linux-kernel - [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

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Date:   Fri,  5 Oct 2018 08:53:00 +0200
From:   Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
To:     Jeffrey Hugo <jhugo@...eaurora.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Timur Tabi <timur@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
Subject: [PATCH v5 3/3] gpiolib: Show correct direction from the beginning

Current code assumes that the direction is input if direction_input
function is set.
This might not be the case on GPIOs with programmable direction.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
---
 drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 907019b67a58..e016b22658ff 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1349,20 +1349,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
-	for (i = 0; i < chip->ngpio; i++) {
-		struct gpio_desc *desc = &gdev->descs[i];
-
-		desc->gdev = gdev;
-
-		/* REVISIT: most hardware initializes GPIOs as inputs (often
-		 * with pullups enabled) so power usage is minimized. Linux
-		 * code should set the gpio direction first thing; but until
-		 * it does, and in case chip->get_direction is not set, we may
-		 * expose the wrong direction in sysfs.
-		 */
-		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
-	}
-
 #ifdef CONFIG_PINCTRL
 	INIT_LIST_HEAD(&gdev->pin_ranges);
 #endif
@@ -1391,6 +1377,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 	if (status)
 		goto err_remove_chip;
 
+	for (i = 0; i < chip->ngpio; i++) {
+		struct gpio_desc *desc = &gdev->descs[i];
+
+		desc->gdev = gdev;
+
+		if (chip->get_direction && gpiochip_line_is_valid(chip, i))
+			desc->flags = !chip->get_direction(chip, i) ?
+					(1 << FLAG_IS_OUT) : 0;
+		else
+			desc->flags = !chip->direction_input ?
+					(1 << FLAG_IS_OUT) : 0;
+	}
+
 	acpi_gpiochip_add(chip);
 
 	machine_gpiochip_add(chip);
-- 
2.19.0