Initial import

1 files changed, 487 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-wm831x.c b/drivers/rtc/rtc-wm831x.c
new file mode 100644
index 000000000..75aea4c4d
--- /dev/null
+++ b/drivers/rtc/rtc-wm831x.c
@@ -0,0 +1,487 @@
+/*
+ *	Real Time Clock driver for Wolfson Microelectronics WM831x
+ *
+ *	Copyright (C) 2009 Wolfson Microelectronics PLC.
+ *
+ *  Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
+ *
+ *  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/module.h>
+#include <linux/kernel.h>
+#include <linux/time.h>
+#include <linux/rtc.h>
+#include <linux/slab.h>
+#include <linux/bcd.h>
+#include <linux/interrupt.h>
+#include <linux/ioctl.h>
+#include <linux/completion.h>
+#include <linux/mfd/wm831x/core.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/random.h>
+
+/*
+ * R16416 (0x4020) - RTC Write Counter
+ */
+#define WM831X_RTC_WR_CNT_MASK                  0xFFFF  /* RTC_WR_CNT - [15:0] */
+#define WM831X_RTC_WR_CNT_SHIFT                      0  /* RTC_WR_CNT - [15:0] */
+#define WM831X_RTC_WR_CNT_WIDTH                     16  /* RTC_WR_CNT - [15:0] */
+
+/*
+ * R16417 (0x4021) - RTC Time 1
+ */
+#define WM831X_RTC_TIME_MASK                    0xFFFF  /* RTC_TIME - [15:0] */
+#define WM831X_RTC_TIME_SHIFT                        0  /* RTC_TIME - [15:0] */
+#define WM831X_RTC_TIME_WIDTH                       16  /* RTC_TIME - [15:0] */
+
+/*
+ * R16418 (0x4022) - RTC Time 2
+ */
+#define WM831X_RTC_TIME_MASK                    0xFFFF  /* RTC_TIME - [15:0] */
+#define WM831X_RTC_TIME_SHIFT                        0  /* RTC_TIME - [15:0] */
+#define WM831X_RTC_TIME_WIDTH                       16  /* RTC_TIME - [15:0] */
+
+/*
+ * R16419 (0x4023) - RTC Alarm 1
+ */
+#define WM831X_RTC_ALM_MASK                     0xFFFF  /* RTC_ALM - [15:0] */
+#define WM831X_RTC_ALM_SHIFT                         0  /* RTC_ALM - [15:0] */
+#define WM831X_RTC_ALM_WIDTH                        16  /* RTC_ALM - [15:0] */
+
+/*
+ * R16420 (0x4024) - RTC Alarm 2
+ */
+#define WM831X_RTC_ALM_MASK                     0xFFFF  /* RTC_ALM - [15:0] */
+#define WM831X_RTC_ALM_SHIFT                         0  /* RTC_ALM - [15:0] */
+#define WM831X_RTC_ALM_WIDTH                        16  /* RTC_ALM - [15:0] */
+
+/*
+ * R16421 (0x4025) - RTC Control
+ */
+#define WM831X_RTC_VALID                        0x8000  /* RTC_VALID */
+#define WM831X_RTC_VALID_MASK                   0x8000  /* RTC_VALID */
+#define WM831X_RTC_VALID_SHIFT                      15  /* RTC_VALID */
+#define WM831X_RTC_VALID_WIDTH                       1  /* RTC_VALID */
+#define WM831X_RTC_SYNC_BUSY                    0x4000  /* RTC_SYNC_BUSY */
+#define WM831X_RTC_SYNC_BUSY_MASK               0x4000  /* RTC_SYNC_BUSY */
+#define WM831X_RTC_SYNC_BUSY_SHIFT                  14  /* RTC_SYNC_BUSY */
+#define WM831X_RTC_SYNC_BUSY_WIDTH                   1  /* RTC_SYNC_BUSY */
+#define WM831X_RTC_ALM_ENA                      0x0400  /* RTC_ALM_ENA */
+#define WM831X_RTC_ALM_ENA_MASK                 0x0400  /* RTC_ALM_ENA */
+#define WM831X_RTC_ALM_ENA_SHIFT                    10  /* RTC_ALM_ENA */
+#define WM831X_RTC_ALM_ENA_WIDTH                     1  /* RTC_ALM_ENA */
