xref: /openbmc/linux/drivers/rtc/rtc-palmas.c (revision 745b7908)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * rtc-palmas.c -- Palmas Real Time Clock driver.
4 
5  * RTC driver for TI Palma series devices like TPS65913,
6  * TPS65914 power management IC.
7  *
8  * Copyright (c) 2012, NVIDIA Corporation.
9  *
10  * Author: Laxman Dewangan <ldewangan@nvidia.com>
11  */
12 
13 #include <linux/bcd.h>
14 #include <linux/errno.h>
15 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel.h>
18 #include <linux/mfd/palmas.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/rtc.h>
22 #include <linux/types.h>
23 #include <linux/platform_device.h>
24 #include <linux/pm.h>
25 
26 struct palmas_rtc {
27 	struct rtc_device	*rtc;
28 	struct device		*dev;
29 	unsigned int		irq;
30 };
31 
32 /* Total number of RTC registers needed to set time*/
33 #define PALMAS_NUM_TIME_REGS	(PALMAS_YEARS_REG - PALMAS_SECONDS_REG + 1)
34 
35 static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm)
36 {
37 	unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
38 	struct palmas *palmas = dev_get_drvdata(dev->parent);
39 	int ret;
40 
41 	/* Copy RTC counting registers to static registers or latches */
42 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
43 		PALMAS_RTC_CTRL_REG_GET_TIME, PALMAS_RTC_CTRL_REG_GET_TIME);
44 	if (ret < 0) {
45 		dev_err(dev, "RTC CTRL reg update failed, err: %d\n", ret);
46 		return ret;
47 	}
48 
49 	ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
50 			rtc_data, PALMAS_NUM_TIME_REGS);
51 	if (ret < 0) {
52 		dev_err(dev, "RTC_SECONDS reg read failed, err = %d\n", ret);
53 		return ret;
54 	}
55 
56 	tm->tm_sec = bcd2bin(rtc_data[0]);
57 	tm->tm_min = bcd2bin(rtc_data[1]);
58 	tm->tm_hour = bcd2bin(rtc_data[2]);
59 	tm->tm_mday = bcd2bin(rtc_data[3]);
60 	tm->tm_mon = bcd2bin(rtc_data[4]) - 1;
61 	tm->tm_year = bcd2bin(rtc_data[5]) + 100;
62 
63 	return ret;
64 }
65 
66 static int palmas_rtc_set_time(struct device *dev, struct rtc_time *tm)
67 {
68 	unsigned char rtc_data[PALMAS_NUM_TIME_REGS];
69 	struct palmas *palmas = dev_get_drvdata(dev->parent);
70 	int ret;
71 
72 	rtc_data[0] = bin2bcd(tm->tm_sec);
73 	rtc_data[1] = bin2bcd(tm->tm_min);
74 	rtc_data[2] = bin2bcd(tm->tm_hour);
75 	rtc_data[3] = bin2bcd(tm->tm_mday);
76 	rtc_data[4] = bin2bcd(tm->tm_mon + 1);
77 	rtc_data[5] = bin2bcd(tm->tm_year - 100);
78 
79 	/* Stop RTC while updating the RTC time registers */
80 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
81 		PALMAS_RTC_CTRL_REG_STOP_RTC, 0);
82 	if (ret < 0) {
83 		dev_err(dev, "RTC stop failed, err = %d\n", ret);
84 		return ret;
85 	}
86 
87 	ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG,
88 		rtc_data, PALMAS_NUM_TIME_REGS);
89 	if (ret < 0) {
90 		dev_err(dev, "RTC_SECONDS reg write failed, err = %d\n", ret);
91 		return ret;
92 	}
93 
94 	/* Start back RTC */
95 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
96 		PALMAS_RTC_CTRL_REG_STOP_RTC, PALMAS_RTC_CTRL_REG_STOP_RTC);
97 	if (ret < 0)
98 		dev_err(dev, "RTC start failed, err = %d\n", ret);
99 	return ret;
100 }
101 
102 static int palmas_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
103 {
104 	struct palmas *palmas = dev_get_drvdata(dev->parent);
105 	u8 val;
106 
107 	val = enabled ? PALMAS_RTC_INTERRUPTS_REG_IT_ALARM : 0;
108 	return palmas_write(palmas, PALMAS_RTC_BASE,
109 		PALMAS_RTC_INTERRUPTS_REG, val);
110 }
111 
112 static int palmas_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
113 {
114 	unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
115 	u32 int_val;
116 	struct palmas *palmas = dev_get_drvdata(dev->parent);
117 	int ret;
118 
119 	ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE,
