[PATCH v2 5/5] misc/pca9552: Add qom set and get

["Cédric Le Goater" <clg@kaod.org>]

From: Joel Stanley <joel@jms.id.au>

Following the pattern of the work recently done with the ASPEED GPIO
model, this adds support for inspecting and modifying the PCA9552 LEDs
from the monitor.

 (qemu) qom-set  /machine/unattached/device[17] led0 on
 (qemu) qom-set  /machine/unattached/device[17] led0 off
 (qemu) qom-set  /machine/unattached/device[17] led0 pwm0
 (qemu) qom-set  /machine/unattached/device[17] led0 pwm1

Signed-off-by: Joel Stanley <joel@jms.id.au>
[clg: - removed the "qom-get" examples from the commit log
      - merged memory leak fixes from Joel ]
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 hw/misc/pca9552.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/hw/misc/pca9552.c b/hw/misc/pca9552.c
index 73be28d9369c..efd961e04148 100644
--- a/hw/misc/pca9552.c
+++ b/hw/misc/pca9552.c
@@ -15,12 +15,16 @@
 #include "hw/misc/pca9552.h"
 #include "hw/misc/pca9552_regs.h"
 #include "migration/vmstate.h"
+#include "qapi/error.h"
+#include "qapi/visitor.h"
 
 #define PCA9552_LED_ON   0x0
 #define PCA9552_LED_OFF  0x1
 #define PCA9552_LED_PWM0 0x2
 #define PCA9552_LED_PWM1 0x3
 
+static const char *led_state[] = {"on", "off", "pwm0", "pwm1"};
+
 static uint8_t pca9552_pin_get_config(PCA9552State *s, int pin)
 {
     uint8_t reg   = PCA9552_LS0 + (pin / 4);
@@ -169,6 +173,82 @@ static int pca9552_event(I2CSlave *i2c, enum i2c_event event)
     return 0;
 }
 
+static void pca9552_get_led(Object *obj, Visitor *v, const char *name,
+                            void *opaque, Error **errp)
+{
+    PCA9552State *s = PCA9552(obj);
+    int led, rc, reg;
+    uint8_t state;
+
+    rc = sscanf(name, "led%2d", &led);
+    if (rc != 1) {
+        error_setg(errp, "%s: error reading %s", __func__, name);
+        return;
+    }
+    if (led < 0 || led > s->nr_leds) {
+        error_setg(errp, "%s invalid led %s", __func__, name);
+        return;
+    }
+    /*
+     * Get the LSx register as the qom interface should expose the device
+     * state, not the modeled 'input line' behaviour which would come from
+     * reading the INPUTx reg
+     */
+    reg = PCA9552_LS0 + led / 4;
+    state = (pca9552_read(s, reg) >> (led % 8)) & 0x3;
+    visit_type_str(v, name, (char **)&led_state[state], errp);
+}
+
+/*
+ * Return an LED selector register value based on an existing one, with
+ * the appropriate 2-bit state value set for the given LED number (0-3).
+ */
+static inline uint8_t pca955x_ledsel(uint8_t oldval, int led_num, int state)
+{
+        return (oldval & (~(0x3 << (led_num << 1)))) |
+                ((state & 0x3) << (led_num << 1));
+}
+
+static void pca9552_set_led(Object *obj, Visitor *v, const char *name,
+                            void *opaque, Error **errp)
+{
+    PCA9552State *s = PCA9552(obj);
+    Error *local_err = NULL;
+    int led, rc, reg, val;
+    uint8_t state;
+    char *state_str;
+
+    visit_type_str(v, name, &state_str, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+    rc = sscanf(name, "led%2d", &led);
+    if (rc != 1) {
+        error_setg(errp, "%s: error reading %s", __func__, name);
+        return;
+    }
+    if (led < 0 || led > s->nr_leds) {
+        error_setg(errp, "%s invalid led %s", __func__, name);
+        return;
+    }
+
+    for (state = 0; state < ARRAY_SIZE(led_state); state++) {
+        if (!strcmp(state_str, led_state[state])) {
+            break;
+        }
+    }
+    if (state >= ARRAY_SIZE(led_state)) {
+        error_setg(errp, "%s invalid led state %s", __func__, state_str);
+        return;
+    }
+
+    reg = PCA9552_LS0 + led / 4;
+    val = pca9552_read(s, reg);
+    val = pca955x_ledsel(val, led % 4, state);
+    pca9552_write(s, reg, val);
+}
+
 static const VMStateDescription pca9552_vmstate = {
     .name = "PCA9552",
     .version_id = 0,
@@ -204,6 +284,7 @@ static void pca9552_reset(DeviceState *dev)
 static void pca9552_initfn(Object *obj)
 {
     PCA9552State *s = PCA9552(obj);
+    int led;
 
     /* If support for the other PCA955X devices are implemented, these
      * constant values might be part of class structure describing the
@@ -211,6 +292,15 @@ static void pca9552_initfn(Object *obj)
      */
     s->max_reg = PCA9552_LS3;
     s->nr_leds = 16;
+
+    for (led = 0; led < s->nr_leds; led++) {
+        char *name;
+
+        name = g_strdup_printf("led%d", led);
+        object_property_add(obj, name, "bool", pca9552_get_led, pca9552_set_led,
+                            NULL, NULL, NULL);
+        g_free(name);
+    }
 }
 
 static void pca9552_class_init(ObjectClass *klass, void *data)
-- 
2.21.1