mfd: Add rtc support to 88pm860x

Enable rtc function in 88pm860x PMIC.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

3 files changed, 438 insertions, 0 deletions

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index b8f4e9e..8e437e2 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -125,6 +125,16 @@ comment "I2C RTC drivers"
 
 if I2C
 
+config RTC_DRV_88PM860X
+	tristate "Marvell 88PM860x"
+	depends on RTC_CLASS && I2C && MFD_88PM860X
+	help
+	  If you say yes here you get support for RTC function in Marvell
+	  88PM860x chips.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-88pm860x.
+
 config RTC_DRV_DS1307
 	tristate "Dallas/Maxim DS1307/37/38/39/40, ST M41T00, EPSON RX-8025"
 	help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 9574748..612f5a8 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -15,6 +15,7 @@ rtc-core-$(CONFIG_RTC_INTF_SYSFS) += rtc-sysfs.o
 
 # Keep the list ordered.
 
+obj-$(CONFIG_RTC_DRV_88PM860X)  += rtc-88pm860x.o
 obj-$(CONFIG_RTC_DRV_AB3100)	+= rtc-ab3100.o
 obj-$(CONFIG_RTC_DRV_AB8500)	+= rtc-ab8500.o
 obj-$(CONFIG_RTC_DRV_AT32AP700X)+= rtc-at32ap700x.o
diff --git a/drivers/rtc/rtc-88pm860x.c b/drivers/rtc/rtc-88pm860x.c
new file mode 100644
index 0000000..64b847b
--- /dev/null
+++ b/drivers/rtc/rtc-88pm860x.c
@@ -0,0 +1,427 @@
+/*
+ * Real Time Clock driver for Marvell 88PM860x PMIC
+ *
+ * Copyright (c) 2010 Marvell International Ltd.
+ * Author:	Haojian Zhuang <haojian.zhuang@marvell.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/rtc.h>
+#include <linux/delay.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/88pm860x.h>
+
+#define VRTC_CALIBRATION
+
+struct pm860x_rtc_info {
+	struct pm860x_chip	*chip;
+	struct i2c_client	*i2c;
+	struct rtc_device	*rtc_dev;
+	struct device		*dev;
+	struct delayed_work	calib_work;
+
+	int			irq;
+	int			vrtc;
+	int			(*sync)(unsigned int ticks);
+};
+
+#define REG_VRTC_MEAS1		0x7D
+
+#define REG0_ADDR		0xB0
+#define REG1_ADDR		0xB2
+#define REG2_ADDR		0xB4
+#define REG3_ADDR		0xB6
+
+#define REG0_DATA		0xB1
+#define REG1_DATA		0xB3
+#define REG2_DATA		0xB5
+#define REG3_DATA		0xB7
+
+/* bit definitions of Measurement Enable Register 2 (0x51) */
+#define MEAS2_VRTC		(1 << 0)
+
+/* bit definitions of RTC Register 1 (0xA0) */
+#define ALARM_EN		(1 << 3)
+#define ALARM_WAKEUP		(1 << 4)
+#define ALARM			(1 << 5)
+#define RTC1_USE_XO		(1 << 7)
+
+#define VRTC_CALIB_INTERVAL	(HZ * 60 * 10)		/* 10 minutes */
+
+static irqreturn_t rtc_update_handler(int irq, void *data)
+{
+	struct pm860x_rtc_info *info = (struct pm860x_rtc_info *)data;
+	int mask;
+
+	mask = ALARM | ALARM_WAKEUP;
+	pm860x_set_bits(info->i2c, PM8607_RTC1, mask | ALARM_EN, mask);
+	rtc_update_irq(info->rtc_dev, 1, RTC_AF);
+	return IRQ_HANDLED;
+}
+
+static int pm860x_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
+
+	if (enabled)
+		pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM, ALARM);
+	else
+		pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM, 0);
+	return 0;
+}
+
+/*
+ * Calculate the next alarm time given the requested alarm time mask
+ * and the current time.
+ */
+static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now,
+				struct rtc_time *alrm)
+{
+	unsigned long next_time;
+	unsigned long now_time;
