[PATCHv4] RTC:driver for Cortina's SOC

[PATCHv4] RTC:driver for Cortina's SOC

[Hans Ulli Kroll]

this is the fourth round of including the RTC driver for
Gemini SoC.

changes from v1

v2:
- usage of readl/write
- spaces around *
- line wrapping at open parenthesis.
- add MAINTANERS for driver
v3:
- spaces around * (again)
- line wrapping at open parenthesis (again)
- add depends on ARCH_GEMINI found by Paul
v4:
- COMPILE_TEST requested by Arnd
- some typos found by Joe
- add HAS_IOMEM found by Geert

Ulli

From: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Subject: [PATCHv4] RTC:driver for Cortina's SOC
In-Reply-To: 

[PATCHv4 1/1] RTC:driver for Cortina's SOC

[Hans Ulli Kroll]

Driver for the on chip RTC found on Cortina's SoC Gemini.

Signed-off-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
---
 MAINTAINERS              |   3 +-
 drivers/rtc/Kconfig      |  11 +++
 drivers/rtc/Makefile     |   1 +
 drivers/rtc/rtc-gemini.c | 191 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 205 insertions(+), 1 deletion(-)
 create mode 100644 drivers/rtc/rtc-gemini.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 1622775..2e91f68 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -975,9 +975,10 @@ S:	Maintained
 ARM/CORTINA SYSTEMS GEMINI ARM ARCHITECTURE
 M:	Hans Ulli Kroll <ulli.kroll@googlemail.com>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
-T:	git git://git.berlios.de/gemini-board
+T:	git git://github.com/ulli-kroll/linux.git
 S:	Maintained
 F:	arch/arm/mach-gemini/
+F:	drivers/rtc/rtc-gemini.c
 
 ARM/CSR SIRFPRIMA2 MACHINE SUPPORT
 M:	Barry Song <baohua@kernel.org>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 6149ae0..392dd13 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1362,6 +1362,17 @@ config RTC_DRV_ARMADA38X
 	  This driver can also be built as a module. If so, the module
 	  will be called armada38x-rtc.
 