+#define WM831X_RTC_PINT_FREQ_MASK               0x0070  /* RTC_PINT_FREQ - [6:4] */
+#define WM831X_RTC_PINT_FREQ_SHIFT                   4  /* RTC_PINT_FREQ - [6:4] */
+#define WM831X_RTC_PINT_FREQ_WIDTH                   3  /* RTC_PINT_FREQ - [6:4] */
+
+/*
+ * R16422 (0x4026) - RTC Trim
+ */
+#define WM831X_RTC_TRIM_MASK                    0x03FF  /* RTC_TRIM - [9:0] */
+#define WM831X_RTC_TRIM_SHIFT                        0  /* RTC_TRIM - [9:0] */
+#define WM831X_RTC_TRIM_WIDTH                       10  /* RTC_TRIM - [9:0] */
+
+#define WM831X_SET_TIME_RETRIES	5
+#define WM831X_GET_TIME_RETRIES	5
+
+struct wm831x_rtc {
+	struct wm831x *wm831x;
+	struct rtc_device *rtc;
+	unsigned int alarm_enabled:1;
+};
+
+static void wm831x_rtc_add_randomness(struct wm831x *wm831x)
+{
+	int ret;
+	u16 reg;
+
+	/*
+	 * The write counter contains a pseudo-random number which is
+	 * regenerated every time we set the RTC so it should be a
+	 * useful per-system source of entropy.
+	 */
+	ret = wm831x_reg_read(wm831x, WM831X_RTC_WRITE_COUNTER);
+	if (ret >= 0) {
+		reg = ret;
+		add_device_randomness(&reg, sizeof(reg));
+	} else {
+		dev_warn(wm831x->dev, "Failed to read RTC write counter: %d\n",
+			 ret);
+	}
+}
+
+/*
+ * Read current time and date in RTC
+ */
+static int wm831x_rtc_readtime(struct device *dev, struct rtc_time *tm)
+{
+	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
+	struct wm831x *wm831x = wm831x_rtc->wm831x;
+	u16 time1[2], time2[2];
+	int ret;
+	int count = 0;
+
+	/* Has the RTC been programmed? */
+	ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
+	if (ret < 0) {
+		dev_err(dev, "Failed to read RTC control: %d\n", ret);
+		return ret;
+	}
+	if (!(ret & WM831X_RTC_VALID)) {
+		dev_dbg(dev, "RTC not yet configured\n");
+		return -EINVAL;
+	}
+
+	/* Read twice to make sure we don't read a corrupt, partially
+	 * incremented, value.
+	 */
+	do {
+		ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
+				       2, time1);
+		if (ret != 0)
+			continue;
+
+		ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
+				       2, time2);
+		if (ret != 0)
+			continue;
+
+		if (memcmp(time1, time2, sizeof(time1)) == 0) {
+			u32 time = (time1[0] << 16) | time1[1];
+
+			rtc_time_to_tm(time, tm);
+			return rtc_valid_tm(tm);
+		}
+
+	} while (++count < WM831X_GET_TIME_RETRIES);
+
+	dev_err(dev, "Timed out reading current time\n");
+
+	return -EIO;
+}
+
+/*
+ * Set current time and date in RTC
+ */
+static int wm831x_rtc_set_mmss(struct device *dev, unsigned long time)
+{
+	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
+	struct wm831x *wm831x = wm831x_rtc->wm831x;
+	struct rtc_time new_tm;
+	unsigned long new_time;
+	int ret;
+	int count = 0;
+
+	ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_1,
+			       (time >> 16) & 0xffff);
+	if (ret < 0) {
+		dev_err(dev, "Failed to write TIME_1: %d\n", ret);
+		return ret;
+	}
+
+	ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_2, time & 0xffff);
+	if (ret < 0) {
+		dev_err(dev, "Failed to write TIME_2: %d\n", ret);
+		return ret;
+	}
+
+	/* Wait for the update to complete - should happen first time
+	 * round but be conservative.
