[RFC v1 PATCH 6/6] drivers: rtc: Add support for Qualcomm PMIC8058 RTC

[Trilok Soni <tsoni@codeaurora.org>]

From: Anirudh Ghayal <aghayal@codeaurora.org>

PMIC8058 is Qualcomm's power management IC. A
32-bit RTC is housed inside this PMIC. The RTC driver
uses SSBI to communicate with the RTC module.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>
---
 drivers/rtc/Kconfig            |    9 +
 drivers/rtc/Makefile           |    1 +
 drivers/rtc/rtc-pm8058.c       |  487 ++++++++++++++++++++++++++++++++++++++++
 include/linux/rtc/rtc-pm8058.h |   29 +++
 4 files changed, 526 insertions(+), 0 deletions(-)
 create mode 100644 drivers/rtc/rtc-pm8058.c
 create mode 100644 include/linux/rtc/rtc-pm8058.h

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2883428..9f4ea00 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -665,6 +665,15 @@ config RTC_DRV_NUC900
 	  If you say yes here you get support for the RTC subsystem of the
 	  NUC910/NUC920 used in embedded systems.
 
+config RTC_DRV_PM8058
+	tristate "Qualcomm PMIC8058 RTC"
+	depends on PMIC8058
+	help
+	  Say Y here if you want to support the Qualcomm PMIC8058 RTC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called pmic8058-rtc.
+
 comment "on-CPU RTC drivers"
 
 config RTC_DRV_DAVINCI
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 4c2832d..d7a4f7d 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -73,6 +73,7 @@ obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o
 obj-$(CONFIG_RTC_DRV_PCF8583)	+= rtc-pcf8583.o
 obj-$(CONFIG_RTC_DRV_PCF2123)	+= rtc-pcf2123.o
 obj-$(CONFIG_RTC_DRV_PCF50633)	+= rtc-pcf50633.o
+obj-$(CONFIG_RTC_DRV_PM8058)	+= rtc-pm8058.o
 obj-$(CONFIG_RTC_DRV_PL030)	+= rtc-pl030.o
 obj-$(CONFIG_RTC_DRV_PL031)	+= rtc-pl031.o
 obj-$(CONFIG_RTC_DRV_PS3)	+= rtc-ps3.o
diff --git a/drivers/rtc/rtc-pm8058.c b/drivers/rtc/rtc-pm8058.c
new file mode 100644
index 0000000..9fef82d
--- /dev/null
+++ b/drivers/rtc/rtc-pm8058.c
@@ -0,0 +1,487 @@
+/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rtc.h>
+#include <linux/mfd/pmic8058.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/rtc/rtc-pm8058.h>
+
+/* RTC control registers */
+#define PM8058_RTC_CTRL		0x1E8
+#define PM8058_RTC_ALARM_CTRL	0x1E9
+#define PM8058_RTC_TEST		0x1F6
+
+/* RTC register bases */
+#define PM8058_RTC_READ_BASE	0x1EE
+#define PM8058_RTC_WRITE_BASE	0x1EA
+#define PM8058_RTC_ALARM_BASE	0x1F2
+
+/* RTC_CTRL register bit fields */
+#define PM8058_RTC_ENABLE	BIT(7)
+#define PM8058_RTC_ALARM_ENABLE	BIT(1)
+
+#define NUM_8_BIT_RTC_REGS	0x4
+
+/**
+ * struct pm8058_rtc - rtc driver internal structure
+ * @rtc0 - rtc device for this driver
+ * @rtc_irq - rtc irq number
+ * @rtc_alarm_irq - rtc alarm irq number
+ * @pm_chip - pointer to pm8058 parent structure
+ */
+struct pm8058_rtc {
+	struct rtc_device *rtc0;
+	int rtc_irq;
+	int rtc_alarm_irq;
+	struct pm8058_chip *pm_chip;
+};
+
+static int
+pm8058_rtc_read_bytes(struct pm8058_rtc *rtc_dd, u8 *rtc_val, int base)
+{
+	int i, rc;
+
+	/* Read the 32-bit register value, 8 bits at a time. */
+	for (i = 0; i < NUM_8_BIT_RTC_REGS; i++) {
+		rc = pm8058_read(rtc_dd->pm_chip, base + i, &rtc_val[i], 1);
+		if (rc < 0) {
+			pr_err("PM8058 read failed\n");
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+static int
+pm8058_rtc_write_bytes(struct pm8058_rtc *rtc_dd, u8 *rtc_val, int base)
+{
+	int i, rc;
+
+	/* Write the 32-bit register value, 8 bits at a time. */
+	for (i = 0; i < NUM_8_BIT_RTC_REGS; i++) {
+		rc = pm8058_write(rtc_dd->pm_chip, base + i, &rtc_val[i], 1);
+		if (rc < 0) {
+			pr_err("PM8058 read failed\n");
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Steps to write the RTC registers.
