[linux.git] / drivers / rtc / rtc-wm831x.c

/*
 *	Real Time Clock driver for Wolfson Microelectronics WM831x
 *
 *	Copyright (C) 2009 Wolfson Microelectronics PLC.
 *
 *  Author: Mark Brown <[email protected]>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/bcd.h>
#include <linux/interrupt.h>
#include <linux/ioctl.h>
#include <linux/completion.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/random.h>

/*
 * R16416 (0x4020) - RTC Write Counter
 */
#define WM831X_RTC_WR_CNT_MASK                  0xFFFF  /* RTC_WR_CNT - [15:0] */
#define WM831X_RTC_WR_CNT_SHIFT                      0  /* RTC_WR_CNT - [15:0] */
#define WM831X_RTC_WR_CNT_WIDTH                     16  /* RTC_WR_CNT - [15:0] */

/*
 * R16417 (0x4021) - RTC Time 1
 */
#define WM831X_RTC_TIME_MASK                    0xFFFF  /* RTC_TIME - [15:0] */
#define WM831X_RTC_TIME_SHIFT                        0  /* RTC_TIME - [15:0] */
#define WM831X_RTC_TIME_WIDTH                       16  /* RTC_TIME - [15:0] */

/*
 * R16418 (0x4022) - RTC Time 2
 */
#define WM831X_RTC_TIME_MASK                    0xFFFF  /* RTC_TIME - [15:0] */
#define WM831X_RTC_TIME_SHIFT                        0  /* RTC_TIME - [15:0] */
#define WM831X_RTC_TIME_WIDTH                       16  /* RTC_TIME - [15:0] */

/*
 * R16419 (0x4023) - RTC Alarm 1
 */
#define WM831X_RTC_ALM_MASK                     0xFFFF  /* RTC_ALM - [15:0] */
#define WM831X_RTC_ALM_SHIFT                         0  /* RTC_ALM - [15:0] */
#define WM831X_RTC_ALM_WIDTH                        16  /* RTC_ALM - [15:0] */

/*
 * R16420 (0x4024) - RTC Alarm 2
 */
#define WM831X_RTC_ALM_MASK                     0xFFFF  /* RTC_ALM - [15:0] */
#define WM831X_RTC_ALM_SHIFT                         0  /* RTC_ALM - [15:0] */
#define WM831X_RTC_ALM_WIDTH                        16  /* RTC_ALM - [15:0] */

/*
 * R16421 (0x4025) - RTC Control
 */
#define WM831X_RTC_VALID                        0x8000  /* RTC_VALID */
#define WM831X_RTC_VALID_MASK                   0x8000  /* RTC_VALID */
#define WM831X_RTC_VALID_SHIFT                      15  /* RTC_VALID */
#define WM831X_RTC_VALID_WIDTH                       1  /* RTC_VALID */
#define WM831X_RTC_SYNC_BUSY                    0x4000  /* RTC_SYNC_BUSY */
#define WM831X_RTC_SYNC_BUSY_MASK               0x4000  /* RTC_SYNC_BUSY */
#define WM831X_RTC_SYNC_BUSY_SHIFT                  14  /* RTC_SYNC_BUSY */
#define WM831X_RTC_SYNC_BUSY_WIDTH                   1  /* RTC_SYNC_BUSY */
#define WM831X_RTC_ALM_ENA                      0x0400  /* RTC_ALM_ENA */
#define WM831X_RTC_ALM_ENA_MASK                 0x0400  /* RTC_ALM_ENA */
#define WM831X_RTC_ALM_ENA_SHIFT                    10  /* RTC_ALM_ENA */
#define WM831X_RTC_ALM_ENA_WIDTH                     1  /* RTC_ALM_ENA */
#define WM831X_RTC_PINT_FREQ_MASK               0x0070  /* RTC_PINT_FREQ - [6:4] */
#define WM831X_RTC_PINT_FREQ_SHIFT                   4  /* RTC_PINT_FREQ - [6:4] */
#define WM831X_RTC_PINT_FREQ_WIDTH                   3  /* RTC_PINT_FREQ - [6:4] */

