This patch disables the square wave output of the M41T62 RTC used on Canyonlands & Glacier. Here the explanation:
The serial real-time clock part used in the design is an STMicro M41T62. This part has a full-time 32KHz square wave output that is connected to the TmrClk input to the processor. The default state for this square wave output is enabled so the output runs continuously when the board is powered normally and also from the battery. The TmrClk input to the processor goes to ground when the power is removed from the board/processor, and therefore the running square wave output is driving ground which drains the battery quickly.
Signed-off-by: Stefan Roese sr@denx.de --- board/amcc/canyonlands/canyonlands.c | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/board/amcc/canyonlands/canyonlands.c b/board/amcc/canyonlands/canyonlands.c index 4e3b349..5bf4b18 100644 --- a/board/amcc/canyonlands/canyonlands.c +++ b/board/amcc/canyonlands/canyonlands.c @@ -22,6 +22,7 @@ #include <ppc440.h> #include <libfdt.h> #include <fdt_support.h> +#include <i2c.h> #include <asm/processor.h> #include <asm/io.h> #include <asm/mmu.h> @@ -393,6 +394,7 @@ int misc_init_r(void) u32 sdr0_srst1 = 0; u32 eth_cfg; u32 pvr = get_pvr(); + u8 val;
/* * Set EMAC mode/configuration (GMII, SGMII, RGMII...). @@ -420,6 +422,15 @@ int misc_init_r(void) sdr0_srst1 &= ~SDR0_SRST1_AHB; mtsdr(SDR0_SRST1, sdr0_srst1);
+ /* + * RTC/M41T62: + * Disable square wave output: Batterie will be drained + * quickly, when this output is not disabled + */ + val = i2c_reg_read(CFG_I2C_RTC_ADDR, 0xa); + val &= ~0x40; + i2c_reg_write(CFG_I2C_RTC_ADDR, 0xa, val); + return 0; }