clk: imx: clk-audiomix: Add reset controller

Audiomix block control can be a reset controller for
Enhanced Audio Return Channel (EARC), which is one of
modules in this audiomix subsystem.

The reset controller is supported by the auxiliary device
framework.

Signed-off-by: Shengjiu Wang <[e-mail]>
Reviewed-by: Frank Li <[e-mail]>
Reviewed-by: Marco Felsch <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Abel Vesa <[e-mail]>

drivers/clk/imx/Kconfig

···
 	tristate "IMX8MP CCM Clock Driver"
 	depends on ARCH_MXC || COMPILE_TEST
 	select MXC_CLK
+	select AUXILIARY_BUS if RESET_CONTROLLER
 	help
 	    Build the driver for i.MX8MP CCM Clock Driver
 

drivers/clk/imx/clk-imx8mp-audiomix.c

···
  * Copyright (C) 2022 Marek Vasut <[e-mail]>
  */
 
+#include <linux/auxiliary_bus.h>
 #include <linux/clk-provider.h>
 #include <linux/device.h>
 #include <linux/io.h>
···
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/slab.h>
 
 #include <dt-bindings/clock/imx8mp-clock.h>
 
···
 	struct clk_hw_onecell_data clk_data;
 };
 
+#if IS_ENABLED(CONFIG_RESET_CONTROLLER)
+
+static void clk_imx8mp_audiomix_reset_unregister_adev(void *_adev)
+{
+	struct auxiliary_device *adev = _adev;
+
+	auxiliary_device_delete(adev);
+	auxiliary_device_uninit(adev);
+}
+
+static void clk_imx8mp_audiomix_reset_adev_release(struct device *dev)
+{
+	struct auxiliary_device *adev = to_auxiliary_dev(dev);
+
+	kfree(adev);
+}
+
+static int clk_imx8mp_audiomix_reset_controller_register(struct device *dev,
+							 struct clk_imx8mp_audiomix_priv *priv)
+{
+	struct auxiliary_device *adev __free(kfree) = NULL;
+	int ret;
+
+	if (!of_property_present(dev->of_node, "#reset-cells"))
+		return 0;
+
+	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
+	if (!adev)
+		return -ENOMEM;
+
+	adev->name = "reset";
+	adev->dev.parent = dev;
+	adev->dev.release = clk_imx8mp_audiomix_reset_adev_release;
+
+	ret = auxiliary_device_init(adev);
+	if (ret)
+		return ret;
+
+	ret = auxiliary_device_add(adev);
+	if (ret) {
+		auxiliary_device_uninit(adev);
+		return ret;
+	}
+
+	return devm_add_action_or_reset(dev, clk_imx8mp_audiomix_reset_unregister_adev,
+					no_free_ptr(adev));
+}
+
+#else /* !CONFIG_RESET_CONTROLLER */
+
+static int clk_imx8mp_audiomix_reset_controller_register(struct clk_imx8mp_audiomix_priv *priv)
+{
+	return 0;
+}
+
+#endif /* !CONFIG_RESET_CONTROLLER */
+
 static void clk_imx8mp_audiomix_save_restore(struct device *dev, bool save)
 {
 	struct clk_imx8mp_audiomix_priv *priv = dev_get_drvdata(dev);
···
 
 	ret = devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_onecell_get,
 					  clk_hw_data);
+	if (ret)
+		goto err_clk_register;
+
+	ret = clk_imx8mp_audiomix_reset_controller_register(dev, priv);
 	if (ret)
 		goto err_clk_register;