1 /*
2  * rtc-palmas.c -- Palmas Real Time Clock driver.
3 
4  * RTC driver for TI Palma series devices like TPS65913,
5  * TPS65914 power management IC.
6  *
7  * Copyright (c) 2012, NVIDIA Corporation.
8  *
9  * Author: Laxman Dewangan <ldewangan@nvidia.com>
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public License as
13  * published by the Free Software Foundation version 2.
14  *
15  * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
16  * whether express or implied; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
23  * 02111-1307, USA
24  */
25 
26 #include <linux/bcd.h>
27 #include <linux/errno.h>
28 #include <linux/init.h>
29 #include <linux/interrupt.h>
30 #include <linux/kernel.h>
31 #include <linux/mfd/palmas.h>
32 #include <linux/module.h>
33 #include <linux/of.h>
34 #include <linux/rtc.h>
35 #include <linux/types.h>
36 #include <linux/platform_device.h>
37 #include <linux/pm.h>
38 
39 struct palmas_rtc {
40 	struct rtc_device	*rtc;
41 	struct device		*dev;
42 	unsigned int		irq;
43 };
44 
45 /* Total number of RTC registers needed to set time*/
46 #define PALMAS_NUM_TIME_REGS	(PALMAS_YEARS_REG - PALMAS_SECONDS_REG + 1)
47 
palmas_rtc_read_time(struct device * dev,struct rtc_time * tm)48 static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm)
49 {
50 	unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
51 	struct palmas *palmas = dev_get_drvdata(dev->parent);
52 	int ret;
53 
54 	/* Copy RTC counting registers to static registers or latches */
55 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
56 		PALMAS_RTC_CTRL_REG_GET_TIME, PALMAS_RTC_CTRL_REG_GET_TIME);
57 	if (ret < 0) {
58 		dev_err(dev, "RTC CTRL reg update failed, err: %d\n", ret);
59 		return ret;
60 	}
61 
62 	ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
63 			rtc_data, PALMAS_NUM_TIME_REGS);
64 	if (ret < 0) {
65 		dev_err(dev, "RTC_SECONDS reg read failed, err = %d\n", ret);
66 		return ret;
67 	}
68 
69 	tm->tm_sec = bcd2bin(rtc_data[0]);
70 	tm->tm_min = bcd2bin(rtc_data[1]);
71 	tm->tm_hour = bcd2bin(rtc_data[2]);
72 	tm->tm_mday = bcd2bin(rtc_data[3]);
73 	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
74 	tm->tm_year = bcd2bin(rtc_data[5]) + 100;
75 
76 	return ret;
77 }
78 
palmas_rtc_set_time(struct device * dev,struct rtc_time * tm)79 static int palmas_rtc_set_time(struct device *dev, struct rtc_time *tm)
80 {
81 	unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
82 	struct palmas *palmas = dev_get_drvdata(dev->parent);
83 	int ret;
84 
85 	rtc_data[0] = bin2bcd(tm->tm_sec);
86 	rtc_data[1] = bin2bcd(tm->tm_min);
87 	rtc_data[2] = bin2bcd(tm->tm_hour);
88 	rtc_data[3] = bin2bcd(tm->tm_mday);
89 	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
90 	rtc_data[5] = bin2bcd(tm->tm_year - 100);
91 
92 	/* Stop RTC while updating the RTC time registers */
93 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
94 		PALMAS_RTC_CTRL_REG_STOP_RTC, 0);
95 	if (ret < 0) {
96 		dev_err(dev, "RTC stop failed, err = %d\n", ret);
97 		return ret;
98 	}
99 
100 	ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
101 		rtc_data, PALMAS_NUM_TIME_REGS);
102 	if (ret < 0) {
103 		dev_err(dev, "RTC_SECONDS reg write failed, err = %d\n", ret);
104 		return ret;
105 	}
106 
107 	/* Start back RTC */
108 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
109 		PALMAS_RTC_CTRL_REG_STOP_RTC, PALMAS_RTC_CTRL_REG_STOP_RTC);
110 	if (ret < 0)
111 		dev_err(dev, "RTC start failed, err = %d\n", ret);
112 	return ret;
113 }
114 
palmas_rtc_alarm_irq_enable(struct device * dev,unsigned enabled)115 static int palmas_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
116 {
117 	struct palmas *palmas = dev_get_drvdata(dev->parent);
118 	u8 val;
119 
120 	val = enabled ? PALMAS_RTC_INTERRUPTS_REG_IT_ALARM : 0;
121 	return palmas_write(palmas, PALMAS_RTC_BASE,
122 		PALMAS_RTC_INTERRUPTS_REG, val);
123 }
124 
palmas_rtc_read_alarm(struct device * dev,struct rtc_wkalrm * alm)125 static int palmas_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