/*
 * R16422 (0x4026) - RTC Trim
 */
#define WM831X_RTC_TRIM_MASK                    0x03FF  /* RTC_TRIM - [9:0] */
#define WM831X_RTC_TRIM_SHIFT                        0  /* RTC_TRIM - [9:0] */
#define WM831X_RTC_TRIM_WIDTH                       10  /* RTC_TRIM - [9:0] */

#define WM831X_SET_TIME_RETRIES	5
#define WM831X_GET_TIME_RETRIES	5

struct wm831x_rtc {
	struct wm831x *wm831x;
	struct rtc_device *rtc;
	unsigned int alarm_enabled:1;
};

static void wm831x_rtc_add_randomness(struct wm831x *wm831x)
{
	int ret;
	u16 reg;

	/*
	 * The write counter contains a pseudo-random number which is
	 * regenerated every time we set the RTC so it should be a
	 * useful per-system source of entropy.
	 */
	ret = wm831x_reg_read(wm831x, WM831X_RTC_WRITE_COUNTER);
	if (ret >= 0) {
		reg = ret;
		add_device_randomness(&reg, sizeof(reg));
	} else {
		dev_warn(wm831x->dev, "Failed to read RTC write counter: %d\n",
			 ret);
	}
}

/*
 * Read current time and date in RTC
 */
static int wm831x_rtc_readtime(struct device *dev, struct rtc_time *tm)
{
	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
	struct wm831x *wm831x = wm831x_rtc->wm831x;
	u16 time1[2], time2[2];
	int ret;
	int count = 0;

	/* Has the RTC been programmed? */
	ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
	if (ret < 0) {
		dev_err(dev, "Failed to read RTC control: %d\n", ret);
		return ret;
	}
	if (!(ret & WM831X_RTC_VALID)) {
		dev_dbg(dev, "RTC not yet configured\n");
		return -EINVAL;
	}

	/* Read twice to make sure we don't read a corrupt, partially
	 * incremented, value.
	 */
	do {
		ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
				       2, time1);
		if (ret != 0)
			continue;

		ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
				       2, time2);
		if (ret != 0)
			continue;

		if (memcmp(time1, time2, sizeof(time1)) == 0) {
			u32 time = (time1[0] << 16) | time1[1];

			rtc_time_to_tm(time, tm);
			return 0;
		}

	} while (++count < WM831X_GET_TIME_RETRIES);

	dev_err(dev, "Timed out reading current time\n");

	return -EIO;
}

/*
 * Set current time and date in RTC
 */
static int wm831x_rtc_set_mmss(struct device *dev, unsigned long time)
{
	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
	struct wm831x *wm831x = wm831x_rtc->wm831x;
	struct rtc_time new_tm;
	unsigned long new_time;
	int ret;
	int count = 0;

	ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_1,
			       (time >> 16) & 0xffff);
	if (ret < 0) {
		dev_err(dev, "Failed to write TIME_1: %d\n", ret);
		return ret;
	}

	ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_2, time & 0xffff);
	if (ret < 0) {
		dev_err(dev, "Failed to write TIME_2: %d\n", ret);
		return ret;
	}

	/* Wait for the update to complete - should happen first time
	 * round but be conservative.
	 */
	do {
		msleep(1);

		ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
		if (ret < 0)
			ret = WM831X_RTC_SYNC_BUSY;
	} while (!(ret & WM831X_RTC_SYNC_BUSY) &&
		 ++count < WM831X_SET_TIME_RETRIES);

	if (ret & WM831X_RTC_SYNC_BUSY) {
		dev_err(dev, "Timed out writing RTC update\n");
		return -EIO;
	}

	/* Check that the update was accepted; security features may
	 * have caused the update to be ignored.
	 */
	ret = wm831x_rtc_readtime(dev, &new_tm);
	if (ret < 0)
		return ret;

	ret = rtc_tm_to_time(&new_tm, &new_time);
	if (ret < 0) {
		dev_err(dev, "Failed to convert time: %d\n", ret);
		return ret;
	}

