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path: root/drivers/gpio/gpio-tqmx86.c
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Diffstat (limited to 'drivers/gpio/gpio-tqmx86.c')
-rw-r--r--drivers/gpio/gpio-tqmx86.c110
1 files changed, 80 insertions, 30 deletions
diff --git a/drivers/gpio/gpio-tqmx86.c b/drivers/gpio/gpio-tqmx86.c
index 3a28c1f273..f2e7e8754d 100644
--- a/drivers/gpio/gpio-tqmx86.c
+++ b/drivers/gpio/gpio-tqmx86.c
@@ -6,6 +6,7 @@
* Vadim V.Vlasov <vvlasov@dev.rtsoft.ru>
*/
+#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/gpio/driver.h>
@@ -28,16 +29,25 @@
#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)
+/* 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 */
+#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];
};
@@ -64,15 +74,10 @@ static void tqmx86_gpio_set(struct gpio_chip *chip, unsigned int offset,
{
struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
unsigned long flags;
- u8 val;
raw_spin_lock_irqsave(&gpio->spinlock, flags);
- val = tqmx86_gpio_read(gpio, TQMX86_GPIOD);
- if (value)
- val |= BIT(offset);
- else
- val &= ~BIT(offset);
- tqmx86_gpio_write(gpio, val, TQMX86_GPIOD);
+ __assign_bit(offset, gpio->output, value);
+ tqmx86_gpio_write(gpio, bitmap_get_value8(gpio->output, 0), TQMX86_GPIOD);
raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
}
@@ -107,21 +112,38 @@ 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;
+
+ 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);
+ 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));
}
@@ -131,16 +153,12 @@ 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);
}
@@ -151,7 +169,7 @@ 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:
@@ -161,19 +179,16 @@ 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 */
}
- 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;
@@ -184,8 +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);
@@ -194,6 +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);
@@ -277,6 +320,13 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
tqmx86_gpio_write(gpio, (u8)~TQMX86_DIR_INPUT_MASK, TQMX86_GPIODD);
+ /*
+ * Reading the previous output state is not possible with TQMx86 hardware.
+ * Initialize all outputs to 0 to have a defined state that matches the
+ * shadow register.
+ */
+ tqmx86_gpio_write(gpio, 0, TQMX86_GPIOD);
+
chip = &gpio->chip;
chip->label = "gpio-tqmx86";
chip->owner = THIS_MODULE;