linux-kernel - [PATCH v2 1/2] rtc: m48t59: Use platform

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Message-Id: <fb25eb97521363ab8a18d2fd499cb4c76209cebf.1728340717.git.fthain@linux-m68k.org>
Date: Tue, 08 Oct 2024 09:38:37 +1100
From: Finn Thain <fthain@...ux-m68k.org>
To: "David S. Miller" <davem@...emloft.net>,
    Andreas Larsson <andreas@...sler.com>,
    Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: Daniel Palmer <daniel@...f.com>,
    Michael Pavone <pavone@...rodev.com>,
    linux-m68k@...ts.linux-m68k.org,
    linux-rtc@...r.kernel.org,
    sparclinux@...r.kernel.org,
    linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] rtc: m48t59: Use platform_data struct for year offset
 value

Instead of hard-coded values and ifdefs, store the year offset in the
platform_data struct.

Tested-by: Daniel Palmer <daniel@...f.com>
Signed-off-by: Finn Thain <fthain@...ux-m68k.org>
---
I tested this for regressions using qemu-system-sparc64.
Also, Daniel tested the RTC functionality on his MVME147 system.
---
 arch/sparc/kernel/time_32.c |  1 +
 arch/sparc/kernel/time_64.c |  1 +
 drivers/rtc/rtc-m48t59.c    | 26 ++++----------------------
 include/linux/rtc/m48t59.h  |  3 +++
 4 files changed, 9 insertions(+), 22 deletions(-)

diff --git a/arch/sparc/kernel/time_32.c b/arch/sparc/kernel/time_32.c
index 08bbdc458596..578fd0d49f30 100644
--- a/arch/sparc/kernel/time_32.c
+++ b/arch/sparc/kernel/time_32.c
@@ -255,6 +255,7 @@ static void mostek_write_byte(struct device *dev, u32 ofs, u8 val)
 static struct m48t59_plat_data m48t59_data = {
 	.read_byte = mostek_read_byte,
 	.write_byte = mostek_write_byte,
+	.yy_offset = 68,
 };
 
 /* resource is set at runtime */
diff --git a/arch/sparc/kernel/time_64.c b/arch/sparc/kernel/time_64.c
index 60f1c8cc5363..b32f27f929d1 100644
--- a/arch/sparc/kernel/time_64.c
+++ b/arch/sparc/kernel/time_64.c
@@ -544,6 +544,7 @@ static void mostek_write_byte(struct device *dev, u32 ofs, u8 val)
 static struct m48t59_plat_data m48t59_data = {
 	.read_byte	= mostek_read_byte,
 	.write_byte	= mostek_write_byte,
+	.yy_offset	= 68,
 };
 
 static struct platform_device m48t59_rtc = {
diff --git a/drivers/rtc/rtc-m48t59.c b/drivers/rtc/rtc-m48t59.c
index f0f6b9b6daec..4c339fb45b5c 100644
--- a/drivers/rtc/rtc-m48t59.c
+++ b/drivers/rtc/rtc-m48t59.c
@@ -71,7 +71,7 @@ static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
 	/* Issue the READ command */
 	M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 
-	tm->tm_year	= bcd2bin(M48T59_READ(M48T59_YEAR));
+	tm->tm_year	= bcd2bin(M48T59_READ(M48T59_YEAR)) + pdata->yy_offset;
 	/* tm_mon is 0-11 */
 	tm->tm_mon	= bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
 	tm->tm_mday	= bcd2bin(M48T59_READ(M48T59_MDAY));
@@ -82,10 +82,6 @@ static int m48t59_rtc_read_time(struct device *dev, struct rtc_time *tm)
 		dev_dbg(dev, "Century bit is enabled\n");
 		tm->tm_year += 100;	/* one century */
 	}
-#ifdef CONFIG_SPARC
-	/* Sun SPARC machines count years since 1968 */
-	tm->tm_year += 68;
-#endif
 
 	tm->tm_wday	= bcd2bin(val & 0x07);
 	tm->tm_hour	= bcd2bin(M48T59_READ(M48T59_HOUR) & 0x3F);
@@ -106,12 +102,7 @@ static int m48t59_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	struct m48t59_private *m48t59 = dev_get_drvdata(dev);
 	unsigned long flags;
 	u8 val = 0;
-	int year = tm->tm_year;
-
-#ifdef CONFIG_SPARC
-	/* Sun SPARC machines count years since 1968 */
-	year -= 68;
-#endif
+	int year = tm->tm_year - pdata->yy_offset;
 
 	dev_dbg(dev, "RTC set time %04d-%02d-%02d %02d/%02d/%02d\n",
 		year + 1900, tm->tm_mon, tm->tm_mday,
@@ -162,11 +153,7 @@ static int m48t59_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 	/* Issue the READ command */
 	M48T59_SET_BITS(M48T59_CNTL_READ, M48T59_CNTL);
 
-	tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR));
-#ifdef CONFIG_SPARC
-	/* Sun SPARC machines count years since 1968 */
-	tm->tm_year += 68;
-#endif
+	tm->tm_year = bcd2bin(M48T59_READ(M48T59_YEAR)) + pdata->yy_offset;
 	/* tm_mon is 0-11 */
 	tm->tm_mon = bcd2bin(M48T59_READ(M48T59_MONTH)) - 1;
 
@@ -197,12 +184,7 @@ static int m48t59_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 	struct rtc_time *tm = &alrm->time;
 	u8 mday, hour, min, sec;
 	unsigned long flags;
-	int year = tm->tm_year;
-
-#ifdef CONFIG_SPARC
-	/* Sun SPARC machines count years since 1968 */
-	year -= 68;
-#endif
+	int year = tm->tm_year - pdata->yy_offset;
 
 	/* If no irq, we don't support ALARM */
 	if (m48t59->irq == NO_IRQ)
diff --git a/include/linux/rtc/m48t59.h b/include/linux/rtc/m48t59.h
index 9465d5405fe2..6ac1eb2cbeac 100644
--- a/include/linux/rtc/m48t59.h
+++ b/include/linux/rtc/m48t59.h
@@ -56,6 +56,9 @@ struct m48t59_plat_data {
 	void __iomem *ioaddr;
 	/* offset to RTC registers, automatically set according to the type */
 	unsigned int offset;
+
+	/* YY digits (in RTC) are offset, i.e. year is 1900 + yy_offset + YY */
+	time64_t yy_offset;
 };
 
 #endif /* _LINUX_RTC_M48T59_H_ */
-- 
2.39.5