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Subject[PATCH v7 23/24] rtc: Add driver for Maxim 77802 PMIC Real-Time-Clock
Date
The MAX7802 PMIC has a Real-Time-Clock (RTC) with two alarms.
This patch adds support for the RTC and is based on a driver
added by Simon Glass to the Chrome OS kernel 3.8 tree.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
---

Changes since v6:
- Remove unused code for SMPL and WTSR. Suggested by Krzysztof Kozlowski.
- Don't spam the kernel log with unimportant info and just print for debug.
Suggested by Krzysztof Kozlowski.
- Use ARRAY_SIZE() instead of constant value. Suggested by Krzysztof Kozlowski.
- Remove duplicated register setup. Suggested by Krzysztof Kozlowski.
- Don't free/unregister managed allocated resources.
Suggested by Krzysztof Kozlowski.
---
drivers/rtc/Kconfig | 10 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-max77802.c | 508 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 519 insertions(+)
create mode 100644 drivers/rtc/rtc-max77802.c

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index a672dd1..243ac72 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -288,6 +288,16 @@ config RTC_DRV_MAX77686
This driver can also be built as a module. If so, the module
will be called rtc-max77686.

+config RTC_DRV_MAX77802
+ tristate "Maxim 77802 RTC"
+ depends on MFD_MAX77686
+ help
+ If you say yes here you will get support for the
+ RTC of Maxim MAX77802 PMIC.
+
+ This driver can also be built as a module. If so, the module
+ will be called rtc-max77802.
+
config RTC_DRV_RS5C372
tristate "Ricoh R2025S/D, RS5C372A/B, RV5C386, RV5C387A"
help
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 70347d0..247de78 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_RTC_DRV_MAX8998) += rtc-max8998.o
obj-$(CONFIG_RTC_DRV_MAX8997) += rtc-max8997.o
obj-$(CONFIG_RTC_DRV_MAX6902) += rtc-max6902.o
obj-$(CONFIG_RTC_DRV_MAX77686) += rtc-max77686.o
+obj-$(CONFIG_RTC_DRV_MAX77802) += rtc-max77802.o
obj-$(CONFIG_RTC_DRV_MC13XXX) += rtc-mc13xxx.o
obj-$(CONFIG_RTC_DRV_MCP795) += rtc-mcp795.o
obj-$(CONFIG_RTC_DRV_MSM6242) += rtc-msm6242.o
diff --git a/drivers/rtc/rtc-max77802.c b/drivers/rtc/rtc-max77802.c
new file mode 100644
index 0000000..f8898ff
--- /dev/null
+++ b/drivers/rtc/rtc-max77802.c
@@ -0,0 +1,508 @@
+/*
+ * RTC driver for Maxim MAX77802
+ *
+ * Copyright (C) 2013 Google, Inc
+ *
+ * Copyright (C) 2012 Samsung Electronics Co.Ltd
+ *
+ * based on rtc-max8997.c
+ *
+ * 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/slab.h>
+#include <linux/rtc.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/max77686-private.h>
+#include <linux/irqdomain.h>
+#include <linux/regmap.h>
+
+/* RTC Control Register */
+#define BCD_EN_SHIFT 0
+#define BCD_EN_MASK (1 << BCD_EN_SHIFT)
+#define MODEL24_SHIFT 1
+#define MODEL24_MASK (1 << MODEL24_SHIFT)
+/* RTC Update Register1 */
+#define RTC_UDR_SHIFT 0
+#define RTC_UDR_MASK (1 << RTC_UDR_SHIFT)
+#define RTC_RBUDR_SHIFT 4
+#define RTC_RBUDR_MASK (1 << RTC_RBUDR_SHIFT)
+/* RTC Hour register */
+#define HOUR_PM_SHIFT 6
+#define HOUR_PM_MASK (1 << HOUR_PM_SHIFT)
+/* RTC Alarm Enable */
+#define ALARM_ENABLE_SHIFT 7
+#define ALARM_ENABLE_MASK (1 << ALARM_ENABLE_SHIFT)
+
+/* For the RTCAE1 register, we write this value to enable the alarm */
+#define ALARM_ENABLE_VALUE 0x77
+
+#define MAX77802_RTC_UPDATE_DELAY_US 200
+
+enum {
+ RTC_SEC = 0,
+ RTC_MIN,
+ RTC_HOUR,
