1/*
  2 * TX4939 internal RTC driver
  3 * Based on RBTX49xx patch from CELF patch archive.
  4 *
  5 * This file is subject to the terms and conditions of the GNU General Public
  6 * License.  See the file "COPYING" in the main directory of this archive
  7 * for more details.
  8 *
  9 * (C) Copyright TOSHIBA CORPORATION 2005-2007
 10 */
 11#include <linux/rtc.h>
 12#include <linux/platform_device.h>
 13#include <linux/interrupt.h>
 14#include <linux/module.h>
 15#include <linux/io.h>
 16#include <linux/gfp.h>
 17
 18#define TX4939_RTCCTL_ALME	0x00000080
 19#define TX4939_RTCCTL_ALMD	0x00000040
 20#define TX4939_RTCCTL_BUSY	0x00000020
 21
 22#define TX4939_RTCCTL_COMMAND	0x00000007
 23#define TX4939_RTCCTL_COMMAND_NOP	0x00000000
 24#define TX4939_RTCCTL_COMMAND_GETTIME	0x00000001
 25#define TX4939_RTCCTL_COMMAND_SETTIME	0x00000002
 26#define TX4939_RTCCTL_COMMAND_GETALARM	0x00000003
 27#define TX4939_RTCCTL_COMMAND_SETALARM	0x00000004
 28
 29#define TX4939_RTCTBC_PM	0x00000080
 30#define TX4939_RTCTBC_COMP	0x0000007f
 31
 32#define TX4939_RTC_REG_RAMSIZE	0x00000100
 33#define TX4939_RTC_REG_RWBSIZE	0x00000006
 34
 35struct tx4939_rtc_reg {
 36	__u32 ctl;
 37	__u32 adr;
 38	__u32 dat;
 39	__u32 tbc;
 40};
 41
 42struct tx4939rtc_plat_data {
 43	struct rtc_device *rtc;
 44	struct tx4939_rtc_reg __iomem *rtcreg;
 45	spinlock_t lock;
 46};
 47
 48static struct tx4939rtc_plat_data *get_tx4939rtc_plat_data(struct device *dev)
 49{
 50	return platform_get_drvdata(to_platform_device(dev));
 51}
 52
 53static int tx4939_rtc_cmd(struct tx4939_rtc_reg __iomem *rtcreg, int cmd)
 54{
 55	int i = 0;
 56
 57	__raw_writel(cmd, &rtcreg->ctl);
 58	/* This might take 30us (next 32.768KHz clock) */
 59	while (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_BUSY) {
 60		/* timeout on approx. 100us (@ GBUS200MHz) */
 61		if (i++ > 200 * 100)
 62			return -EBUSY;
 63		cpu_relax();
 64	}
 65	return 0;
 66}
 67
 68static int tx4939_rtc_set_mmss(struct device *dev, unsigned long secs)
 69{
 70	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
 71	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
 72	int i, ret;
 73	unsigned char buf[6];
 74
 75	buf[0] = 0;
 76	buf[1] = 0;
 77	buf[2] = secs;
 78	buf[3] = secs >> 8;
 79	buf[4] = secs >> 16;
 80	buf[5] = secs >> 24;
 81	spin_lock_irq(&pdata->lock);
 82	__raw_writel(0, &rtcreg->adr);
 83	for (i = 0; i < 6; i++)
 84		__raw_writel(buf[i], &rtcreg->dat);
 85	ret = tx4939_rtc_cmd(rtcreg,
 86			     TX4939_RTCCTL_COMMAND_SETTIME |
 87			     (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
 88	spin_unlock_irq(&pdata->lock);
 89	return ret;
 90}
 91
 92static int tx4939_rtc_read_time(struct device *dev, struct rtc_time *tm)
 93{
 94	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
 95	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
 96	int i, ret;
 97	unsigned long sec;
 98	unsigned char buf[6];
 99
100	spin_lock_irq(&pdata->lock);
101	ret = tx4939_rtc_cmd(rtcreg,
102			     TX4939_RTCCTL_COMMAND_GETTIME |
103			     (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
104	if (ret) {
105		spin_unlock_irq(&pdata->lock);
106		return ret;
107	}
108	__raw_writel(2, &rtcreg->adr);