	/* Allow a second of change in case of tick */
	if (new_time - time > 1) {
		dev_err(dev, "RTC update not permitted by hardware\n");
		return -EPERM;
	}

	return 0;
}

/*
 * Read alarm time and date in RTC
 */
static int wm831x_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
	int ret;
	u16 data[2];
	u32 time;

	ret = wm831x_bulk_read(wm831x_rtc->wm831x, WM831X_RTC_ALARM_1,
			       2, data);
	if (ret != 0) {
		dev_err(dev, "Failed to read alarm time: %d\n", ret);
		return ret;
	}

	time = (data[0] << 16) | data[1];

	rtc_time_to_tm(time, &alrm->time);

	ret = wm831x_reg_read(wm831x_rtc->wm831x, WM831X_RTC_CONTROL);
	if (ret < 0) {
		dev_err(dev, "Failed to read RTC control: %d\n", ret);
		return ret;
	}

	if (ret & WM831X_RTC_ALM_ENA)
		alrm->enabled = 1;
	else
		alrm->enabled = 0;

	return 0;
}

static int wm831x_rtc_stop_alarm(struct wm831x_rtc *wm831x_rtc)
{
	wm831x_rtc->alarm_enabled = 0;

	return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
			       WM831X_RTC_ALM_ENA, 0);
}

static int wm831x_rtc_start_alarm(struct wm831x_rtc *wm831x_rtc)
{
	wm831x_rtc->alarm_enabled = 1;

	return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
			       WM831X_RTC_ALM_ENA, WM831X_RTC_ALM_ENA);
}

static int wm831x_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
	struct wm831x *wm831x = wm831x_rtc->wm831x;
	int ret;
	unsigned long time;

	ret = rtc_tm_to_time(&alrm->time, &time);
	if (ret < 0) {
		dev_err(dev, "Failed to convert time: %d\n", ret);
		return ret;
	}

	ret = wm831x_rtc_stop_alarm(wm831x_rtc);
	if (ret < 0) {
		dev_err(dev, "Failed to stop alarm: %d\n", ret);
		return ret;
	}

	ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_1,
			       (time >> 16) & 0xffff);
	if (ret < 0) {
		dev_err(dev, "Failed to write ALARM_1: %d\n", ret);
		return ret;
	}

	ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_2, time & 0xffff);
	if (ret < 0) {
		dev_err(dev, "Failed to write ALARM_2: %d\n", ret);
		return ret;
	}

	if (alrm->enabled) {
		ret = wm831x_rtc_start_alarm(wm831x_rtc);
		if (ret < 0) {
			dev_err(dev, "Failed to start alarm: %d\n", ret);
			return ret;
		}
	}

	return 0;
}

static int wm831x_rtc_alarm_irq_enable(struct device *dev,
				       unsigned int enabled)
{
	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);

	if (enabled)
		return wm831x_rtc_start_alarm(wm831x_rtc);
	else
		return wm831x_rtc_stop_alarm(wm831x_rtc);
}

static irqreturn_t wm831x_alm_irq(int irq, void *data)
{
	struct wm831x_rtc *wm831x_rtc = data;

	rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_AF);

	return IRQ_HANDLED;
}

static const struct rtc_class_ops wm831x_rtc_ops = {
	.read_time = wm831x_rtc_readtime,
	.set_mmss = wm831x_rtc_set_mmss,
	.read_alarm = wm831x_rtc_readalarm,
	.set_alarm = wm831x_rtc_setalarm,
	.alarm_irq_enable = wm831x_rtc_alarm_irq_enable,
};

#ifdef CONFIG_PM
/* Turn off the alarm if it should not be a wake source. */
static int wm831x_rtc_suspend(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
	int ret, enable;

	if (wm831x_rtc->alarm_enabled && device_may_wakeup(&pdev->dev))
		enable = WM831X_RTC_ALM_ENA;
	else
		enable = 0;

	ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
			      WM831X_RTC_ALM_ENA, enable);
	if (ret != 0)
		dev_err(&pdev->dev, "Failed to update RTC alarm: %d\n", ret);

	return 0;
}

/* Enable the alarm if it should be enabled (in case it was disabled to
 * prevent use as a wake source).
 */
static int wm831x_rtc_resume(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
	int ret;

	if (wm831x_rtc->alarm_enabled) {
		ret = wm831x_rtc_start_alarm(wm831x_rtc);
		if (ret != 0)
			dev_err(&pdev->dev,
				"Failed to restart RTC alarm: %d\n", ret);
	}

	return 0;
}

/* Unconditionally disable the alarm */
static int wm831x_rtc_freeze(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
	int ret;

	ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
			      WM831X_RTC_ALM_ENA, 0);
	if (ret != 0)
		dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n", ret);

	return 0;
}
#else
#define wm831x_rtc_suspend NULL
#define wm831x_rtc_resume NULL
#define wm831x_rtc_freeze NULL
#endif

static int wm831x_rtc_probe(struct platform_device *pdev)
{
	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
	struct wm831x_rtc *wm831x_rtc;
	int alm_irq = wm831x_irq(wm831x, platform_get_irq_byname(pdev, "ALM"));
	int ret = 0;

	wm831x_rtc = devm_kzalloc(&pdev->dev, sizeof(*wm831x_rtc), GFP_KERNEL);
	if (wm831x_rtc == NULL)
		return -ENOMEM;

	platform_set_drvdata(pdev, wm831x_rtc);
	wm831x_rtc->wm831x = wm831x;

	ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
	if (ret < 0) {
		dev_err(&pdev->dev, "Failed to read RTC control: %d\n", ret);
		goto err;
	}
	if (ret & WM831X_RTC_ALM_ENA)
		wm831x_rtc->alarm_enabled = 1;

	device_init_wakeup(&pdev->dev, 1);

	wm831x_rtc->rtc = devm_rtc_device_register(&pdev->dev, "wm831x",
					      &wm831x_rtc_ops, THIS_MODULE);
	if (IS_ERR(wm831x_rtc->rtc)) {
		ret = PTR_ERR(wm831x_rtc->rtc);
		goto err;
	}

	ret = devm_request_threaded_irq(&pdev->dev, alm_irq, NULL,
				wm831x_alm_irq,
				IRQF_TRIGGER_RISING, "RTC alarm",
				wm831x_rtc);
	if (ret != 0) {
		dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
			alm_irq, ret);
	}

	wm831x_rtc_add_randomness(wm831x);

	return 0;

err:
	return ret;
}

static const struct dev_pm_ops wm831x_rtc_pm_ops = {
	.suspend = wm831x_rtc_suspend,
	.resume = wm831x_rtc_resume,

	.freeze = wm831x_rtc_freeze,
	.thaw = wm831x_rtc_resume,
	.restore = wm831x_rtc_resume,

	.poweroff = wm831x_rtc_suspend,
};

static struct platform_driver wm831x_rtc_driver = {
	.probe = wm831x_rtc_probe,
	.driver = {
		.name = "wm831x-rtc",
		.pm = &wm831x_rtc_pm_ops,
	},
};

module_platform_driver(wm831x_rtc_driver);