126 {
127 	unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
128 	u32 int_val;
129 	struct palmas *palmas = dev_get_drvdata(dev->parent);
130 	int ret;
131 
132 	ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE,
133 			PALMAS_ALARM_SECONDS_REG,
134 			alarm_data, PALMAS_NUM_TIME_REGS);
135 	if (ret < 0) {
136 		dev_err(dev, "RTC_ALARM_SECONDS read failed, err = %d\n", ret);
137 		return ret;
138 	}
139 
140 	alm->time.tm_sec = bcd2bin(alarm_data[0]);
141 	alm->time.tm_min = bcd2bin(alarm_data[1]);
142 	alm->time.tm_hour = bcd2bin(alarm_data[2]);
143 	alm->time.tm_mday = bcd2bin(alarm_data[3]);
144 	alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
145 	alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
146 
147 	ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_INTERRUPTS_REG,
148 			&int_val);
149 	if (ret < 0) {
150 		dev_err(dev, "RTC_INTERRUPTS reg read failed, err = %d\n", ret);
151 		return ret;
152 	}
153 
154 	if (int_val & PALMAS_RTC_INTERRUPTS_REG_IT_ALARM)
155 		alm->enabled = 1;
156 	return ret;
157 }
158 
palmas_rtc_set_alarm(struct device * dev,struct rtc_wkalrm * alm)159 static int palmas_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
160 {
161 	unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
162 	struct palmas *palmas = dev_get_drvdata(dev->parent);
163 	int ret;
164 
165 	ret = palmas_rtc_alarm_irq_enable(dev, 0);
166 	if (ret < 0) {
167 		dev_err(dev, "Disable RTC alarm failed\n");
168 		return ret;
169 	}
170 
171 	alarm_data[0] = bin2bcd(alm->time.tm_sec);
172 	alarm_data[1] = bin2bcd(alm->time.tm_min);
173 	alarm_data[2] = bin2bcd(alm->time.tm_hour);
174 	alarm_data[3] = bin2bcd(alm->time.tm_mday);
175 	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
176 	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
177 
178 	ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE,
179 		PALMAS_ALARM_SECONDS_REG, alarm_data, PALMAS_NUM_TIME_REGS);
180 	if (ret < 0) {
181 		dev_err(dev, "ALARM_SECONDS_REG write failed, err = %d\n", ret);
182 		return ret;
183 	}
184 
185 	if (alm->enabled)
186 		ret = palmas_rtc_alarm_irq_enable(dev, 1);
187 	return ret;
188 }
189 
palmas_clear_interrupts(struct device * dev)190 static int palmas_clear_interrupts(struct device *dev)
191 {
192 	struct palmas *palmas = dev_get_drvdata(dev->parent);
193 	unsigned int rtc_reg;
194 	int ret;
195 
196 	ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
197 				&rtc_reg);
198 	if (ret < 0) {
199 		dev_err(dev, "RTC_STATUS read failed, err = %d\n", ret);
200 		return ret;
201 	}
202 
203 	ret = palmas_write(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
204 			rtc_reg);
205 	if (ret < 0) {
206 		dev_err(dev, "RTC_STATUS write failed, err = %d\n", ret);
207 		return ret;
208 	}
209 	return 0;
210 }
211 
palmas_rtc_interrupt(int irq,void * context)212 static irqreturn_t palmas_rtc_interrupt(int irq, void *context)
213 {
214 	struct palmas_rtc *palmas_rtc = context;
215 	struct device *dev = palmas_rtc->dev;
216 	int ret;
217 
218 	ret = palmas_clear_interrupts(dev);
219 	if (ret < 0) {
220 		dev_err(dev, "RTC interrupt clear failed, err = %d\n", ret);
221 		return IRQ_NONE;
222 	}
223 
224 	rtc_update_irq(palmas_rtc->rtc, 1, RTC_IRQF | RTC_AF);
225 	return IRQ_HANDLED;
226 }
227 
228 static const struct rtc_class_ops palmas_rtc_ops = {
229 	.read_time	= palmas_rtc_read_time,
230 	.set_time	= palmas_rtc_set_time,
231 	.read_alarm	= palmas_rtc_read_alarm,
232 	.set_alarm	= palmas_rtc_set_alarm,
233 	.alarm_irq_enable = palmas_rtc_alarm_irq_enable,
234 };
235 
palmas_rtc_probe(struct platform_device * pdev)236 static int palmas_rtc_probe(struct platform_device *pdev)
237 {
238 	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
239 	struct palmas_rtc *palmas_rtc = NULL;
240 	int ret;
241 	bool enable_bb_charging = false;
242 	bool high_bb_charging = false;
243 
244 	if (pdev->dev.of_node) {
245 		enable_bb_charging = of_property_read_bool(pdev->dev.of_node,
