Fixed MTP to work with TWRP

drivers/rtc/rtc-sa1100.c

@@ -0,0 +1,364 @@
+/*
+ * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx
+ *
+ * Copyright (c) 2000 Nils Faerber
+ *
+ * Based on rtc.c by Paul Gortmaker
+ *
+ * Original Driver by Nils Faerber <nils@kernelconcepts.de>
+ *
+ * Modifications from:
+ *   CIH <cih@coventive.com>
+ *   Nicolas Pitre <nico@fluxnic.net>
+ *   Andrew Christian <andrew.christian@hp.com>
+ *
+ * Converted to the RTC subsystem and Driver Model
+ *   by Richard Purdie <rpurdie@rpsys.net>
+ *
+ * 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/platform_device.h>
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+
+#include <mach/hardware.h>
+#include <mach/irqs.h>
+
+#if defined(CONFIG_ARCH_PXA) || defined(CONFIG_ARCH_MMP)
+#include <mach/regs-rtc.h>
+#endif
+
+#define RTC_DEF_DIVIDER		(32768 - 1)
+#define RTC_DEF_TRIM		0
+#define RTC_FREQ		1024
+
+struct sa1100_rtc {
+	spinlock_t		lock;
+	int			irq_1hz;
+	int			irq_alarm;
+	struct rtc_device	*rtc;
+	struct clk		*clk;
+};
+
+static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id)
+{
+	struct sa1100_rtc *info = dev_get_drvdata(dev_id);
+	struct rtc_device *rtc = info->rtc;
+	unsigned int rtsr;
+	unsigned long events = 0;
+
+	spin_lock(&info->lock);
+
+	rtsr = RTSR;
+	/* clear interrupt sources */
+	RTSR = 0;
+	/* Fix for a nasty initialization problem the in SA11xx RTSR register.
+	 * See also the comments in sa1100_rtc_probe(). */
+	if (rtsr & (RTSR_ALE | RTSR_HZE)) {
+		/* This is the original code, before there was the if test
+		 * above. This code does not clear interrupts that were not
+		 * enabled. */
+		RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2);
+	} else {
+		/* For some reason, it is possible to enter this routine
+		 * without interruptions enabled, it has been tested with
+		 * several units (Bug in SA11xx chip?).
+		 *
+		 * This situation leads to an infinite "loop" of interrupt
+		 * routine calling and as a result the processor seems to
+		 * lock on its first call to open(). */
+		RTSR = RTSR_AL | RTSR_HZ;
+	}
+
+	/* clear alarm interrupt if it has occurred */
+	if (rtsr & RTSR_AL)
+		rtsr &= ~RTSR_ALE;
+	RTSR = rtsr & (RTSR_ALE | RTSR_HZE);
+
+	/* update irq data & counter */
+	if (rtsr & RTSR_AL)
+		events |= RTC_AF | RTC_IRQF;
+	if (rtsr & RTSR_HZ)
+		events |= RTC_UF | RTC_IRQF;
+
+	rtc_update_irq(rtc, 1, events);
+
+	spin_unlock(&info->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int sa1100_rtc_open(struct device *dev)
+{
+	struct sa1100_rtc *info = dev_get_drvdata(dev);
+	struct rtc_device *rtc = info->rtc;
+	int ret;
+
+	ret = request_irq(info->irq_1hz, sa1100_rtc_interrupt, 0, "rtc 1Hz", dev);
+	if (ret) {
+		dev_err(dev, "IRQ %d already in use.\n", info->irq_1hz);
+		goto fail_ui;
+	}
+	ret = request_irq(info->irq_alarm, sa1100_rtc_interrupt, 0, "rtc Alrm", dev);
+	if (ret) {
+		dev_err(dev, "IRQ %d already in use.\n", info->irq_alarm);
+		goto fail_ai;
+	}
+	rtc->max_user_freq = RTC_FREQ;
+	rtc_irq_set_freq(rtc, NULL, RTC_FREQ);
+
+	return 0;
+
+ fail_ai:
+	free_irq(info->irq_1hz, dev);
+ fail_ui:
+	clk_disable_unprepare(info->clk);
+	return ret;
+}
+
+static void sa1100_rtc_release(struct device *dev)
+{
+	struct sa1100_rtc *info = dev_get_drvdata(dev);
+
+	spin_lock_irq(&info->lock);
+	RTSR = 0;
+	spin_unlock_irq(&info->lock);
+
+	free_irq(info->irq_alarm, dev);
+	free_irq(info->irq_1hz, dev);
+}
+
+static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+	struct sa1100_rtc *info = dev_get_drvdata(dev);
+
+	spin_lock_irq(&info->lock);
+	if (enabled)
+		RTSR |= RTSR_ALE;
+	else
+		RTSR &= ~RTSR_ALE;
+	spin_unlock_irq(&info->lock);
+	return 0;
+}
+
+static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	rtc_time_to_tm(RCNR, tm);
+	return 0;
+}
+
+static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	unsigned long time;
+	int ret;
+
+	ret = rtc_tm_to_time(tm, &time);
+	if (ret == 0)
+		RCNR = time;
+	return ret;
+}
+
+static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	u32	rtsr;
+
+	rtsr = RTSR;
+	alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0;
+	alrm->pending = (rtsr & RTSR_AL) ? 1 : 0;
+	return 0;
+}
+
+static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct sa1100_rtc *info = dev_get_drvdata(dev);
+	unsigned long time;
+	int ret;
+
+	spin_lock_irq(&info->lock);
+	ret = rtc_tm_to_time(&alrm->time, &time);
+	if (ret != 0)
+		goto out;
+	RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL);
+	RTAR = time;
+	if (alrm->enabled)
+		RTSR |= RTSR_ALE;
+	else
+		RTSR &= ~RTSR_ALE;
+out:
+	spin_unlock_irq(&info->lock);
+
+	return ret;
+}
+