MODULE_AUTHOR("Mark Brown <[email protected]>");
MODULE_DESCRIPTION("RTC driver for the WM831x series PMICs");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-rtc");
Commit	Line	Data
35c86bf6 MB	1	/*
	2	* Real Time Clock driver for Wolfson Microelectronics WM831x
	3	*
	4	* Copyright (C) 2009 Wolfson Microelectronics PLC.
	5	*
	6	* Author: Mark Brown <[email protected]>
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms of the GNU General Public License as published by the
	10	* Free Software Foundation; either version 2 of the License, or (at your
	11	* option) any later version.
	12	*
	13	*/
	14
	15	#include <linux/module.h>
	16	#include <linux/kernel.h>
	17	#include <linux/time.h>
	18	#include <linux/rtc.h>
5a0e3ad6	19	#include <linux/slab.h>
35c86bf6 MB	20	#include <linux/bcd.h>
	21	#include <linux/interrupt.h>
	22	#include <linux/ioctl.h>
	23	#include <linux/completion.h>
	24	#include <linux/mfd/wm831x/core.h>
	25	#include <linux/delay.h>
	26	#include <linux/platform_device.h>
9dccf55f	27	#include <linux/random.h>
35c86bf6 MB	28
	29	/*
	30	* R16416 (0x4020) - RTC Write Counter
	31	*/
	32	#define WM831X_RTC_WR_CNT_MASK 0xFFFF /* RTC_WR_CNT - [15:0] */
	33	#define WM831X_RTC_WR_CNT_SHIFT 0 /* RTC_WR_CNT - [15:0] */
	34	#define WM831X_RTC_WR_CNT_WIDTH 16 /* RTC_WR_CNT - [15:0] */
	35
	36	/*
	37	* R16417 (0x4021) - RTC Time 1
	38	*/
	39	#define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */
	40	#define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */
	41	#define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */
	42
	43	/*
	44	* R16418 (0x4022) - RTC Time 2
	45	*/
	46	#define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */
	47	#define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */
	48	#define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */
	49
	50	/*
	51	* R16419 (0x4023) - RTC Alarm 1
	52	*/
	53	#define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */
	54	#define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */
	55	#define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */
	56
	57	/*
	58	* R16420 (0x4024) - RTC Alarm 2
	59	*/
	60	#define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */
	61	#define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */
	62	#define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */
	63
	64	/*
	65	* R16421 (0x4025) - RTC Control
	66	*/
	67	#define WM831X_RTC_VALID 0x8000 /* RTC_VALID */
	68	#define WM831X_RTC_VALID_MASK 0x8000 /* RTC_VALID */
	69	#define WM831X_RTC_VALID_SHIFT 15 /* RTC_VALID */
	70	#define WM831X_RTC_VALID_WIDTH 1 /* RTC_VALID */
	71	#define WM831X_RTC_SYNC_BUSY 0x4000 /* RTC_SYNC_BUSY */
	72	#define WM831X_RTC_SYNC_BUSY_MASK 0x4000 /* RTC_SYNC_BUSY */
	73	#define WM831X_RTC_SYNC_BUSY_SHIFT 14 /* RTC_SYNC_BUSY */
	74	#define WM831X_RTC_SYNC_BUSY_WIDTH 1 /* RTC_SYNC_BUSY */
	75	#define WM831X_RTC_ALM_ENA 0x0400 /* RTC_ALM_ENA */
	76	#define WM831X_RTC_ALM_ENA_MASK 0x0400 /* RTC_ALM_ENA */
	77	#define WM831X_RTC_ALM_ENA_SHIFT 10 /* RTC_ALM_ENA */
	78	#define WM831X_RTC_ALM_ENA_WIDTH 1 /* RTC_ALM_ENA */
	79	#define WM831X_RTC_PINT_FREQ_MASK 0x0070 /* RTC_PINT_FREQ - [6:4] */
	80	#define WM831X_RTC_PINT_FREQ_SHIFT 4 /* RTC_PINT_FREQ - [6:4] */
	81	#define WM831X_RTC_PINT_FREQ_WIDTH 3 /* RTC_PINT_FREQ - [6:4] */
	82
	83	/*
	84	* R16422 (0x4026) - RTC Trim
	85	*/
	86	#define WM831X_RTC_TRIM_MASK 0x03FF /* RTC_TRIM - [9:0] */
	87	#define WM831X_RTC_TRIM_SHIFT 0 /* RTC_TRIM - [9:0] */
	88	#define WM831X_RTC_TRIM_WIDTH 10 /* RTC_TRIM - [9:0] */
	89
	90	#define WM831X_SET_TIME_RETRIES 5
	91	#define WM831X_GET_TIME_RETRIES 5
92
93	struct wm831x_rtc {