+ RTC_WEEKDAY,
+ RTC_MONTH,
+ RTC_YEAR,
+ RTC_DATE,
+ RTC_NR_TIME
+};
+
+struct max77802_rtc_info {
+ struct device *dev;
+ struct max77686_dev *max77802;
+ struct i2c_client *rtc;
+ struct rtc_device *rtc_dev;
+ struct mutex lock;
+
+ struct regmap *regmap;
+
+ int virq;
+ int rtc_24hr_mode;
+};
+
+enum MAX77802_RTC_OP {
+ MAX77802_RTC_WRITE,
+ MAX77802_RTC_READ,
+};
+
+static inline int max77802_rtc_calculate_wday(u8 shifted)
+{
+ int counter = -1;
+
+ while (shifted) {
+ shifted >>= 1;
+ counter++;
+ }
+
+ return counter;
+}
+
+static void max77802_rtc_data_to_tm(u8 *data, struct rtc_time *tm,
+ int rtc_24hr_mode)
+{
+ tm->tm_sec = data[RTC_SEC] & 0xff;
+ tm->tm_min = data[RTC_MIN] & 0xff;
+ if (rtc_24hr_mode)
+ tm->tm_hour = data[RTC_HOUR] & 0x1f;
+ else {
+ tm->tm_hour = data[RTC_HOUR] & 0x0f;
+ if (data[RTC_HOUR] & HOUR_PM_MASK)
+ tm->tm_hour += 12;
+ }
+
+ tm->tm_wday = max77802_rtc_calculate_wday(data[RTC_WEEKDAY] & 0xff);
+ tm->tm_mday = data[RTC_DATE] & 0x1f;
+ tm->tm_mon = (data[RTC_MONTH] & 0x0f) - 1;
+
+ tm->tm_year = data[RTC_YEAR] & 0xff;
+ tm->tm_yday = 0;
+ tm->tm_isdst = 0;
+}
+
+static int max77802_rtc_tm_to_data(struct rtc_time *tm, u8 *data)
+{
+ data[RTC_SEC] = tm->tm_sec;
+ data[RTC_MIN] = tm->tm_min;
+ data[RTC_HOUR] = tm->tm_hour;
+ data[RTC_WEEKDAY] = 1 << tm->tm_wday;
+ data[RTC_DATE] = tm->tm_mday;
+ data[RTC_MONTH] = tm->tm_mon + 1;
+ data[RTC_YEAR] = tm->tm_year;
+
+ return 0;
+}
+
+static int max77802_rtc_update(struct max77802_rtc_info *info,
+ enum MAX77802_RTC_OP op)
+{
+ int ret;
+ unsigned int data;
+
+ if (op == MAX77802_RTC_WRITE)
+ data = 1 << RTC_UDR_SHIFT;
+ else
+ data = 1 << RTC_RBUDR_SHIFT;
+
+ ret = regmap_update_bits(info->max77802->regmap,
+ MAX77802_RTC_UPDATE0, data, data);
+ if (ret < 0)
+ dev_err(info->dev, "%s: fail to write update reg(ret=%d, data=0x%x)\n",
+ __func__, ret, data);
+ else {
+ /* Minimum delay required before RTC update. */
+ usleep_range(MAX77802_RTC_UPDATE_DELAY_US,
+ MAX77802_RTC_UPDATE_DELAY_US * 2);
+ }
+
+ return ret;
+}
+
+static int max77802_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct max77802_rtc_info *info = dev_get_drvdata(dev);
+ u8 data[RTC_NR_TIME];
+ int ret;
+
+ mutex_lock(&info->lock);
+
+ ret = max77802_rtc_update(info, MAX77802_RTC_READ);
+ if (ret < 0)
+ goto out;
+
+ ret = regmap_bulk_read(info->max77802->regmap,
+ MAX77802_RTC_SEC, data, RTC_NR_TIME);
+ if (ret < 0) {
+ dev_err(info->dev, "%s: fail to read time reg(%d)\n", __func__,
+ ret);
+ goto out;
+ }
+
+ max77802_rtc_data_to_tm(data, tm, info->rtc_24hr_mode);
+
+ ret = rtc_valid_tm(tm);
+
+out:
+ mutex_unlock(&info->lock);
+ return ret;
+}
+
+static int max77802_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct max77802_rtc_info *info = dev_get_drvdata(dev);
+ u8 data[RTC_NR_TIME];
+ int ret;
+
+ ret = max77802_rtc_tm_to_data(tm, data);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&info->lock);
+
+ ret = regmap_bulk_write(info->max77802->regmap,
+ MAX77802_RTC_SEC, data, RTC_NR_TIME);
+ if (ret < 0) {
+ dev_err(info->dev, "%s: fail to write time reg(%d)\n", __func__,
+ ret);
+ goto out;
+ }
+
+ ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
+
+out:
+ mutex_unlock(&info->lock);
+ return ret;
+}
+
+static int max77802_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct max77802_rtc_info *info = dev_get_drvdata(dev);
+ u8 data[RTC_NR_TIME];
+ unsigned int val;
+ int ret;
+
+ mutex_lock(&info->lock);