+
+	next->tm_year = now->tm_year;
+	next->tm_mon = now->tm_mon;
+	next->tm_mday = now->tm_mday;
+	next->tm_hour = alrm->tm_hour;
+	next->tm_min = alrm->tm_min;
+	next->tm_sec = alrm->tm_sec;
+
+	rtc_tm_to_time(now, &now_time);
+	rtc_tm_to_time(next, &next_time);
+
+	if (next_time < now_time) {
+		/* Advance one day */
+		next_time += 60 * 60 * 24;
+		rtc_time_to_tm(next_time, next);
+	}
+}
+
+static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char buf[8];
+	unsigned long ticks, base, data;
+
+	pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
+	dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
+		buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
+	base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
+
+	/* load 32-bit read-only counter */
+	pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
+	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	ticks = base + data;
+	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
+		base, data, ticks);
+
+	rtc_time_to_tm(ticks, tm);
+
+	return 0;
+}
+
+static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char buf[4];
+	unsigned long ticks, base, data;
+
+	if ((tm->tm_year < 70) || (tm->tm_year > 138)) {
+		dev_dbg(info->dev, "Set time %d out of range. "
+			"Please set time between 1970 to 2038.\n",
+			1900 + tm->tm_year);
+		return -EINVAL;
+	}
+	rtc_tm_to_time(tm, &ticks);
+
+	/* load 32-bit read-only counter */
+	pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
+	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	base = ticks - data;
+	dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
+		base, data, ticks);
+
+	pm860x_page_reg_write(info->i2c, REG0_DATA, (base >> 24) & 0xFF);
+	pm860x_page_reg_write(info->i2c, REG1_DATA, (base >> 16) & 0xFF);
+	pm860x_page_reg_write(info->i2c, REG2_DATA, (base >> 8) & 0xFF);
+	pm860x_page_reg_write(info->i2c, REG3_DATA, base & 0xFF);
+
+	if (info->sync)
+		info->sync(ticks);
+	return 0;
+}
+
+static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
+	unsigned char buf[8];
+	unsigned long ticks, base, data;
+	int ret;
+
+	pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
+	dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
+		buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
+	base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
+
+	pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
+	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	ticks = base + data;
+	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
+		base, data, ticks);
+
+	rtc_time_to_tm(ticks, &alrm->time);
+	ret = pm860x_reg_read(info->i2c, PM8607_RTC1);
+	alrm->enabled = (ret & ALARM_EN) ? 1 : 0;
+	alrm->pending = (ret & (ALARM | ALARM_WAKEUP)) ? 1 : 0;
+	return 0;
+}
+
+static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct pm860x_rtc_info *info = dev_get_drvdata(dev);
+	struct rtc_time now_tm, alarm_tm;
+	unsigned long ticks, base, data;
+	unsigned char buf[8];
+	int mask;
+
+	pm860x_set_bits(info->i2c, PM8607_RTC1, ALARM_EN, 0);
+
+	pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf);
+	dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1],
+		buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]);
+	base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7];
