gpio: use raw spinlock for gpio chip shadowed data

In case of PREEMPT_RT, there is a raw_spinlock -> spinlock dependency
as the lockdep report shows.

__irq_set_handler
  irq_get_desc_buslock
    __irq_get_desc_lock
      raw_spin_lock_irqsave(&desc->lock, *flags);  // raw spinlock get here
  __irq_do_set_handler
    mask_ack_irq
      dwapb_irq_ack
        spin_lock_irqsave(&gc->bgpio_lock, flags); // sleep able spinlock
  irq_put_desc_busunlock

Replace with a raw lock to avoid BUGs. This lock is only used to access
registers, and It's safe to replace with the raw lock without bad
influence.

[   15.090359][    T1] =============================
[   15.090365][    T1] [ BUG: Invalid wait context ]
[   15.090373][    T1] 5.10.59-rt52-00983-g186a6841c682-dirty #3 Not tainted
[   15.090386][    T1] -----------------------------
[   15.090392][    T1] swapper/0/1 is trying to lock:
[   15.090402][    T1] 70ff00018507c188 (&gc->bgpio_lock){....}-{3:3}, at: _raw_spin_lock_irqsave+0x1c/0x28
[   15.090470][    T1] other info that might help us debug this:
[   15.090477][    T1] context-{5:5}
[   15.090485][    T1] 3 locks held by swapper/0/1:
[   15.090497][    T1]  #0: c2ff0001816de1a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock+0x98/0x104
[   15.090553][    T1]  #1: ffff90001485b4b8 (irq_domain_mutex){+.+.}-{4:4}, at: irq_domain_associate+0xbc/0x6d4
[   15.090606][    T1]  #2: 4bff000185d7a8e0 (lock_class){....}-{2:2}, at: _raw_spin_lock_irqsave+0x1c/0x28
[   15.090654][    T1] stack backtrace:
[   15.090661][    T1] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.10.59-rt52-00983-g186a6841c682-dirty #3
[   15.090682][    T1] Hardware name: Horizon Robotics Journey 5 DVB (DT)
[   15.090692][    T1] Call trace:
......
[   15.090811][    T1]  _raw_spin_lock_irqsave+0x1c/0x28
[   15.090828][    T1]  dwapb_irq_ack+0xb4/0x300
[   15.090846][    T1]  __irq_do_set_handler+0x494/0xb2c
[   15.090864][    T1]  __irq_set_handler+0x74/0x114
[   15.090881][    T1]  irq_set_chip_and_handler_name+0x44/0x58
[   15.090900][    T1]  gpiochip_irq_map+0x210/0x644

Signed-off-by: Schspa Shi <schspa@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Doug Berger <opendmb@gmail.com>
Acked-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/gpio/gpio-menz127.c b/drivers/gpio/gpio-menz127.c
index 1e21c661d79d..a035a9bcb57c 100644
--- a/drivers/gpio/gpio-menz127.c
+++ b/drivers/gpio/gpio-menz127.c
@@ -64,7 +64,7 @@ static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio,
 		debounce /= 50;
 	}
 
-	spin_lock(&gc->bgpio_lock);
+	raw_spin_lock(&gc->bgpio_lock);
 
 	db_en = readl(priv->reg_base + MEN_Z127_DBER);
 
@@ -79,7 +79,7 @@ static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio,
 	writel(db_en, priv->reg_base + MEN_Z127_DBER);
 	writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio));
 
-	spin_unlock(&gc->bgpio_lock);
+	raw_spin_unlock(&gc->bgpio_lock);
 
 	return 0;
 }
@@ -91,7 +91,7 @@ static int men_z127_set_single_ended(struct gpio_chip *gc,
 	struct men_z127_gpio *priv = gpiochip_get_data(gc);
 	u32 od_en;
 
-	spin_lock(&gc->bgpio_lock);
+	raw_spin_lock(&gc->bgpio_lock);
 	od_en = readl(priv->reg_base + MEN_Z127_ODER);
 
 	if (param == PIN_CONFIG_DRIVE_OPEN_DRAIN)
@@ -101,7 +101,7 @@ static int men_z127_set_single_ended(struct gpio_chip *gc,
 		od_en &= ~BIT(offset);
 
 	writel(od_en, priv->reg_base + MEN_Z127_ODER);
-	spin_unlock(&gc->bgpio_lock);
+	raw_spin_unlock(&gc->bgpio_lock);
 
 	return 0;
 }