diff options
Diffstat (limited to 'drivers/rtc/rtc-armada38x.c')
| -rw-r--r-- | drivers/rtc/rtc-armada38x.c | 216 |
1 files changed, 148 insertions, 68 deletions
diff --git a/drivers/rtc/rtc-armada38x.c b/drivers/rtc/rtc-armada38x.c index 21f355c37eab..713fa0d077cd 100644 --- a/drivers/rtc/rtc-armada38x.c +++ b/drivers/rtc/rtc-armada38x.c @@ -1,22 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * RTC driver for the Armada 38x Marvell SoCs * * Copyright (C) 2015 Marvell * * Gregory Clement <gregory.clement@free-electrons.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/delay.h> #include <linux/io.h> #include <linux/module.h> #include <linux/of.h> -#include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/rtc.h> @@ -28,6 +22,10 @@ #define RTC_IRQ_AL_EN BIT(0) #define RTC_IRQ_FREQ_EN BIT(1) #define RTC_IRQ_FREQ_1HZ BIT(2) +#define RTC_CCR 0x18 +#define RTC_CCR_MODE BIT(15) +#define RTC_CONF_TEST 0x1C +#define RTC_NOMINAL_TIMING BIT(13) #define RTC_TIME 0xC #define RTC_ALARM1 0x10 @@ -73,8 +71,9 @@ struct armada38x_rtc { void __iomem *regs_soc; spinlock_t lock; int irq; + bool initialized; struct value_to_freq *val_to_freq; - struct armada38x_rtc_data *data; + const struct armada38x_rtc_data *data; }; #define ALARM1 0 @@ -219,28 +218,43 @@ static int armada38x_rtc_read_time(struct device *dev, struct rtc_time *tm) time = rtc->data->read_rtc_reg(rtc, RTC_TIME); spin_unlock_irqrestore(&rtc->lock, flags); - rtc_time_to_tm(time, tm); + rtc_time64_to_tm(time, tm); return 0; } +static void armada38x_rtc_reset(struct armada38x_rtc *rtc) +{ + u32 reg; + + reg = rtc->data->read_rtc_reg(rtc, RTC_CONF_TEST); + /* If bits [7:0] are non-zero, assume RTC was uninitialized */ + if (reg & 0xff) { + rtc_delayed_write(0, rtc, RTC_CONF_TEST); + msleep(500); /* Oscillator startup time */ + rtc_delayed_write(0, rtc, RTC_TIME); + rtc_delayed_write(SOC_RTC_ALARM1 | SOC_RTC_ALARM2, rtc, + RTC_STATUS); + rtc_delayed_write(RTC_NOMINAL_TIMING, rtc, RTC_CCR); + } + rtc->initialized = true; +} + static int armada38x_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct armada38x_rtc *rtc = dev_get_drvdata(dev); - int ret = 0; unsigned long time, flags; - ret = rtc_tm_to_time(tm, &time); + time = rtc_tm_to_time64(tm); - if (ret) - goto out; + if (!rtc->initialized) + armada38x_rtc_reset(rtc); spin_lock_irqsave(&rtc->lock, flags); rtc_delayed_write(time, rtc, RTC_TIME); spin_unlock_irqrestore(&rtc->lock, flags); -out: - return ret; + return 0; } static int armada38x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) @@ -259,7 +273,7 @@ static int armada38x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) spin_unlock_irqrestore(&rtc->lock, flags); alrm->enabled = val ? 1 : 0; - rtc_time_to_tm(time, &alrm->time); + rtc_time64_to_tm(time, &alrm->time); return 0; } @@ -270,12 +284,8 @@ static int armada38x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) u32 reg = ALARM_REG(RTC_ALARM1, rtc->data->alarm); u32 reg_irq = ALARM_REG(RTC_IRQ1_CONF, rtc->data->alarm); unsigned long time, flags; - int ret = 0; - - ret = rtc_tm_to_time(&alrm->time, &time); - if (ret) - goto out; + time = rtc_tm_to_time64(&alrm->time); spin_lock_irqsave(&rtc->lock, flags); @@ -288,8 +298,7 @@ static int armada38x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) spin_unlock_irqrestore(&rtc->lock, flags); -out: - return ret; + return 0; } static int armada38x_rtc_alarm_irq_enable(struct device *dev, @@ -343,18 +352,109 @@ static irqreturn_t armada38x_rtc_alarm_irq(int irq, void *data) return IRQ_HANDLED; } +/* + * The information given in the Armada 388 functional spec is complex. + * They give two different formulas for calculating the offset value, + * but when considering "Offset" as an 8-bit signed integer, they both + * reduce down to (we shall rename "Offset" as "val" here): + * + * val = (f_ideal / f_measured - 1) / resolution where f_ideal = 32768 + * + * Converting to time, f = 1/t: + * val = (t_measured / t_ideal - 1) / resolution where t_ideal = 1/32768 + * + * => t_measured / t_ideal = val * resolution + 1 + * + * "offset" in the RTC interface is defined as: + * t = t0 * (1 + offset * 1e-9) + * where t is the desired period, t0 is the measured period with a zero + * offset, which is t_measured above. With t0 = t_measured and t = t_ideal, + * offset = (t_ideal / t_measured - 1) / 1e-9 + * + * => t_ideal / t_measured = offset * 1e-9 + 1 + * + * so: + * + * offset * 1e-9 + 1 = 1 / (val * resolution + 1) + * + * We want "resolution" to be an integer, so resolution = R * 1e-9, giving + * offset = 1e18 / (val * R + 1e9) - 1e9 + * val = (1e18 / (offset + 1e9) - 1e9) / R + * with a common transformation: + * f(x) = 1e18 / (x + 1e9) - 1e9 + * offset = f(val * R) + * val = f(offset) / R + * + * Armada 38x supports two modes, fine mode (954ppb) and coarse mode (3815ppb). + */ +static long armada38x_ppb_convert(long ppb) +{ + long div = ppb + 1000000000L; + + return div_s64(1000000000000000000LL + div / 2, div) - 1000000000L; +} + +static int armada38x_rtc_read_offset(struct device *dev, long *offset) +{ + struct armada38x_rtc *rtc = dev_get_drvdata(dev); + unsigned long ccr, flags; + long ppb_cor; + + spin_lock_irqsave(&rtc->lock, flags); + ccr = rtc->data->read_rtc_reg(rtc, RTC_CCR); + spin_unlock_irqrestore(&rtc->lock, flags); + + ppb_cor = (ccr & RTC_CCR_MODE ? 3815 : 954) * (s8)ccr; + /* ppb_cor + 1000000000L can never be zero */ + *offset = armada38x_ppb_convert(ppb_cor); + + return 0; +} + +static int armada38x_rtc_set_offset(struct device *dev, long offset) +{ + struct armada38x_rtc *rtc = dev_get_drvdata(dev); + unsigned long ccr = 0; + long ppb_cor, off; + + /* + * The maximum ppb_cor is -128 * 3815 .. 127 * 3815, but we + * need to clamp the input. This equates to -484270 .. 488558. + * Not only is this to stop out of range "off" but also to + * avoid the division by zero in armada38x_ppb_convert(). + */ + offset = clamp(offset, -484270L, 488558L); + + ppb_cor = armada38x_ppb_convert(offset); + + /* + * Use low update mode where possible, which gives a better + * resolution of correction. + */ + off = DIV_ROUND_CLOSEST(ppb_cor, 954); + if (off > 127 || off < -128) { + ccr = RTC_CCR_MODE; + off = DIV_ROUND_CLOSEST(ppb_cor, 3815); + } + + /* + * Armada 388 requires a bit pattern in bits 14..8 depending on + * the sign bit: { 0, ~S, S, S, S, S, S } + */ + ccr |= (off & 0x3fff) ^ 0x2000; + rtc_delayed_write(ccr, rtc, RTC_CCR); + + return 0; +} + static const struct rtc_class_ops armada38x_rtc_ops = { .read_time = armada38x_rtc_read_time, .set_time = armada38x_rtc_set_time, .read_alarm = armada38x_rtc_read_alarm, .set_alarm = armada38x_rtc_set_alarm, .alarm_irq_enable = armada38x_rtc_alarm_irq_enable, -}; - -static const struct rtc_class_ops armada38x_rtc_ops_noirq = { - .read_time = armada38x_rtc_read_time, - .set_time = armada38x_rtc_set_time, - .read_alarm = armada38x_rtc_read_alarm, + .read_offset = armada38x_rtc_read_offset, + .set_offset = armada38x_rtc_set_offset, }; static const struct armada38x_rtc_data armada38x_data = { @@ -373,7 +473,6 @@ static const struct armada38x_rtc_data armada8k_data = { .alarm = ALARM2, }; -#ifdef CONFIG_OF static const struct of_device_id armada38x_rtc_of_match_table[] = { { .compatible = "marvell,armada-380-rtc", @@ -386,25 +485,18 @@ static const struct of_device_id armada38x_rtc_of_match_table[] = { {} }; MODULE_DEVICE_TABLE(of, armada38x_rtc_of_match_table); -#endif static __init int armada38x_rtc_probe(struct platform_device *pdev) { - const struct rtc_class_ops *ops; - struct resource *res; struct armada38x_rtc *rtc; - const struct of_device_id *match; - int ret; - - match = of_match_device(armada38x_rtc_of_match_table, &pdev->dev); - if (!match) - return -ENODEV; rtc = devm_kzalloc(&pdev->dev, sizeof(struct armada38x_rtc), GFP_KERNEL); if (!rtc) return -ENOMEM; + rtc->data = of_device_get_match_data(&pdev->dev); + rtc->val_to_freq = devm_kcalloc(&pdev->dev, SAMPLE_NR, sizeof(struct value_to_freq), GFP_KERNEL); if (!rtc->val_to_freq) @@ -412,21 +504,21 @@ static __init int armada38x_rtc_probe(struct platform_device *pdev) spin_lock_init(&rtc->lock); - res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc"); - rtc->regs = devm_ioremap_resource(&pdev->dev, res); + rtc->regs = devm_platform_ioremap_resource_byname(pdev, "rtc"); if (IS_ERR(rtc->regs)) return PTR_ERR(rtc->regs); - res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc-soc"); - rtc->regs_soc = devm_ioremap_resource(&pdev->dev, res); + rtc->regs_soc = devm_platform_ioremap_resource_byname(pdev, "rtc-soc"); if (IS_ERR(rtc->regs_soc)) return PTR_ERR(rtc->regs_soc); rtc->irq = platform_get_irq(pdev, 0); - - if (rtc->irq < 0) { - dev_err(&pdev->dev, "no irq\n"); + if (rtc->irq < 0) return rtc->irq; - } + + rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc->rtc_dev)) + return PTR_ERR(rtc->rtc_dev); + if (devm_request_irq(&pdev->dev, rtc->irq, armada38x_rtc_alarm_irq, 0, pdev->name, rtc) < 0) { dev_warn(&pdev->dev, "Interrupt not available.\n"); @@ -434,30 +526,18 @@ static __init int armada38x_rtc_probe(struct platform_device *pdev) } platform_set_drvdata(pdev, rtc); - if (rtc->irq != -1) { - device_init_wakeup(&pdev->dev, 1); - ops = &armada38x_rtc_ops; - } else { - /* - * If there is no interrupt available then we can't - * use the alarm - */ - ops = &armada38x_rtc_ops_noirq; - } - rtc->data = (struct armada38x_rtc_data *)match->data; - + if (rtc->irq != -1) + device_init_wakeup(&pdev->dev, true); + else + clear_bit(RTC_FEATURE_ALARM, rtc->rtc_dev->features); /* Update RTC-MBUS bridge timing parameters */ rtc->data->update_mbus_timing(rtc); - rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name, - ops, THIS_MODULE); - if (IS_ERR(rtc->rtc_dev)) { - ret = PTR_ERR(rtc->rtc_dev); - dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret); - return ret; - } - return 0; + rtc->rtc_dev->ops = &armada38x_rtc_ops; + rtc->rtc_dev->range_max = U32_MAX; + + return devm_rtc_register_device(rtc->rtc_dev); } #ifdef CONFIG_PM_SLEEP @@ -494,7 +574,7 @@ static struct platform_driver armada38x_rtc_driver = { .driver = { .name = "armada38x-rtc", .pm = &armada38x_rtc_pm_ops, - .of_match_table = of_match_ptr(armada38x_rtc_of_match_table), + .of_match_table = armada38x_rtc_of_match_table, }, }; |