+
+	/* load 32-bit read-only counter */
+	pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf);
+	data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0];
+	ticks = base + data;
+	dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n",
+		base, data, ticks);
+
+	rtc_time_to_tm(ticks, &now_tm);
+	rtc_next_alarm_time(&alarm_tm, &now_tm, &alrm->time);
+	/* get new ticks for alarm in 24 hours */
+	rtc_tm_to_time(&alarm_tm, &ticks);
+	data = ticks - base;
+
+	buf[0] = data & 0xff;
+	buf[1] = (data >> 8) & 0xff;
+	buf[2] = (data >> 16) & 0xff;
+	buf[3] = (data >> 24) & 0xff;
+	pm860x_bulk_write(info->i2c, PM8607_RTC_EXPIRE1, 4, buf);
+	if (alrm->enabled) {
+		mask = ALARM | ALARM_WAKEUP | ALARM_EN;
+		pm860x_set_bits(info->i2c, PM8607_RTC1, mask, mask);
+	} else {
+		mask = ALARM | ALARM_WAKEUP | ALARM_EN;
+		pm860x_set_bits(info->i2c, PM8607_RTC1, mask,
+				ALARM | ALARM_WAKEUP);
+	}
+	return 0;
+}
+
+static const struct rtc_class_ops pm860x_rtc_ops = {
+	.read_time	= pm860x_rtc_read_time,
+	.set_time	= pm860x_rtc_set_time,
+	.read_alarm	= pm860x_rtc_read_alarm,
+	.set_alarm	= pm860x_rtc_set_alarm,
+	.alarm_irq_enable = pm860x_rtc_alarm_irq_enable,
+};
+
+#ifdef VRTC_CALIBRATION
+static void calibrate_vrtc_work(struct work_struct *work)
+{
+	struct pm860x_rtc_info *info = container_of(work,
+		struct pm860x_rtc_info, calib_work.work);
+	unsigned char buf[2];
+	unsigned int sum, data, mean, vrtc_set;
+	int i;
+
+	for (i = 0, sum = 0; i < 16; i++) {
+		msleep(100);
+		pm860x_bulk_read(info->i2c, REG_VRTC_MEAS1, 2, buf);
+		data = (buf[0] << 4) | buf[1];
+		data = (data * 5400) >> 12;	/* convert to mv */
+		sum += data;
+	}
+	mean = sum >> 4;
+	vrtc_set = 2700 + (info->vrtc & 0x3) * 200;
+	dev_dbg(info->dev, "mean:%d, vrtc_set:%d\n", mean, vrtc_set);
+
+	sum = pm860x_reg_read(info->i2c, PM8607_RTC_MISC1);
+	data = sum & 0x3;
+	if ((mean + 200) < vrtc_set) {
+		/* try higher voltage */
+		if (++data == 4)
+			goto out;
+		data = (sum & 0xf8) | (data & 0x3);
+		pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
+	} else if ((mean - 200) > vrtc_set) {
+		/* try lower voltage */
+		if (data-- == 0)
+			goto out;
+		data = (sum & 0xf8) | (data & 0x3);
+		pm860x_reg_write(info->i2c, PM8607_RTC_MISC1, data);
+	} else
+		goto out;
+	dev_dbg(info->dev, "set 0x%x to RTC_MISC1\n", data);
+	/* trigger next calibration since VRTC is updated */
+	schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
+	return;
+out:
+	/* disable measurement */
+	pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
+	dev_dbg(info->dev, "finish VRTC calibration\n");
+	return;
+}
+#endif
+
+static int __devinit pm860x_rtc_probe(struct platform_device *pdev)
+{
+	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
+	struct pm860x_rtc_pdata *pdata = NULL;
+	struct pm860x_rtc_info *info;
+	struct rtc_time tm;
+	unsigned long ticks = 0;
+	int ret;
+
+	pdata = pdev->dev.platform_data;
+	if (pdata == NULL)
+		dev_warn(&pdev->dev, "No platform data!\n");
+
+	info = kzalloc(sizeof(struct pm860x_rtc_info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	info->irq = platform_get_irq(pdev, 0);
+	if (info->irq < 0) {
+		dev_err(&pdev->dev, "No IRQ resource!\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	info->chip = chip;
