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imx233: rework early time power init

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The current code does hazardous tweaks to the power subsystem: indeed if one
boots with USB plugged and some stub powers on the DCDC switch, it will fail.
Indeed, a hardware bug prevents from going back to linear regulators (see
errata) so we cannot expect to reach a known state (linreg on, dcdc off)
on each configuration and in particular, powering down the 4p2 rail in
such a configuration will result in a power brownout.
This commit works around this issue by not touching the initial power
configuration until USB is (un)plugged, which are the best spots to get
known states.

Change-Id: I8741a3995df8ae61ca1c887a3ecb7903d0ac5136
This commit is contained in:
Amaury Pouly 2014-02-04 00:28:26 +01:00
parent 61dbeb60b7
commit c043ecf9e1
1 changed files with 15 additions and 26 deletions
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41
firmware/target/arm/imx233/powermgmt-imx233.c
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@ -58,35 +58,13 @@ void imx233_powermgmt_init(void)
BF_WR(POWER_VDDDCTRL, LINREG_OFFSET, 2);
BF_WR(POWER_VDDACTRL, LINREG_OFFSET, 2);
BF_WR(POWER_VDDIOCTRL, LINREG_OFFSET, 2);
/* enable DCDC (more efficient) */
BF_SET(POWER_5VCTRL, ENABLE_DCDC);
BF_CLR(POWER_5VCTRL, DCDC_XFER);
#else
BF_SET(POWER_5VCTRL, LINREG_OFFSET);
BF_SET(POWER_5VCTRL, EN_DCDC1);
BF_SET(POWER_5VCTRL, EN_DCDC2);
#endif
#if IMX233_SUBTARGET >= 3780
/* adjust arbitration between 4.2 and battery */
BF_WR(POWER_DCDC4P2, CMPTRIP, 0); /* 85% */
BF_WR(POWER_DCDC4P2, DROPOUT_CTRL, 0xe); /* select greater, 200 mV drop */
#endif
#if IMX233_SUBTARGET >= 3700
/* enable a few bits controlling the DC-DC as recommended by Freescale */
BF_SET(POWER_LOOPCTRL, TOGGLE_DIF);
BF_SET(POWER_LOOPCTRL, EN_CM_HYST);
BF_CLR(POWER_LOOPCTRL, EN_RCSCALE);
BF_SETV(POWER_LOOPCTRL, EN_RCSCALE, 1);
/* make sure we are in a known state: disable charger */
BF_SET(POWER_CHARGE, PWD_BATTCHRG);
#endif
#if IMX233_SUBTARGET >= 3780
/* make sure we are in a known state: disable 4p2 */
BF_WR(POWER_DCDC4P2, ENABLE_DCDC, 0);
BF_WR(POWER_DCDC4P2, ENABLE_4P2, 0);
BF_SET(POWER_5VCTRL, PWD_CHARGE_4P2);
#else
BF_SET(POWER_5VCTRL, LINREG_OFFSET);
#endif
}
@ -110,6 +88,7 @@ void charging_algorithm_step(void)
#if IMX233_SUBTARGET >= 3780
BF_WR(POWER_DCDC4P2, ENABLE_DCDC, 0);
BF_WR(POWER_DCDC4P2, ENABLE_4P2, 0);
BF_WR(POWER_5VCTRL, CHARGE_4P2_ILIMIT, 1);
BF_SET(POWER_5VCTRL, PWD_CHARGE_4P2);
#endif
charge_state = DISCHARGING;
@ -120,10 +99,14 @@ void charging_algorithm_step(void)
logf("pwrmgmt: discharging -> trickle");
logf("pwrmgmt: begin charging 4p2");
#if IMX233_SUBTARGET >= 3780
/* 5V has been detected: prepare 4.2V power rail for activation */
/* 5V has been detected: prepare 4.2V power rail for activation
* WARNING we can reach this situation when starting after Freescale bootloader
* or after RoLo in a state where the DCDC is running. In this case,
* we must *NOT* disable it or this will shutdown the device. This procedure
* is safe: it will never disable the DCDC and will not reduce the charge
* limit on the 4P2 rail. */
BF_WR(POWER_DCDC4P2, ENABLE_4P2, 1);
BF_SET(POWER_CHARGE, ENABLE_LOAD);
BF_WR(POWER_5VCTRL, CHARGE_4P2_ILIMIT, 1);
BF_CLR(POWER_5VCTRL, PWD_CHARGE_4P2);// FIXME: manual error ?
BF_WR(POWER_DCDC4P2, ENABLE_DCDC, 1);
#endif
@ -147,6 +130,12 @@ void charging_algorithm_step(void)
{
logf("pwrmgmt: enable dcdc and charger");
logf("pwrmgmt: trickle -> charging");
#if IMX233_SUBTARGET >= 3780
/* adjust arbitration between 4.2 and battery */
BF_WR(POWER_DCDC4P2, CMPTRIP, 0); /* 85% */
BF_WR(POWER_DCDC4P2, DROPOUT_CTRL, 0xe); /* select greater, 200 mV drop */
#endif
/* switch to DCDC */
BF_CLR(POWER_5VCTRL, DCDC_XFER);
BF_SET(POWER_5VCTRL, ENABLE_DCDC);
/* enable battery charging */