linux-kernel - [PATCH 1/3] regulator-core: support multiple enable GPIO

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Date:	Thu, 10 Jan 2013 09:46:10 +0000
From:	"Kim, Milo" <Milo.Kim@...com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
CC:	Axel Lin <axel.lin@...ics.com>, "Girdwood, Liam" <lrg@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/3] regulator-core: support multiple enable GPIO

 This patch fixes a limitation in case of multiple enable pin usages.
 Several regulators can be enabled/disabled at the same time by one
 shared GPIO pin.
 If specific GPIO pin is already used, then skip requesting the GPIO.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@...com>
---
 drivers/regulator/core.c |   21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index de47880..21b4247 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1456,6 +1456,23 @@ void devm_regulator_put(struct regulator *regulator)
 }
 EXPORT_SYMBOL_GPL(devm_regulator_put);
 
+static int regulator_enable_gpio_request(struct regulator_dev *rdev,
+					const struct regulator_config *config)
+{
+	struct regulator_dev *r;
+	int gpio = config->ena_gpio;
+
+	list_for_each_entry(r, &regulator_list, list) {
+		if (r->ena_gpio == gpio) {
+			rdev_info(rdev, "GPIO %d is already used\n", gpio);
+			return 0;
+		}
+	}
+
+	return gpio_request_one(gpio, GPIOF_DIR_OUT | config->ena_gpio_flags,
+				rdev_get_name(rdev));
+}
+
 static int _regulator_do_enable(struct regulator_dev *rdev)
 {
 	int ret, delay;
@@ -3420,9 +3437,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
 	dev_set_drvdata(&rdev->dev, rdev);
 
 	if (config->ena_gpio && gpio_is_valid(config->ena_gpio)) {
-		ret = gpio_request_one(config->ena_gpio,
-				       GPIOF_DIR_OUT | config->ena_gpio_flags,
-				       rdev_get_name(rdev));
+		ret = regulator_enable_gpio_request(rdev, config);
 		if (ret != 0) {
 			rdev_err(rdev, "Failed to request enable GPIO%d: %d\n",
 				 config->ena_gpio, ret);
-- 
1.7.9.5


Best Regards,
Milo


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