+	info->i2c = (chip->id == CHIP_PM8607) ? chip->client : chip->companion;
+	info->dev = &pdev->dev;
+	dev_set_drvdata(&pdev->dev, info);
+
+	ret = request_threaded_irq(info->irq, NULL, rtc_update_handler,
+				   IRQF_ONESHOT, "rtc", info);
+	if (ret < 0) {
+		dev_err(chip->dev, "Failed to request IRQ: #%d: %d\n",
+			info->irq, ret);
+		goto out;
+	}
+
+	/* set addresses of 32-bit base value for RTC time */
+	pm860x_page_reg_write(info->i2c, REG0_ADDR, REG0_DATA);
+	pm860x_page_reg_write(info->i2c, REG1_ADDR, REG1_DATA);
+	pm860x_page_reg_write(info->i2c, REG2_ADDR, REG2_DATA);
+	pm860x_page_reg_write(info->i2c, REG3_ADDR, REG3_DATA);
+
+	ret = pm860x_rtc_read_time(&pdev->dev, &tm);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to read initial time.\n");
+		goto out_rtc;
+	}
+	if ((tm.tm_year < 70) || (tm.tm_year > 138)) {
+		tm.tm_year = 70;
+		tm.tm_mon = 0;
+		tm.tm_mday = 1;
+		tm.tm_hour = 0;
+		tm.tm_min = 0;
+		tm.tm_sec = 0;
+		ret = pm860x_rtc_set_time(&pdev->dev, &tm);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "Failed to set initial time.\n");
+			goto out_rtc;
+		}
+	}
+	rtc_tm_to_time(&tm, &ticks);
+	if (pdata && pdata->sync) {
+		pdata->sync(ticks);
+		info->sync = pdata->sync;
+	}
+
+	info->rtc_dev = rtc_device_register("88pm860x-rtc", &pdev->dev,
+					    &pm860x_rtc_ops, THIS_MODULE);
+	ret = PTR_ERR(info->rtc_dev);
+	if (IS_ERR(info->rtc_dev)) {
+		dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+		goto out_rtc;
+	}
+
+	/*
+	 * enable internal XO instead of internal 3.25MHz clock since it can
+	 * free running in PMIC power-down state.
+	 */
+	pm860x_set_bits(info->i2c, PM8607_RTC1, RTC1_USE_XO, RTC1_USE_XO);
+
+#ifdef VRTC_CALIBRATION
+	/* <00> -- 2.7V, <01> -- 2.9V, <10> -- 3.1V, <11> -- 3.3V */
+	if (pdata && pdata->vrtc)
+		info->vrtc = pdata->vrtc & 0x3;
+	else
+		info->vrtc = 1;
+	pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, MEAS2_VRTC);
+
+	/* calibrate VRTC */
+	INIT_DELAYED_WORK(&info->calib_work, calibrate_vrtc_work);
+	schedule_delayed_work(&info->calib_work, VRTC_CALIB_INTERVAL);
+#endif	/* VRTC_CALIBRATION */
+	return 0;
+out_rtc:
+	free_irq(info->irq, info);
+out:
+	kfree(info);
+	return ret;
+}
+
+static int __devexit pm860x_rtc_remove(struct platform_device *pdev)
+{
+	struct pm860x_rtc_info *info = platform_get_drvdata(pdev);
+
+#ifdef VRTC_CALIBRATION
+	flush_scheduled_work();
+	/* disable measurement */
+	pm860x_set_bits(info->i2c, PM8607_MEAS_EN2, MEAS2_VRTC, 0);
+#endif	/* VRTC_CALIBRATION */
+
+	platform_set_drvdata(pdev, NULL);
+	rtc_device_unregister(info->rtc_dev);
+	free_irq(info->irq, info);
+	kfree(info);
+	return 0;
+}
+
+static struct platform_driver pm860x_rtc_driver = {
+	.driver		= {
+		.name	= "88pm860x-rtc",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= pm860x_rtc_probe,
+	.remove		= __devexit_p(pm860x_rtc_remove),
+};
+
+static int __init pm860x_rtc_init(void)
+{
+	return platform_driver_register(&pm860x_rtc_driver);
+}
+module_init(pm860x_rtc_init);
+
+static void __exit pm860x_rtc_exit(void)
+{
+	platform_driver_unregister(&pm860x_rtc_driver);
+}
+module_exit(pm860x_rtc_exit);
+
+MODULE_DESCRIPTION("Marvell 88PM860x RTC driver");
+MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
+MODULE_LICENSE("GPL");