linux-kernel - [PATCH v2 3/6] extcon-gpio: Add support for active-low presence detect pins

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Date:	Tue, 10 Sep 2013 19:25:13 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	Chanwoo Choi <cw00.choi@...sung.com>
Cc:	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	Rob Herring <rob.herring@...xeda.com>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Stephen Warren <swarren@...dotorg.org>,
	Ian Campbell <ian.campbell@...rix.com>,
	MyungJoo Ham <myungjoo.ham@...sung.com>,
	Grant Likely <grant.likely@...aro.org>
Subject: [PATCH v2 3/6] extcon-gpio: Add support for active-low presence
 detect pins


Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
v2: Document gpio_active_low variable in gpio_extcon_platform_data
    Rewrite active-low logic to be easier to read.

 drivers/extcon/extcon-gpio.c       |    4 ++++
 include/linux/extcon/extcon-gpio.h |    5 +++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/extcon/extcon-gpio.c b/drivers/extcon/extcon-gpio.c
index 862743b..8491f86 100644
--- a/drivers/extcon/extcon-gpio.c
+++ b/drivers/extcon/extcon-gpio.c
@@ -34,6 +34,7 @@
 struct gpio_extcon_data {
 	struct extcon_dev edev;
 	unsigned gpio;
+	bool gpio_active_low;
 	const char *state_on;
 	const char *state_off;
 	int irq;
@@ -49,6 +50,8 @@ static void gpio_extcon_work(struct work_struct *work)
 			     work);
 
 	state = gpio_get_value(data->gpio);
+	if (data->gpio_active_low)
+		state = !state;
 	extcon_set_state(&data->edev, state);
 }
 
@@ -96,6 +99,7 @@ static int gpio_extcon_probe(struct platform_device *pdev)
 
 	extcon_data->edev.name = pdata->name;
 	extcon_data->gpio = pdata->gpio;
+	extcon_data->gpio_active_low = pdata->gpio_active_low;
 	extcon_data->state_on = pdata->state_on;
 	extcon_data->state_off = pdata->state_off;
 	if (pdata->state_on && pdata->state_off)
diff --git a/include/linux/extcon/extcon-gpio.h b/include/linux/extcon/extcon-gpio.h
index 2d8307f..51ef15c 100644
--- a/include/linux/extcon/extcon-gpio.h
+++ b/include/linux/extcon/extcon-gpio.h
@@ -27,6 +27,10 @@
  * struct gpio_extcon_platform_data - A simple GPIO-controlled extcon device.
  * @name	The name of this GPIO extcon device.
  * @gpio	Corresponding GPIO.
+ * @gpio_active_low:
+ * 		Boolean describing whether gpio active state is 1 or 0
+ * 		If true, low state of gpio means active.
+ * 		If false, high state of gpio means active.
  * @debounce	Debounce time for GPIO IRQ in ms.
  * @irq_flags	IRQ Flags (e.g., IRQF_TRIGGER_LOW).
  * @state_on	print_state is overriden with state_on if attached. If Null,
@@ -41,6 +45,7 @@
 struct gpio_extcon_platform_data {
 	const char *name;
 	unsigned gpio;
+	bool gpio_active_low;
 	unsigned long debounce;
 	unsigned long irq_flags;
 
-- 
1.7.9.7

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