120 			PALMAS_ALARM_SECONDS_REG,
121 			alarm_data, PALMAS_NUM_TIME_REGS);
122 	if (ret < 0) {
123 		dev_err(dev, "RTC_ALARM_SECONDS read failed, err = %d\n", ret);
124 		return ret;
125 	}
126 
127 	alm->time.tm_sec = bcd2bin(alarm_data[0]);
128 	alm->time.tm_min = bcd2bin(alarm_data[1]);
129 	alm->time.tm_hour = bcd2bin(alarm_data[2]);
130 	alm->time.tm_mday = bcd2bin(alarm_data[3]);
131 	alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1;
132 	alm->time.tm_year = bcd2bin(alarm_data[5]) + 100;
133 
134 	ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_INTERRUPTS_REG,
135 			&int_val);
136 	if (ret < 0) {
137 		dev_err(dev, "RTC_INTERRUPTS reg read failed, err = %d\n", ret);
138 		return ret;
139 	}
140 
141 	if (int_val & PALMAS_RTC_INTERRUPTS_REG_IT_ALARM)
142 		alm->enabled = 1;
143 	return ret;
144 }
145 
146 static int palmas_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
147 {
148 	unsigned char alarm_data[PALMAS_NUM_TIME_REGS];
149 	struct palmas *palmas = dev_get_drvdata(dev->parent);
150 	int ret;
151 
152 	ret = palmas_rtc_alarm_irq_enable(dev, 0);
153 	if (ret < 0) {
154 		dev_err(dev, "Disable RTC alarm failed\n");
155 		return ret;
156 	}
157 
158 	alarm_data[0] = bin2bcd(alm->time.tm_sec);
159 	alarm_data[1] = bin2bcd(alm->time.tm_min);
160 	alarm_data[2] = bin2bcd(alm->time.tm_hour);
161 	alarm_data[3] = bin2bcd(alm->time.tm_mday);
162 	alarm_data[4] = bin2bcd(alm->time.tm_mon + 1);
163 	alarm_data[5] = bin2bcd(alm->time.tm_year - 100);
164 
165 	ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE,
166 		PALMAS_ALARM_SECONDS_REG, alarm_data, PALMAS_NUM_TIME_REGS);
167 	if (ret < 0) {
168 		dev_err(dev, "ALARM_SECONDS_REG write failed, err = %d\n", ret);
169 		return ret;
170 	}
171 
172 	if (alm->enabled)
173 		ret = palmas_rtc_alarm_irq_enable(dev, 1);
174 	return ret;
175 }
176 
177 static int palmas_clear_interrupts(struct device *dev)
178 {
179 	struct palmas *palmas = dev_get_drvdata(dev->parent);
180 	unsigned int rtc_reg;
181 	int ret;
182 
183 	ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
184 				&rtc_reg);
185 	if (ret < 0) {
186 		dev_err(dev, "RTC_STATUS read failed, err = %d\n", ret);
187 		return ret;
188 	}
189 
190 	ret = palmas_write(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG,
191 			rtc_reg);
192 	if (ret < 0) {
193 		dev_err(dev, "RTC_STATUS write failed, err = %d\n", ret);
194 		return ret;
195 	}
196 	return 0;
197 }
198 
199 static irqreturn_t palmas_rtc_interrupt(int irq, void *context)
200 {
201 	struct palmas_rtc *palmas_rtc = context;
202 	struct device *dev = palmas_rtc->dev;
203 	int ret;
204 
205 	ret = palmas_clear_interrupts(dev);
206 	if (ret < 0) {
207 		dev_err(dev, "RTC interrupt clear failed, err = %d\n", ret);
208 		return IRQ_NONE;
209 	}
210 
211 	rtc_update_irq(palmas_rtc->rtc, 1, RTC_IRQF | RTC_AF);
212 	return IRQ_HANDLED;
213 }
214 
215 static const struct rtc_class_ops palmas_rtc_ops = {
216 	.read_time	= palmas_rtc_read_time,
217 	.set_time	= palmas_rtc_set_time,
218 	.read_alarm	= palmas_rtc_read_alarm,
219 	.set_alarm	= palmas_rtc_set_alarm,
220 	.alarm_irq_enable = palmas_rtc_alarm_irq_enable,
221 };
222 
223 static int palmas_rtc_probe(struct platform_device *pdev)
224 {
225 	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
226 	struct palmas_rtc *palmas_rtc = NULL;
227 	int ret;
228 	bool enable_bb_charging = false;
229 	bool high_bb_charging = false;
230 
231 	if (pdev->dev.of_node) {
232 		enable_bb_charging = of_property_read_bool(pdev->dev.of_node,
233 					"ti,backup-battery-chargeable");
234 		high_bb_charging = of_property_read_bool(pdev->dev.of_node,
235 					"ti,backup-battery-charge-high-current");
