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Diffstat (limited to 'hw/misc/pca9552.c')
-rw-r--r--hw/misc/pca9552.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/hw/misc/pca9552.c b/hw/misc/pca9552.c
index 72b653463f..f00a149d61 100644
--- a/hw/misc/pca9552.c
+++ b/hw/misc/pca9552.c
@@ -36,7 +36,10 @@ typedef struct PCA955xClass PCA955xClass;
DECLARE_CLASS_CHECKERS(PCA955xClass, PCA955X,
TYPE_PCA955X)
-
+/*
+ * Note: The LED_ON and LED_OFF configuration values for the PCA955X
+ * chips are the reverse of the PCA953X family of chips.
+ */
#define PCA9552_LED_ON 0x0
#define PCA9552_LED_OFF 0x1
#define PCA9552_LED_PWM0 0x2
@@ -112,13 +115,18 @@ static void pca955x_update_pin_input(PCA955xState *s)
switch (config) {
case PCA9552_LED_ON:
- qemu_set_irq(s->gpio[i], 1);
- s->regs[input_reg] |= 1 << input_shift;
- break;
- case PCA9552_LED_OFF:
+ /* Pin is set to 0V to turn on LED */
qemu_set_irq(s->gpio[i], 0);
s->regs[input_reg] &= ~(1 << input_shift);
break;
+ case PCA9552_LED_OFF:
+ /*
+ * Pin is set to Hi-Z to turn off LED and
+ * pullup sets it to a logical 1.
+ */
+ qemu_set_irq(s->gpio[i], 1);
+ s->regs[input_reg] |= 1 << input_shift;
+ break;
case PCA9552_LED_PWM0:
case PCA9552_LED_PWM1:
/* TODO */