+ * 1. Disable alarm if enabled.
+ * 2. Write 0x00 to LSB.
+ * 3. Write Byte[1], Byte[2], Byte[3] then Byte[0].
+ * 4. Enable alarm if disabled in step 1.
+ */
+static int
+pm8058_rtc0_set_time(struct device *dev, struct rtc_time *tm)
+{
+	int rc;
+	unsigned long secs = 0;
+	u8 value[4], reg = 0, alarm_enabled = 0, ctrl_reg = 0, i;
+	struct pm8058_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	rtc_tm_to_time(tm, &secs);
+
+	value[0] = secs & 0xFF;
+	value[1] = (secs >> 8) & 0xFF;
+	value[2] = (secs >> 16) & 0xFF;
+	value[3] = (secs >> 24) & 0xFF;
+
+	pr_debug("Seconds value to be written to RTC = %lu\n", secs);
+
+	/* Disable alarm before updating RTC */
+	rc = pm8058_read(rtc_dd->pm_chip, PM8058_RTC_CTRL, &ctrl_reg, 1);
+	if (rc < 0) {
+		pr_err("PM8058 read failed\n");
+		return rc;
+	}
+
+	if (ctrl_reg & PM8058_RTC_ALARM_ENABLE) {
+		alarm_enabled = 1;
+		ctrl_reg &= ~PM8058_RTC_ALARM_ENABLE;
+		rc = pm8058_write(rtc_dd->pm_chip, PM8058_RTC_CTRL,
+							&ctrl_reg, 1);
+		if (rc < 0) {
+			pr_err("PM8058 write failed\n");
+			return rc;
+		}
+	}
+
+	/* Write Byte[1], Byte[2], Byte[3], Byte[0] */
+	reg = 0;
+	rc = pm8058_write(rtc_dd->pm_chip, PM8058_RTC_WRITE_BASE, &reg, 1);
+	if (rc < 0) {
+		pr_err("PM8058 write failed\n");
+		return rc;
+	}
+
+	for (i = 1; i < NUM_8_BIT_RTC_REGS; i++) {
+		rc = pm8058_write(rtc_dd->pm_chip, PM8058_RTC_WRITE_BASE + i,
+								&value[i], 1);
+		if (rc < 0) {
+			pr_err("Write to RTC registers failed\n");
+			return rc;
+		}
+	}
+
+	rc = pm8058_write(rtc_dd->pm_chip, PM8058_RTC_WRITE_BASE,
+							&value[0], 1);
+	if (rc < 0) {
+		pr_err("PM8058 write failed\n");
+		return rc;
+	}
+
+	if (alarm_enabled) {
+		ctrl_reg |= PM8058_RTC_ALARM_ENABLE;
+		rc = pm8058_write(rtc_dd->pm_chip, PM8058_RTC_CTRL,
+							&ctrl_reg, 1);
+		if (rc < 0) {
+			pr_err("PM8058 write failed\n");
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+static int
+pm8058_rtc0_read_time(struct device *dev, struct rtc_time *tm)
+{
+	int rc;
+	u8 value[4], reg;
+	unsigned long secs = 0;
+	struct pm8058_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	rc = pm8058_rtc_read_bytes(rtc_dd, value, PM8058_RTC_READ_BASE);
+	if (rc < 0) {
+		pr_err("RTC time read failed\n");
+		return rc;
+	}
+
+	/*
+	 * Read the LSB again and check if there has been a carry over.