236 	}
237 
238 	palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc),
239 			GFP_KERNEL);
240 	if (!palmas_rtc)
241 		return -ENOMEM;
242 
243 	/* Clear pending interrupts */
244 	ret = palmas_clear_interrupts(&pdev->dev);
245 	if (ret < 0) {
246 		dev_err(&pdev->dev, "clear RTC int failed, err = %d\n", ret);
247 		return ret;
248 	}
249 
250 	palmas_rtc->dev = &pdev->dev;
251 	platform_set_drvdata(pdev, palmas_rtc);
252 
253 	if (enable_bb_charging) {
254 		unsigned reg = PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG;
255 
256 		if (high_bb_charging)
257 			reg = 0;
258 
259 		ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
260 			PALMAS_BACKUP_BATTERY_CTRL,
261 			PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG, reg);
262 		if (ret < 0) {
263 			dev_err(&pdev->dev,
264 				"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
265 			return ret;
266 		}
267 
268 		ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE,
269 			PALMAS_BACKUP_BATTERY_CTRL,
270 			PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN,
271 			PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN);
272 		if (ret < 0) {
273 			dev_err(&pdev->dev,
274 				"BACKUP_BATTERY_CTRL update failed, %d\n", ret);
275 			return ret;
276 		}
277 	}
278 
279 	/* Start RTC */
280 	ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG,
281 			PALMAS_RTC_CTRL_REG_STOP_RTC,
282 			PALMAS_RTC_CTRL_REG_STOP_RTC);
283 	if (ret < 0) {
284 		dev_err(&pdev->dev, "RTC_CTRL write failed, err = %d\n", ret);
285 		return ret;
286 	}
287 
288 	palmas_rtc->irq = platform_get_irq(pdev, 0);
289 
290 	device_init_wakeup(&pdev->dev, 1);
291 	palmas_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
292 				&palmas_rtc_ops, THIS_MODULE);
293 	if (IS_ERR(palmas_rtc->rtc)) {
294 		ret = PTR_ERR(palmas_rtc->rtc);
295 		dev_err(&pdev->dev, "RTC register failed, err = %d\n", ret);
296 		return ret;
297 	}
298 
299 	ret = devm_request_threaded_irq(&pdev->dev, palmas_rtc->irq, NULL,
300 			palmas_rtc_interrupt,
301 			IRQF_TRIGGER_LOW | IRQF_ONESHOT,
302 			dev_name(&pdev->dev), palmas_rtc);
303 	if (ret < 0) {
304 		dev_err(&pdev->dev, "IRQ request failed, err = %d\n", ret);
305 		return ret;
306 	}
307 
308 	return 0;
309 }
310 
311 static void palmas_rtc_remove(struct platform_device *pdev)
312 {
313 	palmas_rtc_alarm_irq_enable(&pdev->dev, 0);
314 }
315 
316 #ifdef CONFIG_PM_SLEEP
317 static int palmas_rtc_suspend(struct device *dev)
318 {
319 	struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
320 
321 	if (device_may_wakeup(dev))
322 		enable_irq_wake(palmas_rtc->irq);
323 	return 0;
324 }
325 
326 static int palmas_rtc_resume(struct device *dev)
327 {
328 	struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev);
329 
330 	if (device_may_wakeup(dev))
331 		disable_irq_wake(palmas_rtc->irq);
332 	return 0;
333 }
334 #endif
335 
336 static SIMPLE_DEV_PM_OPS(palmas_rtc_pm_ops, palmas_rtc_suspend,
337 			 palmas_rtc_resume);
338 
339 #ifdef CONFIG_OF
340 static const struct of_device_id of_palmas_rtc_match[] = {
341 	{ .compatible = "ti,palmas-rtc"},
342 	{ },
343 };
344 MODULE_DEVICE_TABLE(of, of_palmas_rtc_match);
345 #endif
346 
347 static struct platform_driver palmas_rtc_driver = {
348 	.probe		= palmas_rtc_probe,
349 	.remove_new	= palmas_rtc_remove,
350 	.driver		= {
351 		.name	= "palmas-rtc",
352 		.pm	= &palmas_rtc_pm_ops,
353 		.of_match_table = of_match_ptr(of_palmas_rtc_match),
354 	},
355 };
356 
357 module_platform_driver(palmas_rtc_driver);
358 
359 MODULE_ALIAS("platform:palmas_rtc");
360 MODULE_DESCRIPTION("TI PALMAS series RTC driver");
361 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
362 MODULE_LICENSE("GPL v2");
363