[PATCH] mfd: altera-sysmgr: enable raw spinlock feature for stratix10 platform

[Meng Li]

When booting up preempt rt kernel on stratix10 platform, there is
below calltrace:
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:969
in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 1, name: swapper/0
Preemption disabled at:
[<ffff8000100b25b0>] __setup_irq+0xe0/0x730
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.78-rt54-yocto-preempt-rt #1
Hardware name: SoCFPGA Stratix 10 SoCDK (DT)
Call trace:
......
 ___might_sleep+0x144/0x180
 rt_spin_lock+0x34/0x9c
 regmap_lock_spinlock+0x24/0x40
 regmap_write+0x48/0x84
 a10_eccmgr_irq_unmask+0x34/0x40
 ......
 altr_edac_a10_probe+0x16c/0x2b0
 platform_drv_probe+0x60/0xb4
 ......
 ret_from_fork+0x10/0x38

Because regmap_write is invoked under preemption disabled status, and
might trigger sleep. So, enable raw spinlock feature forcibly.

Fixes: f36e789a1f8d ("mfd: altera-sysmgr: Add SOCFPGA System Manager ")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Meng Li <Meng.Li@xxxxxxxxxxxxx>
---
 drivers/mfd/altera-sysmgr.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mfd/altera-sysmgr.c b/drivers/mfd/altera-sysmgr.c
index 591b300d9095..8aad5bbb13b3 100644
--- a/drivers/mfd/altera-sysmgr.c
+++ b/drivers/mfd/altera-sysmgr.c
@@ -83,6 +83,9 @@ static struct regmap_config altr_sysmgr_regmap_cfg = {
 	.fast_io = true,
 	.use_single_read = true,
 	.use_single_write = true,
+#ifdef CONFIG_PREEMPT_RT
+	.use_raw_spinlock = true,
+#endif
 };
 
 /**
-- 
2.17.1