109	for (i = 2; i < 6; i++)
110		buf[i] = __raw_readl(&rtcreg->dat);
111	spin_unlock_irq(&pdata->lock);
112	sec = ((unsigned long)buf[5] << 24) | (buf[4] << 16) |
113		(buf[3] << 8) | buf[2];
114	rtc_time_to_tm(sec, tm);
115	return 0;
116}
117
118static int tx4939_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
119{
120	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
121	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
122	int i, ret;
123	unsigned long sec;
124	unsigned char buf[6];
125
126	if (alrm->time.tm_sec < 0 ||
127	    alrm->time.tm_min < 0 ||
128	    alrm->time.tm_hour < 0 ||
129	    alrm->time.tm_mday < 0 ||
130	    alrm->time.tm_mon < 0 ||
131	    alrm->time.tm_year < 0)
132		return -EINVAL;
133	rtc_tm_to_time(&alrm->time, &sec);
134	buf[0] = 0;
135	buf[1] = 0;
136	buf[2] = sec;
137	buf[3] = sec >> 8;
138	buf[4] = sec >> 16;
139	buf[5] = sec >> 24;
140	spin_lock_irq(&pdata->lock);
141	__raw_writel(0, &rtcreg->adr);
142	for (i = 0; i < 6; i++)
143		__raw_writel(buf[i], &rtcreg->dat);
144	ret = tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_SETALARM |
145			     (alrm->enabled ? TX4939_RTCCTL_ALME : 0));
146	spin_unlock_irq(&pdata->lock);
147	return ret;
148}
149
150static int tx4939_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
151{
152	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
153	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
154	int i, ret;
155	unsigned long sec;
156	unsigned char buf[6];
157	u32 ctl;
158
159	spin_lock_irq(&pdata->lock);
160	ret = tx4939_rtc_cmd(rtcreg,
161			     TX4939_RTCCTL_COMMAND_GETALARM |
162			     (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));
163	if (ret) {
164		spin_unlock_irq(&pdata->lock);
165		return ret;
166	}
167	__raw_writel(2, &rtcreg->adr);
168	for (i = 2; i < 6; i++)
169		buf[i] = __raw_readl(&rtcreg->dat);
170	ctl = __raw_readl(&rtcreg->ctl);
171	alrm->enabled = (ctl & TX4939_RTCCTL_ALME) ? 1 : 0;
172	alrm->pending = (ctl & TX4939_RTCCTL_ALMD) ? 1 : 0;
173	spin_unlock_irq(&pdata->lock);
174	sec = ((unsigned long)buf[5] << 24) | (buf[4] << 16) |
175		(buf[3] << 8) | buf[2];
176	rtc_time_to_tm(sec, &alrm->time);
177	return rtc_valid_tm(&alrm->time);
178}
179
180static int tx4939_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
181{
182	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);
183
184	spin_lock_irq(&pdata->lock);
185	tx4939_rtc_cmd(pdata->rtcreg,
186		       TX4939_RTCCTL_COMMAND_NOP |
187		       (enabled ? TX4939_RTCCTL_ALME : 0));
188	spin_unlock_irq(&pdata->lock);
189	return 0;
190}
191
192static irqreturn_t tx4939_rtc_interrupt(int irq, void *dev_id)
193{
194	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev_id);
195	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
196	unsigned long events = RTC_IRQF;
197
198	spin_lock(&pdata->lock);
199	if (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALMD) {
200		events |= RTC_AF;
201		tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_NOP);
202	}
203	spin_unlock(&pdata->lock);
204	rtc_update_irq(pdata->rtc, 1, events);
205
206	return IRQ_HANDLED;
207}
208
209static const struct rtc_class_ops tx4939_rtc_ops = {
