Do not power BBB/BBG via USB?

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Heinz Hummel

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Dec 23, 2016, 4:25:08 AM12/23/16
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Hello,

I have a BBB which is currently powered via USB and external power supply (and a similar BBG which is powered via USB and via external supply feed into VDD from connected cape).

Now when a user wants to do a full power cycle, all possible power sources have to be disconnected which can be somewhat complicated.

So my question: is there a possibility to disable power supply via USB? E.g. a soldering jumper which has to be opened? Or in case not - is there a possibility to permanently program the PMIC to not to power the board from USB?

Thanks!

Alex Hayman

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Dec 29, 2016, 2:59:47 AM12/29/16
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If you cut that trace on a BBB, then the BBB won't power itself up via USB.
BBB.png

Heinz Hummel

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Jan 2, 2017, 2:29:31 AM1/2/17
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Great - thanks! So there is no way to do that programmatically via PMIC?

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Alex Hayman

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Jan 2, 2017, 1:24:47 PM1/2/17
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I wasn't able to find one.  I believe it's built in to the hardware of http://www.ti.com/lit/ds/symlink/tps65217.pdf
Feel free to review and see if you come to the same conclusion that I did!

Cheers,
Alex


On Monday, January 2, 2017 at 2:29:31 AM UTC-5, Heinz Hummel wrote:
Great - thanks! So there is no way to do that programmatically via PMIC?
2016-12-29 8:59 GMT+01:00 Alex Hayman <al...@markforged.com>:
If you cut that trace on a BBB, then the BBB won't power itself up via USB.

On Friday, December 23, 2016 at 4:25:08 AM UTC-5, Heinz Hummel wrote:
Hello,

I have a BBB which is currently powered via USB and external power supply (and a similar BBG which is powered via USB and via external supply feed into VDD from connected cape).

Now when a user wants to do a full power cycle, all possible power sources have to be disconnected which can be somewhat complicated.

So my question: is there a possibility to disable power supply via USB? E.g. a soldering jumper which has to be opened? Or in case not - is there a possibility to permanently program the PMIC to not to power the board from USB?

Thanks!

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Micka

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Jan 3, 2017, 4:48:55 AM1/3/17
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The proper way is to modify the driver tps65217.c :

diff --git a/drivers/mfd/tps65217.c b/drivers/mfd/tps65217.c
index ca19130..a7ae900 100644
--- a/drivers/mfd/tps65217.c
+++ b/drivers/mfd/tps65217.c
@@ -253,6 +253,7 @@ static int tps65217_probe(struct i2c_client *client,
  bool status_off = false;
  int irq = -1, irq_gpio = -1;
  int ret;
+ bool usb_off = false;
 
  node = client->dev.of_node;
  if (node) {
@@ -265,7 +266,8 @@ static int tps65217_probe(struct i2c_client *client,
  chip_id = (unsigned long)match->data;
  status_off = of_property_read_bool(node,
  "ti,pmic-shutdown-controller");
-
+ usb_off = of_property_read_bool(node,
+                                        "ti,pmic-usb-off");
  /* at first try to get irq via OF method */
  irq = irq_of_parse_and_map(node, 0);
  if (irq <= 0) {
@@ -346,6 +348,16 @@ static int tps65217_probe(struct i2c_client *client,
  dev_warn(tps->dev, "unable to set the status OFF\n");
  }
 
+ if(usb_off){
+ ret = tps65217_set_bits(tps, TPS65217_REG_PPATH,
+                                TPS65217_PPATH_USB_PW_ENABLE, 0,
+                                TPS65217_PROTECT_NONE);
+                if (ret)
+                        dev_warn(tps->dev, "unable to set the USB power OFF\n");
+ else
+ dev_info(tps->dev, "set the USB power OFF\n");
+ }
+
  dev_info(tps->dev, "TPS65217 ID %#x version 1.%d\n",
  (version & TPS65217_CHIPID_CHIP_MASK) >> 4,
  version & TPS65217_CHIPID_REV_MASK);



It worked for me. ( the source is not committed yet because I didn't clean the code )


Le lun. 2 janv. 2017 à 08:29, Heinz Hummel <heinz.h...@gmail.com> a écrit :
Great - thanks! So there is no way to do that programmatically via PMIC?

2016-12-29 8:59 GMT+01:00 Alex Hayman <al...@markforged.com>:
If you cut that trace on a BBB, then the BBB won't power itself up via USB.

On Friday, December 23, 2016 at 4:25:08 AM UTC-5, Heinz Hummel wrote:
Hello,

I have a BBB which is currently powered via USB and external power supply (and a similar BBG which is powered via USB and via external supply feed into VDD from connected cape).

Now when a user wants to do a full power cycle, all possible power sources have to be disconnected which can be somewhat complicated.

So my question: is there a possibility to disable power supply via USB? E.g. a soldering jumper which has to be opened? Or in case not - is there a possibility to permanently program the PMIC to not to power the board from USB?

Thanks!

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Heinz Hummel

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Jan 3, 2017, 4:53:27 AM1/3/17
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Hello Micka,

is this permanent? Means does the PMIC know even after a power cycle to not to use USB power any more? As far as I understood the description of USB_EN in the PPATH register, this is reset to default values after power was turned off...

Thanks :-)


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Micka

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Jan 3, 2017, 5:05:06 AM1/3/17
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For my use case it's perfect:

the board is powered by a cape. we disabled power from USB, because the cape is not made to be powered by the beagle.

and yes you are right, the PPATH is hard reset to 1.

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chao...@yahoo.com

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Jan 3, 2017, 2:18:03 PM1/3/17
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--------------------------------------------
On Tue, 1/3/17, Micka <micka...@gmail.com> wrote:

Subject: Re: [beagleboard] Re: Do not power BBB/BBG via USB?
To: beagl...@googlegroups.com
Date: Tuesday, January 3, 2017, 12:04 PM
b/drivers/mfd/tps65217.c@@ -253,6 +253,7 @@ static
int tps65217_probe(struct i2c_client *client,  bool status_off =
false;  int irq = -1, irq_gpio
= -1;  int ret;+ bool usb_off =
false;   node =
client->dev.of_node;  if (node) {@@ -265,7 +266,8 @@ static
int tps65217_probe(struct i2c_client *client,  chip_id = (unsigned
long)match->data;  status_off =
of_property_read_bool(node,  "ti,pmic-shutdown-controller");-+ usb_off =
of_property_read_bool(node,+                
                     
 "ti,pmic-usb-off");  /* at first try to
get irq via OF method */  irq =
irq_of_parse_and_map(node, 0);  if (irq <= 0)
{@@ -346,6 +348,16 @@
static int tps65217_probe(struct i2c_client
*client,  dev_warn(tps->dev,
"unable to set the status OFF\n");  } + if(usb_off){+ ret =
tps65217_set_bits(tps, TPS65217_REG_PPATH,+                
               TPS65217_PPATH_USB_PW_ENABLE,
0,+                
               TPS65217_PROTECT_NONE);+              
 if (ret)+                
       dev_warn(tps->dev, "unable to set the USB
power OFF\n");+ else+ dev_info(tps->dev,
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