+static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	seq_printf(seq, "trim/divider\t\t: 0x%08x\n", (u32) RTTR);
+	seq_printf(seq, "RTSR\t\t\t: 0x%08x\n", (u32)RTSR);
+
+	return 0;
+}
+
+static const struct rtc_class_ops sa1100_rtc_ops = {
+	.open = sa1100_rtc_open,
+	.release = sa1100_rtc_release,
+	.read_time = sa1100_rtc_read_time,
+	.set_time = sa1100_rtc_set_time,
+	.read_alarm = sa1100_rtc_read_alarm,
+	.set_alarm = sa1100_rtc_set_alarm,
+	.proc = sa1100_rtc_proc,
+	.alarm_irq_enable = sa1100_rtc_alarm_irq_enable,
+};
+
+static int sa1100_rtc_probe(struct platform_device *pdev)
+{
+	struct rtc_device *rtc;
+	struct sa1100_rtc *info;
+	int irq_1hz, irq_alarm, ret = 0;
+
+	irq_1hz = platform_get_irq_byname(pdev, "rtc 1Hz");
+	irq_alarm = platform_get_irq_byname(pdev, "rtc alarm");
+	if (irq_1hz < 0 || irq_alarm < 0)
+		return -ENODEV;
+
+	info = devm_kzalloc(&pdev->dev, sizeof(struct sa1100_rtc), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	info->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(info->clk)) {
+		dev_err(&pdev->dev, "failed to find rtc clock source\n");
+		return PTR_ERR(info->clk);
+	}
+	info->irq_1hz = irq_1hz;
+	info->irq_alarm = irq_alarm;
+	spin_lock_init(&info->lock);
+	platform_set_drvdata(pdev, info);
+
+	ret = clk_prepare_enable(info->clk);
+	if (ret)
+		return ret;
+	/*
+	 * According to the manual we should be able to let RTTR be zero
+	 * and then a default diviser for a 32.768KHz clock is used.
+	 * Apparently this doesn't work, at least for my SA1110 rev 5.
+	 * If the clock divider is uninitialized then reset it to the
+	 * default value to get the 1Hz clock.
+	 */
+	if (RTTR == 0) {
+		RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
+		dev_warn(&pdev->dev, "warning: "
+			"initializing default clock divider/trim value\n");
+		/* The current RTC value probably doesn't make sense either */
+		RCNR = 0;
+	}
+
+	device_init_wakeup(&pdev->dev, 1);
+
+	rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &sa1100_rtc_ops,
+					THIS_MODULE);
+
+	if (IS_ERR(rtc)) {
+		ret = PTR_ERR(rtc);
+		goto err_dev;
+	}
+	info->rtc = rtc;
+
+	/* Fix for a nasty initialization problem the in SA11xx RTSR register.
+	 * See also the comments in sa1100_rtc_interrupt().
+	 *
+	 * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an
+	 * interrupt pending, even though interrupts were never enabled.
+	 * In this case, this bit it must be reset before enabling
+	 * interruptions to avoid a nonexistent interrupt to occur.
+	 *
+	 * In principle, the same problem would apply to bit 0, although it has
+	 * never been observed to happen.
+	 *
+	 * This issue is addressed both here and in sa1100_rtc_interrupt().
+	 * If the issue is not addressed here, in the times when the processor
+	 * wakes up with the bit set there will be one spurious interrupt.
+	 *
+	 * The issue is also dealt with in sa1100_rtc_interrupt() to be on the
+	 * safe side, once the condition that lead to this strange
+	 * initialization is unknown and could in principle happen during
+	 * normal processing.
+	 *
+	 * Notice that clearing bit 1 and 0 is accomplished by writting ONES to
+	 * the corresponding bits in RTSR. */
+	RTSR = RTSR_AL | RTSR_HZ;
+
+	return 0;
+err_dev:
+	clk_disable_unprepare(info->clk);
+	return ret;
+}
+
+static int sa1100_rtc_remove(struct platform_device *pdev)
+{
+	struct sa1100_rtc *info = platform_get_drvdata(pdev);
+
+	if (info)
+		clk_disable_unprepare(info->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int sa1100_rtc_suspend(struct device *dev)
+{
+	struct sa1100_rtc *info = dev_get_drvdata(dev);
+	if (device_may_wakeup(dev))
+		enable_irq_wake(info->irq_alarm);
+	return 0;
+}
+
+static int sa1100_rtc_resume(struct device *dev)
+{
+	struct sa1100_rtc *info = dev_get_drvdata(dev);
+	if (device_may_wakeup(dev))
+		disable_irq_wake(info->irq_alarm);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(sa1100_rtc_pm_ops, sa1100_rtc_suspend,
+			sa1100_rtc_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id sa1100_rtc_dt_ids[] = {
+	{ .compatible = "mrvl,sa1100-rtc", },
+	{ .compatible = "mrvl,mmp-rtc", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, sa1100_rtc_dt_ids);
+#endif
+
+static struct platform_driver sa1100_rtc_driver = {
+	.probe		= sa1100_rtc_probe,
+	.remove		= sa1100_rtc_remove,
+	.driver		= {
+		.name	= "sa1100-rtc",
+		.pm	= &sa1100_rtc_pm_ops,
+		.of_match_table = of_match_ptr(sa1100_rtc_dt_ids),
+	},
+};
+
+module_platform_driver(sa1100_rtc_driver);
+
+MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
+MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:sa1100-rtc");