+	 */
+	do {
+		msleep(1);
+
+		ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
+		if (ret < 0)
+			ret = WM831X_RTC_SYNC_BUSY;
+	} while (!(ret & WM831X_RTC_SYNC_BUSY) &&
+		 ++count < WM831X_SET_TIME_RETRIES);
+
+	if (ret & WM831X_RTC_SYNC_BUSY) {
+		dev_err(dev, "Timed out writing RTC update\n");
+		return -EIO;
+	}
+
+	/* Check that the update was accepted; security features may
+	 * have caused the update to be ignored.
+	 */
+	ret = wm831x_rtc_readtime(dev, &new_tm);
+	if (ret < 0)
+		return ret;
+
+	ret = rtc_tm_to_time(&new_tm, &new_time);
+	if (ret < 0) {
+		dev_err(dev, "Failed to convert time: %d\n", ret);
+		return ret;
+	}
+
+	/* Allow a second of change in case of tick */
+	if (new_time - time > 1) {
+		dev_err(dev, "RTC update not permitted by hardware\n");
+		return -EPERM;
+	}
+
+	return 0;
+}
+
+/*
+ * Read alarm time and date in RTC
+ */
+static int wm831x_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
+	int ret;
+	u16 data[2];
+	u32 time;
+
+	ret = wm831x_bulk_read(wm831x_rtc->wm831x, WM831X_RTC_ALARM_1,
+			       2, data);
+	if (ret != 0) {
+		dev_err(dev, "Failed to read alarm time: %d\n", ret);
+		return ret;
+	}
+
+	time = (data[0] << 16) | data[1];
+
+	rtc_time_to_tm(time, &alrm->time);
+
+	ret = wm831x_reg_read(wm831x_rtc->wm831x, WM831X_RTC_CONTROL);
+	if (ret < 0) {
+		dev_err(dev, "Failed to read RTC control: %d\n", ret);
+		return ret;
+	}
+
+	if (ret & WM831X_RTC_ALM_ENA)
+		alrm->enabled = 1;
+	else
+		alrm->enabled = 0;
+
+	return 0;
+}
+
+static int wm831x_rtc_stop_alarm(struct wm831x_rtc *wm831x_rtc)
+{
+	wm831x_rtc->alarm_enabled = 0;
+
+	return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
+			       WM831X_RTC_ALM_ENA, 0);
+}
+
+static int wm831x_rtc_start_alarm(struct wm831x_rtc *wm831x_rtc)
+{
+	wm831x_rtc->alarm_enabled = 1;
+
+	return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
+			       WM831X_RTC_ALM_ENA, WM831X_RTC_ALM_ENA);
+}
+
+static int wm831x_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
+	struct wm831x *wm831x = wm831x_rtc->wm831x;
+	int ret;
+	unsigned long time;
+
+	ret = rtc_tm_to_time(&alrm->time, &time);
+	if (ret < 0) {
+		dev_err(dev, "Failed to convert time: %d\n", ret);
+		return ret;
+	}
+
+	ret = wm831x_rtc_stop_alarm(wm831x_rtc);
+	if (ret < 0) {
+		dev_err(dev, "Failed to stop alarm: %d\n", ret);
+		return ret;
+	}
+
+	ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_1,
+			       (time >> 16) & 0xffff);
+	if (ret < 0) {
+		dev_err(dev, "Failed to write ALARM_1: %d\n", ret);
+		return ret;
+	}
+
+	ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_2, time & 0xffff);
+	if (ret < 0) {
+		dev_err(dev, "Failed to write ALARM_2: %d\n", ret);
+		return ret;
+	}
+
+	if (alrm->enabled) {
+		ret = wm831x_rtc_start_alarm(wm831x_rtc);
+		if (ret < 0) {
+			dev_err(dev, "Failed to start alarm: %d\n", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int wm831x_rtc_alarm_irq_enable(struct device *dev,
+				       unsigned int enabled)
+{
+	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
+
+	if (enabled)
+		return wm831x_rtc_start_alarm(wm831x_rtc);
+	else
+		return wm831x_rtc_stop_alarm(wm831x_rtc);
+}
+
+static irqreturn_t wm831x_alm_irq(int irq, void *data)
+{
+	struct wm831x_rtc *wm831x_rtc = data;
+
+	rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_AF);
+
+	return IRQ_HANDLED;
+}
+
+static const struct rtc_class_ops wm831x_rtc_ops = {
+	.read_time = wm831x_rtc_readtime,
+	.set_mmss = wm831x_rtc_set_mmss,
+	.read_alarm = wm831x_rtc_readalarm,
+	.set_alarm = wm831x_rtc_setalarm,
+	.alarm_irq_enable = wm831x_rtc_alarm_irq_enable,
+};
+
+#ifdef CONFIG_PM
+/* Turn off the alarm if it should not be a wake source. */
+static int wm831x_rtc_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
+	int ret, enable;
+
+	if (wm831x_rtc->alarm_enabled && device_may_wakeup(&pdev->dev))
+		enable = WM831X_RTC_ALM_ENA;
+	else
+		enable = 0;
+
+	ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
+			      WM831X_RTC_ALM_ENA, enable);
+	if (ret != 0)
+		dev_err(&pdev->dev, "Failed to update RTC alarm: %d\n", ret);
+
+	return 0;
+}
+
+/* Enable the alarm if it should be enabled (in case it was disabled to
+ * prevent use as a wake source).