+	 * If there is, redo the read operation.
+	 */
+	rc = pm8058_read(rtc_dd->pm_chip, PM8058_RTC_READ_BASE, &reg, 1);
+	if (rc < 0) {
+		pr_err("PM8058 read failed\n");
+		return rc;
+	}
+
+	if (unlikely(reg < value[0])) {
+		rc = pm8058_rtc_read_bytes(rtc_dd, value,
+						PM8058_RTC_READ_BASE);
+		if (rc < 0) {
+			pr_err("RTC time read failed\n");
+			return rc;
+		}
+	}
+
+	secs = value[0] | (value[1] << 8) | (value[2] << 16) | (value[3] << 24);
+
+	rtc_time_to_tm(secs, tm);
+
+	rc = rtc_valid_tm(tm);
+	if (rc < 0) {
+		pr_err("Invalid time read from PMIC8058\n");
+		return rc;
+	}
+
+	pr_debug("secs = %lu, h::m:s == %d::%d::%d, d/m/y = %d/%d/%d\n",
+			secs, tm->tm_hour, tm->tm_min, tm->tm_sec,
+			tm->tm_mday, tm->tm_mon, tm->tm_year);
+
+	return 0;
+}
+
+static int
+pm8058_rtc0_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	int rc;
+	u8 value[4], reg;
+	unsigned long secs = 0;
+	struct pm8058_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	/* Check if a alarm is valid */
+	rc = rtc_valid_tm(&alarm->time);
+	if (rc < 0) {
+		pr_err("Alarm time invalid\n");
+		return -EINVAL;
+	}
+
+	rtc_tm_to_time(&alarm->time, &secs);
+
+	value[0] = secs & 0xFF;
+	value[1] = (secs >> 8) & 0xFF;
+	value[2] = (secs >> 16) & 0xFF;
+	value[3] = (secs >> 24) & 0xFF;
+
+	rc = pm8058_rtc_write_bytes(rtc_dd, value, PM8058_RTC_ALARM_BASE);
+	if (rc < 0) {
+		pr_err("Alarm could not be set\n");
+		return rc;
+	}
+
+	rc = pm8058_read(rtc_dd->pm_chip, PM8058_RTC_CTRL, &reg, 1);
+	if (rc < 0) {
+		pr_err("PM8058 read failed\n");
+		return rc;
+	}
+
+	reg = (alarm->enabled) ? (reg | PM8058_RTC_ALARM_ENABLE) :
+					(reg & ~PM8058_RTC_ALARM_ENABLE);
+
+	rc = pm8058_write(rtc_dd->pm_chip, PM8058_RTC_CTRL, &reg, 1);
+	if (rc < 0) {
+		pr_err("PM8058 write failed\n");
+		return rc;
+	}
+
+	pr_debug("Alarm Set for h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
+			alarm->time.tm_hour, alarm->time.tm_min,
+			alarm->time.tm_sec, alarm->time.tm_mday,
+			alarm->time.tm_mon, alarm->time.tm_year);
+
+	return 0;
+}
+
+static int
+pm8058_rtc0_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
+{
+	int rc;
+	u8 value[4], reg;
+	unsigned long secs = 0;
+	struct pm8058_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	/* Check if the alarm is enabled */
+	rc = pm8058_read(rtc_dd->pm_chip, PM8058_RTC_CTRL, &reg, 1);
+	if (rc < 0) {
+		pr_err("PM8058 read failed\n");
+		return rc;
+	}
+	alarm->enabled = !!(reg & PM8058_RTC_ALARM_ENABLE);
+
+	rc = pm8058_rtc_read_bytes(rtc_dd, value,
+					PM8058_RTC_ALARM_BASE);
+	if (rc < 0) {
+		pr_err("RTC alarm time read failed\n");
+		return rc;
