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Message-ID: <20140507002421.GA19711@kahuna>
Date: Tue, 6 May 2014 19:24:21 -0500
From: Nishanth Menon <nm@...com>
To: Felipe Balbi <balbi@...com>
CC: Russell King <linux@....linux.org.uk>,
Tony Lindgren <tony@...mide.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
<dbaryshkov@...il.com>,
Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
<dwmw2@...radead.org>,
Linux ARM Kernel Mailing List
<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] power: twl4030_charger: clear IRQs after handling them
On 16:00-20140425, Felipe Balbi wrote:
> On Fri, Apr 25, 2014 at 03:58:10PM -0500, Nishanth Menon wrote:
> > On 04/16/2014 11:35 AM, Tony Lindgren wrote:
> > > * Felipe Balbi <balbi@...com> [140416 08:18]:
> > >> TRM says we *must* write 1 to each bit we're handling
> > >> in order to clear the IRQ status and bring IRQ line
> > >> low. This patch implements that.
> > >>
> > >> Signed-off-by: Felipe Balbi <balbi@...com>
> > >> ---
> > >>
> > >> Russell, I don't have HW to test, but this should
> > >> solve the problem you saw when not using battery
> > >> with Zoom board. Let me know if it doesn't.
> > >
> > > BTW, looks like we're enabling BCI automatically in twl4030.dtsi
> > > while the legacy booting does not have TWL_COMMON_PDATA_BCI
> > > enabled for LDP. Anyways, for LDP BCI should be enabled for
> > > sure, that's the only way to power at least the earlier LDP
> > > revisions.
> > >
> > I picked up https://patchwork.kernel.org/patch/4002371/ for testing.
> >
> > Unfortunately, it does not seem to work in my tests:
>
> alright, I'll have a look after I get this other issue out of the way.
> Probably not until next week.
I dug a bit more into this earlier today. It makes a little sense
considering that TWL4030 was created in a world where mobile devices did
not consider battery was hot pluggable entity..
Long story short:
a) the BCI interrupt status register is read-on-clear (see
drivers/mfd/twl4030-irq.c set_cor is set to true for bci) - so the patch
https://patchwork.kernel.org/patch/4002371/ is practically a NOP.
b) BATSTS is a result of MADC monitoring the thermistor and is
continually generated. I tried a bunch of tricks that I could come up
with to try to do a hotplug support, but either we have infinite
interrupts (due to regeneration of event) or I loose detection ability.
So, to keep things simple I created the following patch that seems to
handle:
a) no battery connected, powered off charger - bci disabled
b) battery connected, powered off charger - bci active
c) battery connected, no charger - bci active
note: if battery was connected, and booted and we hotplug battery out,
we still have the spam of messages.. that is a seperate patch
(basically do an orderly shutdown - I cant think of anything else we
could possible do there)
Let me know your views.. if this approach is fine, I can post out formal
patches for the same.
-----8<----
>From 9474c7f37990b97c57b72eed917b9153595133ff Mon Sep 17 00:00:00 2001
From: Nishanth Menon <nm@...com>
Date: Tue, 6 May 2014 19:02:49 -0500
Subject: [PATCH] power: twl4030_charger: detect battery presence prior to
enabling charger
TWL4030's Battery Charger seems to be designed for non-hotpluggable
batteries.
If battery is not present in the system, BATSTS is always set with the
expectation that software will take actions to move to a required safe
state (could be power down or disable various charger paths).
It does not seem possible even by manipulating the edge detection
of the event (using BCIEDR2 register) to have a consistent hotplug
handling. This seems to be the result of BATSTS interrupt generated
when the thermistor of the battery pack is disconnected from the
dedicated ADIN1 pin. Clearing the status just results in the status
being regenerated by the monitoring ADC(MADC) and disabling the
edges of event just makes hotplug no longer function. The only
other option is to disable the detection of the MADC by disabling
BCIMFEN4::BATSTSMCHGEN (battery presence detector) - but then, we can
never again detect battery reconnection.