94	struct wm831x *wm831x;
95	struct rtc_device *rtc;
96	unsigned int alarm_enabled:1;
97	};
98
9dccf55f MB	99	static void wm831x_rtc_add_randomness(struct wm831x *wm831x)
	100	{
	101	int ret;
	102	u16 reg;
	103
	104	/*
	105	* The write counter contains a pseudo-random number which is
	106	* regenerated every time we set the RTC so it should be a
	107	* useful per-system source of entropy.
	108	*/
	109	ret = wm831x_reg_read(wm831x, WM831X_RTC_WRITE_COUNTER);
	110	if (ret >= 0) {
	111	reg = ret;
	112	add_device_randomness(&reg, sizeof(reg));
	113	} else {
	114	dev_warn(wm831x->dev, "Failed to read RTC write counter: %d\n",
	115	ret);
	116	}
	117	}
	118
35c86bf6 MB	119	/*
	120	* Read current time and date in RTC
	121	*/
	122	static int wm831x_rtc_readtime(struct device dev, struct rtc_time tm)
	123	{
	124	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
	125	struct wm831x *wm831x = wm831x_rtc->wm831x;
	126	u16 time1[2], time2[2];
	127	int ret;
	128	int count = 0;
	129
	130	/* Has the RTC been programmed? */
	131	ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
	132	if (ret < 0) {
	133	dev_err(dev, "Failed to read RTC control: %d\n", ret);
	134	return ret;
	135	}
	136	if (!(ret & WM831X_RTC_VALID)) {
	137	dev_dbg(dev, "RTC not yet configured\n");
	138	return -EINVAL;
	139	}
	140
	141	/* Read twice to make sure we don't read a corrupt, partially
	142	* incremented, value.
	143	*/
	144	do {
	145	ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
	146	2, time1);
	147	if (ret != 0)
	148	continue;
	149
	150	ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
	151	2, time2);
	152	if (ret != 0)
	153	continue;
	154
	155	if (memcmp(time1, time2, sizeof(time1)) == 0) {
	156	u32 time = (time1[0] << 16) \| time1[1];
	157
	158	rtc_time_to_tm(time, tm);
ab62670e	159	return 0;
35c86bf6 MB	160	}
	161
	162	} while (++count < WM831X_GET_TIME_RETRIES);
	163
	164	dev_err(dev, "Timed out reading current time\n");
	165
	166	return -EIO;
	167	}
	168
	169	/*
	170	* Set current time and date in RTC
	171	*/
	172	static int wm831x_rtc_set_mmss(struct device *dev, unsigned long time)
	173	{
	174	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
	175	struct wm831x *wm831x = wm831x_rtc->wm831x;
	176	struct rtc_time new_tm;
	177	unsigned long new_time;
	178	int ret;
	179	int count = 0;
	180
	181	ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_1,
	182	(time >> 16) & 0xffff);
	183	if (ret < 0) {
	184	dev_err(dev, "Failed to write TIME_1: %d\n", ret);
	185	return ret;
	186	}
	187
	188	ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_2, time & 0xffff);
	189	if (ret < 0) {
	190	dev_err(dev, "Failed to write TIME_2: %d\n", ret);
	191	return ret;
	192	}
	193
	194	/* Wait for the update to complete - should happen first time
	195	* round but be conservative.
	196	*/
	197	do {
	198	msleep(1);
	199
	200	ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
	201	if (ret < 0)
	202	ret = WM831X_RTC_SYNC_BUSY;
	203	} while (!(ret & WM831X_RTC_SYNC_BUSY) &&
	204	++count < WM831X_SET_TIME_RETRIES);
	205
	206	if (ret & WM831X_RTC_SYNC_BUSY) {
	207	dev_err(dev, "Timed out writing RTC update\n");
	208	return -EIO;
	209	}
	210
	211	/* Check that the update was accepted; security features may
	212	* have caused the update to be ignored.
	213	*/
	214	ret = wm831x_rtc_readtime(dev, &new_tm);
	215	if (ret < 0)
	216	return ret;
	217
	218	ret = rtc_tm_to_time(&new_tm, &new_time);
	219	if (ret < 0) {
	220	dev_err(dev, "Failed to convert time: %d\n", ret);
	221	return ret;
	222	}
	223
224	/* Allow a second of change in case of tick */
225	if (new_time - time > 1) {
