Re: [PATCH] extcon-usb-gpio: add enable pin support

From: Sergei Shtylyov
Date: Fri Dec 11 2015 - 13:33:35 EST


On 12/11/2015 06:53 AM, Rob Herring wrote:

Sometimes there's a real OTG chip behind the USB ID signal mapped to a GPIO
pin: in my case it's Maxim Integrated MAX3355E which integrates Vbus charge
pump and comparators and passes thru the ID signal from an OTG connector.
This chip also has the SHDN# pin which should be driven high for the normal
operation and low to save power; it is connected to a GPIO pin as well on,
hence we'll have to teach the driver to parse the new optional device tree
property, "enable-gpio"...

Some wierd spacing going on here.

I like my text properly filling up the given columns. What's the problem? :-)

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>

The patch is against the 'extcon-next' branch of the 'extcon.git' repo.

Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt | 3 +++
drivers/extcon/extcon-usb-gpio.c | 5 +++++
2 files changed, 8 insertions(+)

Index: extcon/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
--- extcon.orig/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
+++ extcon/Documentation/devicetree/bindings/extcon/extcon-usb-gpio.txt
@@ -7,6 +7,9 @@ Required properties:
- compatible: Should be "linux,extcon-usb-gpio"
- id-gpio: gpio for USB ID pin. See gpio binding.

+Optional properties:
+- enable-gpio: gpio for the enable pin. See gpio binding.

Use -gpios as -gpio is deprecated.

Didn't know, thanks.

Index: extcon/drivers/extcon/extcon-usb-gpio.c
--- extcon.orig/drivers/extcon/extcon-usb-gpio.c
+++ extcon/drivers/extcon/extcon-usb-gpio.c
@@ -99,6 +100,8 @@ static int usb_extcon_probe(struct platf
return -ENOMEM;

info->dev = dev;
+ info->enable_gpiod = devm_gpiod_get_optional(&pdev->dev, "enable",
info->id_gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN);
if (IS_ERR(info->id_gpiod)) {
dev_err(dev, "failed to get ID GPIO\n");
@@ -155,6 +158,8 @@ static int usb_extcon_remove(struct plat


+ gpiod_set_value_cansleep(info->enable_gpiod, 0);

Shouldn't you support either polarity?

The gpiolib does that for me -- devm_gpiod_get_optional() should read the polarity from DT.


MBR, Sergei

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