+config RTC_DRV_GEMINI
+	tristate "Gemini SoC RTC"
+	depends on ARCH_GEMINI || COMPILE_TEST
+	depends on HAS_IOMEM 
+	help
+	  If you say Y here you will get support for the
+	  RTC found on Gemini SoC's.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called rtc-gemini.
+
 config RTC_DRV_PS3
 	tristate "PS3 RTC"
 	depends on PPC_PS3
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index c31731c..0fd6e22 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_RTC_DRV_EFI)	+= rtc-efi.o
 obj-$(CONFIG_RTC_DRV_EM3027)	+= rtc-em3027.o
 obj-$(CONFIG_RTC_DRV_EP93XX)	+= rtc-ep93xx.o
 obj-$(CONFIG_RTC_DRV_FM3130)	+= rtc-fm3130.o
+obj-$(CONFIG_RTC_DRV_GEMINI)	+= rtc-gemini.o
 obj-$(CONFIG_RTC_DRV_GENERIC)	+= rtc-generic.o
 obj-$(CONFIG_RTC_DRV_HID_SENSOR_TIME) += rtc-hid-sensor-time.o
 obj-$(CONFIG_RTC_DRV_HYM8563)	+= rtc-hym8563.o
diff --git a/drivers/rtc/rtc-gemini.c b/drivers/rtc/rtc-gemini.c
new file mode 100644
index 0000000..7cec8f4
--- /dev/null
+++ b/drivers/rtc/rtc-gemini.c
@@ -0,0 +1,191 @@
+/*
+ *  Gemini OnChip RTC
+ *
+ *  Copyright (C) 2009 Janos Laube <janos.dev@gmail.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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Original code for older kernel 2.6.15 are from Stormlinksemi
+ * first update from Janos Laube for > 2.6.29 kernels
+ *
+ * checkpatch fixes and usage of rtc-lib code
+ * Hans Ulli Kroll <ulli.kroll@googlemail.com>
+ */
+
+#include <linux/rtc.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <mach/hardware.h>
+
+#define DRV_NAME        "rtc-gemini"
+#define DRV_VERSION     "0.2"
+
+MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
+MODULE_DESCRIPTION("RTC driver for Gemini SoC");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);
+
+struct gemini_rtc {
+	struct rtc_device	*rtc_dev;
+	void __iomem		*rtc_base;
+	int			rtc_irq;
+};
+
+enum gemini_rtc_offsets {
+	GEMINI_RTC_SECOND	= 0x00,
+	GEMINI_RTC_MINUTE	= 0x04,
+	GEMINI_RTC_HOUR		= 0x08,
+	GEMINI_RTC_DAYS		= 0x0C,
+	GEMINI_RTC_ALARM_SECOND	= 0x10,
+	GEMINI_RTC_ALARM_MINUTE	= 0x14,
+	GEMINI_RTC_ALARM_HOUR	= 0x18,
+	GEMINI_RTC_RECORD	= 0x1C,
+	GEMINI_RTC_CR		= 0x20
+};
+
+static irqreturn_t gemini_rtc_interrupt(int irq, void *dev)
+{
+	return IRQ_HANDLED;
+}
+
+/*
+ * Looks like the RTC in the Gemini SoC is (totaly) broken
+ * We can't read/write directly the time from RTC registers.
+ * We must do some "offset" calculation to get the real time
+ *
+ * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does
+ * the same thing, without the rtc-lib.c calls.
+ */
+
+static int gemini_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct gemini_rtc *rtc = dev_get_drvdata(dev);
+
+	unsigned int  days, hour, min, sec;
+	unsigned long offset, time;
+
+	sec  = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
+	min  = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
+	hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
+	days = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
+	offset = readl(rtc->rtc_base + GEMINI_RTC_RECORD);
+
+	time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
+
+	rtc_time_to_tm(time, tm);
+
+	return 0;
+}
+
+static int gemini_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct gemini_rtc *rtc = dev_get_drvdata(dev);
+	unsigned int sec, min, hour, day;
+	unsigned long offset, time;
+
+	if (tm->tm_year >= 2148)	/* EPOCH Year + 179 */
+		return -EINVAL;
+
+	rtc_tm_to_time(tm, &time);
+
+	sec = readl(rtc->rtc_base + GEMINI_RTC_SECOND);
+	min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE);
+	hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR);
+	day = readl(rtc->rtc_base + GEMINI_RTC_DAYS);
+
+	offset = time - (day * 86400 + hour * 3600 + min * 60 + sec);
+
+	writel(offset, rtc->rtc_base + GEMINI_RTC_RECORD);
+	writel(0x01, rtc->rtc_base + GEMINI_RTC_CR);
+
+	return 0;
+}
+
+static struct rtc_class_ops gemini_rtc_ops = {
+	.read_time     = gemini_rtc_read_time,
+	.set_time      = gemini_rtc_set_time,
+};
+
+static int gemini_rtc_probe(struct platform_device *pdev)
+{
+	struct gemini_rtc *rtc;
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	int ret;
+
+	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
+	if (unlikely(!rtc))
+		return -ENOMEM;
+	platform_set_drvdata(pdev, rtc);
+
+	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!res) {
+		ret = -ENODEV;
+		goto err_mem;
+	}
+	rtc->rtc_irq = res->start;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENODEV;
+		goto err_mem;
+	}
+	rtc->rtc_base =	devm_ioremap(&pdev->dev, res->start,
+				    res->end - res->start + 1);
+
+	ret = request_irq(rtc->rtc_irq, gemini_rtc_interrupt,
+			 IRQF_SHARED, pdev->name, dev);
+	if (unlikely(ret))
+		goto err_mem;
+
+	rtc->rtc_dev =	rtc_device_register(pdev->name, dev,
+					   &gemini_rtc_ops, THIS_MODULE);
+	if (likely(IS_ERR(rtc->rtc_dev))) {
+		ret = PTR_ERR(rtc->rtc_dev);
+		goto err_irq;
+	}
+	return 0;
+
+err_irq:
+	free_irq(rtc->rtc_irq, dev);
+
+err_mem:
+	kfree(rtc);
+	return ret;
+}
+
+static int gemini_rtc_remove(struct platform_device *pdev)
+{
+	struct gemini_rtc *rtc = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+
+	free_irq(rtc->rtc_irq, dev);
+	rtc_device_unregister(rtc->rtc_dev);
+	platform_set_drvdata(pdev, NULL);
+	kfree(rtc);
+
+	return 0;
+}
+
+static struct platform_driver gemini_rtc_driver = {
+	.driver		= {
+		.name	= DRV_NAME,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= gemini_rtc_probe,
+	.remove		= gemini_rtc_remove,
+};
+
+module_platform_driver_probe(gemini_rtc_driver, gemini_rtc_probe);
+
-- 
2.4.0