[RFC PATCH] cpuidle: fix device->state_count handling

[Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>]

Use device->state_count instead of driver->state_count in
cpuidle_play_dead(), ladder_select_state() and menu_select().

This allows cpuidle drivers to override maximum allowable
state number for a given device, which is what some cpuidle
drivers would like to do (i.e. EXYNOS cpuidle driver).

Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Amit Daniel Kachhap <amit.daniel@samsung.com>
---
Alternatively, we can make EXYNOS cpuidle driver work without
device->state_count (at a some tiny performance cost?). This
would allow us to remove device->state_count completely as it
is not needed by any other cpuidle driver currently (AFAICS).

 drivers/cpuidle/cpuidle.c          |    2 +-
 drivers/cpuidle/governors/ladder.c |    2 +-
 drivers/cpuidle/governors/menu.c   |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

Index: b/drivers/cpuidle/cpuidle.c
===================================================================
--- a/drivers/cpuidle/cpuidle.c	2013-08-08 14:36:09.611488750 +0200
+++ b/drivers/cpuidle/cpuidle.c	2013-08-08 14:39:02.291486116 +0200
@@ -57,7 +57,7 @@ int cpuidle_play_dead(void)
 		return -ENODEV;
 
 	/* Find lowest-power state that supports long-term idle */
-	for (i = drv->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--)
+	for (i = dev->state_count - 1; i >= CPUIDLE_DRIVER_STATE_START; i--)
 		if (drv->states[i].enter_dead)
 			return drv->states[i].enter_dead(dev, i);
 
Index: b/drivers/cpuidle/governors/ladder.c
===================================================================
--- a/drivers/cpuidle/governors/ladder.c	2013-08-08 14:36:09.611488750 +0200
+++ b/drivers/cpuidle/governors/ladder.c	2013-08-08 14:39:02.299486116 +0200
@@ -87,7 +87,7 @@ static int ladder_select_state(struct cp
 		last_residency = last_state->threshold.promotion_time + 1;
 
 	/* consider promotion */
-	if (last_idx < drv->state_count - 1 &&
+	if (last_idx < dev->state_count - 1 &&
 	    !drv->states[last_idx + 1].disabled &&
 	    !dev->states_usage[last_idx + 1].disable &&
 	    last_residency > last_state->threshold.promotion_time &&
Index: b/drivers/cpuidle/governors/menu.c
===================================================================
--- a/drivers/cpuidle/governors/menu.c	2013-08-08 14:36:09.611488750 +0200
+++ b/drivers/cpuidle/governors/menu.c	2013-08-08 14:39:02.299486116 +0200
@@ -312,7 +312,7 @@ static int menu_select(struct cpuidle_dr
 	 * Find the idle state with the lowest power while satisfying
 	 * our constraints.
 	 */
-	for (i = CPUIDLE_DRIVER_STATE_START; i < drv->state_count; i++) {
+	for (i = CPUIDLE_DRIVER_STATE_START; i < dev->state_count; i++) {
 		struct cpuidle_state *s = &drv->states[i];
 		struct cpuidle_state_usage *su = &dev->states_usage[i];