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path: root/drivers/rtc/rtc-wm831x.c
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Diffstat (limited to 'drivers/rtc/rtc-wm831x.c')
-rw-r--r--drivers/rtc/rtc-wm831x.c487
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");
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-11 20:09:02 +0000