misc/pca9552: Fix inverted input status

The pca9552 INPUT0 and INPUT1 registers are supposed to
hold the logical values of the LED pins.  A logical 0
should be seen in the INPUT0/1 registers for a pin when
its corresponding LSn bits are set to 0, which is also
the state needed for turning on an LED in a typical
usage scenario.  Existing code was doing the opposite
and setting INPUT0/1 bit to a 1 when the LSn bit was
set to 0, so this commit fixes that.

Reviewed-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Signed-off-by: Glenn Miles <milesg@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Author: milesg-github

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 */

tests/qtest/pca9552-test.c

@@ -60,21 +60,21 @@ static void send_and_receive(void *obj, void *data, QGuestAllocator *alloc)
     g_assert_cmphex(value, ==, 0x55);
 
     value = i2c_get8(i2cdev, PCA9552_INPUT0);
-    g_assert_cmphex(value, ==, 0x0);
+    g_assert_cmphex(value, ==, 0xFF);
 
     pca9552_init(i2cdev);
 
     value = i2c_get8(i2cdev, PCA9552_LS0);
     g_assert_cmphex(value, ==, 0x54);
 
     value = i2c_get8(i2cdev, PCA9552_INPUT0);
-    g_assert_cmphex(value, ==, 0x01);
+    g_assert_cmphex(value, ==, 0xFE);
 
     value = i2c_get8(i2cdev, PCA9552_LS3);
     g_assert_cmphex(value, ==, 0x54);
 
     value = i2c_get8(i2cdev, PCA9552_INPUT1);
-    g_assert_cmphex(value, ==, 0x10);
+    g_assert_cmphex(value, ==, 0xEF);
 }
 
 static void pca9552_register_nodes(void)