246 					"ti,backup-battery-chargeable");
247 		high_bb_charging = of_property_read_bool(pdev->dev.of_node,
248 					"ti,backup-battery-charge-high-current");
249 	}
250 
251 	palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc),
252 			GFP_KERNEL);
253 	if (!palmas_rtc)
254 		return -ENOMEM;
255 
256 	/* Clear pending interrupts */
257 	ret = palmas_clear_interrupts(&pdev->dev);
258 	if (ret < 0) {
259 		dev_err(&pdev->dev, "clear RTC int failed, err = %d\n", ret);
260 		return ret;
261 	}
262 
263 	palmas_rtc->dev = &pdev->dev;
264 	platform_set_drvdata(pdev, palmas_rtc);
265 
266 	if (enable_bb_charging) {
267 		unsigned reg = PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG;
268 
269 		if (high_bb_charging)
270 			reg = 0;
271 
272 		ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
273 			PALMAS_BACKUP_BATTERY_CTRL,
274 			PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG, reg);
275 		if (ret < 0) {
276 			dev_err(&pdev->dev,
277 				"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
278 			return ret;
279 		}
280 
281 		ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
282 			PALMAS_BACKUP_BATTERY_CTRL,
283 			PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN,
284 			PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN);
285 		if (ret < 0) {
286 			dev_err(&pdev->dev,
287 				"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
288 			return ret;
289 		}
290 	}
291 
292 	/* Start RTC */
293 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
294 			PALMAS_RTC_CTRL_REG_STOP_RTC,
295 			PALMAS_RTC_CTRL_REG_STOP_RTC);
296 	if (ret < 0) {
297 		dev_err(&pdev->dev, "RTC_CTRL write failed, err = %d\n", ret);
298 		return ret;
299 	}
300 
301 	palmas_rtc->irq = platform_get_irq(pdev, 0);
302 
303 	device_init_wakeup(&pdev->dev, 1);
304 	palmas_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
305 				&palmas_rtc_ops, THIS_MODULE);
306 	if (IS_ERR(palmas_rtc->rtc)) {
307 		ret = PTR_ERR(palmas_rtc->rtc);
308 		dev_err(&pdev->dev, "RTC register failed, err = %d\n", ret);
309 		return ret;
310 	}
311 
312 	ret = devm_request_threaded_irq(&pdev->dev, palmas_rtc->irq, NULL,
313 			palmas_rtc_interrupt,
314 			IRQF_TRIGGER_LOW | IRQF_ONESHOT,
315 			dev_name(&pdev->dev), palmas_rtc);
316 	if (ret < 0) {
317 		dev_err(&pdev->dev, "IRQ request failed, err = %d\n", ret);
318 		return ret;
319 	}
320 
321 	return 0;
322 }
323 
palmas_rtc_remove(struct platform_device * pdev)324 static int palmas_rtc_remove(struct platform_device *pdev)
325 {
326 	palmas_rtc_alarm_irq_enable(&pdev->dev, 0);
327 	return 0;
328 }
329 
330 #ifdef CONFIG_PM_SLEEP
palmas_rtc_suspend(struct device * dev)331 static int palmas_rtc_suspend(struct device *dev)
332 {
333 	struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
334 
335 	if (device_may_wakeup(dev))
336 		enable_irq_wake(palmas_rtc->irq);
337 	return 0;
338 }
339 
palmas_rtc_resume(struct device * dev)340 static int palmas_rtc_resume(struct device *dev)
341 {
342 	struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
343 
344 	if (device_may_wakeup(dev))
345 		disable_irq_wake(palmas_rtc->irq);
346 	return 0;
347 }
348 #endif
349 
350 static SIMPLE_DEV_PM_OPS(palmas_rtc_pm_ops, palmas_rtc_suspend,
351 			 palmas_rtc_resume);
352 
353 #ifdef CONFIG_OF
354 static const struct of_device_id of_palmas_rtc_match[] = {
355 	{ .compatible = "ti,palmas-rtc"},
356 	{ },
357 };
358 MODULE_DEVICE_TABLE(of, of_palmas_rtc_match);
359 #endif
360 
361 static struct platform_driver palmas_rtc_driver = {
362 	.probe		= palmas_rtc_probe,
363 	.remove		= palmas_rtc_remove,
364 	.driver		= {
365 		.name	= "palmas-rtc",
366 		.pm	= &palmas_rtc_pm_ops,
367 		.of_match_table = of_match_ptr(of_palmas_rtc_match),
368 	},
369 };
370 
371 module_platform_driver(palmas_rtc_driver);
372 
373 MODULE_ALIAS("platform:palmas_rtc");
374 MODULE_DESCRIPTION("TI PALMAS series RTC driver");
375 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
376 MODULE_LICENSE("GPL v2");
377