gpio: tqmx86: store IRQ trigger type and unmask status separately

irq_set_type() should not implicitly unmask the IRQ.

All accesses to the interrupt configuration register are moved to a new
helper tqmx86_gpio_irq_config(). We also introduce the new rule that
accessing irq_type must happen while locked, which will become
significant for fixing EDGE_BOTH handling.

Fixes: b868db9 ("gpio: tqmx86: Add GPIO from for this IO controller")
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Link: https://lore.kernel.org/r/6aa4f207f77cb58ef64ffb947e91949b0f753ccd.1717063994.git.matthias.schiffer@ew.tq-group.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: tq-schifferm

drivers/gpio/gpio-tqmx86.c

@@ -29,15 +29,19 @@
 #define TQMX86_GPIIC	3	/* GPI Interrupt Configuration Register */
 #define TQMX86_GPIIS	4	/* GPI Interrupt Status Register */
 
+#define TQMX86_GPII_NONE	0
 #define TQMX86_GPII_FALLING	BIT(0)
 #define TQMX86_GPII_RISING	BIT(1)
 #define TQMX86_GPII_MASK	(BIT(0) | BIT(1))
 #define TQMX86_GPII_BITS	2
+/* Stored in irq_type with GPII bits */
+#define TQMX86_INT_UNMASKED	BIT(2)
 
 struct tqmx86_gpio_data {
 	struct gpio_chip	chip;
 	void __iomem		*io_base;
 	int			irq;
+	/* Lock must be held for accessing output and irq_type fields */
 	raw_spinlock_t		spinlock;
 	DECLARE_BITMAP(output, TQMX86_NGPIO);
 	u8			irq_type[TQMX86_NGPI];
@@ -104,21 +108,32 @@ static int tqmx86_gpio_get_direction(struct gpio_chip *chip,
 	return GPIO_LINE_DIRECTION_OUT;
 }
 
+static void tqmx86_gpio_irq_config(struct tqmx86_gpio_data *gpio, int offset)
+	__must_hold(&gpio->spinlock)
+{
+	u8 type = TQMX86_GPII_NONE, gpiic;
+
+	if (gpio->irq_type[offset] & TQMX86_INT_UNMASKED)
+		type = gpio->irq_type[offset] & TQMX86_GPII_MASK;
+
+	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
+	gpiic &= ~(TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS));
+	gpiic |= type << (offset * TQMX86_GPII_BITS);
+	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+}
+
 static void tqmx86_gpio_irq_mask(struct irq_data *data)
 {
 	unsigned int offset = (data->hwirq - TQMX86_NGPO);
 	struct tqmx86_gpio_data *gpio = gpiochip_get_data(
 		irq_data_get_irq_chip_data(data));
 	unsigned long flags;
-	u8 gpiic, mask;
-
-	mask = TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS);
 
 	raw_spin_lock_irqsave(&gpio->spinlock, flags);
-	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
-	gpiic &= ~mask;
-	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+	gpio->irq_type[offset] &= ~TQMX86_INT_UNMASKED;
+	tqmx86_gpio_irq_config(gpio, offset);
 	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
+
 	gpiochip_disable_irq(&gpio->chip, irqd_to_hwirq(data));
 }
 
@@ -128,16 +143,12 @@ static void tqmx86_gpio_irq_unmask(struct irq_data *data)
 	struct tqmx86_gpio_data *gpio = gpiochip_get_data(
 		irq_data_get_irq_chip_data(data));
 	unsigned long flags;
-	u8 gpiic, mask;
-
-	mask = TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS);
 
 	gpiochip_enable_irq(&gpio->chip, irqd_to_hwirq(data));
+
 	raw_spin_lock_irqsave(&gpio->spinlock, flags);
-	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
-	gpiic &= ~mask;
-	gpiic |= gpio->irq_type[offset] << (offset * TQMX86_GPII_BITS);
-	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+	gpio->irq_type[offset] |= TQMX86_INT_UNMASKED;
+	tqmx86_gpio_irq_config(gpio, offset);
 	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
 }
 
@@ -148,7 +159,7 @@ static int tqmx86_gpio_irq_set_type(struct irq_data *data, unsigned int type)
 	unsigned int offset = (data->hwirq - TQMX86_NGPO);
 	unsigned int edge_type = type & IRQF_TRIGGER_MASK;
 	unsigned long flags;
-	u8 new_type, gpiic;
+	u8 new_type;
 
 	switch (edge_type) {
 	case IRQ_TYPE_EDGE_RISING:
@@ -164,13 +175,10 @@ static int tqmx86_gpio_irq_set_type(struct irq_data *data, unsigned int type)
 		return -EINVAL; /* not supported */
 	}
 
-	gpio->irq_type[offset] = new_type;
-
 	raw_spin_lock_irqsave(&gpio->spinlock, flags);
-	gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
-	gpiic &= ~((TQMX86_GPII_MASK) << (offset * TQMX86_GPII_BITS));
-	gpiic |= new_type << (offset * TQMX86_GPII_BITS);
-	tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
+	gpio->irq_type[offset] &= ~TQMX86_GPII_MASK;
+	gpio->irq_type[offset] |= new_type;
+	tqmx86_gpio_irq_config(gpio, offset);
 	raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
 
 	return 0;