+	}
+
+	secs = value[0] | (value[1] << 8) | (value[2] << 16) | (value[3] << 24);
+
+	rtc_time_to_tm(secs, &alarm->time);
+
+	rc = rtc_valid_tm(&alarm->time);
+	if (rc < 0) {
+		pr_err("Invalid time read from PMIC8058\n");
+		return rc;
+	}
+
+	pr_debug("Alarm set for - h:r:s=%d:%d:%d, d/m/y=%d/%d/%d\n",
+		alarm->time.tm_hour, alarm->time.tm_min,
+				alarm->time.tm_sec, alarm->time.tm_mday,
+				alarm->time.tm_mon, alarm->time.tm_year);
+
+	return 0;
+}
+
+static struct rtc_class_ops pm8058_rtc0_ops = {
+	.read_time	= pm8058_rtc0_read_time,
+	.set_alarm	= pm8058_rtc0_set_alarm,
+	.read_alarm	= pm8058_rtc0_read_alarm,
+};
+
+static irqreturn_t pm8058_alarm_trigger(int irq, void *dev_id)
+{
+	unsigned long events = 0;
+	struct pm8058_rtc *rtc_dd = dev_id;
+
+	events = RTC_IRQF | RTC_AF;
+	rtc_update_irq(rtc_dd->rtc0, 1, events);
+
+	pr_debug("Alarm Triggered !!\n");
+
+	return IRQ_HANDLED;
+}
+
+static int __devinit pm8058_rtc_probe(struct platform_device *pdev)
+{
+	int rc;
+	u8 reg;
+	struct pm8058_rtc *rtc_dd;
+	struct pm8058_chip *pm_chip;
+	struct pm8058_rtc_pdata *pdata = pdev->dev.platform_data;
+
+	if (pdata == NULL) {
+		dev_err(&pdev->dev, "Platform data absent!\n");
+		return -ENXIO;
+	}
+
+	pm_chip = platform_get_drvdata(pdev);
+	if (pm_chip == NULL) {
+		dev_err(&pdev->dev, "Invalid driver information!\n");
+		return -ENXIO;
+	}
+
+	rtc_dd = kzalloc(sizeof(*rtc_dd), GFP_KERNEL);
+	if (rtc_dd == NULL) {
+		dev_err(&pdev->dev, "Unable to allocate memory!\n");
+		return -ENOMEM;
+	}
+
+	rtc_dd->rtc_irq = platform_get_irq(pdev, 0);
+	rtc_dd->rtc_alarm_irq = platform_get_irq(pdev, 1);
+	if (!rtc_dd->rtc_alarm_irq || !rtc_dd->rtc_irq) {
+		dev_err(&pdev->dev, "RTC / Alarm IRQ resource absent!\n");
+		rc = -ENXIO;
+		goto fail_rtc_enable;
+	}
+
+	rtc_dd->pm_chip = pm_chip;
+
+	/* Check if the RTC is on, else turn it on */
+	rc = pm8058_read(pm_chip, PM8058_RTC_CTRL, &reg, 1);
+	if (rc < 0) {
+		dev_err(&pdev->dev, "PM8058 read failed!\n");
+		goto fail_rtc_enable;
+	}
+
+	if (!(reg & PM8058_RTC_ENABLE)) {
+		reg |= PM8058_RTC_ENABLE;
+		rc = pm8058_write(pm_chip, PM8058_RTC_CTRL, &reg, 1);
+		if (rc < 0) {
+			dev_err(&pdev->dev, "PM8058 write failed!\n");
+			goto fail_rtc_enable;
+		}
+	}
+
+	if (pdata->rtc_write_enable == true)
+		pm8058_rtc0_ops.set_time = pm8058_rtc0_set_time,
+
+	/* Register the RTC device */
+	rtc_dd->rtc0 = rtc_device_register("pm8058_rtc0", &pdev->dev,
+				&pm8058_rtc0_ops, THIS_MODULE);
+	if (IS_ERR(rtc_dd->rtc0)) {
+		dev_err(&pdev->dev, "%s: RTC registration failed (%ld)\n",
+					__func__, PTR_ERR(rtc_dd->rtc0));
