i2c: gpio: OF gpio code does not handle defered probe case

When using device-tree and the i2c-gpio driver is called before the
GPIO node has been probed then it needs to correctly defer the probe
instead of returning a permanent error that the gpio numbers are not
valid.

This fixes the following error:
	/i2c@2: invalid GPIO pins, sda=-517/scl=-517

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
(cherry picked from commit 40e7b1153a39e49715a1f75c654d8da66e3638c4)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
(cherry picked from commit 1582407d7809605bc223583d35515829c2ab0071)

Signed-off-by: Damian Hobson-Garcia <dhobsong@igel.co.jp>

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index d9f7e18..02d2d4a 100644 (file)
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -94,6 +94,9 @@ static int of_i2c_gpio_get_pins(struct device_node *np,
        *sda_pin = of_get_gpio(np, 0);
        *scl_pin = of_get_gpio(np, 1);
 
+       if (*sda_pin == -EPROBE_DEFER || *scl_pin == -EPROBE_DEFER)
+               return -EPROBE_DEFER;
+
        if (!gpio_is_valid(*sda_pin) || !gpio_is_valid(*scl_pin)) {
                pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
                       np->full_name, *sda_pin, *scl_pin);