So, detect battery presence based on precharge(which is hardware
automatic state) or default main charger configuration at the time of
probe and enable charger logic only if battery was present.
Reported-by: Russell King <linux@....linux.org.uk>
Signed-off-by: Nishanth Menon <nm@...com>
---
drivers/power/twl4030_charger.c | 43 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 42 insertions(+), 1 deletion(-)
diff --git a/drivers/power/twl4030_charger.c b/drivers/power/twl4030_charger.c
index f141088..14ec220 100644
--- a/drivers/power/twl4030_charger.c
+++ b/drivers/power/twl4030_charger.c
@@ -28,10 +28,13 @@
#define TWL4030_BCIICHG 0x08
#define TWL4030_BCIVAC 0x0a
#define TWL4030_BCIVBUS 0x0c
+#define TWL4030_BCIMFSTS3 0x0F
#define TWL4030_BCIMFSTS4 0x10
#define TWL4030_BCICTL1 0x23
#define TWL4030_BB_CFG 0x12
+#define TWL4030_BCIMFSTS1 0x01
+
#define TWL4030_BCIAUTOWEN BIT(5)
#define TWL4030_CONFIG_DONE BIT(4)
#define TWL4030_BCIAUTOUSB BIT(1)
@@ -52,6 +55,9 @@
#define TWL4030_BBISEL_500uA 0x02
#define TWL4030_BBISEL_1000uA 0x03
+#define TWL4030_BATSTSPCHG BIT(2)
+#define TWL4030_BATSTSMCHG BIT(6)
+
/* BCI interrupts */
#define TWL4030_WOVF BIT(0) /* Watchdog overflow */
#define TWL4030_TMOVF BIT(1) /* Timer overflow */
@@ -145,6 +151,34 @@ static int twl4030bci_read_adc_val(u8 reg)
}
/*
+ * Check if Battery Pack was present
+ */
+static int twl4030_is_battery_present(struct twl4030_bci *bci)
+{
+ int ret;
+ u8 val = 0;
+
+ /* Battery presence in Main charge? */
+ ret = twl_i2c_read_u8(TWL_MODULE_MAIN_CHARGE, &val, TWL4030_BCIMFSTS3);
+ if (ret)
+ return ret;
+ if (val & TWL4030_BATSTSMCHG)
+ return 0;
+
+ /*
+ * OK, It could be that bootloader did not enable main charger,
+ * pre-charge is h/w auto. So, Battery presence in Pre-charge?
+ */
+ ret = twl_i2c_read_u8(TWL4030_MODULE_PRECHARGE, &val, TWL4030_BCIMFSTS1);
+ if (ret)
+ return ret;
+ if (val & TWL4030_BATSTSPCHG)
+ return 0;
+
+ return -ENODEV;
+}
+
+/*
* Check if VBUS power is present
*/
static int twl4030_bci_have_vbus(struct twl4030_bci *bci)
@@ -541,8 +575,14 @@ static int __init twl4030_bci_probe(struct platform_device *pdev)
bci->irq_chg = platform_get_irq(pdev, 0);
bci->irq_bci = platform_get_irq(pdev, 1);
- platform_set_drvdata(pdev, bci);
+ /* Only proceed further *IF* battery is physically present */
+ ret = twl4030_is_battery_present(bci);
+ if (ret) {
+ dev_crit(&pdev->dev, "Battery was not detected:%d\n", ret);
+ goto fail_no_battery;
+ }
+ platform_set_drvdata(pdev, bci);
bci->ac.name = "twl4030_ac";
bci->ac.type = POWER_SUPPLY_TYPE_MAINS;
bci->ac.properties = twl4030_charger_props;
@@ -633,6 +673,7 @@ fail_chg_irq:
fail_register_usb:
power_supply_unregister(&bci->ac);
fail_register_ac:
+fail_no_battery:
kfree(bci);
return ret;
--
1.7.9.5
--
Regards,
Nishanth Menon
--
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