+		rc = PTR_ERR(rtc_dd->rtc0);
+		goto fail_rtc_enable;
+	}
+
+	platform_set_drvdata(pdev, rtc_dd);
+
+	/* Request the alarm IRQ */
+	rc = request_any_context_irq(rtc_dd->rtc_alarm_irq,
+				 pm8058_alarm_trigger, IRQF_TRIGGER_RISING,
+				 "pm8058_rtc_alarm", rtc_dd);
+	if (rc < 0) {
+		dev_err(&pdev->dev, "Request IRQ failed (%d)\n", rc);
+		goto fail_req_irq;
+	}
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	dev_dbg(&pdev->dev, "Probe success !!\n");
+
+	return 0;
+
+fail_req_irq:
+	rtc_device_unregister(rtc_dd->rtc0);
+fail_rtc_enable:
+	kfree(rtc_dd);
+	return rc;
+}
+
+#ifdef CONFIG_PM
+static int pm8058_rtc_resume(struct device *dev)
+{
+	struct pm8058_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		disable_irq_wake(rtc_dd->rtc_alarm_irq);
+
+	return 0;
+}
+
+static int pm8058_rtc_suspend(struct device *dev)
+{
+	struct pm8058_rtc *rtc_dd = dev_get_drvdata(dev);
+
+	if (device_may_wakeup(dev))
+		enable_irq_wake(rtc_dd->rtc_alarm_irq);
+
+	return 0;
+}
+
+static const struct dev_pm_ops pm8058_rtc_pm_ops = {
+	.suspend = pm8058_rtc_suspend,
+	.resume = pm8058_rtc_resume,
+};
+#endif
+
+static int __devexit pm8058_rtc_remove(struct platform_device *pdev)
+{
+	struct pm8058_rtc *rtc_dd = platform_get_drvdata(pdev);
+
+	device_init_wakeup(&pdev->dev, 0);
+	free_irq(rtc_dd->rtc_alarm_irq, rtc_dd);
+	rtc_device_unregister(rtc_dd->rtc0);
+	kfree(rtc_dd);
+
+	return 0;
+}
+
+static struct platform_driver pm8058_rtc_driver = {
+	.probe		= pm8058_rtc_probe,
+	.remove		= __devexit_p(pm8058_rtc_remove),
+	.driver	= {
+		.name	= "pm8058-rtc",
+		.owner	= THIS_MODULE,
+#ifdef CONFIG_PM
+		.pm	= &pm8058_rtc_pm_ops,
+#endif
+	},
+};
+
+static int __init pm8058_rtc_init(void)
+{
+	return platform_driver_register(&pm8058_rtc_driver);
+}
+
+static void __exit pm8058_rtc_exit(void)
+{
+	platform_driver_unregister(&pm8058_rtc_driver);
+}
+
+module_init(pm8058_rtc_init);
+module_exit(pm8058_rtc_exit);
+
+MODULE_ALIAS("platform:pm8058-rtc");
+MODULE_DESCRIPTION("PMIC8058 RTC driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(Anirudh Ghayal "<aghayal@codeaurora.org>");
diff --git a/include/linux/rtc/rtc-pm8058.h b/include/linux/rtc/rtc-pm8058.h
new file mode 100644
index 0000000..51f7c0b
--- /dev/null
+++ b/include/linux/rtc/rtc-pm8058.h
@@ -0,0 +1,29 @@
+/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef __RTC_PM8058_H__
+#define __RTC_PM8058_H__
+
+/**
+ * struct pm8058_rtc_pdata - RTC driver platform data
+ * @rtc_write_enable - variable stating RTC write capability
+ */
+struct pm8058_rtc_pdata {
+	bool rtc_write_enable;
+};
+
+#endif /* __RTC_PM8058_H__ */
-- 
1.7.0.2