+ */
+static int wm831x_rtc_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
+	int ret;
+
+	if (wm831x_rtc->alarm_enabled) {
+		ret = wm831x_rtc_start_alarm(wm831x_rtc);
+		if (ret != 0)
+			dev_err(&pdev->dev,
+				"Failed to restart RTC alarm: %d\n", ret);
+	}
+
+	return 0;
+}
+
+/* Unconditionally disable the alarm */
+static int wm831x_rtc_freeze(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(&pdev->dev);
+	int ret;
+
+	ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
+			      WM831X_RTC_ALM_ENA, 0);
+	if (ret != 0)
+		dev_err(&pdev->dev, "Failed to stop RTC alarm: %d\n", ret);
+
+	return 0;
+}
+#else
+#define wm831x_rtc_suspend NULL
+#define wm831x_rtc_resume NULL
+#define wm831x_rtc_freeze NULL
+#endif
+
+static int wm831x_rtc_probe(struct platform_device *pdev)
+{
+	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
+	struct wm831x_rtc *wm831x_rtc;
+	int alm_irq = wm831x_irq(wm831x, platform_get_irq_byname(pdev, "ALM"));
+	int ret = 0;
+
+	wm831x_rtc = devm_kzalloc(&pdev->dev, sizeof(*wm831x_rtc), GFP_KERNEL);
+	if (wm831x_rtc == NULL)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, wm831x_rtc);
+	wm831x_rtc->wm831x = wm831x;
+
+	ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to read RTC control: %d\n", ret);
+		goto err;
+	}
+	if (ret & WM831X_RTC_ALM_ENA)
+		wm831x_rtc->alarm_enabled = 1;
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	wm831x_rtc->rtc = devm_rtc_device_register(&pdev->dev, "wm831x",
+					      &wm831x_rtc_ops, THIS_MODULE);
+	if (IS_ERR(wm831x_rtc->rtc)) {
+		ret = PTR_ERR(wm831x_rtc->rtc);
+		goto err;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, alm_irq, NULL,
+				wm831x_alm_irq,
+				IRQF_TRIGGER_RISING, "RTC alarm",
+				wm831x_rtc);
+	if (ret != 0) {
+		dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
+			alm_irq, ret);
+	}
+
+	wm831x_rtc_add_randomness(wm831x);
+
+	return 0;
+
+err:
+	return ret;
+}
+
+static const struct dev_pm_ops wm831x_rtc_pm_ops = {
+	.suspend = wm831x_rtc_suspend,
+	.resume = wm831x_rtc_resume,
+
+	.freeze = wm831x_rtc_freeze,
+	.thaw = wm831x_rtc_resume,
+	.restore = wm831x_rtc_resume,
+
+	.poweroff = wm831x_rtc_suspend,
+};
+
+static struct platform_driver wm831x_rtc_driver = {
+	.probe = wm831x_rtc_probe,
+	.driver = {
+		.name = "wm831x-rtc",
+		.pm = &wm831x_rtc_pm_ops,
+	},
+};
+
+module_platform_driver(wm831x_rtc_driver);
+
+MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
+MODULE_DESCRIPTION("RTC driver for the WM831x series PMICs");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:wm831x-rtc");