/* * 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(®, 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 0; } } 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");