[PATCH 1/2] hw/gpio/npcm7xx: Add GPIO DIN object property

[Joe Komlodi]

In cases where the input pin is driven by an entity outside of the
machine, such as a machine the BMC is managing, we need a way to
update the pin state when the external machine drives it.

This allows us to do it via QMP.
For example, to set pin 20 on GPIO controller 0:
{"execute":"qom-set","arguments": {
   "path":"/machine/soc/gpio[0]",
   "property":"gpio-pins-in",
   "value":1048576
}}

1048576 == 0x100000, JSON does not support hex.

Signed-off-by: Joe Komlodi <komlodi@google.com>
---
 hw/gpio/npcm7xx_gpio.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/hw/gpio/npcm7xx_gpio.c b/hw/gpio/npcm7xx_gpio.c
index 3376901ab1..2a7be60d8d 100644
--- a/hw/gpio/npcm7xx_gpio.c
+++ b/hw/gpio/npcm7xx_gpio.c
@@ -20,6 +20,7 @@
 #include "hw/qdev-properties.h"
 #include "migration/vmstate.h"
 #include "qapi/error.h"
+#include "qapi/visitor.h"
 #include "qemu/log.h"
 #include "qemu/module.h"
 #include "qemu/units.h"
@@ -340,6 +341,29 @@ static void npcm7xx_gpio_set_input(void *opaque, int line, 
int level)
     npcm7xx_gpio_update_pins(s, BIT(line));
 }
 
+static void npcm7xx_gpio_get_pins_in(Object *obj, Visitor *v, const char *name,
+                                     void *opaque, Error **errp)
+{
+    uint32_t *pins_in = (uint32_t *)opaque;
+
+    visit_type_uint32(v, name, pins_in, errp);
+}
+
+static void npcm7xx_gpio_set_pins_in(Object *obj, Visitor *v, const char *name,
+                                     void *opaque, Error **errp)
+{
+    NPCM7xxGPIOState *s = NPCM7XX_GPIO(obj);
+    uint32_t new_pins_in;
+
+    if (!visit_type_uint32(v, name, &new_pins_in, errp)) {
+        return;
+    }
+
+    s->ext_driven = new_pins_in;
+    s->ext_level = new_pins_in;
+    npcm7xx_gpio_update_pins(s, new_pins_in);
+}
+
 static void npcm7xx_gpio_enter_reset(Object *obj, ResetType type)
 {
     NPCM7xxGPIOState *s = NPCM7XX_GPIO(obj);
@@ -371,6 +395,10 @@ static void npcm7xx_gpio_init(Object *obj)
 
     qdev_init_gpio_in(dev, npcm7xx_gpio_set_input, NPCM7XX_GPIO_NR_PINS);
     qdev_init_gpio_out(dev, s->output, NPCM7XX_GPIO_NR_PINS);
+
+    object_property_add(obj, "gpio-pins-in", "uint32",
+                        npcm7xx_gpio_get_pins_in,  npcm7xx_gpio_set_pins_in,
+                        NULL, &s->regs[NPCM7XX_GPIO_DIN]);
 }
 
 static const VMStateDescription vmstate_npcm7xx_gpio = {
-- 
2.40.0.348.gf938b09366-goog