[PATCH 1/3] [v2] Revert "gpio: set up initial state from .get_direction()"

Timur Tabi
2017-12-13T18:30:25Z

This reverts commit 72d3200061776264941be1b5a9bb8e926b3b30a5.

We cannot blindly query the direction of all GPIOs when the pins are
first registered. The get_direction callback normally triggers a
read/write to hardware, but we shouldn't be touching the hardware for
an individual GPIO until after it's been properly claimed.

Signed-off-by: Timur Tabi <timur@codeaurora.org>
---
drivers/gpio/gpiolib.c | 31 +++++++------------------------
1 file changed, 7 insertions(+), 24 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 641a5eb552cb..168dd831551d 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1207,31 +1207,14 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
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.
- */
-
- if (chip->get_direction) {
- /*
- * If we have .get_direction, set up the initial
- * direction flag from the hardware.
- */
- int dir = chip->get_direction(chip, i);

- if (!dir)
- set_bit(FLAG_IS_OUT, &desc->flags);
- } else if (!chip->direction_input) {
- /*
- * If the chip lacks the .direction_input callback
- * we logically assume all lines are outputs.
- */
- set_bit(FLAG_IS_OUT, &desc->flags);
- }
+ /* 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