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 b8f4e9e66cd..8e437e2f628 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 9574748d1c7..612f5a88a8e 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 00000000000..64b847b7f97
--- /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");