Free Runner won't turn on

[Andy Green]

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Somebody in the thread at some point said:
| On Mon, 15 Sep 2008 08:54:07 +0100
| Andy Green <andy at openmoko.com> wrote:
|
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|> Somebody in the thread at some point said:
|>
|> | no. shutdown from holding power button seems not to be working
|> anymore | (just freezed with blinking red light).
|>
|> Blinking red light means kernel panic.  It'd be great to have a
|> backtrace from it but you'd need a debug board.
|
| Oh, blinking == kernel panic that is interesting...
| As I wrote already: sometimes I need to remove the
| battery multiple times before it came back, the interesting thing is:
| I remove the battery put it back in after some seconds, power it on
| (with or without AUX), phone does not boot *BUT* starts with
| blinking again -> can u-Boot panic too?
|
| Anyway, I do not have a debug board, sorry.

U-Boot doesn't have panic code, but it does have a bunch of code
intending to stop you booting if your battery is low.

#define	SAFE_POWER_MILLIVOLT	3400

...

static int battery_is_good(void)
{
	/* battery is absent -> don't boot */
	if (pcf50633_reg_read(PCF50633_REG_BVMCTL) & 1)
		return 0;

	/* we could try to boot, but we'll probably die on the way */
	if (pcf50633_read_battvolt() < SAFE_POWER_MILLIVOLT)
		return 0;

	return 1;
}

...

static void wait_for_power(void)
{
	int seconds = 0;
	int led_cycle = 1;

	while (1) {
		poll_charger();

		/* track what the time-critical udc callback allows us */
		if (pcf50633_usb_last_maxcurrent != udc_usb_maxcurrent)
			pcf50633_usb_maxcurrent(udc_usb_maxcurrent);

		/* we have plenty of external power -> try to boot */
		if (pcf50633_usb_last_maxcurrent >= 500)
			break;

		/* cpu_idle sits with interrupts off destroying USB operation
		 * don't run it unless we are in trouble
		 */
		if (!battery_is_good())
			cpu_idle();
		else
			udelay(1000000);

		if (neo1973_new_second()) {
			/*
			 * Probe the battery only if the current LED cycle is
			 * about to end, so that it had time to discharge.
			 */
			if (led_cycle && battery_is_good())
				break;
			seconds++;
		}

		led_cycle = !seconds || (seconds & 1);

		/*
		 * Blink the AUX LED, unless it's broken (which is the case in
		 * GTA02v5 it is) and draws excessive current, which we just
		 * can't afford in this delicate situation.
		 */
		if (gta02_revision > 5)
			neo1973_led(GTA02_LED_AUX_RED, led_cycle);

		/* alternate LED and charger cycles */
		pcf50633_reg_set_bit_mask(PCF50633_REG_MBCC1, 1, !led_cycle);
	}

	/* switch off the AUX LED */
	neo1973_led(GTA02_LED_AUX_RED, 0);
}

If you have A6 PCB revision NAND U-Boot (NOR does not have this) will
slowly blink the light telling you it thinks your battery is too low to
be going on with if it feels it is <3.4V.  Kernel panic blink is much
faster, several times a second.

Welcome to the exciting world of pcf50633 power behaviours, U-Boot
chapter.  In the future, we throw all this out and just do it in Linux.

- -Andy
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