[PATCH 3.12 17/19] misc: atmel_pwm: add deferred-probing support

Greg Kroah-Hartman
2013-11-18T18:40:11Z

From: Johan Hovold <jhovold@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@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/misc/atmel_pwm.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/misc/atmel_pwm.c
+++ b/drivers/misc/atmel_pwm.c
@@ -90,8 +90,10 @@ int pwm_channel_alloc(int index, struct
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)