[PATCH 3/3] hw/gpio: add PCA9536 i2c gpio expander

[Titus Rwantare <titusr@google.com>]

This device has the same register layout as the pca9538, but 4 fewer
gpio pins. This commit lowers the number of pins intialised, and reuses
the pca9539 logic.

Reviewed-by: Hao Wu <wuhaotsh@google.com>
Signed-off-by: Titus Rwantare <titusr@google.com>
---
 hw/gpio/pca_i2c_gpio.c         | 22 ++++++++++++++++++++++
 include/hw/gpio/pca_i2c_gpio.h |  2 ++
 2 files changed, 24 insertions(+)

diff --git a/hw/gpio/pca_i2c_gpio.c b/hw/gpio/pca_i2c_gpio.c
index f77d8d7e84..66dd1d3369 100644
--- a/hw/gpio/pca_i2c_gpio.c
+++ b/hw/gpio/pca_i2c_gpio.c
@@ -414,6 +414,23 @@ static void pca9538_gpio_class_init(ObjectClass *klass, void *data)
     pc->num_pins = PCA9538_NUM_PINS;
 }
 
+static void pca9536_gpio_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    I2CSlaveClass *k = I2C_SLAVE_CLASS(klass);
+    PCAGPIOClass *pc = PCA_I2C_GPIO_CLASS(klass);
+
+    dc->desc = "PCA9536 4-bit I/O expander";
+    dc->realize = pca_i2c_realize;
+    dc->vmsd = &vmstate_pca_i2c_gpio;
+
+    k->event = pca_i2c_event;
+    k->recv = pca9538_recv;
+    k->send = pca9538_send;
+
+    pc->num_pins = PCA9536_NUM_PINS;
+}
+
 static void pca_i2c_gpio_init(Object *obj)
 {
     PCAGPIOState *ps = PCA_I2C_GPIO(obj);
@@ -455,6 +472,11 @@ static const TypeInfo pca_gpio_types[] = {
     .parent = TYPE_PCA_I2C_GPIO,
     .class_init = pca9538_gpio_class_init,
     },
+    {
+    .name = TYPE_PCA9536_GPIO,
+    .parent = TYPE_PCA_I2C_GPIO,
+    .class_init = pca9536_gpio_class_init,
+    },
 };
 
 DEFINE_TYPES(pca_gpio_types);
diff --git a/include/hw/gpio/pca_i2c_gpio.h b/include/hw/gpio/pca_i2c_gpio.h
index 8cd268e8f0..3d2a88ba7b 100644
--- a/include/hw/gpio/pca_i2c_gpio.h
+++ b/include/hw/gpio/pca_i2c_gpio.h
@@ -19,6 +19,7 @@
 
 #define PCA6416_NUM_PINS         16
 #define PCA9538_NUM_PINS         8
+#define PCA9536_NUM_PINS         4
 
 typedef struct PCAGPIOClass {
     I2CSlaveClass parent;
@@ -75,5 +76,6 @@ OBJECT_DECLARE_TYPE(PCAGPIOState, PCAGPIOClass, PCA_I2C_GPIO)
 
 #define TYPE_PCA6416_GPIO "pca6416"
 #define TYPE_PCA9538_GPIO "pca9538"
+#define TYPE_PCA9536_GPIO "pca9536"
 
 #endif
-- 
2.39.1.519.gcb327c4b5f-goog