226	dev_err(dev, "RTC update not permitted by hardware\n");
227	return -EPERM;
228	}
229
230	return 0;
231	}
232
233	/*
234	* Read alarm time and date in RTC
235	*/
236	static int wm831x_rtc_readalarm(struct device dev, struct rtc_wkalrm alrm)
237	{
238	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
239	int ret;
240	u16 data[2];
241	u32 time;
242
243	ret = wm831x_bulk_read(wm831x_rtc->wm831x, WM831X_RTC_ALARM_1,
244	2, data);
245	if (ret != 0) {
246	dev_err(dev, "Failed to read alarm time: %d\n", ret);
247	return ret;
248	}
249
250	time = (data[0] << 16) \| data[1];
251
252	rtc_time_to_tm(time, &alrm->time);
253
254	ret = wm831x_reg_read(wm831x_rtc->wm831x, WM831X_RTC_CONTROL);
255	if (ret < 0) {
256	dev_err(dev, "Failed to read RTC control: %d\n", ret);
257	return ret;
258	}
259
260	if (ret & WM831X_RTC_ALM_ENA)
261	alrm->enabled = 1;
262	else
263	alrm->enabled = 0;
264
265	return 0;
266	}
267
268	static int wm831x_rtc_stop_alarm(struct wm831x_rtc *wm831x_rtc)
269	{
270	wm831x_rtc->alarm_enabled = 0;
271
272	return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
273	WM831X_RTC_ALM_ENA, 0);
274	}
275
276	static int wm831x_rtc_start_alarm(struct wm831x_rtc *wm831x_rtc)
277	{
278	wm831x_rtc->alarm_enabled = 1;
279
280	return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
281	WM831X_RTC_ALM_ENA, WM831X_RTC_ALM_ENA);
282	}
283
284	static int wm831x_rtc_setalarm(struct device dev, struct rtc_wkalrm alrm)
285	{
286	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
287	struct wm831x *wm831x = wm831x_rtc->wm831x;
288	int ret;
289	unsigned long time;
290
291	ret = rtc_tm_to_time(&alrm->time, &time);
292	if (ret < 0) {
293	dev_err(dev, "Failed to convert time: %d\n", ret);
294	return ret;
295	}
296
297	ret = wm831x_rtc_stop_alarm(wm831x_rtc);
298	if (ret < 0) {
299	dev_err(dev, "Failed to stop alarm: %d\n", ret);
300	return ret;
301	}
302
303	ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_1,
304	(time >> 16) & 0xffff);
305	if (ret < 0) {
306	dev_err(dev, "Failed to write ALARM_1: %d\n", ret);
307	return ret;
308	}
309
310	ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_2, time & 0xffff);
311	if (ret < 0) {
312	dev_err(dev, "Failed to write ALARM_2: %d\n", ret);
313	return ret;
314	}
315
316	if (alrm->enabled) {
317	ret = wm831x_rtc_start_alarm(wm831x_rtc);
318	if (ret < 0) {
319	dev_err(dev, "Failed to start alarm: %d\n", ret);
320	return ret;
321	}
322	}
323
324	return 0;
325	}
326
327	static int wm831x_rtc_alarm_irq_enable(struct device *dev,
328	unsigned int enabled)
329	{
330	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
331
332	if (enabled)
333	return wm831x_rtc_start_alarm(wm831x_rtc);
334	else
335	return wm831x_rtc_stop_alarm(wm831x_rtc);
336	}
337
35c86bf6 MB	338	static irqreturn_t wm831x_alm_irq(int irq, void *data)
	339	{
	340	struct wm831x_rtc *wm831x_rtc = data;
	341
	342	rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF \| RTC_AF);
	343
	344	return IRQ_HANDLED;
	345	}
	346
35c86bf6 MB	347	static const struct rtc_class_ops wm831x_rtc_ops = {
	348	.read_time = wm831x_rtc_readtime,
	349	.set_mmss = wm831x_rtc_set_mmss,
	350	.read_alarm = wm831x_rtc_readalarm,
	351	.set_alarm = wm831x_rtc_setalarm,
	352	.alarm_irq_enable = wm831x_rtc_alarm_irq_enable,
35c86bf6 MB	353	};
	354
	355	#ifdef CONFIG_PM
	356	/* Turn off the alarm if it should not be a wake source. */
	357	static int wm831x_rtc_suspend(struct device *dev)
	358	{
	359	struct platform_device *pdev = to_platform_device(dev);
	360	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
	361	int ret, enable;
	362
	363	if (wm831x_rtc->alarm_enabled && device_may_wakeup(&pdev->dev))
