6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
[ Upstream commit 90dd7de4ef7ba584823dfbeba834c2919a4bb55b ]
The TQMx86 GPIO controller only supports falling and rising edge
triggers, but not both. Fix this by implementing a software both-edge
mode that toggles the edge type after every interrupt.
Fixes: b868db94a6a7 ("gpio: tqmx86: Add GPIO from for this IO controller")
Co-developed-by: Gregor Herburger <gregor.herburger@xxxxxxxxxxxx>
Signed-off-by: Gregor Herburger <gregor.herburger@xxxxxxxxxxxx>
Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/515324f0491c4d44f4ef49f170354aca002d81ef.1717063994.git.matthias.schiffer@xxxxxxxxxxxxxxx
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpio/gpio-tqmx86.c | 46 ++++++++++++++++++++++++++++++++++----
1 file changed, 42 insertions(+), 4 deletions(-)
diff --git a/drivers/gpio/gpio-tqmx86.c b/drivers/gpio/gpio-tqmx86.c
index 7e428c872a257..f2e7e8754d95d 100644
--- a/drivers/gpio/gpio-tqmx86.c
+++ b/drivers/gpio/gpio-tqmx86.c
@@ -32,6 +32,10 @@
#define TQMX86_GPII_NONE 0
#define TQMX86_GPII_FALLING BIT(0)
#define TQMX86_GPII_RISING BIT(1)
+/* Stored in irq_type as a trigger type, but not actually valid as a register
+ * value, so the name doesn't use "GPII"
+ */
+#define TQMX86_INT_BOTH (BIT(0) | BIT(1))
#define TQMX86_GPII_MASK (BIT(0) | BIT(1))
#define TQMX86_GPII_BITS 2
/* Stored in irq_type with GPII bits */
@@ -113,9 +117,15 @@ static void tqmx86_gpio_irq_config(struct tqmx86_gpio_data *gpio, int offset)
{
u8 type = TQMX86_GPII_NONE, gpiic;
- if (gpio->irq_type[offset] & TQMX86_INT_UNMASKED)
+ if (gpio->irq_type[offset] & TQMX86_INT_UNMASKED) {
type = gpio->irq_type[offset] & TQMX86_GPII_MASK;
+ if (type == TQMX86_INT_BOTH)
+ type = tqmx86_gpio_get(&gpio->chip, offset + TQMX86_NGPO)
+ ? TQMX86_GPII_FALLING
+ : TQMX86_GPII_RISING;
+ }
+
gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
gpiic &= ~(TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS));
gpiic |= type << (offset * TQMX86_GPII_BITS);
@@ -169,7 +179,7 @@ static int tqmx86_gpio_irq_set_type(struct irq_data *data, unsigned int type)
new_type = TQMX86_GPII_FALLING;
break;
case IRQ_TYPE_EDGE_BOTH:
- new_type = TQMX86_GPII_FALLING | TQMX86_GPII_RISING;
+ new_type = TQMX86_INT_BOTH;
break;
default:
return -EINVAL; /* not supported */
@@ -189,8 +199,8 @@ static void tqmx86_gpio_irq_handler(struct irq_desc *desc)
struct gpio_chip *chip = irq_desc_get_handler_data(desc);
struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
struct irq_chip *irq_chip = irq_desc_get_chip(desc);
- unsigned long irq_bits;
- int i = 0;
+ unsigned long irq_bits, flags;
+ int i;
u8 irq_status;
chained_irq_enter(irq_chip, desc);
@@ -199,6 +209,34 @@ static void tqmx86_gpio_irq_handler(struct irq_desc *desc)
tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS);
irq_bits = irq_status;
+
+ raw_spin_lock_irqsave(&gpio->spinlock, flags);
+ for_each_set_bit(i, &irq_bits, TQMX86_NGPI) {
+ /*
+ * Edge-both triggers are implemented by flipping the edge
+ * trigger after each interrupt, as the controller only supports
+ * either rising or falling edge triggers, but not both.
+ *
+ * Internally, the TQMx86 GPIO controller has separate status
+ * registers for rising and falling edge interrupts. GPIIC
+ * configures which bits from which register are visible in the
+ * interrupt status register GPIIS and defines what triggers the
+ * parent IRQ line. Writing to GPIIS always clears both rising
+ * and falling interrupt flags internally, regardless of the
+ * currently configured trigger.
+ *
+ * In consequence, we can cleanly implement the edge-both
+ * trigger in software by first clearing the interrupt and then
+ * setting the new trigger based on the current GPIO input in
+ * tqmx86_gpio_irq_config() - even if an edge arrives between
+ * reading the input and setting the trigger, we will have a new
+ * interrupt pending.
+ */
+ if ((gpio->irq_type[i] & TQMX86_GPII_MASK) == TQMX86_INT_BOTH)
+ tqmx86_gpio_irq_config(gpio, i);
+ }
+ raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
+
for_each_set_bit(i, &irq_bits, TQMX86_NGPI)
generic_handle_domain_irq(gpio->chip.irq.domain,
i + TQMX86_NGPO);
--
2.43.0
