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From: Tomeu Vizoso <tomeu.vizoso@collabora.com>
To: linux-kernel@vger.kernel.org
Cc: linux-gpio@vger.kernel.org, devicetree@vger.kernel.org,
	linux-tegra@vger.kernel.org,
	Tomeu Vizoso <tomeu.vizoso@collabora.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Grant Likely <grant.likely@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Alexandre Courbot <gnurou@gmail.com>
Subject: [PATCH v2 1/3] gpio: defer probe if pinctrl cannot be found
Date: Tue, 14 Jul 2015 10:29:54 +0200	[thread overview]
Message-ID: <1436862596-27730-2-git-send-email-tomeu.vizoso@collabora.com> (raw)
In-Reply-To: <1436862596-27730-1-git-send-email-tomeu.vizoso@collabora.com>

When an OF node has a pin range for its GPIOs, return -EPROBE_DEFER if
the pin controller isn't available.

Otherwise, the GPIO range wouldn't be set at all unless the pin
controller probed always before the GPIO chip.

With this change, the probe of the GPIO chip will be deferred and will
be retried at a later point, hopefully once the pin controller has been
registered and probed already.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
---

Changes in v2:
- Don't defer probe if the pinctrl node is disabled

 drivers/gpio/gpiolib-of.c | 27 ++++++++++++++++++---------
 drivers/gpio/gpiolib.c    |  5 ++++-
 include/linux/of_gpio.h   |  4 ++--
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 9a0ec48a4737..4e1f73b9136a 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -338,7 +338,7 @@ void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
 EXPORT_SYMBOL(of_mm_gpiochip_remove);
 
 #ifdef CONFIG_PINCTRL
-static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
+static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
 {
 	struct device_node *np = chip->of_node;
 	struct of_phandle_args pinspec;
@@ -349,7 +349,7 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 	struct property *group_names;
 
 	if (!np)
-		return;
+		return 0;
 
 	group_names = of_find_property(np, group_names_propname, NULL);
 
@@ -361,7 +361,7 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 
 		pctldev = of_pinctrl_get(pinspec.np);
 		if (!pctldev)
-			break;
+			return -EPROBE_DEFER;
 
 		if (pinspec.args[2]) {
 			if (group_names) {
@@ -381,7 +381,7 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 					pinspec.args[1],
 					pinspec.args[2]);
 			if (ret)
-				break;
+				return ret;
 		} else {
 			/* npins == 0: special range */
 			if (pinspec.args[1]) {
@@ -411,32 +411,41 @@ static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
 			ret = gpiochip_add_pingroup_range(chip, pctldev,
 						pinspec.args[0], name);
 			if (ret)
-				break;
+				return ret;
 		}
 	}
+
+	return 0;
 }
 
 #else
-static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
+static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
 #endif
 
-void of_gpiochip_add(struct gpio_chip *chip)
+int of_gpiochip_add(struct gpio_chip *chip)
 {
+	int status;
+
 	if ((!chip->of_node) && (chip->dev))
 		chip->of_node = chip->dev->of_node;
 
 	if (!chip->of_node)
-		return;
+		return 0;
 
 	if (!chip->of_xlate) {
 		chip->of_gpio_n_cells = 2;
 		chip->of_xlate = of_gpio_simple_xlate;
 	}
 
-	of_gpiochip_add_pin_range(chip);
+	status = of_gpiochip_add_pin_range(chip);
+	if (status)
+		return status;
+
 	of_node_get(chip->of_node);
 
 	of_gpiochip_scan_hogs(chip);
+
+	return 0;
 }
 
 void of_gpiochip_remove(struct gpio_chip *chip)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index bf4bd1d120c3..a8cab335c0cc 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -287,7 +287,10 @@ int gpiochip_add(struct gpio_chip *chip)
 	INIT_LIST_HEAD(&chip->pin_ranges);
 #endif
 
-	of_gpiochip_add(chip);
+	status = of_gpiochip_add(chip);
+	if (status)
+		goto err_remove_chip;
+
 	acpi_gpiochip_add(chip);
 
 	status = gpiochip_sysfs_register(chip);
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index 69dbe312b11b..f3191828f037 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -54,7 +54,7 @@ extern int of_mm_gpiochip_add(struct device_node *np,
 			      struct of_mm_gpio_chip *mm_gc);
 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
 
-extern void of_gpiochip_add(struct gpio_chip *gc);
+extern int of_gpiochip_add(struct gpio_chip *gc);
 extern void of_gpiochip_remove(struct gpio_chip *gc);
 extern int of_gpio_simple_xlate(struct gpio_chip *gc,
 				const struct of_phandle_args *gpiospec,
@@ -76,7 +76,7 @@ static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
 	return -ENOSYS;
 }
 
-static inline void of_gpiochip_add(struct gpio_chip *gc) { }
+static inline int of_gpiochip_add(struct gpio_chip *gc) { return 0; }
 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
 
 #endif /* CONFIG_OF_GPIO */
-- 
2.4.3


  reply	other threads:[~2015-07-14  8:32 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-14  8:29 [PATCH v2 0/3] Have Tegra's GPIO chip depend explicitly on the pinctrl device Tomeu Vizoso
2015-07-14  8:29 ` Tomeu Vizoso [this message]
2015-07-24  9:15   ` [PATCH v2 1/3] gpio: defer probe if pinctrl cannot be found Tomeu Vizoso
2015-07-28 10:23   ` Linus Walleij
2015-07-14  8:29 ` [PATCH v2 2/3] pinctrl: tegra: Only set the gpio range if needed Tomeu Vizoso
2015-08-06 13:40   ` Tomeu Vizoso
2015-08-13 12:55     ` Linus Walleij
2015-07-14  8:29 ` [PATCH v2 3/3] ARM: tegra: Add gpio-ranges property Tomeu Vizoso
2015-08-13 14:33 ` [PATCH v2 0/3] Have Tegra's GPIO chip depend explicitly on the pinctrl device Thierry Reding

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