[PATCH 3.5 90/90] misc: atmel_pwm: add deferred-probing support

[Luis Henriques]

3.5.7.27 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <jhovold at gmail.com>

commit 5c6d6fd1564138ad048564e48639f842714a90c6 upstream.

Two drivers (atmel-pwm-bl and leds-atmel-pwm) currently depend on the
atmel_pwm driver to have bound to any pwm-device before their devices
are probed.

Support deferred probing of such devices by making sure to return
-EPROBE_DEFER from pwm_channel_alloc when no pwm-device has yet been
bound.

Signed-off-by: Johan Hovold <jhovold at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/misc/atmel_pwm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/atmel_pwm.c b/drivers/misc/atmel_pwm.c
index 28f5aaa..2741108 100644
--- a/drivers/misc/atmel_pwm.c
+++ b/drivers/misc/atmel_pwm.c
@@ -90,8 +90,10 @@ int pwm_channel_alloc(int index, struct pwm_channel *ch)
 	unsigned long	flags;
 	int		status = 0;
 
-	/* insist on PWM init, with this signal pinned out */
-	if (!pwm || !(pwm->mask & 1 << index))
+	if (!pwm)
+		return -EPROBE_DEFER;
+
+	if (!(pwm->mask & 1 << index))
 		return -ENODEV;
 
 	if (index < 0 || index >= PWM_NCHAN || !ch)
-- 
1.8.3.2