At the moment, the desired brownout is at 1.0V. However, this setting cannot be realized by hardware since we have only 3 bits to represent the voltage difference from the target value.
Target value is 1500 mV, brownout target is 1000 mV, voltage steps are 25 mV.
Register content calculation: (1500 [mV] - 1000 [mV]) / 25 [mV] = 20 (decimal) = 0x14
Register takes only 3 bits, that is 0x4.
But 0x4 * 25 [mV] = 100 [mV], that means that actual brownout level is 1500 [mV] - 100 [mV] = 1.4 V.
Minimum possible BO level is 1500 [mV] - 0x7 * 25 [mV] = 1315 [mV].
So lets use this value as desired BO value (which is also the same as FSL bootlets use).
Signed-off-by: Michael Heimpold mhei@heimpold.de Cc: Marek Vasut marex@denx.de Cc: Otavio Salvador otavio@ossystems.com.br Cc: Fabio Estevam fabio.estevam@freescale.com --- arch/arm/cpu/arm926ejs/mxs/spl_power_init.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c index 42f3df2..1972de8 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c @@ -1221,8 +1221,8 @@ void mxs_power_init(void) debug("SPL: Setting VDDIO to 3V3 (brownout @ 3v15)\n"); mxs_power_set_vddx(&mxs_vddio_cfg, 3300, 3150);
- debug("SPL: Setting VDDD to 1V5 (brownout @ 1v0)\n"); - mxs_power_set_vddx(&mxs_vddd_cfg, 1500, 1000); + debug("SPL: Setting VDDD to 1V5 (brownout @ 1v315)\n"); + mxs_power_set_vddx(&mxs_vddd_cfg, 1500, 1315); #ifdef CONFIG_MX23 debug("SPL: Setting mx23 VDDMEM to 2V5 (brownout @ 1v7)\n"); mxs_power_set_vddx(&mxs_vddmem_cfg, 2500, 1700);