diff options
Diffstat (limited to 'drivers/rtc/rtc-wm831x.c')
| -rw-r--r-- | drivers/rtc/rtc-wm831x.c | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-wm831x.c b/drivers/rtc/rtc-wm831x.c new file mode 100644 index 000000000000..79795cdf6ed8 --- /dev/null +++ b/drivers/rtc/rtc-wm831x.c @@ -0,0 +1,523 @@ +/* + * 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/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> + + +/* + * 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; +}; + +/* + * 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 int wm831x_rtc_update_irq_enable(struct device *dev, + unsigned int enabled) +{ + struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); + int val; + + if (enabled) + val = 1 << WM831X_RTC_PINT_FREQ_SHIFT; + else + val = 0; + + return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL, + WM831X_RTC_PINT_FREQ_MASK, val); +} + +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 irqreturn_t wm831x_per_irq(int irq, void *data) +{ + struct wm831x_rtc *wm831x_rtc = data; + + rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_UF); + + 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, + .update_irq_enable = wm831x_rtc_update_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 per_irq = platform_get_irq_byname(pdev, "PER"); + int alm_irq = platform_get_irq_byname(pdev, "ALM"); + int ret = 0; + + wm831x_rtc = kzalloc(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 = rtc_device_register("wm831x", &pdev->dev, + &wm831x_rtc_ops, THIS_MODULE); + if (IS_ERR(wm831x_rtc->rtc)) { + ret = PTR_ERR(wm831x_rtc->rtc); + goto err; + } + + ret = wm831x_request_irq(wm831x, per_irq, wm831x_per_irq, + IRQF_TRIGGER_RISING, "wm831x_rtc_per", + wm831x_rtc); + if (ret != 0) { + dev_err(&pdev->dev, "Failed to request periodic IRQ %d: %d\n", + per_irq, ret); + } + + ret = wm831x_request_irq(wm831x, alm_irq, wm831x_alm_irq, + IRQF_TRIGGER_RISING, "wm831x_rtc_alm", + wm831x_rtc); + if (ret != 0) { + dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n", + alm_irq, ret); + } + + return 0; + +err: + kfree(wm831x_rtc); + return ret; +} + +static int __devexit wm831x_rtc_remove(struct platform_device *pdev) +{ + struct wm831x_rtc *wm831x_rtc = platform_get_drvdata(pdev); + int per_irq = platform_get_irq_byname(pdev, "PER"); + int alm_irq = platform_get_irq_byname(pdev, "ALM"); + + wm831x_free_irq(wm831x_rtc->wm831x, alm_irq, wm831x_rtc); + wm831x_free_irq(wm831x_rtc->wm831x, per_irq, wm831x_rtc); + rtc_device_unregister(wm831x_rtc->rtc); + kfree(wm831x_rtc); + + return 0; +} + +static 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, + .remove = __devexit_p(wm831x_rtc_remove), + .driver = { + .name = "wm831x-rtc", + .pm = &wm831x_rtc_pm_ops, + }, +}; + +static int __init wm831x_rtc_init(void) +{ + return platform_driver_register(&wm831x_rtc_driver); +} +module_init(wm831x_rtc_init); + +static void __exit wm831x_rtc_exit(void) +{ + platform_driver_unregister(&wm831x_rtc_driver); +} +module_exit(wm831x_rtc_exit); + +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"); |