From 72d840c8f7273272f8a992524b63a03a396d081f Mon Sep 17 00:00:00 2001
From: Jian Hu <jian.hu@amlogic.com>
Date: Fri, 28 Jul 2017 14:41:05 +0800
Subject: [PATCH] pwm: fix kernel crash using spinlock_t lock

PD#148269: fix kernel panic when hibenating

1.Using mutex lock instead of spinlock_t lock.
2.Clk_prepare_enable might sleep could not use
  spinlock_t lock.
3.Add spinlock_t lock for clock_mux.
4.Panic message:
	BUG: sleeping function called from invalid context at
	kernel/locking/mutex.c:97
	in_atomic(): 1, irqs_disabled(): 128, pid: 2501, name: sh
	Preemption disabled at:[   69.935889@1] [<ffffff80097af728>]
	meson_pwm_apply+0x48/0x398

Change-Id: Ib2f42c4d757d1bb4bd8e4df0f90f7924be2fa799
Signed-off-by: Jian Hu <jian.hu@amlogic.com>
---
 drivers/amlogic/pwm/pwm_meson.c   | 14 +++++---------
 include/linux/amlogic/pwm_meson.h |  5 +++--
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/amlogic/pwm/pwm_meson.c b/drivers/amlogic/pwm/pwm_meson.c
index bcd477d..76e2893 100644
--- a/drivers/amlogic/pwm/pwm_meson.c
+++ b/drivers/amlogic/pwm/pwm_meson.c
@@ -61,8 +61,6 @@
 #include <linux/amlogic/pwm_meson.h>
 #include <linux/of_device.h>
 
-
-
 struct meson_pwm_channel {
 	unsigned int hi;
 	unsigned int lo;
@@ -75,8 +73,6 @@ struct meson_pwm_channel {
 	struct clk *clk;
 };
 
-
-
 struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
 {
 	return container_of(chip, struct meson_pwm, chip);
@@ -327,13 +323,12 @@ static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 {
 	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
 	struct meson_pwm *meson = to_meson_pwm(chip);
-	unsigned long flags;
 	int err = 0;
 
 	if (!state)
 		return -EINVAL;
 
-	spin_lock_irqsave(&meson->lock, flags);
+	mutex_lock(&meson->lock);
 
 	if (!state->enabled) {
 		meson_pwm_disable(meson, pwm->hwpwm);
@@ -373,7 +368,7 @@ static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	}
 
 unlock:
-	spin_unlock_irqrestore(&meson->lock, flags);
+	mutex_unlock(&meson->lock);
 	return err;
 
 }
@@ -510,7 +505,7 @@ static int meson_pwm_init_channels(struct meson_pwm *meson,
 		channel->mux.shift = mux_reg_shifts[i];
 		channel->mux.mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
 		channel->mux.flags = 0;
-		channel->mux.lock = &meson->lock;
+		channel->mux.lock = &meson->pwm_lock;
 		channel->mux.table = NULL;
 		channel->mux.hw.init = &init;
 
@@ -561,7 +556,8 @@ static int meson_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(meson->base))
 		return PTR_ERR(meson->base);
 
-	spin_lock_init(&meson->lock);
+	mutex_init(&meson->lock);
+	spin_lock_init(&meson->pwm_lock);
 	meson->chip.dev = &pdev->dev;
 	meson->chip.ops = &meson_pwm_ops;
 	meson->chip.base = -1;
diff --git a/include/linux/amlogic/pwm_meson.h b/include/linux/amlogic/pwm_meson.h
index 415c84e..8142869 100644
--- a/include/linux/amlogic/pwm_meson.h
+++ b/include/linux/amlogic/pwm_meson.h
@@ -30,6 +30,7 @@
 #include <linux/pwm.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include <linux/time.h>
 #include <linux/clk.h>
 #include <linux/of_address.h>
@@ -118,8 +119,8 @@ struct meson_pwm {
 	struct meson_pwm_data *data;
 	struct meson_pwm_variant variant;
 	u32 inverter_mask;
-	spinlock_t lock;
-
+	struct mutex lock;
+	spinlock_t pwm_lock;
 	unsigned int clk_mask;
 };
 
-- 
2.7.4