[linux.git] / drivers / rtc / rtc-au1xxx.c

/*
 * Au1xxx counter0 (aka Time-Of-Year counter) RTC interface driver.
 *
 * Copyright (C) 2008 Manuel Lauss <[email protected]>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */

/* All current Au1xxx SoCs have 2 counters fed by an external 32.768 kHz
 * crystal. Counter 0, which keeps counting during sleep/powerdown, is
 * used to count seconds since the beginning of the unix epoch.
 *
 * The counters must be configured and enabled by bootloader/board code;
 * no checks as to whether they really get a proper 32.768kHz clock are
 * made as this would take far too long.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <asm/mach-au1x00/au1000.h>

/* 32kHz clock enabled and detected */
#define CNTR_OK (SYS_CNTRL_E0 | SYS_CNTRL_32S)

static int au1xtoy_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
	unsigned long t;

	t = alchemy_rdsys(AU1000_SYS_TOYREAD);

	rtc_time_to_tm(t, tm);

	return rtc_valid_tm(tm);
}

static int au1xtoy_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
	unsigned long t;

	rtc_tm_to_time(tm, &t);

	alchemy_wrsys(t, AU1000_SYS_TOYWRITE);

	/* wait for the pending register write to succeed.  This can
	 * take up to 6 seconds...
	 */
	while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
		msleep(1);

	return 0;
}

static struct rtc_class_ops au1xtoy_rtc_ops = {
	.read_time	= au1xtoy_rtc_read_time,
	.set_time	= au1xtoy_rtc_set_time,
};

static int au1xtoy_rtc_probe(struct platform_device *pdev)
{
	struct rtc_device *rtcdev;
	unsigned long t;
	int ret;

	t = alchemy_rdsys(AU1000_SYS_CNTRCTRL);
	if (!(t & CNTR_OK)) {
		dev_err(&pdev->dev, "counters not working; aborting.\n");
		ret = -ENODEV;
		goto out_err;
	}

	ret = -ETIMEDOUT;

	/* set counter0 tickrate to 1Hz if necessary */
	if (alchemy_rdsys(AU1000_SYS_TOYTRIM) != 32767) {
		/* wait until hardware gives access to TRIM register */
		t = 0x00100000;
		while ((alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_T0S) && --t)
			msleep(1);

		if (!t) {
			/* timed out waiting for register access; assume
			 * counters are unusable.
			 */
			dev_err(&pdev->dev, "timeout waiting for access\n");
			goto out_err;
		}

		/* set 1Hz TOY tick rate */
		alchemy_wrsys(32767, AU1000_SYS_TOYTRIM);
	}

	/* wait until the hardware allows writes to the counter reg */
	while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
		msleep(1);

	rtcdev = devm_rtc_device_register(&pdev->dev, "rtc-au1xxx",
				     &au1xtoy_rtc_ops, THIS_MODULE);
	if (IS_ERR(rtcdev)) {
		ret = PTR_ERR(rtcdev);
		goto out_err;
	}

	platform_set_drvdata(pdev, rtcdev);

	return 0;

out_err:
	return ret;
}

static struct platform_driver au1xrtc_driver = {
	.driver		= {
		.name	= "rtc-au1xxx",
	},
};

module_platform_driver_probe(au1xrtc_driver, au1xtoy_rtc_probe);

