct rtc_device *rtc = chip->rtc;
227
228	if (rtc)
229		rtc_device_unregister(rtc);
230
231	iounmap(chip->ioaddress);
232	kfree(chip);
233
234	return 0;
235}
236
237static struct platform_driver rtc_device_driver = {
238	.probe	= rtc_probe,
239	.remove = rtc_remove,
240	.driver = {
241		.name	= "v3020",
242		.owner	= THIS_MODULE,
243	},
244};
245
246static __init int v3020_init(void)
247{
248	return platform_driver_register(&rtc_device_driver);
249}
250
251static __exit void v3020_exit(void)
252{
253	platform_driver_unregister(&rtc_device_driver);
254}
255
256module_init(v3020_init);
257module_exit(v3020_exit);
258
259MODULE_DESCRIPTION("V3020 RTC");
260MODULE_AUTHOR("Raphael Assenat");
261MODULE_LICENSE("GPL");
262