ARM: mxs: fix VDDD brownout setting

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>
Acked-by: Marek Vasut <marex@denx.de>

diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c
index 42f3df2ac22862f842c524c11f423d1fd31ffe94..1972de81a8edd2f542814922fb5485ec7e52c409 100644 (file)
--- 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);