rtc: rtc-sh: Support 4-digit year on SH7705/SH7710/SH7712.

All SH-4 parts have a 4-digit year, while the SH-3 parts typically
only use a 2-digit one. The SH7705, SH7710, and SH7712 SH-3 parts
however opted to extend it to 4-digit and still look and act like
an SH-3 RTC in all other ways.

This adds a capability flag (RTC_CAP_4_DIGIT_YEAR) that these
corner-case CPU subtypes can set in their platform data and cleans
up some of the ifdef mess in the driver as a result.

Reported-by: Markus Brunner <super.firetwister@gmail.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 33 insertions, 18 deletions

diff --git a/drivers/rtc/rtc-sh.c b/drivers/rtc/rtc-sh.c
index 93ee05eeaeba..78277a118b67 100644
--- a/drivers/rtc/rtc-sh.c
+++ b/drivers/rtc/rtc-sh.c
@@ -1,7 +1,7 @@
 /*
  * SuperH On-Chip RTC Support
  *
- * Copyright (C) 2006  Paul Mundt
+ * Copyright (C) 2006, 2007  Paul Mundt
  * Copyright (C) 2006  Jamie Lenehan
  *
  * Based on the old arch/sh/kernel/cpu/rtc.c by:
@@ -23,16 +23,19 @@
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
 #include <linux/io.h>
+#include <asm/rtc.h>
 
 #define DRV_NAME        "sh-rtc"
-#define DRV_VERSION     "0.1.2"
+#define DRV_VERSION     "0.1.3"
 
 #ifdef CONFIG_CPU_SH3
 #define rtc_reg_size            sizeof(u16)
 #define RTC_BIT_INVERTED        0       /* No bug on SH7708, SH7709A */
+#define RTC_DEF_CAPABILITIES    0UL
 #elif defined(CONFIG_CPU_SH4)
 #define rtc_reg_size            sizeof(u32)
 #define RTC_BIT_INVERTED        0x40    /* bug on SH7750, SH7750S */
+#define RTC_DEF_CAPABILITIES    RTC_CAP_4_DIGIT_YEAR
 #endif
 
 #define RTC_REG(r)      ((r) * rtc_reg_size)
@@ -80,6 +83,7 @@ struct sh_rtc {
         struct rtc_device *rtc_dev;
         spinlock_t lock;
         int rearm_aie;
+        unsigned long capabilities;     /* See asm-sh/rtc.h for cap bits */
 };
 
 static irqreturn_t sh_rtc_interrupt(int irq, void *dev_id)
@@ -319,14 +323,14 @@ static int sh_rtc_read_time(struct device *dev, struct rtc_time *tm)
                 tm->tm_mday     = BCD2BIN(readb(rtc->regbase + RDAYCNT));
                 tm->tm_mon      = BCD2BIN(readb(rtc->regbase + RMONCNT)) - 1;
 
-#if defined(CONFIG_CPU_SH4)
-                yr  = readw(rtc->regbase + RYRCNT);
-                yr100 = BCD2BIN(yr >> 8);
-                yr &= 0xff;
-#else
-                yr  = readb(rtc->regbase + RYRCNT);
-                yr100 = BCD2BIN((yr == 0x99) ? 0x19 : 0x20);
-#endif
+                if (rtc->capabilities & RTC_CAP_4_DIGIT_YEAR) {
+                        yr  = readw(rtc->regbase + RYRCNT);
+                        yr100 = BCD2BIN(yr >> 8);
+                        yr &= 0xff;
+                } else {
+                        yr  = readb(rtc->regbase + RYRCNT);
+                        yr100 = BCD2BIN((yr == 0x99) ? 0x19 : 0x20);
+                }
 
                 tm->tm_year = (yr100 * 100 + BCD2BIN(yr)) - 1900;
 
@@ -375,14 +379,14 @@ static int sh_rtc_set_time(struct device *dev, struct rtc_time *tm)
         writeb(BIN2BCD(tm->tm_mday), rtc->regbase + RDAYCNT);
         writeb(BIN2BCD(tm->tm_mon + 1), rtc->regbase + RMONCNT);
 
-#ifdef CONFIG_CPU_SH3
-        year = tm->tm_year % 100;
-        writeb(BIN2BCD(year), rtc->regbase + RYRCNT);
-#else
-        year = (BIN2BCD((tm->tm_year + 1900) / 100) << 8) |
-                BIN2BCD(tm->tm_year % 100);
-        writew(year, rtc->regbase + RYRCNT);
-#endif
+        if (rtc->capabilities & RTC_CAP_4_DIGIT_YEAR) {
+                year = (BIN2BCD((tm->tm_year + 1900) / 100) << 8) |
+                        BIN2BCD(tm->tm_year % 100);
+                writew(year, rtc->regbase + RYRCNT);
+        } else {
+                year = tm->tm_year % 100;
+                writeb(BIN2BCD(year), rtc->regbase + RYRCNT);
+        }
 
         /* Start RTC */
         tmp = readb(rtc->regbase + RCR2);
@@ -589,6 +593,17 @@ static int __devinit sh_rtc_probe(struct platform_device *pdev)
                 goto err_badmap;
         }
 
+        rtc->capabilities = RTC_DEF_CAPABILITIES;
+        if (pdev->dev.platform_data) {
+                struct sh_rtc_platform_info *pinfo = pdev->dev.platform_data;
+
+                /*
+                 * Some CPUs have special capabilities in addition to the
+                 * default set. Add those in here.
+                 */
+                rtc->capabilities |= pinfo->capabilities;
+        }
+
         platform_set_drvdata(pdev, rtc);
 
         return 0;