dm: sandbox: i2c: Add a new 'emulation parent' uclass
Sandbox i2c works using emulation drivers which are currently children of
the i2c device:
rtc_0: rtc@43 {
reg = <0x43>;
compatible = "sandbox-rtc";
emul {
compatible = "sandbox,i2c-rtc";
};
};
In this case the emulation device is attached to i2c bus on address 0x43
and provides the Real-Time-Clock (RTC) functionality.
However this is not ideal, since every device on an I2C bus has a child
device. This is only really the case for sandbox, but we want to avoid
special-case code for sandbox.
A better approach seems to be to add a separate node on the bus, an
'emulation parent'. This can be given a bogus address (such as 0xff) and
hides all the emulators away. Then we can use a phandle to point from the
device to the correct emualtor, and only on sandbox. The code to find an
emulator does not interfere with normal i2c operation.
Add a new UCLASS_I2C_EMUL_PARENT uclass which allows finding an emulator
given a bus, and finding a bus given an emulator. This will be used in a
follow-on patch.
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/i2c.h b/include/i2c.h
index d33f827..ccffc19 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -536,6 +536,27 @@
*/
void i2c_dump_msgs(struct i2c_msg *msg, int nmsgs);
+/**
+ * i2c_emul_find() - Find an emulator for an i2c sandbox device
+ *
+ * This looks at the device's 'emul' phandle
+ *
+ * @dev: Device to find an emulator for
+ * @emulp: Returns the associated emulator, if found *
+ * @return 0 if OK, -ENOENT or -ENODEV if not found
+ */
+int i2c_emul_find(struct udevice *dev, struct udevice **emulp);
+
+/**
+ * i2c_emul_get_device() - Find the device being emulated
+ *
+ * Given an emulator this returns the associated device
+ *
+ * @emul: Emulator for the device
+ * @return device that @emul is emulating
+ */
+struct udevice *i2c_emul_get_device(struct udevice *emul);
+
#ifndef CONFIG_DM_I2C
/*