MODULE_DESCRIPTION("Au1xxx TOY-counter-based RTC driver");
MODULE_AUTHOR("Manuel Lauss <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:rtc-au1xxx");
Commit	Line	Data
45fd8a0c ML	1	/*
	2	* Au1xxx counter0 (aka Time-Of-Year counter) RTC interface driver.
	3	*
	4	* Copyright (C) 2008 Manuel Lauss <[email protected]>
	5	*
	6	* This file is subject to the terms and conditions of the GNU General Public
	7	* License. See the file "COPYING" in the main directory of this archive
	8	* for more details.
	9	*/
	10
	11	/* All current Au1xxx SoCs have 2 counters fed by an external 32.768 kHz
	12	* crystal. Counter 0, which keeps counting during sleep/powerdown, is
	13	* used to count seconds since the beginning of the unix epoch.
	14	*
	15	* The counters must be configured and enabled by bootloader/board code;
	16	* no checks as to whether they really get a proper 32.768kHz clock are
	17	* made as this would take far too long.
	18	*/
	19
	20	#include <linux/module.h>
	21	#include <linux/kernel.h>
	22	#include <linux/rtc.h>
	23	#include <linux/init.h>
	24	#include <linux/platform_device.h>
	25	#include <linux/io.h>
	26	#include <asm/mach-au1x00/au1000.h>
	27
	28	/* 32kHz clock enabled and detected */
	29	#define CNTR_OK (SYS_CNTRL_E0 \| SYS_CNTRL_32S)
	30
	31	static int au1xtoy_rtc_read_time(struct device dev, struct rtc_time tm)
	32	{
	33	unsigned long t;
	34
1d09de7d	35	t = alchemy_rdsys(AU1000_SYS_TOYREAD);
45fd8a0c ML	36
	37	rtc_time_to_tm(t, tm);
	38
	39	return rtc_valid_tm(tm);
	40	}
	41
	42	static int au1xtoy_rtc_set_time(struct device dev, struct rtc_time tm)
	43	{
	44	unsigned long t;
	45
	46	rtc_tm_to_time(tm, &t);
	47
1d09de7d	48	alchemy_wrsys(t, AU1000_SYS_TOYWRITE);
45fd8a0c ML	49
	50	/* wait for the pending register write to succeed. This can
	51	* take up to 6 seconds...
	52	*/
1d09de7d	53	while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
45fd8a0c ML	54	msleep(1);
	55
	56	return 0;
	57	}
	58
	59	static struct rtc_class_ops au1xtoy_rtc_ops = {
	60	.read_time = au1xtoy_rtc_read_time,
	61	.set_time = au1xtoy_rtc_set_time,
	62	};
	63
5a167f45	64	static int au1xtoy_rtc_probe(struct platform_device *pdev)
45fd8a0c ML	65	{
	66	struct rtc_device *rtcdev;
	67	unsigned long t;
	68	int ret;
	69
1d09de7d	70	t = alchemy_rdsys(AU1000_SYS_CNTRCTRL);
45fd8a0c ML	71	if (!(t & CNTR_OK)) {
	72	dev_err(&pdev->dev, "counters not working; aborting.\n");
	73	ret = -ENODEV;
	74	goto out_err;
	75	}
	76
	77	ret = -ETIMEDOUT;
	78
	79	/* set counter0 tickrate to 1Hz if necessary */
1d09de7d	80	if (alchemy_rdsys(AU1000_SYS_TOYTRIM) != 32767) {
45fd8a0c ML	81	/* wait until hardware gives access to TRIM register */
45fd8a0c ML	82	t = 0x00100000;
1d09de7d	83	while ((alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_T0S) && --t)
45fd8a0c ML	84	msleep(1);
	85
	86	if (!t) {
	87	/* timed out waiting for register access; assume
	88	* counters are unusable.
	89	*/
	90	dev_err(&pdev->dev, "timeout waiting for access\n");
	91	goto out_err;
	92	}
	93
	94	/* set 1Hz TOY tick rate */
1d09de7d	95	alchemy_wrsys(32767, AU1000_SYS_TOYTRIM);
45fd8a0c ML	96	}
	97
	98	/* wait until the hardware allows writes to the counter reg */
1d09de7d	99	while (alchemy_rdsys(AU1000_SYS_CNTRCTRL) & SYS_CNTRL_C0S)
45fd8a0c ML	100	msleep(1);
45fd8a0c ML	101
6c068605	102	rtcdev = devm_rtc_device_register(&pdev->dev, "rtc-au1xxx",
45fd8a0c ML	103	&au1xtoy_rtc_ops, THIS_MODULE);
	104	if (IS_ERR(rtcdev)) {
	105	ret = PTR_ERR(rtcdev);
	106	goto out_err;
	107	}
	108
	109	platform_set_drvdata(pdev, rtcdev);
	110
	111	return 0;
	112
	113	out_err:
	114	return ret;
	115	}
	116
45fd8a0c ML	117	static struct platform_driver au1xrtc_driver = {
	118	.driver = {
	119	.name = "rtc-au1xxx",
45fd8a0c	120	},
45fd8a0c ML	121	};
45fd8a0c ML	122
aaa83458	123	module_platform_driver_probe(au1xrtc_driver, au1xtoy_rtc_probe);
45fd8a0c ML	124
	125	MODULE_DESCRIPTION("Au1xxx TOY-counter-based RTC driver");
	126	MODULE_AUTHOR("Manuel Lauss <[email protected]>");
	127	MODULE_LICENSE("GPL");
	128	MODULE_ALIAS("platform:rtc-au1xxx");