210	.read_time		= tx4939_rtc_read_time,
211	.read_alarm		= tx4939_rtc_read_alarm,
212	.set_alarm		= tx4939_rtc_set_alarm,
213	.set_mmss		= tx4939_rtc_set_mmss,
214	.alarm_irq_enable	= tx4939_rtc_alarm_irq_enable,
215};
216
217static int tx4939_nvram_read(void *priv, unsigned int pos, void *val,
218			     size_t bytes)
219{
220	struct tx4939rtc_plat_data *pdata = priv;
221	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
222	u8 *buf = val;
223
224	spin_lock_irq(&pdata->lock);
225	for (; bytes; bytes--) {
226		__raw_writel(pos++, &rtcreg->adr);
227		*buf++ = __raw_readl(&rtcreg->dat);
228	}
229	spin_unlock_irq(&pdata->lock);
230	return 0;
231}
232
233static int tx4939_nvram_write(void *priv, unsigned int pos, void *val,
234			      size_t bytes)
235{
236	struct tx4939rtc_plat_data *pdata = priv;
237	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;
238	u8 *buf = val;
239
240	spin_lock_irq(&pdata->lock);
241	for (; bytes; bytes--) {
242		__raw_writel(pos++, &rtcreg->adr);
243		__raw_writel(*buf++, &rtcreg->dat);
244	}
245	spin_unlock_irq(&pdata->lock);
246	return 0;
247}
248
249static int __init tx4939_rtc_probe(struct platform_device *pdev)
250{
251	struct rtc_device *rtc;
252	struct tx4939rtc_plat_data *pdata;
253	struct resource *res;
254	int irq, ret;
255	struct nvmem_config nvmem_cfg = {
256		.name = "rv8803_nvram",
257		.word_size = 4,
258		.stride = 4,
259		.size = TX4939_RTC_REG_RAMSIZE,
260		.reg_read = tx4939_nvram_read,
261		.reg_write = tx4939_nvram_write,
262	};
263
264	irq = platform_get_irq(pdev, 0);
265	if (irq < 0)
266		return -ENODEV;
267	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
268	if (!pdata)
269		return -ENOMEM;
270	platform_set_drvdata(pdev, pdata);
271
272	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
273	pdata->rtcreg = devm_ioremap_resource(&pdev->dev, res);
274	if (IS_ERR(pdata->rtcreg))
275		return PTR_ERR(pdata->rtcreg);
276
277	spin_lock_init(&pdata->lock);
278	tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
279	if (devm_request_irq(&pdev->dev, irq, tx4939_rtc_interrupt,
280			     0, pdev->name, &pdev->dev) < 0)
281		return -EBUSY;
282	rtc = devm_rtc_allocate_device(&pdev->dev);
283	if (IS_ERR(rtc))
284		return PTR_ERR(rtc);
285
286	rtc->ops = &tx4939_rtc_ops;
287	rtc->nvram_old_abi = true;
288
289	pdata->rtc = rtc;
290
291	nvmem_cfg.priv = pdata;
292	ret = rtc_nvmem_register(rtc, &nvmem_cfg);
293	if (ret)
294		return ret;
295
296	return rtc_register_device(rtc);
297}
298
299static int __exit tx4939_rtc_remove(struct platform_device *pdev)
300{
301	struct tx4939rtc_plat_data *pdata = platform_get_drvdata(pdev);
302
303	spin_lock_irq(&pdata->lock);
304	tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);
305	spin_unlock_irq(&pdata->lock);
306	return 0;
307}
308
309static struct platform_driver tx4939_rtc_driver = {
310	.remove		= __exit_p(tx4939_rtc_remove),
311	.driver		= {
312		.name	= "tx4939rtc",
313	},
314};
315
316module_platform_driver_probe(tx4939_rtc_driver, tx4939_rtc_probe);
317
318MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
319MODULE_DESCRIPTION("TX4939 internal RTC driver");
320MODULE_LICENSE("GPL");
321MODULE_ALIAS("platform:tx4939rtc");