+
+ ret = max77802_rtc_update(info, MAX77802_RTC_READ);
+ if (ret < 0)
+ goto out;
+
+ ret = regmap_bulk_read(info->max77802->regmap,
+ MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
+ if (ret < 0) {
+ dev_err(info->dev, "%s:%d fail to read alarm reg(%d)\n",
+ __func__, __LINE__, ret);
+ goto out;
+ }
+
+ max77802_rtc_data_to_tm(data, &alrm->time, info->rtc_24hr_mode);
+
+ alrm->enabled = 0;
+ ret = regmap_read(info->max77802->regmap,
+ MAX77802_RTC_AE1, &val);
+ if (ret < 0) {
+ dev_err(info->dev, "%s:%d fail to read alarm enable(%d)\n",
+ __func__, __LINE__, ret);
+ goto out;
+ }
+ if (val)
+ alrm->enabled = 1;
+
+ alrm->pending = 0;
+ ret = regmap_read(info->max77802->regmap, MAX77802_REG_STATUS2, &val);
+ if (ret < 0) {
+ dev_err(info->dev, "%s:%d fail to read status2 reg(%d)\n",
+ __func__, __LINE__, ret);
+ goto out;
+ }
+
+ if (val & (1 << 2)) /* RTCA1 */
+ alrm->pending = 1;
+
+out:
+ mutex_unlock(&info->lock);
+ return 0;
+}
+
+static int max77802_rtc_stop_alarm(struct max77802_rtc_info *info)
+{
+ int ret;
+
+ if (!mutex_is_locked(&info->lock))
+ dev_warn(info->dev, "%s: should have mutex locked\n", __func__);
+
+ ret = max77802_rtc_update(info, MAX77802_RTC_READ);
+ if (ret < 0)
+ goto out;
+
+ ret = regmap_write(info->max77802->regmap,
+ MAX77802_RTC_AE1, 0);
+ if (ret < 0) {
+ dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
+ __func__, ret);
+ goto out;
+ }
+
+ ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
+out:
+ return ret;
+}
+
+static int max77802_rtc_start_alarm(struct max77802_rtc_info *info)
+{
+ int ret;
+
+ if (!mutex_is_locked(&info->lock))
+ dev_warn(info->dev, "%s: should have mutex locked\n",
+ __func__);
+
+ ret = max77802_rtc_update(info, MAX77802_RTC_READ);
+ if (ret < 0)
+ goto out;
+
+ ret = regmap_write(info->max77802->regmap,
+ MAX77802_RTC_AE1,
+ ALARM_ENABLE_VALUE);
+
+ if (ret < 0) {
+ dev_err(info->dev, "%s: fail to read alarm reg(%d)\n",
+ __func__, ret);
+ goto out;
+ }
+
+ ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
+out:
+ return ret;
+}
+
+static int max77802_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct max77802_rtc_info *info = dev_get_drvdata(dev);
+ u8 data[RTC_NR_TIME];
+ int ret;
+
+ ret = max77802_rtc_tm_to_data(&alrm->time, data);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&info->lock);
+
+ ret = max77802_rtc_stop_alarm(info);
+ if (ret < 0)
+ goto out;
+
+ ret = regmap_bulk_write(info->max77802->regmap,
+ MAX77802_ALARM1_SEC, data, RTC_NR_TIME);
+
+ if (ret < 0) {
+ dev_err(info->dev, "%s: fail to write alarm reg(%d)\n",
+ __func__, ret);
+ goto out;
+ }
+
+ ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
+ if (ret < 0)
+ goto out;
+
+ if (alrm->enabled)
+ ret = max77802_rtc_start_alarm(info);
+out:
+ mutex_unlock(&info->lock);
+ return ret;
+}
+
+static int max77802_rtc_alarm_irq_enable(struct device *dev,
+ unsigned int enabled)
+{
+ struct max77802_rtc_info *info = dev_get_drvdata(dev);
+ int ret;
+
+ mutex_lock(&info->lock);
+ if (enabled)
+ ret = max77802_rtc_start_alarm(info);
+ else
+ ret = max77802_rtc_stop_alarm(info);
+ mutex_unlock(&info->lock);
+
+ return ret;
+}
+
+static irqreturn_t max77802_rtc_alarm_irq(int irq, void *data)
+{
+ struct max77802_rtc_info *info = data;
+
+ dev_dbg(info->dev, "%s:irq(%d)\n", __func__, irq);
+
+ rtc_update_irq(info->rtc_dev, 1, RTC_IRQF | RTC_AF);
+
+ return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops max77802_rtc_ops = {