	364	enable = WM831X_RTC_ALM_ENA;
	365	else
	366	enable = 0;
	367
	368	ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
	369	WM831X_RTC_ALM_ENA, enable);
	370	if (ret != 0)
	371	dev_err(&pdev->dev, "Failed to update RTC alarm: %d\n", ret);
	372
	373	return 0;
	374	}
	375
	376	/* Enable the alarm if it should be enabled (in case it was disabled to
	377	* prevent use as a wake source).
	378	*/
	379	static int wm831x_rtc_resume(struct device *dev)
	380	{
	381	struct platform_device *pdev = to_platform_device(dev);
	382	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
	383	int ret;
	384
	385	if (wm831x_rtc->alarm_enabled) {
	386	ret = wm831x_rtc_start_alarm(wm831x_rtc);
	387	if (ret != 0)
	388	dev_err(&pdev->dev,
	389	"Failed to restart RTC alarm: %d\n", ret);
	390	}
	391
	392	return 0;
	393	}
	394
	395	/* Unconditionally disable the alarm */
	396	static int wm831x_rtc_freeze(struct device *dev)
	397	{
	398	struct platform_device *pdev = to_platform_device(dev);
	399	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
	400	int ret;
	401
	402	ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
	403	WM831X_RTC_ALM_ENA, 0);
	404	if (ret != 0)
	405	dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n", ret);
	406
	407	return 0;
	408	}
	409	#else
	410	#define wm831x_rtc_suspend NULL
	411	#define wm831x_rtc_resume NULL
	412	#define wm831x_rtc_freeze NULL
	413	#endif
	414
	415	static int wm831x_rtc_probe(struct platform_device *pdev)
	416	{
417	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
418	struct wm831x_rtc *wm831x_rtc;
cd99758b	419	int alm_irq = wm831x_irq(wm831x, platform_get_irq_byname(pdev, "ALM"));
35c86bf6 MB	420	int ret = 0;
35c86bf6 MB	421
5f85d20d	422	wm831x_rtc = devm_kzalloc(&pdev->dev, sizeof(*wm831x_rtc), GFP_KERNEL);
35c86bf6 MB	423	if (wm831x_rtc == NULL)
	424	return -ENOMEM;
	425
	426	platform_set_drvdata(pdev, wm831x_rtc);
	427	wm831x_rtc->wm831x = wm831x;
	428
	429	ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
	430	if (ret < 0) {
	431	dev_err(&pdev->dev, "Failed to read RTC control: %d\n", ret);
	432	goto err;
	433	}
	434	if (ret & WM831X_RTC_ALM_ENA)
	435	wm831x_rtc->alarm_enabled = 1;
	436
	437	device_init_wakeup(&pdev->dev, 1);
	438
bc862f44	439	wm831x_rtc->rtc = devm_rtc_device_register(&pdev->dev, "wm831x",
35c86bf6 MB	440	&wm831x_rtc_ops, THIS_MODULE);
	441	if (IS_ERR(wm831x_rtc->rtc)) {
	442	ret = PTR_ERR(wm831x_rtc->rtc);
	443	goto err;
	444	}
	445
fd5231ce JH	446	ret = devm_request_threaded_irq(&pdev->dev, alm_irq, NULL,
	447	wm831x_alm_irq,
	448	IRQF_TRIGGER_RISING, "RTC alarm",
	449	wm831x_rtc);
35c86bf6 MB	450	if (ret != 0) {
	451	dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
	452	alm_irq, ret);
	453	}
	454
9dccf55f MB	455	wm831x_rtc_add_randomness(wm831x);
9dccf55f MB	456
35c86bf6 MB	457	return 0;
	458
	459	err:
35c86bf6 MB	460	return ret;
	461	}
	462
47145210	463	static const struct dev_pm_ops wm831x_rtc_pm_ops = {
35c86bf6 MB	464	.suspend = wm831x_rtc_suspend,
	465	.resume = wm831x_rtc_resume,
	466
	467	.freeze = wm831x_rtc_freeze,
	468	.thaw = wm831x_rtc_resume,
	469	.restore = wm831x_rtc_resume,
	470
	471	.poweroff = wm831x_rtc_suspend,
	472	};
	473
	474	static struct platform_driver wm831x_rtc_driver = {
	475	.probe = wm831x_rtc_probe,
35c86bf6 MB	476	.driver = {
	477	.name = "wm831x-rtc",
	478	.pm = &wm831x_rtc_pm_ops,
	479	},
	480	};
	481
0c4eae66	482	module_platform_driver(wm831x_rtc_driver);
35c86bf6 MB	483
	484	MODULE_AUTHOR("Mark Brown <[email protected]>");
	485	MODULE_DESCRIPTION("RTC driver for the WM831x series PMICs");
	486	MODULE_LICENSE("GPL");
	487	MODULE_ALIAS("platform:wm831x-rtc");