[PATCH] spmi: pmic-arb: Set lockdep class for hierarchical irq domains

[Stephen Boyd <swboyd@chromium.org>]

I see the following lockdep splat in the qcom pinctrl driver when
attempting to suspend the device.

 WARNING: possible recursive locking detected
 5.4.11 #3 Tainted: G        W
 --------------------------------------------
 cat/3074 is trying to acquire lock:
 ffffff81f49804c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94

 but task is already holding lock:
 ffffff81f1cc10c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&irq_desc_lock_class);
   lock(&irq_desc_lock_class);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 6 locks held by cat/3074:
  #0: ffffff81f01d9420 (sb_writers#7){.+.+}, at: vfs_write+0xd0/0x1a4
  #1: ffffff81bd7d2080 (&of->mutex){+.+.}, at: kernfs_fop_write+0x12c/0x1fc
  #2: ffffff81f4c322f0 (kn->count#337){.+.+}, at: kernfs_fop_write+0x134/0x1fc
  #3: ffffffe411a41d60 (system_transition_mutex){+.+.}, at: pm_suspend+0x108/0x348
  #4: ffffff81f1c5e970 (&dev->mutex){....}, at: __device_suspend+0x168/0x41c
  #5: ffffff81f1cc10c0 (&irq_desc_lock_class){-.-.}, at: __irq_get_desc_lock+0x64/0x94

 stack backtrace:
 CPU: 5 PID: 3074 Comm: cat Tainted: G        W         5.4.11 #3
 Hardware name: Google Cheza (rev3+) (DT)
 Call trace:
  dump_backtrace+0x0/0x174
  show_stack+0x20/0x2c
  dump_stack+0xc8/0x124
  __lock_acquire+0x460/0x2388
  lock_acquire+0x1cc/0x210
  _raw_spin_lock_irqsave+0x64/0x80
  __irq_get_desc_lock+0x64/0x94
  irq_set_irq_wake+0x40/0x144
  qpnpint_irq_set_wake+0x28/0x34
  set_irq_wake_real+0x40/0x5c
  irq_set_irq_wake+0x70/0x144
  pm8941_pwrkey_suspend+0x34/0x44
  platform_pm_suspend+0x34/0x60
  dpm_run_callback+0x64/0xcc
  __device_suspend+0x310/0x41c
  dpm_suspend+0xf8/0x298
  dpm_suspend_start+0x84/0xb4
  suspend_devices_and_enter+0xbc/0x620
  pm_suspend+0x210/0x348
  state_store+0xb0/0x108
  kobj_attr_store+0x14/0x24
  sysfs_kf_write+0x4c/0x64
  kernfs_fop_write+0x15c/0x1fc
  __vfs_write+0x54/0x18c
  vfs_write+0xe4/0x1a4
  ksys_write+0x7c/0xe4
  __arm64_sys_write+0x20/0x2c
  el0_svc_common+0xa8/0x160
  el0_svc_handler+0x7c/0x98
  el0_svc+0x8/0xc

Set a lockdep class when we map the irq so that irq_set_wake() doesn't
warn about a lockdep bug that doesn't exist.

Fixes: 12a9eeaebba3 ("spmi: pmic-arb: convert to v2 irq interfaces to support hierarchical IRQ chips")
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Brian Masney <masneyb@onstation.org>
Cc: Lina Iyer <ilina@codeaurora.org>
Cc: Maulik Shah <mkshah@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/spmi/spmi-pmic-arb.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/spmi/spmi-pmic-arb.c b/drivers/spmi/spmi-pmic-arb.c
index 97acc2ba2912..de844b412110 100644
--- a/drivers/spmi/spmi-pmic-arb.c
+++ b/drivers/spmi/spmi-pmic-arb.c
@@ -731,6 +731,7 @@ static int qpnpint_irq_domain_translate(struct irq_domain *d,
 	return 0;
 }
 
+static struct lock_class_key qpnpint_irq_lock_class, qpnpint_irq_request_class;
 
 static void qpnpint_irq_domain_map(struct spmi_pmic_arb *pmic_arb,
 				   struct irq_domain *domain, unsigned int virq,
@@ -746,6 +747,9 @@ static void qpnpint_irq_domain_map(struct spmi_pmic_arb *pmic_arb,
 	else
 		handler = handle_level_irq;
 
+
+	irq_set_lockdep_class(virq, &qpnpint_irq_lock_class,
+			      &qpnpint_irq_request_class);
 	irq_domain_set_info(domain, virq, hwirq, &pmic_arb_irqchip, pmic_arb,
 			    handler, NULL, NULL);
 }
-- 
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