+ .read_time = max77802_rtc_read_time,
+ .set_time = max77802_rtc_set_time,
+ .read_alarm = max77802_rtc_read_alarm,
+ .set_alarm = max77802_rtc_set_alarm,
+ .alarm_irq_enable = max77802_rtc_alarm_irq_enable,
+};
+
+static int max77802_rtc_init_reg(struct max77802_rtc_info *info)
+{
+ u8 data[2];
+ int ret;
+
+ max77802_rtc_update(info, MAX77802_RTC_READ);
+
+ /* Set RTC control register : Binary mode, 24hour mdoe */
+ data[0] = (1 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
+ data[1] = (0 << BCD_EN_SHIFT) | (1 << MODEL24_SHIFT);
+
+ info->rtc_24hr_mode = 1;
+
+ ret = regmap_bulk_write(info->max77802->regmap,
+ MAX77802_RTC_CONTROLM, data, ARRAY_SIZE(data));
+ if (ret < 0) {
+ dev_err(info->dev, "%s: fail to write controlm reg(%d)\n",
+ __func__, ret);
+ return ret;
+ }
+
+ ret = max77802_rtc_update(info, MAX77802_RTC_WRITE);
+ return ret;
+}
+
+static int max77802_rtc_probe(struct platform_device *pdev)
+{
+ struct max77686_dev *max77802 = dev_get_drvdata(pdev->dev.parent);
+ struct max77802_rtc_info *info;
+ int ret;
+
+ dev_dbg(&pdev->dev, "%s\n", __func__);
+
+ info = devm_kzalloc(&pdev->dev, sizeof(struct max77802_rtc_info),
+ GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ mutex_init(&info->lock);
+ info->dev = &pdev->dev;
+ info->max77802 = max77802;
+ info->rtc = max77802->i2c;
+
+ platform_set_drvdata(pdev, info);
+
+ ret = max77802_rtc_init_reg(info);
+
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to initialize RTC reg:%d\n", ret);
+ return ret;
+ }
+
+ device_init_wakeup(&pdev->dev, 1);
+
+ info->rtc_dev = devm_rtc_device_register(&pdev->dev, "max77802-rtc",
+ &max77802_rtc_ops, THIS_MODULE);
+
+ if (IS_ERR(info->rtc_dev)) {
+ ret = PTR_ERR(info->rtc_dev);
+ dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
+ if (ret == 0)
+ ret = -EINVAL;
+ return ret;
+ }
+ info->virq = regmap_irq_get_virq(max77802->rtc_irq_data,
+ MAX77686_RTCIRQ_RTCA1);
+
+ if (info->virq <= 0) {
+ dev_err(&pdev->dev, "Failed to get virtual IRQ %d\n",
+ MAX77686_RTCIRQ_RTCA1);
+ ret = -EINVAL;
+ return ret;
+ }
+
+ ret = devm_request_threaded_irq(&pdev->dev, info->virq, NULL,
+ max77802_rtc_alarm_irq, 0, "rtc-alarm1",
+ info);
+ if (ret < 0)
+ dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n",
+ info->virq, ret);
+
+ return ret;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int max77802_rtc_suspend(struct device *dev)
+{
+ if (device_may_wakeup(dev)) {
+ struct max77802_rtc_info *info = dev_get_drvdata(dev);
+
+ return enable_irq_wake(info->virq);
+ }
+
+ return 0;
+}
+
+static int max77802_rtc_resume(struct device *dev)
+{
+ if (device_may_wakeup(dev)) {
+ struct max77802_rtc_info *info = dev_get_drvdata(dev);
+
+ return disable_irq_wake(info->virq);
+ }
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(max77802_rtc_pm_ops,
+ max77802_rtc_suspend, max77802_rtc_resume);
+
+static const struct platform_device_id rtc_id[] = {
+ { "max77802-rtc", 0 },
+ {},
+};
+
+static struct platform_driver max77802_rtc_driver = {
+ .driver = {
+ .name = "max77802-rtc",
+ .owner = THIS_MODULE,
+ .pm = &max77802_rtc_pm_ops,
+ },
+ .probe = max77802_rtc_probe,
+ .id_table = rtc_id,
+};
+
+module_platform_driver(max77802_rtc_driver);
+
+MODULE_DESCRIPTION("Maxim MAX77802 RTC driver");
+MODULE_AUTHOR("Simon Glass <sjg@chromium.org>");
+MODULE_LICENSE("GPL");
--
2.0.0.rc2


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