rtc: ds1307: factor out century bit handling

The driver has lots of places with chip-specific code what doesn't
necessarily facilitate maintenance.

Let's describe chip-specific differences in century bit handling
in struct chip_desc to improve this.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 9b4106a..9226752 100644 (file)
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -136,6 +136,9 @@ struct chip_desc {
        unsigned                alarm:1;
        u16                     nvram_offset;
        u16                     nvram_size;
+       u8                      century_reg;
+       u8                      century_enable_bit;
+       u8                      century_bit;
        u16                     trickle_charger_reg;
        u8                      trickle_charger_setup;
        u8                      (*do_trickle_setup)(struct ds1307 *, uint32_t,
@@ -151,6 +154,8 @@ static struct chip_desc chips[last_ds_type] = {
        },
        [ds_1337] = {
                .alarm          = 1,
+               .century_reg    = DS1307_REG_MONTH,
+               .century_bit    = DS1337_BIT_CENTURY,
        },
        [ds_1338] = {
                .nvram_offset   = 8,
@@ -158,10 +163,15 @@ static struct chip_desc chips[last_ds_type] = {
        },
        [ds_1339] = {
                .alarm          = 1,
+               .century_reg    = DS1307_REG_MONTH,
+               .century_bit    = DS1337_BIT_CENTURY,
                .trickle_charger_reg = 0x10,
                .do_trickle_setup = &do_trickle_setup_ds1339,
        },
        [ds_1340] = {
+               .century_reg    = DS1307_REG_HOUR,
+               .century_enable_bit = DS1340_BIT_CENTURY_EN,
+               .century_bit    = DS1340_BIT_CENTURY,
                .trickle_charger_reg = 0x08,
        },
        [ds_1388] = {
@@ -169,6 +179,8 @@ static struct chip_desc chips[last_ds_type] = {
        },
        [ds_3231] = {
                .alarm          = 1,
+               .century_reg    = DS1307_REG_MONTH,
+               .century_bit    = DS1337_BIT_CENTURY,
        },
        [rx_8130] = {
                .alarm          = 1,
@@ -328,6 +340,7 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 {
        struct ds1307   *ds1307 = dev_get_drvdata(dev);
        int             tmp, ret;
+       const struct chip_desc *chip = &chips[ds1307->type];
 
        /* read the RTC date and time registers all at once */
        ret = regmap_bulk_read(ds1307->regmap, ds1307->offset, ds1307->regs, 7);
@@ -355,22 +368,9 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t)
        t->tm_mon = bcd2bin(tmp) - 1;
        t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
 
-#ifdef CONFIG_RTC_DRV_DS1307_CENTURY
-       switch (ds1307->type) {
-       case ds_1337:
-       case ds_1339:
-       case ds_3231:
-               if (ds1307->regs[DS1307_REG_MONTH] & DS1337_BIT_CENTURY)
-                       t->tm_year += 100;
-               break;
-       case ds_1340:
-               if (ds1307->regs[DS1307_REG_HOUR] & DS1340_BIT_CENTURY)
-                       t->tm_year += 100;
-               break;
-       default:
-               break;
-       }
-#endif
+       if (ds1307->regs[chip->century_reg] & chip->century_bit &&
+           IS_ENABLED(CONFIG_RTC_DRV_DS1307_CENTURY))
+               t->tm_year += 100;
 
        dev_dbg(dev, "%s secs=%d, mins=%d, "
                "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
@@ -385,6 +385,7 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t)
 static int ds1307_set_time(struct device *dev, struct rtc_time *t)
 {
        struct ds1307   *ds1307 = dev_get_drvdata(dev);
+       const struct chip_desc *chip = &chips[ds1307->type];
        int             result;
        int             tmp;
        u8              *buf = ds1307->regs;
@@ -395,24 +396,14 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)
                t->tm_hour, t->tm_mday,
                t->tm_mon, t->tm_year, t->tm_wday);
 
-#ifdef CONFIG_RTC_DRV_DS1307_CENTURY
        if (t->tm_year < 100)
                return -EINVAL;
 
-       switch (ds1307->type) {
-       case ds_1337:
-       case ds_1339:
-       case ds_3231:
-       case ds_1340:
-               if (t->tm_year > 299)
-                       return -EINVAL;
-       default:
-               if (t->tm_year > 199)
-                       return -EINVAL;
-               break;
-       }
+#ifdef CONFIG_RTC_DRV_DS1307_CENTURY
+       if (t->tm_year > (chip->century_bit ? 299 : 199))
+               return -EINVAL;
 #else
-       if (t->tm_year < 100 || t->tm_year > 199)
+       if (t->tm_year > 199)
                return -EINVAL;
 #endif
 
@@ -427,19 +418,12 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)
        tmp = t->tm_year - 100;
        buf[DS1307_REG_YEAR] = bin2bcd(tmp);
 
-       switch (ds1307->type) {
-       case ds_1337:
-       case ds_1339:
-       case ds_3231:
-               if (t->tm_year > 199)
-                       buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
-               break;
-       case ds_1340:
-               buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN;
-               if (t->tm_year > 199)
-                       buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY;
-               break;
-       case mcp794xx:
+       if (chip->century_enable_bit)
+               buf[chip->century_reg] |= chip->century_enable_bit;
+       if (t->tm_year > 199 && chip->century_bit)
+               buf[chip->century_reg] |= chip->century_bit;
+
+       if (ds1307->type == mcp794xx) {
                /*
                 * these bits were cleared when preparing the date/time
                 * values and need to be set again before writing the
@@ -447,9 +431,6 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)
                 */
                buf[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
                buf[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
-               break;
-       default:
-               break;
        }
 
        dev_dbg(dev, "%s: %7ph\n", "write", buf);