rtc, rv3029: add trickle charger support.

Signed-off-by: Heiko Schocher <hs@denx.de>
Acked-by: Detlev Zundel <dzu@denx.de>

diff --git a/README b/README
index beb1cbb1bc65948cfd946a217a5b3dd76d9f3443..cdbb9de02c68c8ef8ec94be2d2748463b00d2486 100644 (file)
--- a/README
+++ b/README
@@ -748,6 +748,8 @@ The following options need to be configured:
                CONFIG_RTC_ISL1208      - use Intersil ISL1208 RTC
                CONFIG_RTC_MAX6900      - use Maxim, Inc. MAX6900 RTC
                CONFIG_SYS_RTC_DS1337_NOOSC     - Turn off the OSC output for DS1337
+               CONFIG_SYS_RV3029_TCR   - enable trickle charger on
+                                         RV3029 RTC.
 
                Note that if the RTC uses I2C, then the I2C interface
                must also be configured. See I2C Support, below.

diff --git a/drivers/rtc/rv3029.c b/drivers/rtc/rv3029.c
index 3ebc76887465db606f458ebabc65ae16f3da1239..e01216844ad2f282186dd78ae4ea4594f559ab6e 100644 (file)
--- a/drivers/rtc/rv3029.c
+++ b/drivers/rtc/rv3029.c
@@ -25,6 +25,12 @@
 #include <i2c.h>
 #include <rtc.h>
 
+#define RTC_RV3029_CTRL1       0x00
+#define RTC_RV3029_CTRL1_EERE  (1 << 3)
+
+#define RTC_RV3029_CTRL_STATUS 0x03
+#define RTC_RV3029_CTRLS_EEBUSY        (1 << 7)
+
 #define RTC_RV3029_CTRL_RESET  0x04
 #define RTC_RV3029_CTRL_SYS_R  (1 << 4)
 
@@ -42,6 +48,12 @@
 #define RV3029C2_REG_HR_12_24          (1 << 6)  /* 24h/12h mode */
 #define RV3029C2_REG_HR_PM             (1 << 5)  /* PM/AM bit in 12h mode */
 
+#define RTC_RV3029_EEPROM_CTRL 0x30
+#define RTC_RV3029_TRICKLE_1K  (1 << 4)
+#define RTC_RV3029_TRICKLE_5K  (1 << 5)
+#define RTC_RV3029_TRICKLE_20K (1 << 6)
+#define RTC_RV3029_TRICKLE_80K (1 << 7)
+
 int rtc_get( struct rtc_time *tmp )
 {
        int     ret;
@@ -113,6 +125,41 @@ int rtc_set( struct rtc_time *tmp )
        return 0;
 }
 
+/* sets EERE-Bit  (automatic EEPROM refresh) */
+static void set_eere_bit(int state)
+{
+       int ret;
+       unsigned char reg_ctrl1;
+
+       ret = i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_RV3029_CTRL1, 1,
+                       &reg_ctrl1, 1);
+
+       if (state)
+               reg_ctrl1 |= RTC_RV3029_CTRL1_EERE;
+       else
+               reg_ctrl1 &= (~RTC_RV3029_CTRL1_EERE);
+
+       ret = i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_RV3029_CTRL1, 1,
+               &reg_ctrl1, 1);
+}
+
+/* waits until EEPROM page is no longer busy (times out after 10ms*loops) */
+static int wait_eebusy(int loops)
+{
+       int i, ret;
+       unsigned char ctrl_status;
+
+       for (i = 0; i < loops; i++) {
+               ret = i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_RV3029_CTRL_STATUS,
+                       1, &ctrl_status, 1);
+
+               if ((ctrl_status & RTC_RV3029_CTRLS_EEBUSY) == 0)
+                       break;
+               udelay(10000);
+       }
+       return i;
+}
+
 void rtc_reset (void)
 {
        int     ret;
@@ -121,4 +168,44 @@ void rtc_reset (void)
        buf[0] = RTC_RV3029_CTRL_SYS_R;
        ret = i2c_write(CONFIG_SYS_I2C_RTC_ADDR, RTC_RV3029_CTRL_RESET, 1,
                        buf, 1);
+
+#if defined(CONFIG_SYS_RV3029_TCR)
+       /*
+        * because EEPROM_CTRL register is in EEPROM page it is necessary to
+        * disable automatic EEPROM refresh and check if EEPROM is busy
+        * before EEPORM_CTRL register may be accessed
+        */
+       set_eere_bit(0);
+       wait_eebusy(100);
+       /* read current trickle charger setting */
+       ret = i2c_read(CONFIG_SYS_I2C_RTC_ADDR, RTC_RV3029_EEPROM_CTRL,
+                       1, buf, 1);
+       /* enable automatic EEPROM refresh again */
+       set_eere_bit(1);
+
+       /*
+        * to minimize EEPROM access write trickle charger setting only if it
+        * differs from current value
+        */
+       if ((buf[0] & 0xF0) != CONFIG_SYS_RV3029_TCR) {
+               buf[0] = (buf[0] & 0x0F) | CONFIG_SYS_RV3029_TCR;
+               /*
+                * write trickle charger setting (disable autom. EEPROM
+                * refresh and wait until EEPROM is idle)
+                */
+               set_eere_bit(0);
+               wait_eebusy(100);
+               ret = i2c_write(CONFIG_SYS_I2C_RTC_ADDR,
+                               RTC_RV3029_EEPROM_CTRL, 1, buf, 1);
+               /*
+                * it is necessary to wait 10ms before EEBUSY-Bit may be read
+                * (this is not documented in the data sheet yet, but the
+                * manufacturer recommends it)
+                */
+               udelay(10000);
+               /* wait until EEPROM write access is finished */
+               wait_eebusy(100);
+               set_eere_bit(1);
+       }
+#endif
 }